,,! ,,*ildr5',s ,,book ,,( ,,/>s ,,! ,,*ildr5',s ,,book ,,( ,,/>s ,,mitton ,a4,c4 ,,black ,illu/ration3 ,,! ,,moon-,,*ild ,,mu/ ,,keep ,,on ,,runn+ ,,r\nd ,,h]4 ,p4 #aa4 ,,! ,,*ildr5',s ,,book ,,( ,,/>s ---------------------------------------- --------- ,,by ,,! ,,same ,,au?or ,,*ildr5',s ,,book ,,( ,,london ,,conta9+ #ab ,,full-,,page ,,illu/rations ,,9 ,,col\r ,,by ,,john ,,williamson ,,price #fs4 ',! /ories are told 9 a way t is b\nd to rivet att5tion1 & ! hi/orical sket*es w leave a la/+ impression on ! m9ds ( "y read]s :i* w be v useful :5 _! /udies 9 hi/ory become m advanc$4'--,scotsman4 ,,animal ,,autobiographies ,,! ,,dog ,,) #ab ,,full-,,page ,,illu/rations ,,9 ,,col\r ,,by ,j4 ,,williamson ,,price #fs4 ',a true life hi/ory1 writt5 out ( ! fulness ( fir/-h& k by an au?or :o is ?or\ghly acqua9t$ ) all ! ways ( ! fri5d ( man4'--,glasg[ ,h]ald4 ',! /ory is admirably told 9 cle> & fasc9at+ language4'--,freeman's ,j\rnal4 ,a4 ,c4 ,,black4 ,,soho ,,squ>e4 ,,london1 ,w4 ---------------------------------------- --------- ,,ag5ts ,,am]ica ,,! ,,macmillan ,,company #fd #ff ,,fif? ,,av5ue1 ,,new ,,york ,,canada ,,! ,,macmillan ,,company ,,( ,,canada1 ,,ltd4 #bg ,,ri*mond ,,/reet ,,we/1 ,,toronto ,,india ,,macmillan ,,company1 ,,ltd4 ,,macmillan ,,build+1 ,,bombay #cji ,,b[ ,,baza> ,,/reet1 ,,calcutta ,,! ,,*ildr5',s ,,book ,,( ,,/>s ,,by ,g4 ,e4 ,,mitton ,,au?or ,,( ',,! ,,*ildr5',s ,,book ,,( ,,london1' ',,animal ,,autobiographies3 ,,! ,,dog1' ,,etc4 ,,london ,,adam ,,& ,,*>les ,,black #aijg ,publi%$ ,septemb]1 #aijg ,,preface ,x 0 ! int5tion ( ! late ,agnes ,cl]ke to write ! preface to ?is ',*ildr5's ,book ( ,/>s4' ,miss ,cl]ke took a w>m & sympa!tic int]e/ 9 ! au?oress & h] "w1 b h] lam5t$ dea? occurr$ be=e ?is k9dly int5tion c\ld be fulfill$4 ,i _c pret5d to write adequately z h] sub/itute1 b ,i c\ld n resi/ ! appeal made to me by ! au?or1 9 ! "n & = ! sake ( h] de> fri5d & m9e1 to write a few words ( introduction4 ,i am 9 no way responsible ei!r = ! plan or = any portion ( ?is "w1 b ,i c comm5d x z a book1 writt5 9 a simple & pleasant /yle1 calculat$ to awak5 ! int]e/ ( intellig5t *ildr51 & to enable p>5ts o!rwise ignorant or a/ronomy to answ] _m ( ^? puzzl+ que/ions :i* su* *ildr5 (t5 put4 ,,david ,,gill4 ,,au?or',s ,,note ,?is little "w is ! outcome ( _m sugge/ions on ! "p ( fri5ds :o 7 anxi\s to tea* _! small *ildr5 some?+ ( ! m>vels ( ! heav5s1 b f\nd x exce$+ly difficult to get hold ( a book :]e9 ! int5se fasc9ation ( ! subject 0 n lo/ 9 conv5tional phraseology--a book 9 :i* ! /up5d\s facts 7 /at$ 9 language simple en\gh to be read al\d to a *ild )\t p>aphrase4 ,:atev] m]it !re may be 9 ! pres5t "w is due entirely to my fri5d ,agnes ,cl]ke1 ! well-kn[n writ] on a/ronomy2 ! faults are all my own4 ,%e gave me ! impetus to beg9 by h] w>m enc\ragem5t1 & %e help$ me to cont9ue by he>+ e *apt] read z x 0 writt51 & by discuss+ its successor & mak+ sugge/ions = x4 ,?us %e he>d ! :ole book 9 ,,ms4 ,a week aft] ! la/ *apt] _h be5 read to h] ,i />t$ on a j\rney la/+ _m mon?s1 & :ile ,i 0 9 ! ,f> ,ea/ ! news rea*$ me ( h] dea?1 by :i* ! _w is ! poor]4 ,= h] sake1 z he has /at$1 h] fri5d ,sir ,david ,gill1 ,k4,c4,b41 k9dly und]took to supply ! miss+ preface4 ,g4 ,e4 ,,mitton4 ,,cont5ts ,,*apt] ,i ,,page ,,! ,,e>? #a ,,*apt] ,,ii ,,hang+ ,,9 ,,space #ac ,,*apt] ,,iii ,,! ,,%9+ ,,moon #ba ,,*apt] ,,iv ,,! ,,e>?',s ,,bro!rs ,,& ,,si/] #cb ,,*apt] ,v ,,f\r ,,small ,,worlds #dh ,,*apt] ,,vi ,,f\r ,,l>ge ,,worlds #fg ,,*apt] ,,vii ,,! ,,sun #hi ,,*apt] ,,viii ,,%9+ ,,visitors #ajc ,,*apt] ,,ix ,,%oot+ ,,/>s ,,& ,,fi]y ,,balls #abj ,,*apt] ,x ,,! ,,glitt]+ ,,heav5s #ace ,,*apt] ,,xi ,,! ,,con/ellations #adh ,,*apt] ,,xii ,,:at ,,! ,,/>s ,,are ,,made ,,( #aei ,,*apt] ,,xiii ,,re/less ,,/>s #agj ,,*apt] ,,xiv ,,! ,,col\rs ,,( ,,! ,,/>s #agf ,,*apt] ,,xv ,,tempor>y ,,& ,,v>iable ,,/>s #ahh ,,*apt] ,,xvi ,,/> ,,clu/]s ,,& ,,nebul #aig ,,illu/rations ,,pr9t$ ,,9 ,,col\r ,,! ,,moon-,,*ild ,,mu/ ,,keep ,,on ,,runn+ ,,r\nd ,,h] ,frontispiece ,,fac+ ,,page ,,! ,,e>? ,,& ,,moon ,,hang+ ,,9 ,,space #af ,,! ,,engli% ,,summ] ,,& ,,w9t] #dj ,,jupit] ,,& ,,"o ,,( ,,8 ,,moons #gj ,,! ,,planet ,,saturn ,,& ,,two ,,( ,,8 ,,moons #gh ,,flames ,,f ,,! ,,sun #ajj ,,! ,,comet ,,9 ,,! ,,bayeux ,,tape/ry #ajd ,a ,,/ick ,,?ru/ ,,into ,,! ,,wat] ,,appe>s ,,crook$ #aad ,,con/ellations ,,ne> ,,! ,,pole ,,/> #aej ,,orion ,,& ,,8 ,,neighb\rs #aed ,,! ,,spectrum ,,( ,,! ,,sun ,,& ,,sirius #afh ,,illu/rations ,,9 ,,black ,,& ,,:ite ,,page ,,! ,,moon fac+ #bd ,,an ,,eclipse ,,( ,,! ,,moon #bh ,,an ,,eclipse ,,( ,,! ,,sun #bi ,,! ,,moon ,,rais+ ,,! ,,tides #cj ,,comp>ative ,,sizes ,,( ,,! ,,planets #ce ,,diff]5t ,,phases ,,( ,,v5us #ea ,,orbits ,,( ,,m>s1 ,,! ,,e>?1 ,,v5us1 ,,& ,,m]cury #ee ,,map ,,( ,,m>s fac+ #ef ,,orbits ,,( ,,! ,,e>? ,,& ,,m>s #fc ,,jupit] ,,& ,,8 ,,pr9cipal ,,moons #gb ,,sun-,,spots fac+ #ih ,a ,,great ,,comet #aah ,,! ,,great ,,nebula ,,9 ,,&rom$a #bjb ,,! ,,*ildr5',s ,,book ,,( ,,/>s ,,*apt] ,i ,,! ,,e>? ,x is a curi\s fact t :5 we are us$ to ?+s1 we (t5 d n notice !m1 & ?+s :i* we d e day cease to attract our att5tion4 ,we f9d an in/ance ( ?is 9 ! curi\s *ange t comes ov] objects ! fur!r !y are remov$ f u4 ,!y gr[ small] & small]1 s t at a di/ance a gr[n-up p]son looks no l>g] ?an a doll2 & a %ort /ick plant$ 9 ! gr\nd only a few feet away appe>s z long z a mu* long] "o at t5 times ! di/ance4 ,?is process is go+ on all r\nd u e m9ute3 h\ses1 trees1 build+s1 animals1 all seem l>g] or small] 9 proportion to _! di/ance f u4 ,sometimes ,i h se5 a r[ ( ra9drops hang+ on a b> by ! w9d[4 ,:5 ! sun cat*es "o ( !m1 x %9es s brilliantly t x is z dazzl+ z a />2 b my s5se tells me x is a ra9drop1 & n a /> at all4 ,x is only because x is s ne> x seems z bright & important z a mighty /> v1 v f> away4 ,we are s mu* accu/om$ to ?is fact t we get into a habit ( judg+ ! di/ance ( ?+s by _! size4 ,if we see two lights %9+ on a d>k night1 & "o is mu* l>g] ?an ! o!r1 we ?9k t ! bright "o mu/ be ne>] to u2 yet x ne$ n necess>ily be s1 = ! two lights might possibly be at ! same di/ance f u1 & "o be l>ge & ! o!r small4 ,!re is no way 9 :i* we c tell ! tru? by j look+ at !m4 ,n[1 if we g out on any f9e moonlight night & look up at ! sky1 we %all see "o object !re app>5tly mu* l>g] ?an any o!r1 & t is ! moon1 s ! "q t occurs to u at once is1 ,is ! moon really v mu* l>g] ?an any ( ! />s1 or does x only seem s because x is v mu* ne>] to u8 ,z a matt] ( fact1 ! moon is "o ( ! smalle/ objects 9 view1 only1 z x is our ne>e/ neighb\r1 x appe>s v conspicu\s4 ,hav+ le>n$ ?is1 we %all probably look ab\t to see :at else !re is to attract att5tion1 & we may notice "o /> %9+ v brilliantly1 almo/ l a little lamp1 r l[ d[n 9 ! sky1 9 t "p ( x :]e ! sun has lately set4 ,x is s beautifully bright t x makes all ! o!rs look insignificant 9 comp>ison1 yet x is n really l>ge comp>$ ) ! o!rs1 only1 z x comes ne>] to u ?an any?+ else 9 ! sky except ! moon1 x looks l>g] ?an x has any "r to d 9 comp>ison ) ! o!rs4 ,aft] ?is we might jump to ! conclusion t all ! bright l>ge />s are really small & ne> to u1 & all ! fa9tly %9+ ones l>ge & f> away4 ,b t w\ld n be true at all1 = "s bright ones are v f> away & "s fa9t ones comp>atively ne>1 s t all we c d is to le>n ab\t !m f ! p :o h /udi$ !m & f\nd out ab\t !m1 & !n we %all "k ( our own k :i* ( !m seem bright only because !y are ne>] ?an ! o!rs1 & :i* are really v1 v brilliant1 & s /ill %9e brightly1 ?\gh set 9 space at an almo/ inf9ite di/ance f u4 ,! sun1 z we all "k1 appe>s to cross ! sky e day2 he gets up 9 ! ea/ & drops d[n 9 ! we/1 & ! moon does ! same1 only ! moon is unlike ! sun 9 ?is1 t x *anges its %ape cont9ually4 ,we see a cresc5t moon gr[+ e night l>g] & l>g]1 until x becomes full & fat & r\nd1 & !n x gr[s ?9n] & ?9n]1 until x dies away2 & aft] a little :ile x beg9s aga91 & goes ?r\gh all ! same *anges once m4 ,i w tell y :y ?is is s fur!r on1 :5 we h a *apt] all ab\t ! moon4 ,if y wat* ! />s quietly = at lea/ five m9utes1 y w see t !y too are mov+ /eadily on 9 ! same way z ! sun & moon4 ,wat* "o bright /> com+ out f beh9d a *imney-pot1 & aft] ab\t five m9utes y w see t x has *ang$ its place4 ,yet ?is is n true ( all1 = if we wat* c>efully we %all f9d t "s1 fairly high up 9 ! sky1 d n appe> to move at all4 ,! few :i* are mov+ s sl[ly t !y seem to u to /& /ill are at a "p ( ! sky close to ! ,pole ,/>1 s call$ because x is always above ! ,nor? ,pole ( ! e>?4 ,i w expla9 to y h[ to f9d x 9 ! sky = y\rselves lat] on1 b n[ y c ask anyone to po9t x out4 ,wat* x4 ,x appe>s to be fix$ 9 "o place1 :ile ! o!r />s are sw++ r\nd x 9 circles4 ,9 fact1 x is z if we on ! e>? 7 inside a great holl[ globe or ball1 :i* cont9ually turn$ r\nd1 ) ! ,pole ,/> ne> ! top ( ! globe2 & y "k t if y put y\r f+] on ! spot at ! top ( a sp9n+ globe or ball1 y c hold x !re :ile all ! re/ ( ! ball runs r\nd4 ,n[1 if y _h to expla9 ?+s to y\rself1 y w\ld naturally ?9k3 ',"h is ! great solid e>? /&+ /ill1 & ! sun & moon g r\nd x2 ! />s are all turn+ r\nd x too1 j z if !y 7 fix$ on to ! inside ( a holl[ globe2 we on ! e>? are 9 ! middle look+ up at !m2 & ?is great globe is sl[ly :eel+ r\nd u night by night4' ,9 ! *ildhood ( ! _w m5 believ$ t ?is 0 really true--t ! e>? 0 ! c5tre ( ! univ]se1 t ! sun & moon & all ! ho/s ( heav5 7 !re solely to light & b5efit u2 b z ! _w grew wis] ! wond]s ( creation 7 fa?om$ little by little4 ,"s m5 devot$ _! :ole lives to wat*+ ! heav5s1 & ! real /ate ( ?+s 0 gradually reveal$ to !m4 ,! fir/ great discov]y 0 t ( ! daily movem5t ( ! e>?1 its rotation on its own axis1 :i* makes x appe> z if all ^! %9+ ?+s w5t r\nd x4 ,x is inde$ a v difficult matt] to judge :i* ( two objects is mov+ unless we c comp>e !m bo? ) some?+ outside4 ,y mu/ h notic$ ?is :5 y are sitt+ 9 a tra9 at a /ation1 & !re is ano!r tra9 on ! o!r side ( y\rs4 ,= if "o ( ! tra9s moves g5tly1 ei!r y\rs or ! o!r1 y _c tell :i* "o x is unless y look at ! /ation plat=m2 & if y\r position rema9s ! same 9 reg>d to t1 y "k t y\r tra9 is /ill /&+1 :ile ! o!r "o beside x has begun to move4 ,& ,i am q sure t !re is no "o ( u :o has n1 at "o "t or ano!r1 /ood on a bridge & wat*$ ! wat] runn+ away und]nea? until we felt q dizzy1 & x seem$ z if ! wat] 7 /&+ /ill & ! bridge1 ) ourselves on x1 0 fly+ swiftly away backw>ds4 ,x is only :5 we turn to ! banks & f9d !m /&+ /ill1 t we realize ! bridge is n mov+1 & t x is ! runn+ wat] t makes x seem to d s4 ,^! ev]yday in/ances %[ u h[ difficult x is to judge :e!r we are mov+ or an outside object unless we h some?+ else to comp>e ) x4 ,& ! m>vell\s tru? is t1 in/ead ( ! sun & moon & />s roll+ r\nd ! e>?1 x is ! e>? t is sp9n+ r\nd day by day1 :ile ! sun & ! />s are comp>atively /ill2 &1 ?\gh ! moon does move1 yet :5 we see h] get up 9 ! ea/ & g d[n 9 ! we/ t is due to our own movem5t & n to h]s4 ,! e>? turns completely r\nd once 9 a day & night4 ,if y take an orange & /ick a knitt+-ne$le ?r\gh x1 & hold x s t ! ne$le is n q /raight up b a little slant+1 & !n twirl x r\nd1 y w get q a good idea ( ! e>?1 ?\gh ( c\rse !re is no great pole l a gigantic ne$le /uck ?r\gh x1 t is only to make x easy = y to hold x by4 ,9 sp9n+ ! orange y are turn+ x z ! e>? turns day by day1 or1 z a/ronom]s express x1 z x rotates on its axis4 ,!re is a /ory ( a cruel ,ea/]n ,k+ :o told a prison] t he mu/ die if he did n answ] ?ree que/ions correctly1 & ! que/ions 7 v difficult2 ?is is "o ( !m3 ',h[ long w\ld x take a man to g r\nd ! e>? if he nev] /opp$ to eat or dr9k on ! way8' ,& ! prison] answ]$ promptly3 ',if he rose ) ! sun & kept pace ) x all day1 & nev] /opp$ = a mom5t to eat or dr9k1 he w\ld take j tw5ty-f\r h\rs1 ,y\r ,royal ,highness4' ,= 9 ^? days x 0 suppos$ t ! sun w5t r\nd ! e>?4 ,ev]yone is s rem>kably clev] n[adays t ,i am sure !re w be someone clev] en\gh to object t1 if :at ,i h said is true1 !re w\ld be a great draught1 = ! air w\ld be ru%+ pa/ u4 ,b1 z a matt] ( fact1 ! air goes ) u too4 ,if y are inside a railway c>riage ) ! w9d[s %ut y d n feel ! ru% ( air1 because ! air 9 ! c>riage travels ) y2 & x is ! same ?+ on ! e>?4 ,! air :i* surr\nds ! e>? cl+s to x & goes r\nd ) x1 s !re is no cont9u\s breeze f ?is cause4 ,b ! sp9n+ r\nd on its own axis is n ! e>?'s only movem5t1 = all ! "t x is also mov+ on r\nd ! sun1 & once 9 a :ole ye> x completes its j\rney & comes back to ! place f :5ce x />t$4 ,?us ! turn+ r\nd l a top or rotat+ on its axis makes ! day & night1 & ! go+ 9 a great r+ or revolv+ r\nd ! sun makes ! ye>s4 ,our "t is divid$ into o!r sections besides days & ye>s4 ,we h1 = in/ance1 weeks & mon?s4 ,! weeks h no?+ to d ) ! e>?'s movem5ts2 !y are only made by man to break up ! mon?s2 b ! mon?s are really decid$ by some?+ ov] :i* we h no control4 ,!y are due to ! moon1 &1 z ,i h said already1 ! moon mu/ h a *apt] to h]self1 s we won't say any m ab\t ! mon?s "h4 ,if any fri5d ( ours goes to ,india or ,new ,zeal& or ,am]ica1 we look ^u him z a great travell]2 yet e baby :o has liv$ "o ye> on ! e>? has travell$ millions ( miles )\t ! slighte/ ef=t4 ,e day ( our lives we are all flung ?r\gh space )\t kn[+ x or ?9k+ ( x4 ,x is z if we 7 all %ut up 9 a com=table travell+ c>1 & 7 provid$ ) s _m books & pictures & companions t we nev] c>$ to look out ( ! w9d[s1 s t h\r by h\r z we 7 c>ri$ along ov] miles ( space we nev] gave !m a ?\ght4 ,ev5 ! mo/ wond]ful c> ev] made by man rumbles & creaks & %akes1 s t we _c help kn[+ x is mov+2 b ?is beautiful travell+ c>riage ( ours call$ ! e>? makes nev] a creak or groan z %e sp9s 9 h] age-long j\rney4 ,x is always a/oni%+ to me t s few p c>e to look out ( ! w9d[ z we fly along2 mo/ ( !m are f> too mu* absorb$ 9 _! little petty daily conc]ns ev] to lift _! eyes f !m4 ,x is true t sometimes ! bl9ds are d[n1 = ! sky is ?ickly cov]$ ) cl\ds1 & we _c see any?+ ev5 if we want to4 ,x is true also t we _c see mu* ( ! sc5]y 9 ! daytime1 = ! sun %9+ on ! air makes a veil ( blue glory1 :i* hides ! />s2 b on cle> nights we c see on e side numb]s ( />s q z int]e/+ & beautiful z any l&scape2 & yet millions ( p nev] look up1 nev] give a ?\ght to ! wond]ful sc5]y ?r\gh :i* _! c> is ru%+4 ,by reason ( ! onw>d ru% ( ! e>? 9 space we are c>ri$ ov] a di/ance ( at lea/ eighte5 miles e second4 ,?9k ( x3 z we draw a brea? we are eighte5 miles away 9 space f ! po9t we 7 at be=e1 & ?is goes on unceas+ly day & night4 ,^! a/oni%+ facts make u feel h[ small & feeble we are1 b we c take com=t 9 ! ?\ght t ?\gh our bodies are insignificant1 ! bra9 ( man1 :i* has discov]$ ^! />tl+ facts1 mu/ 9 itself be reg>d$ z "o ( ! mo/ m>vell\s ( all ! my/]ies amid :i* we live4 ,well1 we h arriv$ at "s idea ( our e>?'s position2 we "k t ! e>? is turn+ r\nd day by day1 & progress+ r\nd ! sun ye> by ye>1 & t all ar\nd lie ! s5t9el />s1 scatt]$ on a backgr\nd ( inf9ite space4 ,if y take an old] boy or girl & let him or h] /& 9 ! middle to repres5t ! sun1 !n a small] "o w\ld be ! e>?1 & ! smalle/ ( all ! moon2 only 9 tru? we c\ld nev] get anyone l>ge en\gh to repres5t ! sun fairly1 = ! bigge/ giant t ev] liv$ w\ld be mu* too small 9 proportion4 ,! "o repres5t+ ! sun mu/ /& 9 ! middle1 & turn sl[ly r\nd & r\nd4 ,!n let ! e>?-*ild turn too1 & all ! "t %e is sp9n+ l a top %e mu/ be also ha/5+ on 9 a big r+ r\nd ! sun2 b %e mu/ n g too fa/1 = ! little moon-*ild mu/ keep on runn+ r\nd h] all ! "t4 ,& ! moon-*ild mu/ keep h] face turn$ always to ! e>?1 s t ! e>? nev] sees h] back4 ,t is an odd ?+1 isn't x8 ,we h nev] se5 ! o!r side ( ! moon1 :i* goes r\nd u1 always pres5t+ ! same face to u4 ,! e>? is n ! only _w go+ r\nd ! sun2 %e has _m bro!rs & a si/]2 "s are ne>] to ! sun ?an %e is1 & "s are fur!r away1 b all circle r\nd ! great c5tral light-giv] 9 r+s ly+ "o outside ! o!r4 ,^! worlds are call$ planets1 & ! e>? is "o ( !m1 & "o ( ! small] ones1 too1 no?+ s great & important z we might h imag9$4 ,,*apt] ,,ii ,,hang+ ,,9 ,,space ,if y are hold+ some?+ 9 y\r h& & y let x g1 :at happ5s8 ,x falls to ! gr\nd1 ( c\rse4 ,n[1 :y %\ld x d s8 ,y w say3 ',h[ c\ld x d any?+ else8' ,b t is only because y are hamp]$ by cu/om4 ,try to %ake y\rself free1 & ?9k1 ,:y %\ld x g d[n in/ead ( up or any o!r way8 ,! fir/ man :o 0 clev] en\gh to f9d "s sort ( an answ] to ?is "q 0 ! great philosoph] ,sir ,isaac ,newton1 ?\gh he 0 n q ! fir/ to be puzzl$ by x4 ,aft] ye>s ( /udy he discov]$ t e ?+ attracts e o!r ?+ 9 proportion to _! masses 7:i* is :at y "k z weight7 & _! di/ance f ea* o!r4 ,9 m sci5tific language1 we %\ld say e body in/ead ( e ?+1 = ! ^w body does n only mean a liv+ body1 b e lump or mass ( matt] 9 ! univ]se4 ,! e>? is a body 9 ?is s5se1 & s is ! table or any?+ else y c\ld "n4 ,n[ z ! e>? is immeasurably heavi] ?an any?+ t is on x1 x pulls ev]y?+ t[>d itself ) su* =ce t ! little pulls ( o!r ?+s ^u ea* o!r are n notic$4 ,! e>? draws u all t[>d x4 ,x is hold+ u d[n to x e m9ute ( ! day4 ,if we want to move we h to ex]t ano!r =ce 9 ord] to ov]come ?is attraction ( ! e>?1 s we ex]t our own muscles & lift fir/ "o foot & !n ! o!r away f ! e>?1 & ! ef=t we make 9 do+ ?is tires u4 ,all ! :ile y are walk+ or runn+ y are ex]cis+ =ce to lift y\r feet away f ! gr\nd4 ,! pull ( ! e>? is call$ gravitation4 ,j rememb] t1 :ile we g on to some?+ else :i* is almo/ z a/oni%+4 ,we "k t no?+ "h on e>? cont9ues to move = ev]2 ev]y?+ has to be kept go+4 ,any?+ left to itself has a t5d5cy to /op4 ,:y is ?is8 ,?is is because "h 9 ! _w !re is some?+ t fights aga9/ ! mov+ ?+ & tries to /op x1 :e!r x be s5t along ! gr\nd or ?r[n up 9 ! air4 ,y "k :at friction is1 ( c\rse4 ,if y rub y\r h&s along any r\gh sub/ance y w quickly feel x1 b on a smoo? sub/ance y feel x less4 ,t is :y if y s5d a /one sp9n+ along a c>pet or a r\gh road x /ops comp>atively soon1 :]eas if y use ! same am\nt ( =ce & s5d x along a %eet ( ice x goes on mov+ mu* long]4 ,?is k9d ( resi/ance1 :i* we call friction1 is "o ( ! causes :i* is at "w to br+ ?+s to a /&/ill2 & ano!r cause is ! resi/ance ( ! air1 :i* is friction 9 ano!r =m4 ,x may be a p]fectly /ill day1 yet if y are bicycl+ y are break+ ?r\gh ! air all ! "t1 j z y w\ld be ?r\gh wat] 9 swimm+1 only ! resi/ance ( ! air is less ?an t ( wat]4 ,z ! friction or ! resi/ance ( ! air1 or bo? comb9$1 gradually less5s ! pace ( ! /one y s5t (f ) su* =ce1 ! gravitation ( ! e>? beg9s to be felt4 ,:5 ! /one fir/ />t$ ! =ce y gave to x 0 en\gh to ov]come ! gravitation =ce1 b z ! /one moves m sl[ly ! e>?-pull ass]ts itself1 & ! /one drops d[n to ! gr\nd & lies /ill ^u ! surface4 ,n[1 if !re 7 no friction1 & !re=e no resi/ance1 !re w\ld be no reason :y any?+ once set mov+ %\ld n g on mov+ = ev]4 ,! =ce y give to any object y ?r[ is en\gh to ov]come gravitation2 & x is only :5 ! fir/ =ce has be5 dim9i%$ by friction t ! e>? ass]ts its au?ority & pulls ! mov+ object t[>d x4 ,if x 7 possible to get outside ! air & out ( rea* ( ! pull ( ! e>?1 we might fl+ a ball (f into space1 & x w\ld g on 9 a /raight l9e until some?+ pull$ x to itself by ! =ce ( gravity4 ,gravitation affects ev]y?+ connect$ ) ! e>?2 ev5 our air is held to ! e>? by gravitation4 ,x gr[s ?9n] & ?9n] z we get fur!r away f ! e>?4 ,at ! top ( a high m\nta9 ! air is s ?9 t m5 h difficulty 9 brea?+1 & at a c]ta9 height !y c\ld n brea! at all4 ,z !y _c brea! 9 v f9e air1 x is impossible = !m to tell by p]sonal exp]im5t exactly :]e ! air ends2 b !y h tri$ to f9d out 9 o!r ways1 & ?\gh diff]5t m5 h come to diff]5t conclusions on ! subject1 x is safe to say t at ab\t two hundr$ miles above ! e>? !re is no?+ t c\ld be call$ air4 ,?us we c n[ picture our sp9n+ e>? clo!d 9 a g>m5t ( air t cl+s closely ab\t h]1 & gr[s ?9n] & ?9n] until x melts away altoge!r1 = !re is no air 9 space4 ,illu/ration3 ,,! ,,e>? ,,& ,,moon ,,hang+ ,,9 ,,space ,n[ 9 ! beg9n+ ,god made ! _w1 & set x (f by a fir/ impulse4 ,we "k no?+ ab\t ! details1 ?\gh fur!r on y %all he> :at is g5]ally suppos$ to h tak5 place2 we only "k t1 at "s remote age1 ?is _w1 probably v diff]5t f :at x is n[1 toge!r ) ! o!r planets1 0 s5t sp9n+ (f into space on its age-long j\rney4 ,^! planets 7 n s5t (f at r&om1 b mu/ h _h "s p>ticul> connection ) ea* o!r & ) ! sun1 = !y all belong to "o sy/em or family1 & act & react on ea* o!r4 ,n[1 if !y _h be5 at re/ & n 9 movem5t1 !y w\ld h fall5 "r into ! sun1 drawn by ! =ce ( gravitation2 !n !y w\ld h be5 burn$ up1 & !re w\ld h be5 an end ( !m4 ,b ! fir/ =ce _h imp>t$ to !m ! impulse to g on 9 a /raight l9e1 s :5 ! sun pull$ ! result 0 a movem5t betwe5 ! two3 ! planets did n cont9ue to move 9 a /raight l9e1 nei!r did !y fall on to ! sun1 b !y w5t on a c\rse betwe5 ! two--t is1 a circle--= ! sun nev] let !m get "r away f him1 b compell$ !m to move 9 circles r\nd him4 ,!re is a v common in/ance ( ?is k9d ( ?+ :i* we c see1 or p]haps feel1 e day4 ,if y try to sit /ill on a bicycle y tumble (f1 because ! e>? pulls y d[n to itself2 b if1 by us+ ! =ce ( y\r own muscles1 y give ! bicycle a =w>d movem5t ?is resi/s ! e>?-pull1 & ! result is ! bicycle runs along ! gr\nd4 ,x does n get "r away f ! e>?1 n ev5 two or ?ree feet above gr\nd2 x is held to ! e>?1 b /ill x goes =w>d & does n fall ov]1 = ! movem5t is made up ( ! e>?-pull1 :i* holds x to ! gr\nd1 & ! =w>d movem5t1 :i* propels x along4 ,!n aga91 z ano!r in/ance1 if y tie a ball to a /r+ & :irl x r\nd y1 s long z y keep on :irl+ x w n fall to ! gr\nd1 b ! mom5t y /op d[n x drops1 = !re is no?+ to fight aga9/ ! pull ( gravitation4 ,?us we c picture ! e>? & all ! planets z if !y 7 sw++ r\nd ! sun1 held by invisible /r+s4 ,x is ! comb9ation ( two =ces t keeps !m 9 _! places--! fir/ =ce & ! sun's pull4 ,x is v wond]ful to ?9k (4 ,"h we are sw++ 9 space on a ball t seems only l>ge to u because we are s mu* small] ourselves2 !re is no?+ above or bel[ x b space1 yet x travels on day by day & ye> by ye>1 held by invisible =ces t ! bra9 ( man has discov]$ & measur$4 ,( c\rse1 e planet gives a pull at e o!r planet too1 b ^! pulls are s small comp>$ ) t ( ! sun t we ne$ n at pres5t notice !m4 ,!n we come to ano!r po9t4 ,we said t e body pull$ e o!r body 9 proportion to _! weights & _! di/ance4 ,n[1 gravity acts mu* m /rongly :5 ?+s are ne> toge!r ?an :5 !y are f> away f ea* o!r2 s t if a small] body is ne> to ano!r some:at l>g] ?an itself1 x is pull$ by x mu* m /rongly ?an by a v mu* l>g] "o at a consid]ably great] di/ance4 ,we h an in/ance ( ?is 9 ! case ( ! e>? & moon3 z ! e>? responds to ! pull ( ! sun1 s ! moon responds to ! pull ( ! e>?4 ,! moon is s comp>atively ne> to ! e>? t ! e>?-pull =ces h] to keep on go+ r\nd & r\nd1 in/ead ( leav+ h] free to circle r\nd ! sun by h]self2 & yet if y ?9k ( x ! moon does g r\nd ! sun too4 ,recall t game we _h :5 ! sun 0 9 ! middle1 & ! two small] girls1 repres5t+ ! e>? & moon1 w5t r\nd x4 ,! moon-*ild turn$ r\nd ! e>?-*ild1 b all ! :ile ! e>?-*ild 0 go+ r\nd ! sun1 s t 9 a ye>'s "t ! moon _h be5 all r\nd ! sun too1 only n 9 a /raight l9e4 ,! moon is some?+ l a dog :o keeps on danc+ r\nd & r\nd y :5 y g = a walk4 ,he does g = ! walk too1 b he does mu* m ?an t 9 ! same "t4 ,?us we h fur!r complet$ our idea ( our _w4 ,we see x n[ hang+ 9 space1 ) no visible support1 held 9 its place by two mighty =ces2 sp9n+ on ye> aft] ye>1 att5d$ by its satellite ! moon1 :ile we run1 & walk1 & cry1 & laugh1 & play ab\t on its surface--little atoms :o1 except = ! bra9 t ,god has giv5 !m1 w\ld nev] ev5 h kn[n t !y are cont9ually mov+ on ?r\gh endless space4 ,,*apt] ,,iii ,,! ,,%9+ ,,moon ',once ^u a "t1' long1 long ago1 ! e>? 0 n a compact1 r\nd1 h>d body su* z %e is n[1 b mu* l>g] & s(t]1 & z %e rotat$ a fragm5t broke (f f h]2 x did n g "r away f h]1 b /ill w5t on circl+ r\nd ) ! motion x _h inh]it$ f h]4 ,z ! ages pass$ on bo? ! e>? & ?is fragm5t1 :i* _h be5 v hot1 cool$ d[n1 & 9 cool+ became small]1 s t ! di/ance betwe5 !m 0 great] ?an x _h be5 be=e !y %rank4 ,& !re 7 o!r causes also t t5d$ to ?ru/ ! two fur!r f ea* o!r4 ,yet1 comp>$ ) ! o!r heav5ly bodies1 !y are /ill ne>1 & by look+ up into ! sky at night y c g5]ally see ?is mighty fragm5t1 :i* is a qu>t] ! diamet] ( ! e>?--t is to say1 a qu>t] ! wid? ( ! e>? measur$ f side to side ?r\gh ! middle4 ,x is--z1 ( c\rse1 y h guess$--! moon4 ,! moon is ! ne>e/ body to u 9 all space1 & s va/ is ! di/ance t sep>ates u f ! />s t we speak z if %e 7 n v f> (f1 yet comp>$ ) ! size ( ! e>? ! space ly+ betwe5 u & h] is v great4 ,if y w5t "r r\nd ! _w at ! ?icke/ "p--t is to say1 9 ! region ( ! ,equator--& :5 y arriv$ at y\r />t+-po9t w5t (f once aga91 & s on until y _h be5 r\nd t5 times1 y w\ld only !n h travell$ ab\t z f> z f ! e>? to ! moon6 ,! e>? is n ! only planet :i* has a moon1 or z x is call$1 a satellite1 9 att5dance4 ,"s ( ! l>g] planets h sev]al1 b !re is n "o to comp>e ) our moon4 ,:i* w\ld y pref] if y _h ! *oice1 ?ree or f\r small moons1 "s ( !m n mu* l>g] ?an a v big bright />1 or an int]e/+ l>ge body l our own moon8 ,i "k :i* ,i %\ld say4 ',y say t ! moon broke (f f ! e>?1 s p]haps !re may be "s p liv+ on h]1' ,i he> someone exclaim4 ,if !re is "o ?+ we h f\nd out c]ta9ly ab\t ! moon1 x is t no life1 z we "k x1 c\ld exi/ !re1 = !re is nei!r air nor wat]4 ,:e!r %e ev] _h any air or wat]1 & if s1 :y !y disappe>$1 are que/ions we _c answ]4 ,we only "k t n[ %e is a dead _w4 ,bright & beautiful z %e is1 %$d+ on u a pale1 pure light1 9 vivid contra/ ) ! fi]y yell[ rays ( ! sun1 yet %e is dead & lifeless & /ill4 ,we c exam9e h] surface ) ! telescope1 & see x all v pla9ly4 ,ev5 ) a l>ge op]a-glass ^? m>k+s :i*1 to ! nak$ eye1 seem to be l a que] di/ort$ face are *ang$1 & %[ up z ! %ad[s ( great m\nta9s4 ,we c only see "o side ( ! moon1 because z ,i h said1 %e keeps always ! same face turn$ to ! e>?2 b z %e sways slightly 9 h] orbit1 we cat* a glimpse ( sometimes a little m on "o side & sometimes a little m on ! o!r1 & s we c judge t ! unse5 "p is v mu* ! same z t turn$ t[>d u4 ,at fir/ x is difficult to realize :at x means to h no air4 ,besides support+ life 9 e brea? t is drawn by liv+ creatures1 ! air does num]\s o!r k9d (fices = u--= in/ance1 x c>ries s\nd4 ,suppos+ ! mo/ t]rific volcano explod$ 9 an airless _w1 x c\ld n be he>d4 ,! air s]ves z a scre5 by day to keep (f ! burn+ heat ( ! sun's rays1 & z a blanket by night to keep 9 ! heat & n let x escape too quickly4 ,if !re 7 no air !re c\ld be no wat]1 = all wat] w\ld evaporate & vani% at once4 ,imag9e ! _w depriv$ ( air2 !n ! sun's rays w\ld fall ) su* fi]c5ess t ev5 ! /ronge/ tropical sun we "k w\ld be z no?+ 9 comp>ison ) x1 & e gre5 ?+ w\ld %rivel up & die2 ?is scor*+ sun w\ld %9e out ( a black sky 9 :i* ! />s w\ld all be visible 9 ! daytime1 n hidd5 by ! s(t blue veil ( air1 z !y are n[4 ,at night ! in/ant ! sun disappe>$ bel[ ! horizon black d>kness w\ld set 91 = our l+]+ twilight is due to ! reflection ( ! sun 9 ! upp] lay]s ( air1 & a bitt]ness ( dea?ly cold w\ld fall ^u ! e>?--cold fi]c] ?an t ( ! ,arctic regions--& ev]y?+ w\ld be froz5 solid4 ,x w\ld ne$ b a %ort "t to r$uce ! e>? to ! condition ( ! moon1 :]e !re is no?+ to %rivel up1 no?+ to freeze4 ,h] surface is made up ( b>r51 arid rocks1 & h] sc5]y consi/s ( icy black %ad[s & scor*+ :ite pla9s4 ,illu/ration3 ,p>is ,obs]vatory4 ,,! ,,moon4 ,! black %ad[s def9e ! m\nta9s1 & trem5d\s m\nta9s !y are4 ,mo/ ( !m h crat]s4 ,a crat] is l a cup1 & g5]ally has a little peak 9 ! middle ( x4 ,?is is ! summit ( a volcano1 & :5 ! volcano has bur/ up & vomit$ out floods ( lava & dbris1 ?is has fall5 d[n 9 a r+ a little di/ance away f x1 leav+ a cle> space next to ! peak1 s t1 z ! m\nta9 ceases vomit+ & ! lava cools d[n1 ! r+ h>d5s & =ms a circul> ridge4 ,! crat]s on ! moon are imm5se1 n only 9 proportion to h] size1 b imm5se ev5 accord+ to our ideas on ! e>?4 ,"o ( ! l>ge/ crat]s 9 our own _w is 9 ,japan1 & ?is measures sev5 miles across1 :ile 9 ! moon crat]s ( fifty1 sixty1 & ev5 a hundr$ miles are by no means uncommon1 ?\gh !re are also hundr$s & ?\s&s ( small] ones4 ,we c see ! surface ( ! moon v pla9ly ) ! magnific5t telescopes t h n[ be5 made1 & ) ! be/ ( ^! any?+ ! size ( a l>ge t[n w\ld be pla9ly visible4 ,ne$less to say1 no t[n ev] has be5 or ev] w be se5 ^u ! moon6 ,all ^! m\nta9s & crat]s %[ t at "o "t ! moon mu/ h be5 convuls$ ) t]rific di/urbances1 f> worse ?an any?+ t we h any k ( on our e>?2 b ?is mu/ h be5 ages ago1 :ile ! moon /ill probably _h an atmosph]e ( its own4 ,n[ x has long be5 quiet4 ,no?+ *anges !re2 ev5 ! =ces t are always at "w on ! e>?--namely1 damp & m\ld & wat]--alt]+ ! surface & break+ up ! rocks1 d n act !re1 :]e !re is no moi/ure ( any sort4 ,s f> z we c see1 ! purpose ( ! moon is to be ! s]vant ( ! e>?1 to give h] light by night & to raise ! tides4 ,beautiful light x is1 s(t & my/]i\s--light t *ildr5 d n (t5 h a *ance ( see+1 = !y are g5]ally 9 b$ be=e ! moon rises :5 %e is at ! full4 ,we "k t ! moon has no heat ( h] own--%e p>t$ ) all t long ago2 %e _c give u gl[+ light f brilliant flames1 z ! sun does2 %e %9es only by ! reflection ( ! sun on h] surface1 & ?is is ! reason :y %e appe>s to *ange h] %ape s con/antly4 ,%e does n really *ange2 ! :ole r\nd moon is always !re1 only "p ( x is 9 %ad[4 ,sometimes y c see ! d>k "p z well z ! bright4 ,:5 !re is a cresc5t moon x looks z if x 7 encircl+ ! re/2 "s p call x1 'see+ ! old moon 9 ! new moon's arms4' ,i don't "k if y w\ld guess :y x is we c see ! d>k "p !n1 or h[ x is light$ up4 ,x is by reason ( our own %9+1 = we give light to ! moon1 z %e does to u4 ,! sun's rays /rike on ! e>?1 & are reflect$ on to ! moon1 s t ! moon is light$ by e>?%9e z we are light$ by moon%9e1 & x is ^! reflect$ e>?-rays t light up ! d>k "p ( ! moon & enable u to see x4 ,:at a j\rney ^! rays h _h6 ,!y travel f ! sun to ! e>?1 & ! e>? to ! moon1 & !n back to ! e>? aga96 ,f ! moon ! e>? mu/ appe> a mu* bigg] & m glori\s spectacle ?an %e does to u--f\r times wid] across & probably bright]--= ! sun's light /rikes (t5 on our cl\ds1 :i* %9e m brilliantly ?an h] surface4 ,once aga9 we mu/ use an illu/ration to expla9 ! subject4 ,set a lamp 9 ! middle ( a d>k room1 & let t be ! sun1 !n take a small ball to repres5t ! e>? & a small] "o = ! moon4 ,place ! moon-ball betwe5 ! lamp & ! e>?-ball4 ,y w see t ! side turn$ to ! e>?-ball is d>k1 b if y move ! moon to "o side ( ! e>?1 !n f ! e>? half ( x appe>s light & half d>k2 if y put x "r away f ! lamp1 on ! out] side ( ! e>?1 x is all glori\sly lit up1 unless x happ5s to be exactly beh9d ! e>?1 :5 ! e>?'s %ad[ w d>k5 x4 ,?is is ! full explanation ( all ! *anges ( ! moon4 ,illu/ration3 ,,an ,,eclipse ,,( ,,! ,,moon4 ,does x ev] fall )9 ! e>?'s %ad[8 ,yes1 x does2 = z x passes r\nd ! e>? x is n always at ! same level1 b sometimes a little high] & sometimes a little l[]1 & :5 x *ances to pass exactly beh9d x ent]s ! %ad[ & disappe>s4 ,t is :at we call an eclipse ( ! moon4 ,x is no?+ m ?an ! e>?'s %ad[ ?r[n on to ! moon1 & z ! %ad[ is r\nd t is "o ( ! pro(s t ! e>? is r\nd too4 ,b !re is ano!r k9d ( eclipse--! eclipse ( ! sun2 & ?is is caus$ by ! moon h]self4 ,= :5 %e is ne>e/ to ! sun1 at new moon--t is to say1 :5 h] d>k side is t[>d u1 & %e happ5s to get exactly betwe5 u & ! sun--%e %uts out ! face ( ! sun f u2 = ?\gh %e is t9y comp>$ ) him1 %e is s mu* ne>] to u t %e appe>s almo/ ! same size1 & c blot him "r out4 ,?us ! eclipses ( bo? sun & moon are n difficult to und]/&3 t ( ! moon c only happ5 at full moon1 :5 %e is fur!/ f ! sun1 & x is caus$ by ! e>?'s %ad[ fall+ ^u ! moon2 & t ( ! sun at new moon1 :5 %e is ne>e/ to him1 & x is caus$ by ! solid body ( ! moon com+ betwe5 u & ! sun4 ,illu/ration3 ,,an ,,eclipse ,,( ,,! ,,sun4 ,besides giv+ u light by night1 ! moon s]ves o!r important purposes1 & ! mo/ important ( all is ! rais+ ( ! tides4 ,)\t ! ris+ ( ! sea twice 9 e day & night our coa/s w\ld become f\l & un:olesome1 = all ! dead fi% & rott+ /uff ly+ on ! bea* w\ld poison ! air4 ,! sea tides sc\r our coa/s day by day ) nev]-ceas+ en]gy1 & !y s5d a great brea? ( fre%ness up our l>ge riv]s to delight _m p f> inl&4 ,! moon does mo/ ( ?is "w1 ?\gh %e is a little help$ by ! sun4 ,! reason ( ?is is t ! moon is s ne> to ! e>? t1 ?\gh h] pull is a comp>atively small "o1 x is v /rongly felt4 ,%e _c displace ! actual surface to any great ext5t1 z x is s solid2 b :5 x comes to ! wat] %e c & does displace t1 s t ! wat] rises up 9 answ] to h] pull1 & z ! e>? turns r\nd ! rais$-up wat] lags beh9d1 rea*+ backw>d t[>d ! moon1 & is drawn up on ! bea*1 & makes high tide4 ,b x is /opp$ !re1 & meantime1 by reason ( ! e>?'s movem5t1 ! moon is left f> beh9d1 & pulls ! wat] to itself fur!r on1 :5 ! fir/ high tide relapses & falls d[n aga94 ,at l5g? ! moon gets r\nd to q ! opposite side ( ! e>? to t :]e %e began1 & !re %e makes a high tide too2 b z %e draws ! wat] to h]self %e draws also ! solid e>? b5ea? ! wat] to h] 9 "s degree1 & s pulls x away f ! place :]e ! fir/ high tide occurr$1 leav+ ! wat] !re deep] ?an be=e1 & s caus+ a second>y high tide4 ,illu/ration3 ,,! ,,moon ,,rais+ ,,! ,,tides4 ,! sun has "s influ5ce on ! tides too1 & :5 moon & sun are 9 ! same l9e1 z at full & new moon1 !n ! tides are highe/1 & are call$ spr+ tides2 b :5 !y pull 9 diff]5t directions1 z :5 x is half-moon1 !n ! tides are l[e/ & are call$ neap tides4 ,,*apt] ,,iv ,,! ,,e>?',s ,,bro!rs ,,& ,,si/] ,! e>? is n ! only _w t1 pois$ 9 space1 sw+s ar\nd ! sun4 ,x is "o ( a family call$ ! ,sol> ,sy/em1 :i* means ! sy/em controll$ & gov]n$ by ! sun4 ,:5 we look up at ! glori\s sky1 />-/udd$ night by night1 x might seem to u t ! />s move only by reason ( ! e>?'s rotation2 b :5 m5 fir/ began to /udy ! heav5s att5tively--& ?is is s long ago t ! record ( x is n to be f\nd--!y notic$ t1 :ile e %9+ object 9 ! sky 0 app>5tly mov+ r\nd u1 !re 7 a few :i* also _h ano!r movem5t1 a prop] motion ( _! own1 l ! moon4 ,^! curi\s />s1 :i* appe>$ to w&] ab\t among ! o!r />s1 !y call$ planets1 or w&]]s4 ,& ! reason1 :i* 0 pres5tly discov]$1 ( our be+ able to see ^! movem5ts 0 t ^! planets are v mu* ne>] to u ?an any ( ! real />s1 & 9 fact =m "p ( our own sol> sy/em1 :ile ! />s are at immeasurable di/ances away4 ,( all ! objects 9 ! heav5s ! planets are ! mo/ int5sely int]e/+ to u2 = ?\gh remov$ f u by millions ( miles1 ! f>-rea*+ telescope br+s "s ( !m )9 su* range t we c see _! surfaces & discov] _! movem5ts 9 a way q impossible ) ! />s4 ,& "h1 if any:]e1 might we expect to f9d traces ( o!r liv+ be+s l ourselves2 =1 aft] all ! e>? is b a planet1 n a v l>ge nor a v small "o1 & 9 no v /rik+ position comp>$ ) ! o!r planets2 & ?us1 argu+ by :at seems common-s5se1 we say1 ,if ?is "o planet has liv+ be+s on its surface1 may n ! o!r planets prove to be homes = liv+ be+s also8 ,c\nt+ our own e>?1 !re are eight ( ^! worlds 9 our sol> sy/em1 & also a numb] ( t9y planets1 call$ a/]oids2 ^! likewise g r\nd ! sun1 b are v mu* small] ?an any ( ! fir/ eight1 & /& 9 a class by !mselves1 s t :5 ! planets are m5tion$ x is g5]ally ! eight l>ge well-kn[n planets :i* are ref]r$ to4 ,if we g back = a mom5t to ! illu/ration ( ! l>ge lamp repres5t+ our sun1 we %all n[ be able to fill 9 ! picture ) mu* m detail4 ,! orbits ( ! planets1 z _! pa?s r\nd ! sun are call$1 lie l great circles "o outside ano!r at v>i\s di/ances1 & d n t\* or cut ea* o!r4 ,:]e d y suppose our own place to be8 ,w x be ! ne>e/ to ! sun or ! fur!/ away f him8 ,z a matt] ( fact1 x is nei!r1 we come ?ird 9 ord] f ! sun1 = two small] planets1 "o v small & ! o!r ne>ly z l>ge z ! e>?1 circle r\nd & r\nd ! sun 9 orbits ly+ inside ours4 ,n[ if we want to place objects ar\nd our lamp-sun :i* w repres5t ^! planets 9 size1 & to put !m 9 places correspond+ to _! real positions1 we %\ld f9d no room l>ge en\gh to give u ! space we ought to h4 ,we mu/ take ! lamp out into a great op5 field1 :]e we %all n be limit$ by walls4 ,!n ! smalle/ planet1 nam$ ,m]cury1 :i* lies ne>e/ ( all to ! sun1 w\ld h to be repres5t$ by a pea comp>atively close to ! sun2 ,v5us1 ! next1 w\ld be a gre5gage plum1 & w\ld be ab\t twice z f> away2 !n w\ld come ! e>?1 a slightly l>g] plum1 ab\t half z f> aga9 z ,v5us4 ,aft] ?is !re w\ld be a less] planet1 call$ ,m>s1 l a m>ble4 ,^! are ! fir/ f\r1 all comp>atively small2 beyond !m !re is a va/ gap1 9 :i* we f9d ! a/]oids1 & aft] ?is we come to f\r l>g] planets1 mighty inde$ z reg>ds ourselves1 = if our e>? 7 a gre5gage plum1 ! fir/ ( ^!1 ,jupit]1 w\ld h to be ! size ( a football at lea/1 & ! next1 ,saturn1 a small] football1 :ile ,uranus & ,neptune1 ! two fur!/ out1 w\ld be ab\t ! size ( ! toy balloons *ildr5 play )4 ,! out]mo/ "o1 ,neptune1 w\ld be ?irty times z f> f ! sun z we are4 ,illu/ration3 ,,comp>ative ,,sizes ,,( ,,! ,,planets4 ,?is is ! sol> sy/em1 & 9 x ! only ?+ t %9es by its own light is ! sun2 all ! re/1 ! planets & _! moons1 %9e only because ! rays ( light f ! sun /rike on _! surfaces & are reflect$ (f aga94 ,our e>? %9es l t1 & f ! ne>] planets mu/ appe> z a brilliant />4 ,! little sol> sy/em is sep>at$ by di/ances beyond ! realm ( ?\ght f ! re/ ( ! univ]se4 ,va/ z are ! int]vals betwe5 ourselves & our planet>y neighb\rs1 !y are z no?+ to ! space t sep>ates u f ! ne>e/ ( ! /eady %9+ fix$ />s4 ,:y1 remov$ z f> f u z ! />s1 ! sun himself w\ld h sunk to a po9t ( light2 & z = ! planets1 ! l>ge/ ( !m1 ,jupit]1 c\ld n possibly be se54 ,?us1 :5 we look at ^? />s across ! great gulf ( space1 we "k t ?\gh we see !m !y _c see u1 & t to !m our sun mu/ seem only a />2 consequ5tly we argue t p]haps ^! />s !mselves are suns ) families ( planets atta*$ to !m2 & ?\gh !re are reasons = ?9k+ t ?is is n ! case ) all1 x may be ) "s4 ,n[ if1 aft] le>n+ ?is1 we look aga9 at ! sky1 we d s ) v diff]5t eyes1 = we realize t "s ( ^! %9+ bodies are l ourselves 9 _m ?+s1 & are %9+ only ) a light borr[$ f ! sun1 :ile o!rs are mighty gl[+ suns !mselves1 %9+ by _! own light1 "s great] & bright]1 "s less ?an our sun4 ,! next ?+ to d is to le>n :i* are />s & :i* are planets4 ,( ! planets y w soon le>n to pick out "o or two1 & w recognize !m ev5 if !y d *ange _! places--= in/ance1 ,v5us is at times v conspicu\s1 %9+ z an ev5+ /> 9 ! we/ soon aft] ! sun goes d[n1 or u a morn+ /> be=e he gets up1 ?\gh y are n s likely to see h] !n2 anyway1 %e is nev] f\nd v f> f ! sun4 ,jupit] is ! only o!r planet t comp>es ) h] 9 brilliancy1 & he %9es mo/ beautifully4 ,he is1 ( c\rse1 mu* fur!r away f u ?an ,v5us1 b s mu* l>g] t he rivals h] 9 brightness4 ,saturn c be q easily se5 z a conspicu\s object1 too1 if y "k :]e to look = him1 & ,m>s is sometimes v bright ) a r$di% gl[4 ,! o!rs y w\ld n be able to di/+ui%4 ,x is to our e>?'s family ( ^! eight l>ge planets go+ /eadily r\nd ! same sun t we mu/ give our att5tion fir/1 be=e go+ on to ! di/ant />s4 ,_m ( ! planets are accompani$ by satellites or moons1 :i* circle r\nd !m4 ,we may say t ! sun is our p>5t--fa!r1 "m1 :at y w--& t ! planets are ! family ( *ildr51 & t ! moons are _! *ildr54 ,our e>?1 y see1 has only "o *ild1 b t a v f9e "o1 ( :i* %e may well be pr\d4 ,:5 ,i say t ! planets g r\nd ! sun 9 circles ,i am only speak+ g5]ally2 z a matt] ( fact1 ! orbits ( ! planets are n p]fect circles1 ?\gh "s are m circul> ?an o!rs4 ,in/ead ( ?is !y are z a circle might look if x 7 press$ 9 f two sides1 & ?is is call$ an ellipse4 ,! pa? ( our own e>? r\nd ! sun is "o ( ! mo/ ne>ly circul> ( !m all1 & yet ev5 9 h] orbit %e is a good deal ne>] to ! sun at "o "t ?an ano!r4 ,w\ld y be surpris$ to he> t %e is ne>] 9 our w9t] & fur!r away 9 our summ]8 ,yet t is ! case4 ,& = ! fir/ mom5t x seems absurd2 = :at !n makes ! summ] hott] ?an ! w9t]8 ,t is due to an altoge!r diff]5t cause2 x dep5ds on ! position ( ! e>?'s axis4 ,if t axis 7 q /raight up & d[n 9 ref]5ce to ! e>?'s pa? r\nd ! sun we %\ld h equal days & nights all ! ye> r\nd1 b x is n2 x leans ov] a little1 s t at "o "t ! ,nor? ,pole po9ts t[>ds ! sun & at ano!r "t away f x1 :ile ! ,s\? ,pole is po9t+ fir/ away f x & !n t[>d x 9 exactly ! rev]se way4 ,:5 ! ,nor? ,pole po9ts to ! sun we 9 ! ,nor!rn ,hemisph]e h our summ]4 ,to und]/& ?is y mu/ look at ! picture1 :i* w make x mu* cle>] ?an any words ( m9e c d4 ,! d>k "p is ! night1 & ! light "p ! day4 ,:5 we are hav+ summ] any p>ticul> spot on ! ,nor!rn ,hemisph]e has q a long way to travel 9 ! light1 & only a v %ort bit 9 ! d>k1 & ! fur!r nor? y g ! long] ! day & %ort] ! night1 until "r up ne> ! ,nor? ,pole1 )9 ! ,arctic ,circle1 x is daylight all ! "t4 ,y h1 p]haps1 he>d ( ! 'midnight sun' t p g to see 9 ! ,nor?1 & :at ! expression means is t at :at %\ld be midnight ! sun is /ill !re4 ,he seems j to circle r\nd ! horizon1 nev] v f> above1 b nev] dipp+ bel[ x4 ,:5 ! sun is high ov]head1 8 rays /rike d[n ) mu* m =ce ?an :5 he is l[4 ,x is1 = in/ance1 hott] at mid-day ?an 9 ! ev5+4 ,n[1 :5 ! ,nor? ,pole is b[$ t[>d ! sun1 ! sun appe>s to u to be high] 9 ! sky4 ,9 ! ,briti% ,isles he nev] climbs q to ! z5i?1 z we call ! po9t /raight above our heads2 he always keeps on ! s\!rn side ( t1 s t our %ad[s are ?r[n nor?w>d at mid-day1 b yet he gets ne>] to x ?an he does 9 w9t]4 ,look at ! picture ( ! e>? z x is 9 w9t]4 ,!n we h long nights & %ort days1 & ! sun nev] appe>s to climb v high1 because we are turn$ away f him4 ,dur+ ! %ort days we d n receive a great deal ( heat1 & dur+ ! long night ! heat we h receiv$ has "t to evaporate to a great ext5t4 ,^! two reasons--! great] or less height ( ! sun 9 ! sky & ! l5g? ( ! days--are q en\gh to acc\nt = ! diff]5ce betwe5 our summ] & w9t]4 ,!re is "o r int]e/+ po9t to rememb]1 & t is t 9 ! ,nor!rn ,hemisph]e1 :e!r x is w9t] or summ]1 ! sun is s\? at mid-day1 s t y c always f9d ! nor? !n1 = y\r %ad[ w po9t nor?w>ds4 ,illu/ration3 ,,! ,,engli% ,,summ] 7,,left7 ,,& ,,w9t] 7,,"r74 ,new ,zeal& & ,au/ralia & o!r c\ntries plac$ 9 ! ,s\!rn ,hemisph]e1 z we are 9 ! ,nor!rn1 h _! summ] :ile we h w9t]1 & w9t] :ile we h summ]1 & _! summ] is w>m] ?an ours1 because x comes :5 ! e>? 9 its j\rney is ?ree million miles ne>] to ! sun ?an 9 our summ]4 ,all ?is seems to ref] to ! e>? alone1 & ?is *apt] %\ld be ab\t ! planets2 b1 aft] all1 :at applies to "o planet applies to ano!r 9 "s degree1 & we c turn to ! o!rs ) mu* m int]e/ n[ to see if _! axes are b[$ t[>d ! sun z ours is4 ,x is believ$ t 9 ! case ( ,m]cury1 9 reg>d to its pa? r\nd ! sun1 ! axis is /raight up & d[n2 if x is ! *anges ( ! seasons mu/ dep5d on ! ne>ness ( ,m]cury to ! sun & no?+ else1 & z he is a great deal ne>] at "o "t ?an ano!r1 ?is might make a v consid]able diff]5ce4 ,"s ( ! planets are l ! e>? 9 reg>d to ! position ( _! axes1 b ! two out]mo/ ones1 ,uranus & ,neptune1 are v peculi>1 = "o pole is turn$ "r t[>d ! sun & ! o!r "r away f x1 s t 9 "o hemisph]e !re is cont9u\s day all ! summ]1 9 ! o!r !re is cont9u\s night1 & !n ! process is rev]s$4 ,b ^! little peculi>ities we %all h to note m p>ticul>ly 9 ! acc\nt ( ! planets sep>ately4 ,!re is a curi\s fact 9 reg>d to ! di/ances ( ! planets f ! sun4 ,ea* "o1 aft] ! fir/1 is1 v r\ghly1 ab\t d\ble ! di/ance f ! sun ( ! "o inside x4 ,?is holds good = all ! fir/ f\r1 !n !re is a great gap :]e we might expect to f9d ano!r planet1 aft] :i* foll[ ! f\r l>ge planets4 ,n[1 ?is gap puzzl$ a/ronom]s greatly2 = ?\gh !re seem$ to be no reason :y ! planets %\ld be at regul> di/ances "o outside ! o!r1 yet !re ! fact 01 & t ! s]ies %\ld be brok5 by a miss+ planet 0 annoy+4 ,s v c>eful se>* 0 made1 & a ?rill ( excitem5t w5t all ?r\gh ! sci5tific _w :5 x 0 kn[n t a t9y planet _h be5 discov]$ 9 ! "r place4 ,b ?is 0 n ! end ( x1 = )9 a few ye>s ?ree or f\r m t9y planets 7 obs]v$ n f> f ! fir/ "o1 &1 z ye>s roll$ on1 "o aft] ano!r 0 discov]$ until n[ ! numb] am\nts to ov] six hundr$ & o!rs are p]petually be+ add$ to ! li/6 ,"h 0 a new feature 9 ! sol> sy/em1 a b& ( t9y planets n "o ( :i* 0 to be comp>$ 9 size ) ! lea/ ( ^? already kn[n4 ,! l>ge/ may be ab\t z l>ge z ,europe1 & o!rs p]haps ab\t ! size ( ,wales1 :ile !re may be _m t h only a few squ>e miles ( surface altoge!r1 & are too small = u to see4 ,to acc\nt = ?is /range discov]y _m !ories 7 advanc$4 ,"o 0 t !re _h be5 a planet--x might be ab\t ! size ( ,m>s--:i* _h bur/ up 9 a great explosion1 & t ^! 7 ! pieces--a v int]e/+ & excit+ idea1 b "o :i* prov$ to be impossible4 ,! explanation n[ g5]ally accept$ is a little complicat$1 & to und]/& x we mu/ g back = a bit4 ,:5 we 7 talk+ ( ! e>? & ! moon we realiz$ t once long ago ! moon mu/ h be5 a "p ( ! e>?1 at a "t :5 ! e>? 0 mu* l>g] & s(t] ?an %e n[ is2 to put x 9 ! correct way1 we %\ld say :5 %e 0 less d5se4 ,!re is no ne$ to expla9 ! ^w 'd5se1' = 9 its ord9>y s5se we use x e day1 b 9 an a/ronomical s5se x does n mean exactly ! same ?+4 ,ev]y?+ is made up ( m9ute p>ticles or atoms1 & :5 ^! atoms are n v close toge!r ! body !y compose is loose 9 texture1 :ile if !y are clos] toge!r ! body is firm]4 ,= in/ance1 air is less d5se ?an wat]1 & wat] ?an e>?1 & e>? ?an /eel4 ,y see at once by ?is t ! m d5sity a ?+ has ! heavi] x is2 = z a body is attract$ to ano!r body by e atom or p>ticle 9 x1 s if x has m p>ticles x w be m /rongly attract$4 ,?us on ! e>? ! d5s] ?+s are really heavi]4 ,b 'weight' is only a ^w we use 9 connection ) ! e>?2 x means ! e>?'s pull+ p[] t[>d any p>ticul> ?+ at ! surface1 & if we 7 "r out 9 space away f ! e>?1 ! pull+ p[] ( ! e>? w\ld be less1 & s ! weight w\ld be less2 & z x w\ld be impossible always to /ate j h[ f> away a ?+ 0 f ! e>?1 a/ronom]s talk ab\t d5sity1 :i* means ! numb] ( p>ticles a body conta9s 9 proportion to o!r bodies4 ,?us ! planet ,jupit] is v mu* l>g] ?an ! e>?1 b 8 d5sity is less4 ,t does n mean to say t if ,jupit] 7 9 "o scale & ! e>? 9 ! o!r he w\ld weigh less1 because he is s v mu* bigg] he w\ld outweigh ! e>? /ill2 8 total mass w\ld be great] ?an t ( ! e>?1 b x means t a piece ( ,jupit] ! same size z a piece ( ! e>? w\ld weigh less "u ! same conditions4 ,n[1 be=e !re 7 any planets at all or any sun1 9 ! place ( our sol> sy/em 0 a va/ gase\s cl\d call$ a nebula1 :i* sl[ly rotat$1 & ?is rotation 0 ! fir/ impulse or =ce :i* ,god gave x4 ,x 0 n at all d5se1 & z x rotat$ a "p broke (f1 & inh]it+ ! fir/ impulse1 w5t on rotat+ too4 ,! impulse w\ld h s5t x (f 9 a /raight l9e1 b ! pull ( gravity f ! nebula held x 9 place1 & x circl$ r\nd2 !n ! nebula1 z x rotat$1 contract$ a little1 & occupi$ less space & grew d5s]1 & pres5tly a second piece 0 ?r[n (f1 to become 9 "t ano!r planet4 ,! same process 0 repeat$ ) ,saturn1 & !n ) ! huge ,jupit]4 ,! nebula 0 always rotat+ & always contract+4 ,& z x behav$1 s did ! planets 9 _! turn2 !y spun r\nd & cool$ & contract$1 & ! moons 7 flung (f f !m1 j z !y--! planets--_h be5 flung (f f ! p>5t nebula4 ,n[1 aft] ! orig9al nebula _h p>t$ ) ! mighty mass ( ,jupit]1 x nev] aga9 made an ef=t s great1 & = a long "t ! fragm5ts t 7 deta*$ 7 s small z h>dly to be wor? call+ planets2 !y 7 ! a/]oids1 little lumps & fragm5ts t ! nebula left beh9d4 ,b z x /ill contract$ 9 "t !re came ,m>s2 & hav+ recov]$ a little1 ! nebula ) m en]gy got rid ( ! e>?1 & next ,v5us1 & la/ly little ,m]cury1 ! smalle/ ( ! eight planets4 ,!n x contract$ fur!r1 & p]haps y c guess :at ! rema9d] ( x is--! sun2 & by sp9n+ 9 a pla/ic /ate ! sun1 l ! e>?1 has become a globe1 r\nd & comp>atively smoo?2 & its d5sity is n[ too great to all[ ( its los+ any m fragm5ts1 s1 z f> z we c see1 ! sol> sy/em is complete4 ,?is !ory ( ! orig9 ( ! planets is call$ ! nebula !ory4 ,we _c prove x1 b !re are s _m facts t c only be expla9$ by x1 we h /rong reason = believ+ t some?+ ( ! k9d mu/ h happ5$4 ,:5 we come to speak ( ! />ry heav5s we %all see t !re are _m masses ( gl[+ gas :i* are nebul ( ! same sort1 & :i* =m an object-lesson 9 our own hi/ory4 ,we h spok5 r lightly ( ! nebula rotat+ & ?r[+ (f planets2 b we mu/ n ?9k ( all ?is z hav+ happ5$ 9 a %ort "t4 ,x is almo/ z impossible = ! human m9d to conceive ! ages requir$ = su* sl[ *anges z to grasp ! great gulfs ( space t sep>ate u f ! />s4 ,we c only d x by comp>ison4 ,y "k :at a second is1 & h[ ! seconds race pa/ )\t ceas+ day & night4 ,x makes "o giddy to picture ! seconds !re are 9 a ye>2 yet if ea* "o ( ^? seconds 0 a ye> 9 itself1 :at !n8 ,t seems a /up5d\s "t1 b x is no?+ comp>$ ) ! "t ne$$ to =m a nebula into a planet>y sy/em4 ,if we _h five ?\s& ( su* ye>s1 ) e second 9 !m a ye>1 we %\ld !n only h c\nt$ "o billion real ye>s1 & billions mu/ h pass$ s9ce ! sun 0 a gase\s nebula fill+ ! out]mo/ b\nds ( our sy/em6 ,,*apt] ,v ,,f\r ,,small ,,worlds ,:at mu/ ! sun appe> to ,m]cury1 :o is s mu* ne>] to him ?an we are8 ,to und]/& t we %\ld h to imag9e our sun increas$ to eight or n9e times 8 app>5t size1 & p\r+ out f> great] heat & light ?an any?+ t we h "h1 ev5 9 ! tropics4 ,x 0 at fir/ suppos$ t ,m]cury mu/ h an extra ?ick cov]+ ( cl\ds to protect him f ?is trem5d\s gl>e2 b rec5t obs]vations t5d to prove t1 f> f ?is1 he is s+ul>ly free f cl\d4 ,z ?is is s1 no life z we "k x c\ld possibly exi/ on ,m]cury4 ,8 ye>--! "t he takes to g r\nd ! sun & come back to ! same place aga9--is eighty-eight days1 or ab\t "o-qu>t] ( ours4 ,z 8 orbit is mu* m l an ellipse ?an a circle1 x foll[s t he is mu* ne>] to ! sun at "o "t ?an at ano!r--9 fact1 :5 he is ne>e/1 ! size ( ! sun mu/ seem ?ree & a half times great] ?an :5 he is fur!/ away f x6 ,ev5 at ! be/ ,m]cury is v difficult to obs]ve1 & :at we c le>n ab\t him is n mu*2 b1 z we h he>d1 8 axis is suppos$ to be upright4 ,if s 8 seasons _c dep5d on ! b5d t[>d or away f ! sun1 b mu/ be influ5c$ solely by ! *anges 9 8 di/ance f ! sun1 :i* are mu* great] ?an 9 our own ease4 ,!re is "s reason to believe1 too1 t ,m]cury's day & ye> are ! same l5g?4 ,?is means t z ! planet circles r\nd ! sun he turns once4 ,if ?is is s ! sun w %9e on "o half ( ! planet1 produc+ an accumulat$ heat t]rific to ?9k (2 :ile ! o!r side is plung$ 9 blackness4 ,! side :i* faces ! sun mu/ be heat$ to a pit* inconceivable to u dur+ ! ne>] half ( ! orbit--a pit* at :i* e sub/ance mu/ be at boil+-po9t1 & :i* no life z we "k x c\ld possibly endure4 ,se5 f our po9t ( view1 ,m]cury goes ?r\gh all ! phases ( ! moon1 z he %9es by ! reflect$ light ( ! sun2 b ?is po9t we %all consid] m p>ticul>ly 9 reg>d to ,v5us1 z ,v5us is ne>] to u & easi] to /udy4 ,= a long "t a/ronom]s _h a fancy t !re might be ano!r planet ev5 ne>] to ! sun ?an ,m]cury1 p]haps hidd5 f u by ! great gl>e ( ! sun4 ,!y ev5 nam$ ?is imag9>y planet ,vulcan1 & "s ?\ght !y _h se5 x1 b x is tol]ably c]ta9 t ,vulcan exi/$ only 9 imag9ation4 ,m]cury is ! ne>e/ planet to ! sun1 & also ! smalle/1 ( c\rse except+ ! a/]oids4 ,x is ab\t ?ree ?\s& miles 9 diamet]1 & z our moon is two ?\s& miles1 x is n s mu* bigg] ?an t4 ,s f> z we are conc]n$1 x is improbable we %all ev] "k v mu* m ab\t ?is little planet4 ,b next we come to ,v5us1 our beautiful bright neighb\r1 :o approa*es ne>] to u ?an any o!r heav5ly body except ! moon4 ,alas6 :5 %e is ne>e/1 %e l ,m]cury1 turns h] d>k side t[>d u1 com+ 9 betwe5 u & ! sun1 s t we _c obs]ve h] at all4 ,ev]yone mu/ h notic$ ,v5us1 h[ev] c>elessly !y h look$ at ! sky2 b x is likely t f> m p h se5 h] z an ev5+ ?an a morn+ />1 = mo/ p are 9 b$ :5 ! sun rises1 & x is only be=e sunrise or aft] sunset we c see ,v5us well4 ,%e is at h] be/ f our po9t ( view :5 %e seems to u to be fur!/ f ! sun1 = !n we c /udy h] be/1 & at ^! times %e appe>s l a half or ?ree-qu>t] moon1 z we only see a "p ( ! side f :i* ! sunlight is reflect$4 ,%e %9es l a little silv] lamp1 excell+ e o!r planet1 ev5 ,jupit]1 ! l>ge/ ( all4 ,if we look at h] ev5 ) ! nak$ eye1 we c see t %e is elongat$ or drawn out1 b h] brilliance prev5ts u f see+ h] %ape exactly2 to d ?is we mu/ use a telescope4 ,illu/ration3 ,,diff]5t ,,phases ,,( ,,v5us4 ,x is a curi\s fact t "s planets %9e mu* m brightly ?an o!rs1 )\t reg>d to _! size--t is to say1 ! surface on :i* ! sun's rays /rike is ( great] reflect+ p[] 9 "s ?an 9 o!rs4 ,"o ( ! brighte/ ?+s 9 ,nature t we c imag9e is a bank ( sn[ 9 sunlight2 x is s dazzl+ t we h to look away or w9k h>d at ! sight2 & ! reflective p[] ( ! surface ( ,v5us is z dazzl+ z if %e 7 made ( sn[4 ,?is is probably because ! light /rikes on ! upp] surface ( ! cl\ds :i* surr\nd h]4 ,9 great contra/ to ?is is ! surface ( ,m]cury1 :i* reflects z dully z a mass ( lead4 ,our own moon has n a high reflect+ p[]1 z w be easily und]/ood if we imag9e :at ! _w w\ld be if condemn$ to p]petual moonlight only4 ,x w\ld1 inde$1 be a sad deprivation if ! m\rnful cold light ( ! moon1 welcome en\gh z a *ange f sunlight1 7 to take ! place ( sunlight 9 ! daytime4 ,= a v long "t a/ronom]s c\ld n discov] :at "t ,v5us took 9 rotat+ on h] own axis--t is to say1 :at ! l5g? ( h] day 04 ,%e is difficult to obs]ve1 & 9 ord] to f9d out ! rotation x is necess>y to note "s fix$ object on ! surface :i* turns r\nd ) ! planet & comes back to ! same place aga91 s t ! "t x takes 9 its j\rney c be measur$4 ,b ! surface ( ,v5us is always *ang+1 s t x is impossible to judge at all c]ta9ly4 ,op9ions diff] greatly1 "s a/ronom]s hold+ t ,v5us's day is n mu* long] ?an an e>?ly day1 :ile o!rs believe t ! planet's day is equal to h] ye>1 j z 9 ! case ( ,m]cury4 ,v5us's ye> is #bbe days1 or ab\t sev5 & a half ( our mon?s1 & if1 inde$1 h] day & ye> are ! same l5g?1 v peculi> effects w\ld foll[4 ,= in/ance1 t]rible heat w\ld be absorb$ by ! side ( ! planet fac+ ! sun 9 ! p]petual summ]2 & ! cold :i* w\ld be felt 9 ! dre>y w9t]'s night w\ld f> exce$ our bitt]e/ ,arctic climate4 ,we _c b fancy t any be+s :o might live on a planet ( ?is k9d mu/ be diff]5t altoge!r f ourselves4 ,!n1 !re is ano!r po9t3 ev5 "h on e>? v /rong w9ds are caus$ by ! heat+ ( ! tropics2 ! hot air1 be+ light] ?an ! cold air1 rises1 & ! cold] air f ! poles ru%es 9 to supply its place4 ,?is causes w9d1 b ! w9ds :i* w\ld be rais$ on ,v5us by ! ru% ( air f ! icy side ( ! planet to ! hot "o w\ld be tornadoes su* z we c\ld b fa9tly dream (4 ,x is1 ( c\rse1 useless to speculate :5 we "k s little1 b 9 a subject s int5sely int]e/+ we _c help guess+ a little4 ,v5us is only slightly small] ?an ! e>?1 & h] d5sity is n v unlike ours2 !re=e ! pull ( gravity mu/ be pretty mu* !re :at x is "h--t is to say1 ?+s w weigh at h] surface ab\t ! same z !y d "h4 ,h] orbit is ne>ly a circle1 s t h] di/ance f ! sun does n v>y mu*1 & ! heat w n be mu* great] f ?is cause at "o "t ( ! ye> ?an ano!r4 ,z h] orbit is tilt$ up a little %e does n pass betwe5 u & ! sun at ea* revolution1 b occasionally %e does s1 & ?is pass+ is call$ a transit4 ,_m important facts h be5 le>n$ by wat*+ ^! transits4 ,m]cury also has transits across ! sun1 b z %e is s mu* small] ?an ,v5us !y are n ( su* great importance4 ,x 0 by ! close obs]vation ( ,v5us dur+ h] transits t ! di/ance f ! e>? to ! sun 0 fir/ measur$4 ,n until ! ye> #bjjd w ano!r transit ( ,v5us occur4 ,x is n difficult to imag9e t ! e>? mu/ appe> a spl5did spectacle f ,v5us1 :5ce %e is se5 to great advantage4 ,:5 ne>e/ to u %e mu/ see u l a little moon1 ) m>k+s z ! cont95ts & seas rotate1 & ^! w *ange z !y are obscur$ by ! cl\ds roll+ ov] !m4 ,at ! ,nor? & ,s\? ,poles w be glitt]+ ice-caps1 gr[+ l>g] & small] z !y turn t[>d or away f ! sun4 ,a brilliant spectacle6 ,illu/ration3 ,,orbits ,,( ,,m>s1 ,,! ,,e>?1 ,,v5us1 ,,& ,,m]cury4 ,we might say ) a sigh1 ',if only we c\ld see su* a _w6' ,well1 we c see a _w--n inde$1 s l>ge z ,v5us1 yet a _w t comes almo/ z ne> to u z ,v5us does1 & :i*1 unlike h]1 is outside u 9 ord] f ! sun1 s t :5 x is ne>e/ to u ! full sunlight is on x4 ,?is is ,m>s1 our neighb\r on ! o!r side1 & ( all ! fasc9at+ objects 9 ! sky ,m>s is ! mo/ fasc9at+1 = !re1 if any:]e1 %\ld we be likely to discov] be+s l ourselves6 ,m>s takes r m ?an half an h\r long] to rotate ?an we d1 & z he is s mu* small] ?an ! e>?1 ?is means t he moves r\nd m sl[ly4 ,8 axis is b5t at ne>ly ! same angle z ours is4 ,m>s is mu* small] ?an ! e>?1 8 diamet] is ab\t twice t ( ! moon1 & 8 d5sity is ab\t ?ree-qu>t]s t ( ! e>?1 s t altoge!r1 ) 8 small] size & less d5sity1 any?+ weigh+ a hundr$ p\nds "h w\ld only weigh "s =ty p\nds on ,m>s2 & if1 by "s miracul\s ag5cy1 y 7 sudd5ly transport$ !re1 y w\ld f9d y\rself s light t y c\ld jump enorm\s di/ances ) little ef=t1 & skip & hop z if y 7 on spr+s4 ,illu/ration3 ,memoirs ( ! ,briti% ,a/ronomical ,association4 ,,map ,,( ,,m>s4 ,look at ! map ( ,m>s1 9 :i* ! surface appe>s to be cut up into l& & wat]1 cont95ts & oceans4 ,! m5 :o fir/ obs]v$ ,m>s ) accuracy saw t "s p>ts 7 ( a r$di% col\r & o!rs gre5i%1 & argu+ f our own _w1 !y call$ ! gre5i% p>ts seas & ! r$di% l&4 ,= a long :ile no "o d\bt$ t we actually look$ on a _w l our own1 m especially z !re 0 suppos$ to be a cov]+ ( atmosph]e4 ,! s-call$ l& & wat] are mu* m cut up & mix$ toge!r ?an ours1 x is true4 ,"h & !re is a l>ge sea1 l t m>k$ ',m>e ,au/rale1' b o!rwise ! wat] & ! l& are /rangely int]m+l$4 ,! r$ col\r ( ! "p !y nam$ l& puzzl$ a/ronom]s a good deal1 = our l& se5 at ! same di/ance w\ld n appe> s r$1 & !y came at la/ to ! conclusion t vegetation on ,m>s mu/ be r$ in/ead ( gre56 ,b aft] a :ile ano!r di/urb+ fact turn$ up to upset _! !ories1 & t 0 t !y saw canals1 or :at !y call$ canals1 on ,m>s4 ,^! 7 long1 /raight1 d>k m>k+s1 su* z y see on ! map4 ,x is true t "s p nev] saw ^! m>k+s at all1 & disbeliev$ 9 _! exi/5ce2 b o!rs saw !m cle>ly1 & wat*$ !m *ange--fir/ g fa9t] & !n d>k] aga94 ,& q rec5tly a photograph has be5 obta9$ :i* %[s !m pla9ly1 s !y mu/ h an exi/5ce1 & _c be only 9 ! eye ( ! obs]v]1 z ! mo/ sceptical p 7 wont to sugge/4 ,b fur!r ?an ?is1 "o a/ronom] ann\nc$ t "s ( ^! l9es appe>$ to be d\ble1 yet :5 he look$ at !m aga9 !y _h gr[n s+le4 ,x 0 l a conjur+ trick4 ,great excitem5t 0 ar\s$ by ?is1 = if ! canals 7 alt]$ s greatly x really did look z if !re 7 intellig5t be+s on ,m>s capable ( work+ at !m4 ,9 any case1 if ^! are really canals1 to make !m w\ld be a /up5d\s feat1 & if !y are artificial--t is1 made by be+s & n natural--!y %[ a v high p[] ( eng9e]+4 ,imag9e anyone on e>? mak+ a canal _m miles wide & two ?\s& miles long6 ,x is inconceivable1 b t is ! feat attribut$ to ! ,m>tians4 ,! suppos$ d\bl+ ( ! canals1 z ,i say1 caus$ a great deal ( talk1 & v few p c\ld see t !y 7 d\ble at all4 ,ev5 n[ ! fact is d\bt$1 yet !re seems e reason to believe x is true4 ,!y d n all appe> to be d\ble1 & ^? t d are always ! same ones1 :ile o!rs und\bt$ly rema9 s+le all ! "t4 ,b ! canals d n exhau/ ! wond]s ( ,m>s4 ,at ea* pole !re is an ice-cap resembl+ ^? f\nd at our own poles1 & ?is tells u pretty pla9ly some?+ ab\t ! climate ( ,m>s1 & t !re is wat] !re4 ,?is ice-cap melts :5 ! pole :i* x surr\nds is direct$ t[>d ! sun1 & sometimes 9 a hot summ] x dw9dles d[n almo/ to no?+1 9 a way t ! ice-caps at ! poles ( ! e>? nev] d4 ,a curi\s appe>ance has be5 notic$ :5 x is melt+3 a d>k %ad[ seems to gr[ und]nea? ! edge ( x & ext5ds gradually1 & z x ext5ds ! canals ne> x appe> mu* d>k] & cle>] ?an !y did be=e1 & !n ! canals fur!r s\? und]go ! same *ange4 ,?is looks z if ! melt+ ( ! sn[ fill$ up ! canals ) wat]1 & 0 a means ( wat]+ ! planet by a sy/em totally diff]5t f any?+ we "k "h1 :]e our poles are surr\nd$ by oceans1 & ! ice-caps d n 9 ! lea/ affect our wat]-supply4 ,b1 !n1 ano!r /range fact _h to be tak5 into consid]ation4 ,^! /raight l9es call$ canals ran out ov] ! seas occasionally1 & x 0 impossible to believe t if !y 7 canals !y c\ld d t4 ,o!r ?+s began to be discuss$1 su* z ! fact t ! gre5 p>ts ( ,m>s did n always rema9 gre54 ,9 :at is ! spr+time ( ,m>s !y are s1 b aft]w>ds !y become yell[1 & /ill lat] 9 ! season p>ts ne> ! pole turn br[n4 ,?us ! idea t ! gre5i% p>ts are seas _h to be q giv5 up1 ?\gh x appe>$ s attractive4 ,! idea n[ g5]ally believ$ is t ! gre5i% p>ts are vegetation--trees & bu%es & s on1 & t ! r$ p>ts are des]ts ( r$di% s&1 :i* require irrigation--t is to say1 wat]+--be=e any?+ c be gr[n on !m4 ,! app>5t d\bl+ ( ! canals may be due to ! gre5 vegetation spr++ up along ! banks4 ,?is might =m two broad l9es1 :ile ! canal itself w\ld n be se51 & :5 ! vegetation dies d[n1 we %\ld see only ! tr5* ( ! canal1 :i* w\ld possibly appe> fa9t & s+le4 ,!re=e ! arrangem5ts on ,m>s appe> to be a ri* & a b>r5 season on ea* hemisph]e1 ! gr[? be+ caus$ by ! melt+ ( ! pol> ice-cap1 :i* s5ds floods d[n ev5 beyond ! ,equator4 ,if we c\ld imag9e ! same ?+ on e>? we %\ld h to ?9k ( pieces ( l& ly+ dre> & dry & dead 9 w9t] betwe5 /raight canal-l dit*es ( va/ size4 ,a little wat] might rema9 9 ^! dit*es possibly1 b n en\gh to wat] ! surr\nd+ l&4 ,!n1 z summ] progress$1 we %\ld he>1 ',! floods are com+1' & ea* deep1 huge canal w\ld be fill$ up ) a tide ( wat]1 p5etrat+ fur!r & fur!r4 ,! wat] drawn up into ! air w\ld fall 9 dew or ra94 ,vegetation w\ld spr+ up1 especially ne> ! canal banks1 & in/ead ( dre>y wa/es ri* gr[?s w\ld cov] ! l&1 gradually dy+ d[n aga9 9 ! w9t]4 ,s f> ,m>s seems 9 "s important respects v diff]5t f ! e>?4 ,he is also less fav\rably plac$ ?an we are1 = be+ s mu* fur!r f ! sun1 he receives v mu* less heat & light4 ,8 ye>s are #fhg ( our days1 or "o ye> & t5 & a half mon?s1 & 8 atmosph]e is n s d5se z ours4 ,) ?is great] di/ance f ! sun & less air we might suppose ! temp]ature w\ld be v cold inde$1 & t ! surface w\ld be fro/-b\nd1 n only at ! poles1 b f> d[n t[>ds ! ,equator4 ,in/ead ( ?is be+ s1 z we h se51 ! pol> caps melt m ?an ^? on ! e>?4 ,we c only surmise !re mu/ be "s comp5sation we d n "k ( t s(t5s d[n ! rig\r ( ! seasons1 & makes !m mild] ?an we %\ld suppose possible4 ,( c\rse1 ! "o absorb+ "q is1 ,are !re p on ,m>s8 ,to ?is x is at pres5t impossible to reply4 ,we c only say ! planet seems 9 e way fitt$ to support life1 ev5 if x is a little diff]5t f our e>?4 ,x is mo/ c]ta9ly a liv+ _w1 n a dead "o l ! moon1 & z our k increases we may "s day be able to answ] ! "q :i* s ?rills u4 ,our opportunities = ! obs]vation ( ,m>s v>y v greatly1 = z ! e>?'s orbit lies inside t ( ,m>s1 we c be/ see him :5 we are betwe5 him & ! sun4 ,( c\rse1 x mu/ be rememb]$ t ! e>? & ! o!r planets are s inf9itely small 9 reg>d to ! space betwe5 !m t !re is no possibility ( any "o ( !m gett+ 9 su* a position t x w\ld ?r[ a %ad[ on any o!r or eclipse x4 ,! planets are l specks 9 space1 & c\ld n int]f]e ) "o ano!r 9 ?is way4 ,:5 ,m>s1 !re=e1 is 9 a l9e ) u & ! sun we c see him be/1 b "s ( ^! times are bett] ?an o!rs1 = ?is reason--! e>?'s orbit is ne>ly a circle1 & t ( ,m>s m ( an ellipse4 ,illu/ration3 ,,orbits ,,( ,,! ,,e>? ,,& ,,m>s4 ,look at ! illu/ration & rememb] t ,m>s' ye> is n q two ( ours--t is to say1 e "t we sw+ r\nd our orbit we cat* him up 9 a diff]5t place1 = he w h progress$ less ?an half 8 orbit :ile we g "r r\nd ours4 ,sometimes :5 we ov]take him he may be at t "p :i* is fur!/ away f u1 or he may be at t "p :i* is ne>e/ to u1 & if he is 9 ! latt] position we c see him be/4 ,n[ at ^!1 ! mo/ fav\rable times ( all1 he is /ill m ?an ?irty-five millions ( miles away--t is to say1 "o hundr$ & =ty times z f> z ! moon1 yet comp>atively we c see him v well4 ,he is com+ ne>] & ne>] to u1 & v soon w be ne>] ?an he has be5 s9ce #ahib1 or fifte5 ye>s ago4 ,!n _m telescopes w be direct$ on him1 & mu* may be le>n$ ab\t him4 ,= a long "t x 0 suppos$ t ,m>s _h no moons1 & :5 ,dean ,swift wrote ',gulliv]'s ,travels' he want$ to make ! ,laputans d some?+ v clev]1 s he describ$ _! discov]y ( two moons att5d+ ,m>s1 & to make x q absurd he said t :5 !y obs]v$ ^! moons !y f\nd t "o ( !m w5t r\nd ! planet 9 ab\t t5 h\rs4 ,n[1 z ,m>s takes m ?an tw5ty-f\r h\rs to rotate1 ?is 0 consid]$ ridicul\s1 = no moon kn[n !n took less "t to g r\nd its prim>y _w ?an ! prim>y _w took to turn on its own axis4 ,our own moon1 ( c\rse1 takes ?irty times z long--t is a mon? conta9s ?irty days4 ,!n "o hundr$ & fifty ye>s lat] ?is je/ ( ,dean ,swift's came true1 = two moons 7 really discov]$ revolv+ r\nd ,m>s1 & "o ( !m does actually take less "t to complete its orbit ?an ! planet does to rotate--namely1 a little m ?an sev5 h\rs6 ,s ! absurdity 9 ',gulliv]'s ,travels' 0 a k9d ( prophecy6 ,^! two moons are v small1 ! out] "o p]haps five or six miles 9 diamet]1 & ! inn] "o ab\t sev52 !re=e f ,m>s ! out] "o1 ,deimos1 _c look mu* m ?an a brilliant />1 & ! inn] "o w\ld be b a fif? "p ! app>5t wid? ( our own moon4 ,s ,m>s is n v well (f1 aft] all4 ,/ill1 !re is great v>iety1 = x mu/ be odd to see ! same moon appe>+ ?ree times 9 ! day1 %[+ all ! diff]5t phases z x goes f new to full1 ev5 ?\gh x is small6 ,su* wond]ful discov]ies h already be5 made t x is n too mu* to say t p]haps "s day we may be able to e/abli% "s sort ( communication ) ,m>s1 & if x be inhabit$ by any intellig5t be+s1 we may be able to signal to !m2 b x is almo/ impossible t any contrivance c\ld bridge ! gulf ( airless space t sep>ates u1 & x is n likely t holiday trips to ,m>s w ev] become fa%ionable6 ,,*apt] ,,vi ,,f\r ,,l>ge ,,worlds ,i h told y ab\t ! f\r less] worlds ( :i* our e>? is "o1 & y "k t beyond ,m>s1 ! la/ ( !m1 !re lies a va/ space1 9 :i* are f\nd ! a/]oids1 ^? /range small planets circl+ ne> to ea* o!r1 l a sw>m ( bees4 ,aft] ?is !re comes ,jupit]1 :o is s enorm\s1 s sup]b 9 size comp>$ ) u1 t he might well s]ve z ! sun ( a little sy/em ( 8 own4 ,y rememb] t we repres5t$ him by a football1 :ile ! e>? 0 only a gre5gage plum4 ,b ,jupit] himself is f> less 9 comp>ison ) ! sun ?an we are 9 comp>ison ) him4 ,he diff]s f ! planets we h he>d ab\t up to ! pres5t 9 t he seems to gl[ ) "s heat t he does n receive f ! sun4 ,! illum9ation :i* makes him appe> z a /> to u is1 ( c\rse1 m]ely reflect$ sunlight1 & :at we see is ! ext]nal cov]+1 8 envelope ( cl\d4 ,!re is e reason to believe t ! great bulk ( ,jupit] is /ill at a high temp]ature4 ,we "k t 9 ! dep?s ( ! e>? !re is /ill pl5ty ( heat1 :i* e n[ & !n makes its pres5ce felt by bur/+ up ?r\gh ! v5ts we call volcanoes1 ! weak spots 9 ! e>?'s cru/2 b our surface long ago cool$1 = ! outside ( any body gets cool be=e ! inside1 z y may h f\nd if ev] y 7 try+ to eat hot porridge1 & circl$ r\nd ! edge ( ! plate ) a spoon4 ,a l>ge body cools m sl[ly ?an a small "o1 & x is possible t ,jupit]1 be+ s mu* l>g] ?an we are1 has tak5 long] to cool4 ,"o reason we h = ?9k+ ?is is t he is s v light comp>$ ) 8 size--9 o!r words1 8 d5sity is s small t x is n possible he c\ld be made ( mat]ials su* z ! e>? is made (4 ,z ,i said1 :5 we /udy him ?r\gh telescopes we see j ! ext]ior1 ! out] envelope ( cl\d1 & z we %\ld expect1 ?is *anges cont9ually1 & appe>s z a s]ies ( belts1 ow+ to ! rotation ( ! planet4 ,jupit]'s rotation is v rapid2 ?\gh he is s mu* great] ?an ! e>?1 he takes less ?an half ! "t ! e>? does to turn r\nd--t is to say1 only t5 h\rs4 ,8 days & nights ( five h\rs ea* seem %ort to u1 accu/om$ to measure ?+s by our own e/imates4 ,b we mu/ rememb] t ev]y?+ is relative2 t is to say1 !re is really no su* ?+ z fa/ or sl[2 x is all by comp>ison4 ,a spid] runs fa/ comp>$ ) a snail1 b ei!r is t]ribly sl[ comp>$ ) an express tra92 & ! spe$ ( an express tra9 itself is no?+ to ! velocity ( light4 ,9 ! same way !re is no?+ absolutely great or small2 x is all by comp>ison4 ,we say h[ m>vell\s x is t a little insect has all ! me*anism ( life 9 its body :5 x is s t9y1 b if we imag9e t insect magnifi$ by a p[]ful microscope until x appe>s q l>ge1 ! m>vel ceases4 ,aga91 imag9e a man walk+ on ! surface ( ! e>? z se5 f a great di/ance ?r\gh a telescope3 he w\ld seem less ?an an insect1 & we might ask h[ c\ld ! me*anism ( life be compress$ into any?+ s small8 ,?us1 :5 we say enorm\s or t9y we mu/ always rememb] we are only speak+ by ! measurem5ts ( our own /&>ds4 ,!re is no?+ v /rik+ ab\t ,jupit]'s orbit4 ,he takes betwe5 elev5 & twelve ( our ye>s to get r\nd ! sun1 s y see1 ?\gh 8 day is %ort]1 8 ye> is long] ?an ours4 ,& ?is is n only because 8 pa? is mu* l>g]1 b because by ! law ( gravity ! m di/ant a planet is f ! sun ! m sl[ly x travels1 s t :ile ! e>? spe$s ov] eighte5 miles ,jupit] has only done eight4 ,( c\rse1 we mu/ be c>eful to rememb] ! diff]5ce betwe5 rotation & revolution4 ,jupit] rotates mu* quick] ?an ! e>?--t is to say1 he turns r\nd m quickly--b he actually gets ov] ! gr\nd m sl[ly4 ,! sun appe>s mu* small] to him ?an x does to u1 & he receives consid]ably less light & heat4 ,!re are v>i\s spots on 8 surface1 & "o rem>kable feature is a d>k m>k1 :i* is call$ ! 'great r$ spot4' ,if z we suppose :at we see ( ! planet is m]ely ! cl\dy upp] atmosph]e1 we %\ld n expect to f9d any?+ p]man5t !re1 = ! m>k+s w\ld *ange f day to day1 & ?is !y d ) ?is exception--t ?is spot1 d>k r$ 9 col\r1 has be5 se5 = _m ye>s1 turn+ z ! planet turn$4 ,x 0 fir/ notic$ 9 #ahgh1 & 0 suppos$ to be "s great m\nta9 or excresc5ce peep+ up ?r\gh ! cl\ds4 ,x grew /rong] & d>k] = sev]al ye>s1 & !n seem$ to fade1 & 0 n s easily se51 & ?\gh /ill rema9+ x is n[ pale4 ,b1 mo/ />tl+ to say1 x has %ift$ its position a little--t is1 x takes a few seconds long] to get r\nd ! planet ?an x did at fir/4 ,a few seconds1 y w say1 b t is no?+6 ,x does n seem mu*1 b x %[s h[ m>vell\sly accurate a/ronom]s are4 ,discov]ies ( va/ importance h be5 made f obs]v+ a few seconds' discrepancy 9 ! "t ! heav5ly bodies take 9 _! j\rneys1 & ! fact t ?is spot takes a little long] 9 its rotation ?an x did at fir/ %[s t x _c be atta*$ to ! body ( ! planet4 ,x is impossible = x to be ! summit ( a m\nta9 or any?+ ( t sort4 ,:at c x be8 ,no "o has yet answ]$ t "q4 ,illu/ration3 ,,jupit] ,,& ,,"o ,,( ,,8 ,,moons ,:5 we get to ! *apt] on ! sun1 we %all f9d curiosities respect+ ! spots !re z well4 ,jupit] has sev5 moons1 & f\r ( ^! are comp>atively l>ge4 ,!y h ! hon\r ( hav+ be5 ! fir/ heav5ly bodies ev] actually discov]$1 = ! six l>ge planets ne>e/ ! sun h be5 kn[n s long t !re is no record ( _! fir/ discov]y1 & ( c\rse our own moon has always be5 kn[n4 ,galileo1 :o inv5t$ ! telescope1 turn$ x on to ! sky 9 #afaj1 :5 our ,k+ ,*>les ,i4 0 on ! ?rone1 & he saw ^! curi\s bodies :i* at fir/ he c\ld n believe to be moons4 ,! f\r :i* he saw v>y 9 size f two ?\s& "o hundr$ miles 9 diamet] to ne>ly ?ree ?\s& six hundr$4 ,y rememb] our own moon is two ?\s& miles across1 s ev5 ! smalle/ is l>g] ?an %e4 ,!y g r\nd at ab\t ! same level z ! planet's ,equator1 & !re=e !y cross "r 9 front ( him1 & g beh9d him once 9 e revolution4 ,s9ce !n ! o!r ?ree h be5 discov]$ 9 ! b& ( ,jupit]'s satellites--"o a small moon clos] to him ?an any ( ! fir/ set1 & two o!rs fur!r out4 ,x 0 by obs]vation ( ! fir/ f\r1 h[ev]1 t v int]e/+ results 7 obta9$4 ,ma!maticians calculat$ ! "t t ^! satellites ought to disappe> beh9d ,jupit] & reappe> aga91 b !y f\nd t ?is did n happ5 exactly at ! "t pr$ict$2 sometimes ! moons disappe>$ soon] ?an !y %\ld h done1 & sometimes lat]4 ,!n ?is 0 discov]$ to h "s relation to ! di/ance ( our e>? f ,jupit]4 ,:5 he 0 at ! f> side ( 8 imm5se orbit he 0 mu* m di/ant f u ?an :5 he 0 on ! ne>] side--9 fact1 ! diff]5ce may am\nt to m ?an ?ree hundr$ millions ( miles4 ,& x occurr$ to "s clev] man t ! irregul>ities 9 "t we notic$ 9 ! eclipses ( ! satellites correspond$ ) ! di/ance ( ,jupit] f u4 ,! fur!r he drew away f u1 ! lat] 7 ! eclipses1 & z he came ne>] !y grew e>li]4 ,by a brilliant inspiration1 ?is 0 attribut$ to ! "t light took to travel f !m to u1 & ?is 0 ! fir/ "t anyone _h be5 able to measure ! velocity or spe$ ( light4 ,= all practical purposes1 on ! e>?'s surface we hold light to be in/antane\s1 & well we may1 = light c\ld travel m ?an eight times r\nd ! _w 9 "o second4 ,x makes "o's bra9 reel to ?9k ( su* a ?+4 ,!n ?9k h[ f> ,jupit] mu/ be away f u at ! fur!/1 :5 y he> t sometimes ^! eclipses 7 delay$ sev5te5 m9utes--m9utes1 n seconds--because x took t "t = light to cross ! gulf to u6 ,illu/ration3 ,,jupit] ,,& ,,8 ,,pr9cipal ,,moons4 ,s\nd is v sl[ comp>$ ) light1 & t is :y1 if y wat* a man hamm]+ at a di/ance1 ! /roke he gives ! nail does n co9cide ) ! bang t rea*es y1 = light gets to y practically at once1 & ! s\nd comes aft] x4 ,no s\nd c travel )\t air1 z we h he>d1 !re=e no s\nd rea*es u across space4 ,if ! moon 7 to bl[ up into a million pieces we %\ld see ! amaz+ spectacle1 b %\ld he> no?+ ( x4 ,light travels ev]y:]e ?r\gh\t ! univ]se1 & by ! use ( ?is univ]sal c>ri] we h le>nt all t we "k ab\t ! />s & planets4 ,:5 ! "t t light takes to travel _h be5 asc]ta9$ by means ( ,jupit]'s satellites1 a /ill m important problem c\ld be solv$--t 0 our own di/ance f ! sun1 :i* be=e _h only be5 kn[n approximately1 & ?is 0 calculat$ to be n9ety-two millions sev5 hundr$ ?\s& miles1 ?\gh sometimes we are a little ne>] & sometimes a little fur!r away4 ,jupit] is m>vell\s1 b beyond him lies ! mo/ wond]ful body 9 ! :ole sol> sy/em4 ,we h f\nd curiosities on our way out3 we h /udi$ ! problem ( ! a/]oids1 ( ! little moon t goes r\nd ,m>s 9 less "t ?an ,m>s himself rotates2 we h consid]$ ! 'great r$ spot' on ,jupit]1 :i* app>5tly moves indep5d5tly ( ! planet2 b no?+ h we f\nd z yet to comp>e ) ! r+s ( ,saturn4 ,may y see ?is amaz+ sight ?r\gh a telescope "o day6 ,look at ! picture ( ?is wond]ful sy/em1 & ?9k :at x w\ld be l if ! e>? 7 surr\nd$ ) simil> r+s6 ,! fir/ "q :i* occurs to all ( u is :at mu/ ! sky look l f ,saturn8 ,:at mu/ x be to look up ov]head & see sev]al great hoops or ar*es ext5d+ f "o horizon to ano!r1 reflect+ light 9 diff]5t degrees ( int5sity8 ,x w\ld be z if we saw sev]al imm5se ra9b[s1 f> l>g] ?an any e>?ly ra9b[1 & ( pure light1 n split into col\rs1 ext5d+ p]man5tly across ! sky1 & n[ & !n brok5 by ! black %ad[ ( ! planet itself z x came betwe5 !m & ! sun4 ,h[ev]1 we mu/ beg9 at ! beg9n+1 & f9d out ab\t ,saturn himself be=e we puzzle ourselves ov] 8 r+s4 ,saturn is n a v great deal less ?an ,jupit]1 ?\gh1 s small are ! o!r planets 9 comp>ison1 t if ,saturn & all ! re/ 7 roll$ toge!r1 !y w\ld n make "o mass s bulky z ,jupit]6 ,saturn is s light--9 o!r words1 8 d5sity is s small--t he is actually light] ?an wat]4 ,he is ! lighte/1 9 comp>ison ) 8 size1 ( any ( ! planets4 ,!re=e he _c be made l>gely ( solid l&1 z our e>? is1 b mu/ be to a great ext5t1 compos$ ( air & gase\s vap\r1 l 8 mighty neighb\r4 ,he approa*es at times z ne> to ,jupit] z ,jupit] does to u1 & on ^! occasions he mu/ pres5t a spl5did spectacle to ,jupit]4 ,he takes no less ?an tw5ty-n9e & a half ( our ye>s to complete 8 /ately m>* ar\nd ! sun1 & 8 axis is a little m b5t ?an ours2 b1 ( c\rse1 at 8 great di/ance f ! sun1 ?is _c h ! same effect on ! seasons t x does ) u4 ,saturn turns fa/ on 8 axis1 b n s fa/ z ,jupit]1 & 9 turn+ 8 face1 or :at we call 8 surface1 pres5ts mu* ! same appe>ance to u t we might expect1 = x *anges v frequ5tly & looks l cl\d belts4 ,! m>vell\s feature ab\t ,saturn is1 ( c\rse1 ! r+s4 ,!re are ?ree ( ^!1 ly+ "o )9 ! o!r1 & sep>at$ by a f9e l9e f ea* o!r4 ,! middle "o is mu* ! broade/1 probably ab\t t5 ?\s& miles 9 wid?1 & ! inn] "o1 :i* is ! d>ke/1 0 n discov]$ until "s "t aft] ! o!rs4 ,z ! planet sw+s 9 8 orbit ! r+s naturally appe> v diff]5t to u at diff]5t times4 ,sometimes we c only see !m edgewise1 & !n ev5 9 ! l>ge/ telescope !y are only l a /reak ( light1 & ?is %[s t !y _c be m ?an fifty or sixty miles 9 ?ickness4 ,! "o :i* is ne>e/ to ,saturn's surface does n approa* him )9 t5 ?\s& miles4 ,saturn has no less ?an t5 satellites1 9 addition to ! r+s1 s t 8 midnight sky mu/ pres5t a magnific5t spectacle4 ,! r+s1 :i* d n %9e by _! own light b by reflect$ sunlight1 are solid en\gh to ?r[ a %ad[ on ! body ( ! planet1 & !mselves receive 8 %ad[4 ,sometimes = days toge!r a l>ge "p ( ,saturn mu/ suff] eclipse b5ea? ! encircl+ r+s1 b at o!r times1 at night1 :5 ! r+s are cle> ( ! planet's body1 s t ! light is n cut (f f !m1 !y mu/ appe> z radiant ar*es ( glory spann+ ! sky4 ,! subject ( ^! r+s is s complicat$ by ! v>iety ( _! *anges t x is difficult = u ev5 to ?9k ab\t x4 ,x is "o ( ! mo/ m>vell\s ( all ! features ( our planet>y sy/em4 ,:at are ^! r+s8 :at are !y made (8 ,x has be5 positively prov$ t !y _c be made ( cont9u\s matt]1 ei!r liquid or solid1 = ! =ce ( gravity act+ on !m f ! planet w\ld te> !m to pieces4 ,:at1 !n1 c !y be8 ,x is n[ pretty g5]ally believ$ t !y are compos$ ( multitudes ( t9y bodies1 ea* sep>ate1 & circl+ sep>ately r\nd ! great planet1 z ! a/]oids circle r\nd ! sun4 ,z ea* "o is deta*$ f its neighb\r & obeys its own impulses1 !re is none ( ! /ra9 & wr5* !re w\ld be 7 !y all connect$4 ,accord+ to ! laws :i* gov]n planet>y bodies1 ^? :i* are ne>e/ to ! planet w travel m quickly ?an ^? :i* are fur!r away4 ,( c\rse1 z we look at !m f s great a di/ance1 & z !y are mov+1 !y appe> to u to be cont9u\s4 ,x is conjectur$ t ! comp>ative d>kness ( ! inside r+ is caus$ by ! fact t !re are few] ( ! bodies !re to reflect ! sunlight4 ,!n1 9 addition to ! r+s1 en\gh !mselves to di/+ui% him f all o!r planets1 !re are ! t5 moons ( ri*ly-end[$ ,saturn to be consid]$4 ,x is difficult to ga!r mu* ab\t ^! moons1 on acc\nt ( our great di/ance f !m4 ,! l>ge/ is probably twice ! diamet] ( our own moon4 ,"o ( !m seems to be mu* bright]--t is to say1 ( high] reflect+ p[]--on "o side ?an ! o!r1 & by di/+ui%+ ! sides & wat*+ c>efully1 a/ronom]s h come to ! conclusion t x pres5ts always ! same face to ,saturn 9 ! same way z our own moon does to u2 9 fact1 !re is reason to ?9k t all ! moons ( l>ge planets d ?is4 ,illu/ration3 ,,! ,,planet ,,saturn ,,) ,,two ,,( ,,8 ,,moons4 ,all ! moons lie outside ! r+s1 & "s at a v great di/ance f ,saturn1 s t !y c only appe> small z se5 f him4 ,yet at ! wor/ !y mu/ be bright] ?an ord9>y />s1 & add greatly to ! v>iations 9 ! sky sc5]y ( ?is beautiful planet4 ,9 connection ) ,saturn's moons !re is ano!r ( ^? a/oni%+ facts t are cont9ually cropp+ up to rem9d u t1 h[ev] mu* we "k1 !re is su* a va/ deal ( :i* we are /ill ignorant4 ,s f> 9 deal+ ) all ! planets & moons 9 ! sol> sy/em we h made no rem>k on ! way !y rotate or revolve1 because !y all g 9 ! same direction1 & t direction is call$ c\nt]-clockwise1 :i* means t if y /& fac+ a clock & turn y\r h& sl[ly r\nd ! opposite direction to t 9 :i* ! h&s g1 y w be turn+ x 9 ! same way t ! e>? rotates on its axis & revolves 9 its orbit4 ,x is1 p]haps1 j z well to give "h a ^w ( caution4 ,rotat+ ( c\rse means a planet's turn+ on its own axis1 revolv+ means its c\rse 9 its orbit r\nd ! sun4 ,m]cury1 ,v5us1 ,e>?1 ,m>s1 ,jupit]1 & all _! moons1 z well z ,saturn himself1 rotate on _! axes 9 ?is "o direction--c\nt]-clockwise--& revolve 9 ! same direction z !y rotate4 ,ev5 ! que] little moon ( ,m>s1 :i* runs r\nd him quick] ?an he rotates1 obeys ?is same rule4 ,n9e ( ,saturn's moons foll[ ?is example1 b "o indep5d5t little "o1 :i* has be5 nam$ ,phoebe1 & is f> out f ! planet1 actually revolves 9 ! opposite way4 ,we _c see h[ x rotates1 b if1 z we said j n[1 x turns ! same face always to ,saturn1 !n ( c\rse x rotates ! wrong way too4 ,a !ory has be5 sugge/$ to acc\nt = ?is curi\s fact1 b x c\ld n be made intelligible to anyone :o has n /udi$ r high ma!matics1 s !re we mu/ j leave x1 & put x 9 ! cab9et ( curiosities we h already collect$ on our way out to ,saturn4 ,= ages pa/ m5 h kn[n & wat*$ ! planets ly+ )9 ! orbit ( ,saturn1 & !y _h made up _! m9ds t ?is 0 ! limit ( our sy/em4 ,b 9 #agha a great a/ronom] nam$ ,h]s*el 0 wat*+ ! heav5s ?r\gh a telescope :5 he notic$ "o /range object t he 0 c]ta9 0 no />4 ,! va/ di/ance ( ! />s prev5ts _! hav+ any def9ite outl9e1 or :at is call$ a disc4 ,! rays d>t out f !m 9 all directions & !re is no 'edge' to !m1 b 9 ! case ( ! planets x is possible to see a disc ) a telescope1 & ?is object :i* attract$ ,h]s*el's att5tion _h c]ta9ly a disc4 ,he did n imag9e he _h discov]$ a new planet1 because at t "t ! a/]oids _h n be5 f\nd1 & no "o ?\ght t !re c\ld be any m planets4 ,yet ,h]s*el knew t ?is 0 n a />1 s he call$ x a comet6 ,he 0 actually ! fir/ :o discov]$ x1 = he knew x 0 n a fix$ />1 b x 0 aft] 8 ann\ncem5t ( ?is fact t "s "o else1 obs]v+ x c>efully1 f\nd x to be a real planet ) an orbit ly+ outside t ( ,saturn1 !n ! fur!/ b\nd>y ( ! sol> sy/em4 ,h]s*el sugge/$ call+ x ,georgius ,sidus1 9 hon\r ( ,george ,,iii41 !n ,k+2 b luckily ?is pond]\s "n 0 n adopt$1 & z ! o!r planets _h be5 call$ aft] ! ,olympian deities1 & ,uranus 0 ! fa!r ( ,saturn1 x 0 call$ ,uranus4 ,x 0 subsequ5tly f\nd t ?is new planet _h already be5 obs]v$ by o!r a/ronom]s & catalogu$ z a /> no less ?an sev5te5 times1 b until ,h]s*el's cle> sight _h detect$ ! diff]5ce betwe5 x & ! fix$ />s no "o _h paid any att5tion to x4 ,uranus is v f> away f ! sun1 & c only sometimes be se5 z a small /> by p :o "k exactly :]e to look = him4 ,9 fact1 8 di/ance f ! sun is n9ete5 times t ( ! e>?4 ,yet to %[ at all he mu/ be ( great size1 & t size has actually be5 f\nd out by ! mo/ delicate exp]im5ts4 ,if we g back to our =m] comp>ison1 we %all rememb] t if ! e>? 7 l a gre5gage plum1 !n ,uranus w\ld be 9 comp>ison ab\t ! size ( "o ( ^? col\r$ balloons *ildr5 play )2 !re=e he is mu* l>g] ?an ! e>?4 ,9 ?is f> di/ant orbit ! huge planet takes eighty-f\r ( our ye>s to complete "o ( 8 own4 ,a man on ! e>? w h gr[n f babyhood to boyhood1 f boyhood to ! prime ( life1 & liv$ long] ?an mo/ m51 :ile ,uranus has only once circl$ 9 8 pa?4 ,b 9 deal+ ) ,uranus we come to ano!r ( ^? />tl+ problems ( :i* a/ronomy is full4 ,s f> we h dealt ) planets :i* are m or less upright1 :i* rotate ) a rotation l t ( a top4 ,n[ take a top & lay x on "o side on ! table1 ) "o ( its poles po9t+ t[>d ! great lamp we us$ = ! sun & ! o!r po9t+ away4 ,t is ! way ,uranus gets r\nd 8 pa?1 on 8 side6 ,he rotates ! wrong way r\nd comp>$ ) ! planets we h already spok5 (1 b he revolves ! same way r\nd ! sun t all ! o!rs d4 ,x seems wond]ful t ev5 s mu* c be f\nd out ab\t a body s f> f u1 b we "k m3 we h discov]$ t ,uranus is made ( light] mat]ial ?an ! e>?2 8 d5sity is less4 ,h[ c t be kn[n8 ,well1 y rememb] e body attracts e o!r body 9 proportion to ! atoms x conta9s4 ,if1 !re=e1 !re 7 any bodies ne> to ,uranus1 x c\ld be calculat$ by 8 influ5ce on !m :at 0 8 own mass1 :i*1 z y rememb]1 is ! ^w we use to express :at w\ld be weight 7 x at ! e>?'s surface2 & f> away z ,uranus is1 ! bodies f :i* su* calculations may be made h be5 discov]$1 = he has no less ?an f\r satellites1 or moons4 ,consid]+ n[ ! peculi> position ( ! planet1 we might expect to f9d ^! moons revolv+ 9 a v diff]5t way f o!rs1 & ?is is inde$ ! case4 ,!y turn r\nd ! planet at ab\t its ,equator--t is to say1 if y hold ! top repres5t+ ,uranus z 0 sugge/$ j n[1 ^! moons w\ld g above & bel[ ! planet 9 pass+ r\nd x4 ,only we mu/ rememb] !re is really no su* ?+ z above & bel[ absolutely4 ,we :o are on "o side ( ! _w po9t up to ! sky & d[n to ! e>?1 :ile ! p on ! o!r side ( ! e>?1 say at ,new ,zeal&1 also po9t up to ! sky & d[n to ! e>?1 b _! po9t+s are directly ! opposite ( ours4 ,s :5 we speak ( moons go+ above & bel[ t is only because1 = ! mom5t1 we are repres5t+ ,uranus z a top we hold 9 our h&s1 & s we speak ( above & bel[ z !y are to u4 ,x 0 ,h]s*el :o discov]$ ^! satellites1 z well z ! planet1 & = ^! great a*ievem5ts he occupies "o ( ! gr&e/ places 9 ! rle ( names ( :i* ,engl& is pr\d4 ,b he did mu* m ?an ?is3 8 improvem5ts 9 ! con/ruction ( telescopes1 & 8 devotion to a/ronomy 9 _m o!r ways1 w\ld h caus$ him to be rememb]$ )\t any?+ else4 ,( ,uranus's satellites "o1 ! ne>e/1 goes r\nd 9 ab\t two & a half days1 & ! "o t is fur!/ away takes ab\t ?irte5 & a half days1 s bo? h a %ort] p]iod ?an our moon4 ,! discov]y ( ,uranus fill$ ! :ole civiliz$ _w ) wond]4 ,! a/ronom]s :o _h se5 him1 b miss$ f9d+ out t he 0 a planet1 mu/ h felt bitt]ly mortifi$1 & :5 he 0 discov]$ he 0 obs]v$ ) ! utmo/ accuracy & c>e4 ,! calculations made to det]m9e 8 pa? 9 ! sky 7 ! easi] because he _h be5 not$ z a /> 9 sev]al catalogues previ\sly1 s t 8 position = "s "t pa/ 0 kn[n4 ,ev]ybody :o work$ at a/ronomy began to obs]ve him4 ,f ^! facts ma!maticians set to "w1 &1 by ab/ruse calculations1 work$ out exactly ! orbit 9 :i* he ought to move2 !n 8 movem5ts 7 aga9 wat*$1 & behold he foll[$ ! pa? pr$ict$ = him2 b !re 0 a small diff]5ce "h & !re3 he did n foll[ x exactly4 ,n[1 9 ! heav5s !re is a reason = ev]y?+1 ?\gh we may n always be clev] en\gh to f9d x out1 & x 0 easily guess$ t x 0 n by accid5t t ,uranus did n precisely foll[ ! pa? calculat$ = him4 ,! planets all act & react on "o ano!r1 z we "k1 accord+ to _! mass & _! di/ance1 & 9 ! calculations ! pull ( ,jupit] on ,saturn & ( ,saturn on ,uranus 7 kn[n & all[$ =4 ,b ,uranus 0 pull$ by "s unse5 influ5ce also4 ,a "y ,engli%man nam$ ,adams1 by "s ab/ruse & difficult ma!matical "w f> beyond ! p[] ( ord9>y bra9s1 f\nd out n only ! fact t !re mu/ be ano!r planet ne>ly z l>ge z ,uranus 9 an orbit outside 81 b actually pr$ict$ :]e su* a planet might be se5 if anyone w\ld look = x4 ,he gave 8 results to a pr(essor ( a/ronomy at ,cambridge4 ,n[1 x seems an easy ?+ to say to anyone1 ',look out = a planet 9 su* & su* a "p ( ! sky1' b 9 reality1 :5 ! telescope is turn$ to t "p ( ! sky1 />s are se5 9 su* numb]s t1 )\t v c>eful comp>ison ) a /> *>t1 x is impossible to say :i* are fix$ />s & :i*1 if any1 is an intrud]4 ,!re happ5$ to be no /> *>t ( ?is k9d = ! p>ticul> "p ( ! sky want$1 & ?us a long "t elaps$ & ! planet 0 n id5tifi$4 ,meantime a "y ,fr5*man nam$ ,lev]ri] _h also tak5 up ! same inve/igation1 &1 )\t kn[+ any?+ ( ,adams' "w1 _h come to ! same conclusion4 ,he s5t 8 results to ! ,b]l9 ,obs]vatory1 :]e a /> *>t su* z 0 want$ 0 actually j be+ made4 ,by ! use ( ?is ! ,b]l9 a/ronom]s at once id5tifi$ ?is new memb] ( our sy/em1 & ann\nc$ to ! a/oni%$ _w t ano!r l>ge planet1 mak+ eight altoge!r1 _h be5 discov]$4 ,!n ! ,engli% a/ronom]s rememb]$ t !y too held 9 _! h&s ! means = mak+ ?is wond]ful discov]y1 b1 by hav+ all[$ s mu* "t to elapse1 !y _h let ! hon\r g to ,france4 ,h[ev]1 ! names ( ,adams & ,lev]ri] w always be c\pl$ toge!r z ! discov]]s ( ! new planet1 :i* 0 call$ ,neptune4 ,! m>vel is t by pure reason+ ! m9d ( man c\ld h a*iev$ su* results4 ,if ! obs]vation ( ,uranus is difficult1 h[ mu* m t ( ,neptune1 :i* is /ill fur!r plung$ 9 space6 ,yet by pati5ce a few facts h be5 glean$ ab\t him4 ,he is n v diff]5t 9 size f ,uranus4 ,he also is ( v slight d5sity4 ,8 ye> includes "o hundr$ & sixty-five ( ours1 s t s9ce 8 discov]y 9 #ahdf he has only _h "t to get r\nd less ?an a ?ird ( 8 pa?4 ,8 axis is ev5 m tilt$ ov] ?an t ( ,uranus1 s t if we comp>e ,uranus to a top held horizontally1 ,neptune w be l a top ) "o end po9t+ d[nw>ds4 ,he rotates 9 ?is extraord9>y position1 9 ! same mann] z ,uranus--namely1 ! o!r way ov] f all ! o!r planets1 b he revolves1 z !y all d1 c\nt]-clockwise4 ,se5 f ,neptune ! sun c only appe> ab\t z l>ge z ,v5us appe>s to u at h] be/1 & ! light & heat receiv$ are b "o n9e-hundre? "p ( :at he s5ds u4 ,yet s brilliant is sun%9e t ev5 !n ! light t falls on ,neptune mu/ be v consid]able1 mu* m ?an t :i* we receive f ,v5us1 = ! sun itself gl[s1 & f ,v5us ! light is only reflect$4 ,! sun1 small z x mu/ appe>1 w %9e ) ! radiance ( a gl[+ electric light4 ,to get "s idea ( ! brilliance ( sunlight1 sit ne> a scre5 ( leaves on "s sunny day :5 ! sun is high ov]head1 & note ! int5se radiance ( ev5 ! t9y rays :i* %9e ?r\gh ! small holes 9 ! leaves4 ,! sc9tillat+ light is m glori\s ?an any diamond1 %oot+ out col\r$ rays 9 all directions4 ,a small sun ! app>5t size ( ,v5us w\ld1 !re=e1 give en\gh light = practical purposes to su* a _w z ,neptune1 ev5 ?\gh to u a _w s illum9at$ w\ld seem to be condemn$ to a p]petual twilight4 ,,*apt] ,,vii ,,! ,,sun ,s f> we h ref]r$ to ! sun j s mu* z 0 necess>y to %[ ! planets rotat+ r\nd him1 & to ackn[l$ge him z ! s\rce ( all our light & heat2 b we h n exam9$ 9 detail ?is m>vell\s furnace t n\ri%es all ! life on our planet & burns on ) undim9i%$ spl5d\r f ye> to ye>1 )\t ?\ght or ef=t on our "p4 ,to su/a9 a fire on ! e>? mu* "t & c>e & exp5se are necess>y2 fuel has to be con/antly suppli$1 & m5 h to /oke ! fire to keep x burn+4 ,consid]+ t ! sun is n only va/ly l>g] ?an all ! fires on ! e>? put toge!r1 b also ?an ! e>? itself1 ! "q v naturally occurs to u1 ,:o supplies ! fuel1 & :o does ! /ok+ on ! sun8 ,be=e we answ] ?is we mu/ try to get "s idea ( ! size ( ?is /up5d\s body4 ,x is n ! lea/ use attempt+ to und]/& x by pla9 figures1 = ! figures w\ld be too great to make any impression on u--!y w\ld be practically mean+less2 we mu/ turn to "s o!r me?od4 ,suppose1 = in/ance1 t ! sun 7 a holl[ ball2 !n1 if ! e>? 7 set at ! c5tre1 ! moon c\ld revolve r\nd h] at ! same di/ance %e is n[1 & !re w\ld be z great a di/ance betwe5 ! moon & ! %ell ( ! sun z !re is betwe5 ! moon & ! e>?4 ,?is gives u a little idea ( ! size ( ! sun4 ,aga91 if we g back to t sol> sy/em 9 :i* we repres5t$ ! planets by v>i\s objects f a pea to a football1 & set a lamp 9 ! c5tre to d duty = ! sun1 :at size d y suppose t lamp w\ld h to be really to repres5t ! sun 9 proportion to ! planets8 ,well1 if our gre5gage plum :i* did duty = ! e>? 7 ab\t ?ree-qu>t]s ( an in* 9 diamet] we %\ld want a lamp ) a flame z tall z ! talle/ man y "k1 & ev5 !n x w\ld n give a correct idea unless y imag9$ t man ext5d+ 8 arms widely1 & y drew r\nd him a circle & fill$ 9 all ! circle ) flame6 ,if ?is glori\s flame burnt cle> & fair & bright1 radiat+ beams ( light all ar\nd1 ! little gre5gage plum w\ld n h to be too ne>1 or x w\ld be %rivell$ up z 9 ! bla/ ( a furnace4 ,to place x at any?+ resembl+ ! di/ance x is f ! sun 9 reality y w\ld h to walk away f ! flam+ light = ab\t ?ree hundr$ /eps1 & set x d[n !re2 !n1 aft] hav+ done all ?is1 y w\ld h "s little idea ( ! relative sizes ( ! sun & ! e>?1 & ( ! di/ance betwe5 !m4 ,( c\rse1 all ! o!r planets w\ld h to be at correspond+ di/ances4 ,on ?is same scale1 ,neptune1 ! fur!/ out1 w\ld be ?ree miles f our artificial sun6 ,x seems prepo/]\s to ?9k t "s specks s small z to be q invisible1 specks t crawl ab\t on t plum1 h d>$ to weigh & measure ! gigantic sun2 b yet !y h done x1 & !y h ev5 decid$ :at he is made (4 ,! result ( ! exp]im5ts is t we "k ! sun to be a ball ( gl[+ gas at a temp]ature s high t no?+ we h on e>? c\ld ev5 comp>e ) x4 ,( 8 radiat+ beams ext5d+ 9 all directions few inde$ fall on our little plum1 b ^? t d are ! s\rce ( all life1 :e!r animal or vegetable4 ,if ! sun's rays 7 cut (f f u1 we %\ld die at once4 ,ev5 ! coal we use to keep u w>m is b sun's heat /or$ up ages ago1 :5 ! luxuriant tropical vegetation sprang up 9 ! w>m? & !n fell d[n & 0 buri$ 9 ! e>?4 ,at night we are /ill enjoy+ ! b5efit ( ! sun's rays--t is1 ( ^? :i* are reta9$ by our atmosph]e2 = if none rema9$ ev5 ! v air itself w\ld freeze1 & by ! next morn+ n "o inhabitant w\ld be left alive to tell ! awful tale4 ,yet all ?is life & gr[? & heat we receive on ! :ole e>? is b "o "p 9 two ?\s& two hundr$ millions ( p>ts t g out 9 all directions into space4 ,x has be5 calculat$ t ! heat :i* falls on to all ! planets toge!r _c be m ?an "o "p 9 "o hundr$ millions & ! o!r millions ( p>ts seem to u to be simply wa/$4 ,= untold ages ! sun has be5 p\r+ out ?is prodigal pr(usion ( glory1 & z we "k t ?is _c g on )\t "s sort ( comp5sation1 we want to und]/& :at keeps up ! fires 9 ! sun4 ,x is true t ! sun is s enorm\s t he might g on burn+ = a v long "t )\t burn+ "r away2 b1 !n1 ev5 if he is huge1 8 exp5diture is also huge4 ,if he _h be5 made ( solid coal he w\ld h be5 all us$ up 9 ab\t six ?\s& ye>s1 burn+ at ! pace he does4 ,n[1 we "k t ! anci5t ,egyptians kept c>eful note ( ! heav5ly bodies1 & if ! sun 7 really burn+ away he mu/ h be5 v mu* l>g] 9 _! "t2 b we h no record ( ?is2 on ! contr>y1 all records ( ! sun ev5 to five ?\s& ye>s ago %[ t he 0 mu* ! same z at pres5t4 ,x is evid5t t we mu/ se>* else:]e = an explanation4 ,x has be5 sugge/$ t 8 furnace is suppli$ by ! numb] ( meteors t fall into him4 ,meteors are small bodies ( ! same mat]ials z ! planets1 & may be lik5$ to ! du/ ( ! sol> sy/em4 ,x is n difficult to calculate ! am\nt ( matt] he w\ld require on ?is assumption to keep him go+1 & ! am\nt requir$ is s great z to make x practically impossible t ?is is ! s\rce ( 8 supply4 ,we h se5 t all matt] influ5ces all o!r matt]1 & ! quantity ( meteoric /uff t w\ld be requir$ to support ! sun's exp5diture w\ld be en\gh to h a s]i\s effect on ,m]cury1 an effect t w\ld c]ta9ly h be5 notic$4 ,!re c1 !re=e1 be no su* mass ( matt] ne> ! sun1 & ?\gh !re is no d\bt a c]ta9 numb] ( meteors d fall into 8 furnaces day by day1 x is n ne>ly en\gh to acc\nt = 8 cont9u\s radiation4 ,x seems aft] ?is z if no?+ else c\ld be sugge/$2 b yet an answ] has be5 f\nd1 an answ] s wond]ful t x is m l a fairy tale ?an reality4 ,to beg9 at ! beg9n+1 we mu/ g back to ! "t :5 ! sun 0 only a great gase\s nebula fill+ all ! space includ$ 9 ! orbit ( ,neptune4 ,?is nebula 0 n 9 itself hot1 b z x rotat$ x contract$4 ,n[1 heat is really only a =m ( en]gy1 & en]gy & heat c be int]*ang$ easily4 ,?is is a v />tl+ ?+ :5 he>d = ! fir/ "t1 b x is kn[n z surely z we "k any?+ & has be5 prov$ aga9 & aga94 ,:5 a savage wants to make a fire he turns a piece ( h>d wood v v quickly betwe5 8 palms--twiddles x1 we %\ld say expressively--into a hole 9 ano!r piece ( wood1 until a sp>k bur/s out4 ,:at is ! sp>k8 ,x is ! en]gy ( ! savage's "w turn$ to heat4 ,:5 a horse /rikes 8 iron-%od ho(s h>d on ! pavem5t y see sp>ks fly2 t is caus$ by ! en]gy ( ! horse's leg4 ,:5 y pump h>d at y\r bicycle y feel y\r pump gett+ q hot1 = "p ( ! en]gy y are putt+ into y\r "w is trans=m$ into heat2 & s on 9 numb]less in/ances4 ,no en]getic action ( any k9d 9 ?is _w takes place )\t "s ( ! en]gy be+ turn$ into heat1 ?\gh 9 _m in/ances ! am\nt is s small z to be unnoticeable4 ,no?+ falls to ! gr\nd )\t "s heat be+ g5]at$4 ,n[1 :5 ?is great nebula fir/ began its rem>kable c>e]1 by ! action ( gravity all ! p>ticles 9 x 7 drawn t[>d ! c5tre2 little by little !y fell 91 & ! nebula became small]4 ,we are n n[ conc]n$ ) ! orig9 ( ! planets--we leave t aside2 we are only contemplat+ ! "p ( ! nebula :i* rema9$ to become ! sun4 ,n[ ^! p>ticles be+ drawn inw>d ea* g5]at$ "s heat1 s z ! nebula contract$ its temp]ature rose4 ,?r\gh\t ! ages1 ov] ! space ( millions & millions ( miles1 x contract$ & grew hott]4 ,x /ill rema9$ gase\s1 b at la/ x got to an imm5se temp]ature1 & is ! sun z we "k x4 ,:at !n keeps x %9+8 ,x is /ill contract+1 b sl[ly1 s sl[ly t x is q imp]ceptible to our f9e/ in/rum5ts4 ,x has be5 calculat$ t if x contracts two hundr$ & fifty feet 9 diamet] 9 a ye>1 ! en]gy ?us ga9$ & turn$ into heat is q suffici5t to acc\nt = its :ole ye>ly output4 ,?is is inde$ m>vell\s4 ,9 comp>ison ) ! sun's size two hundr$ & fifty feet is no?+4 ,x w\ld take n9e ?\s& ye>s at ?is rate be=e any dim9ution c\ld be notic$ by our f9e/ in/rum5ts6 ,"h is a s\rce ( heat :i* c cont9ue = c\ntless ages )\t exhau/ion4 ,?us to all int5ts & purposes we may say ! sun's %9+ is inexhau/ible4 ,yet we mu/ foll[ out ! tra9 ( reason+1 & see :at w happ5 9 ! end1 9 eras & eras ( "t1 if no?+ int]v5es4 ,well1 "s gase\s bodies are f> f9] & m t5u\s ?an o!rs1 & :5 a gase\s body contracts x is all ! "t gett+ d5s]2 z x gr[s d5s] & d5s] x at la/ becomes liquid1 & !n solid1 & !n x ceases to contract1 z ( c\rse ! p>ticles ( a solid body _c fall freely t[>d ! c5tre1 z ^? ( a gase\s body c4 ,our e>? has long ago rea*$ ?is /age4 ,:5 solid ! action ceases1 & ! heat is no m kept up by ?is s\rce ( en]gy1 !re=e ! body beg9s to cool--surface fir/1 & la/ly ! int]ior2 x cools m quickly ! small] x is4 ,our moon has p>t$ ) all h] heat long ago1 :ile ! e>? /ill reta9s "s int]nally4 ,9 ! sun1 !re=e1 we h an object-lesson ( ! /ages ?r\gh :i* all ! planets mu/ h pass$4 ,!y h all once be5 gl[+ hot1 & "s may be /ill hot ev5 on ! surface1 z we h se5 !re is reason to believe is ! case ) ,jupit]4 ,by ?is m>vell\s arrangem5t = ! cont9u$ heat ( ! sun we c see t ! w>m? ( our planets is assur$ = untold ages4 ,!re is no ne$ to fe> t ! sun w we> out by burn+4 ,8 brightness w cont9ue = ages beyond ! ?\ghts ( man4 ,besides ?is1 a few o!r ?+s h be5 discov]$ ab\t him4 ,he is1 ( c\rse1 exceptionally difficult to obs]ve2 = ?\gh he is s l>ge1 :i* %\ld make x easy1 he is s brilliant t anyone reg>d+ him ?r\gh a telescope )\t ! precaution ( prep>$ glasses to keep (f a great "p ( ! light w\ld be bl9d$ at once4 ,"o mo/ rem>kable fact ab\t ! sun is t 8 surface is fleck$ ) spots1 :i* appe> sometimes 9 great] numb]s & sometimes 9 less1 & ! reason & %ape ( ^! spots h greatly ex]cis$ m5's m9ds4 ,sometimes !y are l>ge en\gh to be se5 )\t a telescope at all1 m]ely by look+ ?r\gh a piece ( smok$ or col\r$ glass1 :i* cuts (f ! mo/ ov]p[]+ rays4 ,:5 !y are visible l ?is !y are enorm\s1 l>ge en\gh to swall[ _m e>?s 9 _! dep?s4 ,at o!r times !y may be obs]v$ by ! telescope1 !n !y may be ab\t five ?\s& miles across4 ,sometimes "o spot c be foll[$ by an a/ronom] z x passes all across ! sun1 disappe>s at ! edge1 & aft] a lapse ( "t comes back aga9 r\nd ! o!r edge4 ,?is fir/ %[$ m5 t ! sun1 l all ! planets1 rotat$ on 8 axis1 & gave !m ! means ( f9d+ out h[ long he took 9 do+ s4 ,b ! spots %[$ a mo/ surpris+ result1 = !y took slightly diff]5t times 9 mak+ _! j\rney r\nd ! sun1 times :i* diff]$ accord+ to _! position4 ,= in/ance1 a spot ne> ! equator ( ! sun took tw5ty-five days to make ! circuit1 :ile "o high] up or l[] d[n took tw5ty-six days1 & "o fur!r out tw5ty-sev52 s t if ^! spots are1 z c]ta9ly believ$1 actually on ! surface1 ! conclusion is t ! sun does n rotate all 9 "o piece1 b t "s p>ts g fa/] ?an o!rs4 ,no "o c really expla9 h[ ?is c\ld be1 b x is c]ta9ly m easily und]/ood 9 ! case ( a body ( gas ?an ( a solid body1 :5 x w\ld be simply impossible to conceive4 ,! spots seem to keep pr9cipally a little nor? & a little s\? ( ! equator2 !re are v few actually at x1 & none f\nd ne> ! poles1 b no reason = ?is di/ribution has be5 discov]$4 ,x has be5 not$ t ab\t e elev5 ye>s ! greate/ numb] ( spots appe>s1 & t !y become few] aga91 m\nt+ up 9 numb] to ! next elev5 ye>s1 & s on4 ,all ^! curi\s facts %[ !re is mu* yet to be solv$ ab\t ! sun4 ,! spots 7 suppos$ = long to be eruptions bur/+ up above ! surface1 b n[ !y are g5]ally held to be deep depressions l sauc]s1 probably caus$ by viol5t tempe/s1 & x is ?\ght t ! inru% ( cool] matt] f above makes !m look d>k] ?an ! o!r p>ts ( ! sun's surface4 ,b :5 we use ! words 'cool]' & 'd>k]1' we mean only by comp>ison1 = 9 reality ! d>k p>ts ( ! spots are bright] ?an electric light4 ,illu/ration3 ,royal ,obs]vatory1 ,gre5wi*4 ,,sun-,,spots4 ,! fact t ! spots are 9 reality depressions or holes is %[n by _! *ange ( appe>ance z !y pass ov] ! face ( ! sun t[>d ! edge2 = ! *ange ( %ape is exactly t :i* w\ld be caus$ by =e%ort5+4 ,x s\nds odd to say t ! be/ "t = obs]v+ ! sun is dur+ a total eclipse1 = !n ! sun's body is hidd5 by ! moon4 ,b yet to a c]ta9 ext5t ?is is true1 & ! reason is t ! sun's own brilliance is our greate/ h9drance 9 obs]v+ him1 8 rays are s dazzl+ t !y light up our own atmosph]e1 :i* prev5ts u see+ ! edges4 ,n[1 dur+ a total eclipse1 :5 ne>ly all ! rays are cut (f1 we c see m>vell\s ?+s1 :i* are invisible at o!r times4 ,b total eclipses are few & f> betwe51 & s :5 "o is approa*+ a/ronom]s make great prep>ations be=eh&4 ,a total eclipse is n visible f all p>ts ( ! _w1 b only f t small "p on :i* ! %ad[ ( ! moon falls1 & z ! e>? travels1 ?is %ad[1 :i* is really a r\nd spot1 passes along1 mak+ a d>k b&4 ,9 ?is b& a/ronom]s *oose ! be/ obs]vatories1 & !re !y take up _! /ations4 ,! d>k body ( ! moon fir/ appe>s to cut a little piece out ( ! side ( ! sun1 & z x sails on1 gradually blott+ out m & m1 eag] telescopes foll[ x2 at la/ x cov]s up ! :ole sun1 & !n a m>vell\s spectacle appe>s1 = all r\nd ! edges ( ! black moon are se5 glori\s r$ /ream]s & ar*es & filam5ts ( m>vell\s %apes1 cont9ually *ang+4 ,^! are ?r[n aga9/ a backgr\nd ( pale gre5 light t surr\nds ! black moon & ! hidd5 sun4 ,9 e>ly days a/ronom]s ?\ght ^! wond]ful col\r$ /ream]s belong$ to ! moon2 b x 0 soon prov$ t !y really are "p ( ! sun1 & are only invisible at ord9>y times1 because our atmosph]e is too bright to all[ !m to be se54 ,an in/rum5t has n[ be5 inv5t$ to cut (f mo/ ( ! light ( ! sun1 & :5 ?is is atta*$ to a telescope ^! prom95ces1 z !y are call$1 c be se5 at any "t1 s t !re is no ne$ to wait = an eclipse4 ,illu/ration3 ,,! ,,e>? ,,z ,,x ,,w\ld ,,appe> ,,9 ,,comp>ison ,,) ,,! ,,flames ,,%oot+ ,,out ,,f ,,! ,,sun4 ,:at are ^! m>vell\s /ream]s & filam5ts8 ,!y are :at !y seem1 eruptions ( fi]y matt] dis*>g$ f ! ev]-palpitat+ sun ?\s&s ( miles into surr\nd+ space4 ,!y are = ev] %oot+ out & bur/+ & fall+ back1 fireworks on a scale too enorm\s = u to conceive4 ,"s ( ^! brilliant flames ext5d = ?ree hundr$ ?\s& miles1 s t 9 comp>ison ) "o ( !m ! :ole _w w\ld be b a t9y ball1 & ?is is go+ on day & night )\t cessation4 ,look at ! picture :]e ! arti/ has made a little black ball to repres5t ! e>? z %e w\ld appe> if %e c\ld be se5 9 ! mid/ ( ! flames %oot+ out f ! sun4 ,d n make a mi/ake & ?9k ! e>? really c\ld be 9 ?is position2 %e is only %[n !re s t y may see h[ t9y %e is 9 comp>ison ) ! sun4 ,all ! "t y h liv$ & y\r fa!r1 & gr&fa!r1 & "r back to ! beg9n+s ( ,engli% hi/ory1 & f>1 f> fur!r into ! dim ages1 ?is /up5d\s exhibition ( en]gy & p[] has cont9u$1 & only ( late ye>s has anyone kn[n any?+ ab\t x2 ev5 n[ a m]e h&ful ( p d "k1 & ! re/1 :o are w>m$ & f$ & kept alive by ! graci\s beams ( ?is great revolv+ gl[+ fireball1 nev] give x a ?\ght4 ,i said j n[ a pale gre5 halo surr\nd$ ! sun1 ext5d+ f> beyond ! prom95ces2 ?is is call$ ! corona & c only be se5 dur+ an eclipse4 ,x surr\nds ! sun 9 a k9d ( %ell1 & !re is reason to believe t x too is made ( lum9\s /uff eject$ by ! sun 9 its burn+ fury4 ,x is compos$ ( l>ge /ream]s or filam5ts1 :i* seem to %oot out 9 all directions2 g5]ally ^! are n mu* l>g] ?an ! app>5t wid? ( ! sun1 b sometimes !y ext5d mu* fur!r4 ,! puzzle is1 ?is corona _c be an atmosph]e 9 any way resembl+ t ( our e>?2 = ! gravitational =ce ( ! sun1 ow+ to its enorm\s size1 is s great t x w\ld make any su* atmosph]e cl+ to x mu* m d5sely ne> to ! surface1 :ile x w\ld be ?9n] high] up1 & ! corona is n d5se 9 any way1 b ?9 & t5u\s ?r\gh\t4 ,?is makes x v difficult to expla92 x is suppos$ t "s k9d ( electrical =ce ent]s into ! problem1 b :at x is exactly we are f> f kn[+ yet4 ,,*apt] ,,viii ,,%9+ ,,visitors ,our sol> sy/em is set by itself 9 ! mid/ ( a great space1 & s f> z we h le>nt ab\t x 9 ?is book ev]y?+ 9 x seems ord]ly3 ! planets g r\nd ! sun & ! satellites g r\nd ! planets1 9 orbits m or less regul>2 !re seems no place = any?+ else4 ,b :5 we h consid]$ ! planets & ! satellites1 we h n exhau/$ all ! bodies :i* own allegiance to ! sun4 ,!re is ano!r class1 made up ( /range & weird memb]s1 :i* fla% 9 & out ( ! sy/em1 com+ & go+ 9 all directions & at all times--sometimes appe>+ )\t w>n+1 sometimes return+ ) a c]ta9 regul>ity1 sometimes retir+ to inf9ite dep?s ( space1 :]e no human eye w ev] see !m m4 ,^! /range visitors are call$ comets1 & are ( all %apes & sizes & nev] twice alike4 ,ev5 z we wat* !m !y gr[ & *ange1 & !n dim9i% 9 spl5d\r4 ,"s are s va/ t m5 see !m z flam+ signs 9 ! sky1 & reg>d !m ) awe & wond]2 "s _c be se5 at all )\t ! help ( ! telescope4 ,f ! v e>lie/ ages ^? t 7 l>ge en\gh to be se5 )\t glasses h be5 reg>d$ ) a/oni%m5t4 ,m5 us$ to ?9k t !y 7 signs f heav5 =etell+ great ev5ts 9 ! _w4 ,timid p pr$ict$ t ! end ( ! _w w\ld come by collision ) "o ( !m4 ,o!rs1 aga91 fancifully lik5$ !m to fi%es 9 t sea ( space 9 :i* we swim--fi%es gigantic & t]rify+1 end[$ ) s5se & w4 ,x is p]haps unnecess>y to say t comets are no m alive ?an is our own e>?1 & z = caus+ ! end ( ! _w by collision1 !re is e reason to believe ! e>? has be5 m ?an once "r ?r\gh a comet's tail1 & yet no "o except sci5tific m5 ev5 discov]$ x4 ,^! my/]i\s visitors f ! out] regions ( space 7 call$ comets f a ,greek ^w signify+ hair1 = !y (t5 leave a long lum9\s trail beh9d1 :i* resembles ! filam5ts ( a woman's hair4 ,x is n (t5 t "o appe>s l>ge & bright en\gh to be se5 by ! nak$ eye1 & :5 x does x is n likely to be soon =gott54 ,9 ! ye> #aiaj su* a comet is expect$1 a comet :i* at its =m] appe>ance compell$ univ]sal att5tion by its brilliancy & /rang5ess4 ,at ! "t ( ! ,norman ,conque/ ( ,engl& a comet believ$ to be ! v same "o 0 /ret*+ its glori\s tail half across ! sky1 & ! ,normans see+ x1 took x z a good om51 fancy+ t x =etold _! success4 ,! hi/ory ( ! ,norman ,conque/ 0 work$ 9 tape/ry--t is to say1 9 :at we %\ld call crewels on a /rip ( l95--& 9 ?is record ! comet duly appe>s4 ,look at him 9 ! picture z ! ,normans fanci$ him4 ,he has a r$ head ) blue flames />t+ f x1 & sev]al tails4 ,! little gr\p ( m5 on ! left are po9t+ & *att]+ ab\t him4 ,we c judge :at an impression ?is comet mu/ h made to be record$ 9 su* an important piece ( "w4 ,illu/ration3 ,,! ,,comet ,,9 ,,! ,,bayeux ,,tape/ry4 ,b we are gett+ on too fa/4 ,we h yet to le>n h[ anyone c "k t ! comet :i* appe>$ at ! "t ( ! ,norman ,conque/ is ! same z t :i* has come back aga9 at diff]5t times1 & above all1 h[ anyone c tell t x w come aga9 9 ! ye> #aiaj4 ,all ?is involves a long /ory4 ,be=e ! inv5tion ( telescopes ( c\rse only ^? comets c\ld be se5 :i* 7 ( great size & f9e appe>ance4 ,9 ^? days m5 did n realize t our _w 0 b "o ( a numb] & ( no great importance except to ourselves1 & !y always took ^! blaz+ appe>ances 9 ! heav5s z a p>ticul> w>n+ to ! human race4 ,b :5 a/ronom]s1 by ! aid ( ! telescope1 f\nd t = "o comet se5 by ! eye !re 7 hundr$s :i* no mortal eye unaid$ c\ld see1 ?is idea seem$1 to say ! lea/ ( x1 unlikely4 ,yet ev5 !n comets 7 look$ ^u z caprici\s visitors f out] space2 odd creatures drawn into our sy/em by ! attraction ( ! sun1 :o disappe>$1 nev] to return4 ,x 0 ,newton1 ! same g5ius :o disclos$ to u ! laws ( gravity1 :o fir/ decl>$ t comets mov$ 9 orbits1 only t ^! orbits 7 f> m erratic ?an any ( ^? foll[$ by ! planets4 ,s f> we h suppos$ t ! planets 7 all on :at we %\ld call a level--t is to say1 we h reg>d$ !m z if !y 7 float+ 9 a sea ( wat] ar\nd ! sun2 b ?is is only approximately correct1 = ! orbits ( ! planets are n all at "o level4 ,if y _h a numb] ( sl5d] hoops or r+s to repres5t ! planet>y orbits1 y w\ld h to tilt "o a little ?is way & ano!r a little t way1 only nev] s f> b t a l9e ?r\gh ! c5tre ( ! hoop f "o side to ano!r c\ld pass ?r\gh ! sun4 ,! way 9 :i* ! planet>y orbits are tilt$ is slight 9 comp>ison ) t ( ! orbits ( comets1 = ^! are at all sorts ( angles--"s turn$ almo/ sideways1 & o!rs slant+1 & all ( !m are ellipses long drawn out & mu* m irregul> ?an ! planet>y orbits2 b erratic z !y are1 9 e case a l9e drawn ?r\gh ! sun & ext5d$ bo? ways w\ld t\* ea* side ( ! orbits4 ,a great a/ronom] call$ ,halley1 :o 0 born 9 ! "t ( ! ,commonweal?1 0 lucky en\gh to see a v brilliant comet1 & ! sight int]e/$ him s mu* t he made all ! calculations necess>y to f9d out j 9 :at direction x 0 travell+ 9 ! heav5s4 ,he f\nd out t x foll[$ an ellipse :i* br\ght x v ne> to ! sun at "o "p ( its j\rney1 & c>ri$ x f> beyond ! orbit ( ! e>?1 "r out to t ( ,neptune1 at ! o!r4 ,!n he began to se>* ! records = o!r comets :i* _h be5 obs]v$ be=e 8 "t4 ,he f\nd t two p>ticul>ly bright ones _h be5 c>efully not$--"o ab\t sev5ty-five ye>s be=e t :i* he _h se51 & ! o!r sev5ty-five ye>s be=e t aga94 ,bo? ^! comets _h be5 wat*$ s sci5tifically t ! pa?s 9 :i* !y _h travell$ c\ld be comput$4 ,a brilliant inspiration came to ,halley4 ,he believ$ t in/ead ( ^! ?ree1 8 own & ! o!r two1 be+ diff]5t comets1 !y 7 ! same "o1 :i* return$ to ! sun ab\t e sev5ty-five ye>s4 ,?is c\ld be prov$1 = if ?is idea 7 correct1 ( c\rse ! comet w\ld return aga9 9 ano!r sev5ty-five ye>s1 unless some?+ un=ese5 occurr$4 ,b ,halley 0 9 ! prime ( life3 he c\ld n hope to live to see 8 =eca/ v]ifi$4 ,! only ?+ he c\ld d 0 to note d[n exact p>ticul>s1 by means ( :i* o!rs :o liv$ aft] him might recognize 8 comet4 ,& s :5 ! "t came = its return1 ?\gh ,halley 0 9 8 grave1 numb]s ( a/ronom]s 7 wat*+ eag]ly to see ! fulfilm5t ( 8 pr$iction4 ,! comet did inde$ appe>1 & s9ce !n x has be5 se5 once aga91 & n[ we expect x to come back 9 ! ye> #aiaj1 :5 y & ,i may see x = ourselves4 ,:5 ! id5tity ( ! comet 0 fully e/abli%$ m5 began to se>* fur!r back /ill1 to comp>e ! records ( o!r previ\s brilliant comets1 & f\nd t ?is "o _h be5 notic$ _m times be=e1 & once z ,i said1 at ! "t ( ! ,norman ,conque/4 ,halley's comet is peculi> 9 _m ways4 ,= in/ance1 x is unusual t s l>ge & int]e/+ a comet %\ld return )9 a comp>atively limit$ "t4 ,x is ! small] comets1 ^? t c only be se5 telescopically1 t usually run 9 small orbits4 ,! smalle/ orbits take ab\t ?ree & a half ye>s to trav]se1 & "s ( ! l>ge/ orbits kn[n require a p]iod ( "o hundr$ & t5 ?\s& ye>s4 ,betwe5 ^! two limits lies e possible v>iety ( p]iod4 ,"o comet1 se5 ab\t ! "t ,napoleon 0 born1 0 calculat$ to take two ?\s& ye>s to complete its j\rney1 & ano!r1 a v brilliant "o se5 9 #ahhb1 mu/ j\rney = eight hundr$ ye>s be=e x aga9 comes ne> to ! sun4 ,b we nev] "k :at might happ51 = at any mom5t a comet :i* has trav]s$ a long solit>y pa?way 9 out] d>kness may fla% sudd5ly into our k51 & be = ! fir/ "t not$ & record$1 be=e fly+ (f at an angle :i* mu/ take x = ev] fur!r & fur!r f ! sun4 ,ev]y?+ connect$ ) comets is my/]i\s & mo/ fasc9at+4 ,f out ( ! icy regions ( space a body appe>s2 :at x is we "k n1 b x is se5 at fir/ z a hairy or s(tly-gl[+ />1 & x 0 ?us t ,h]s*el mi/ook ,uranus = a comet :5 he fir/ discov]$ x4 ,z x draws ne>] ! comet s5ds out "s fan-l projections t[>d ! sun1 enclos+ its nucleus 9 filmy wrapp+s l a cocoon ( light1 & x travels fa/] & fa/]4 ,f its head %oots out a tail--x may be m ?an "o--gr[+ 9 spl5d\r & wid?1 & always po9t+ away f ! sun4 ,s enorm\s are "s ( ^! tails t :5 ! comet's head is close to ! sun ! tail ext5ds f> beyond ! orbit ( ! e>?4 ,fa/] /ill & fa/] flies ! comet1 = z we h se5 x is a consequ5ce ( ! law ( gravitation t ! ne>] planets are to ! sun ! fa/] !y move 9 _! orbits1 & ! same rule applies to comets too4 ,z ! comet da%es up to ! sun 8 pace becomes some?+ indescribable2 x has be5 reckon$ = "s comets at ?ree hundr$ miles a second6 ,b behold1 z ! head flies r\nd ! sun ! tail is always project$ outw>ds4 ,! nucleus or head may be s ne> to ! sun t ! heat x receives w\ld be suffici5t to r$uce molt5 iron to vap\r2 b ?is does n seem to affect x3 only ! tail exp&s4 ,sometimes x becomes two or m tails1 & z x sweeps r\nd beh9d ! head x has to cov] a mu* great] space 9 ! same "t1 & !re=e x mu/ travel ev5 fa/] ?an ! head4 ,! pace is su* t no calculations c acc\nt = x1 if ! tail is compos$ ( matt] 9 any s5se z we "k x4 ,!n :5 ! sun is pass$ ! comet s9ks away aga91 & z x goes ! tail dies d[n & f9ally disappe>s4 ,! comet itself dw9dles to a hairy /> once m & goes--:i!r8 ,into space s remote t we _c ev5 dream ( x--f> away into cold m appall+ ?an any?+ we c\ld measure1 ! cold ( absolute space4 ,m & m sl[ly x travels1 always away & away1 until ! sun1 a %ort "t back a huge furnace cov]+ all ! sky1 is n[ b a fa9t />4 ,?us on its lonely j\rney unse5 & unkn[n ! comet goes4 ,?is comet :i* we h tak5 z an illu/ration is a typical "o1 b all are n ! same4 ,"s h no tails at all1 & nev] develop any2 "s *ange utt]ly ev5 z !y are wat*$4 ,! same comet is s diff]5t at diff]5t times t ! only possible way ( id5tify+ x is by kn[+ its pa?1 & ev5 ?is is n a c]ta9 me?od1 = "s comets appe> to travel at int]vals along ! same pa?6 ,n[ we come to ! "q t mu/ h be5 9 ! m9d ( ev]yone f ! beg9n+ ( ?is *apt]1 ,:at are comets8 ,?is "q no "o c answ] def9itely1 = !re are _m ?+s s puzzl+ ab\t ^! /range appe>ances t x is difficult ev5 to sugge/ an explanation4 ,yet a good deal is kn[n4 ,9 ! fir/ place1 we are c]ta9 t comets h v little d5sity--t is to say1 !y are indescribably ?91 ?9n] ?an ! ?9ne/ k9d ( gas2 & air1 :i* we always ?9k s ?91 w\ld be almo/ l a blanket comp>$ ) ! mat]ial ( comets4 ,?is we judge because !y ex]cise no sort ( influ5ce on any ( ! planet>y bodies !y draw ne> to1 :i* !y c]ta9ly w\ld d if !y 7 made ( any k9d ( solid matt]4 ,!y come sometimes v close to "s ( ! planets4 ,a comet 0 s ne> to ,jupit] t x 0 actually 9 among 8 moons4 ,! comet 0 viol5tly agitat$2 he 0 pull$ 9 fact "r out ( 8 old pa?1 & has be5 go+ on a new "o ev] s9ce2 b he did n ex]cise ! smalle/ effect on ,jupit]1 or ev5 on ! moons4 ,&1 z ,i said e>li] 9 ?is *apt]1 we on ! e>? h be5 actually 9 ! folds ( a comet's tail4 ,?is a/oni%+ fact happ5$ 9 ,june1 #ahfa4 ,"o ev5+ aft] ! sun _h set a gold5-yell[ disc1 surr\nd$ ) filmy wrapp+s1 appe>$ 9 ! sky4 ,! sun's light1 diffus$ ?r\gh\t our atmosph]e1 _h prev5t$ its be+ se5 soon]4 ,?is 0 app>5tly ! comet's head4 ,x is describ$ z '?\gh a numb] ( light1 hazy cl\ds 7 float+ ar\nd a m9iature full moon4' ,f ?is a cone ( light ext5d$ f> up into ! sky1 & :5 ! head disappe>$ bel[ ! horizon ?is tail 0 se5 to rea* to ! z5i?4 ,b t 0 n all4 ,/range %afts ( light seem$ to hang "r ov]head1 & c\ld only be acc\nt$ = by suppos+ t !y 7 caus$ by ano!r tail hang+ /raight above u1 s t we look$ up at x =e%ort5$ by p]spective4 ,! comet's head lay betwe5 ! e>? & ! sun1 & its tail1 :i* ext5d$ ov] _m millions ( miles1 /ret*$ out beh9d 9 su* a way t ! e>? mu/ h gone "r ?r\gh x4 ,! fact t ! comet ex]cis$ no p]ceptible influ5ce on ! e>? at all1 & t !re 7 n ev5 any unacc\ntable magnetic /orms or displays ( electricity1 may reassure u s t if ev] we d aga9 come 9 contact ) "o ( ^! extremely f9e1 ?9 bodies1 we ne$ n be afraid4 ,!re is ano!r way 9 :i* we c judge ( ! wond]ful t5uity or ?9ness ( comets--t is1 t ! smalle/ />s c be se5 ?r\gh _! tails1 ev5 ?\gh ^? tails mu/ be _m ?\s&s ( miles 9 ?ickness4 ,n[1 if ! tails 7 any?+ approa*+ ! d5sity ( our own atmosph]e1 ! />s :5 se5 ?r\gh !m w\ld appe> to be mov$ out ( _! places4 ,?is s\nds odd1 & requires a ^w ( explanation4 ,! fact is t any?+ se5 ?r\gh any transp>5t m$ium l wat] or air is :at is call$ refract$--t is to say1 ! rays com+ f x look b5t4 ,ev]yone is q famili> ) ?is 9 ev]yday life1 ?\gh p]haps !y may n h notic$ x4 ,y _c ?ru/ a /ick into ! wat] )\t see+ t x looks crook$4 ,air be+ less d5se ?an wat] has n q s /rong a refract+ p[]1 b /ill x has "s4 ,we _c prove x 9 j ! same way1 because we are all inside ! atmosph]e ourselves1 & !re is no possibility ( ?ru/+ a /ick into x f ! outside6 ,! only way we "k x is by look+ at some?+ :i* is 'outside' already1 & we f9d pl5ty ( objects 9 ! sky4 ,z a matt] ( fact1 ! />s are all a little pull$ out ( _! places by be+ se5 ?r\gh ! air1 & ?\gh ( c\rse we d n notice ?is1 a/ronom]s "k x & h to make all[ance = x4 ,! effect is mo/ noticeable 9 ! case ( ! sun :5 he is go+ d[n1 = ! atmosph]e b5ds 8 rays up1 & ?\gh we see him a great gl[+ r$ ball on ! horizon1 & wat* him1 z we ?9k1 drop gradually out ( sight1 we are really look+ at him = ! la/ mom5t or two :5 he has already gone1 = ! rays are b5t up by ! air & 8 image l+]s :5 ! real sun has disappe>$4 ,illu/ration3 ,a ,,/ick ,,?ru/ ,,into ,,! ,,wat] ,,appe>s ,,crook$4 ,!re=e 9 look+ ?r\gh ! lum9\s /uff t =ms a comet's tail a/ronom]s might well expect to see ! />s displac$1 b n a sign ( ?is appe>s4 ,x is difficult to imag9e1 !re=e1 :at ! tail c be made (4 ,! idea is t ! sun ex]cises a sort ( repulsive effect on c]ta9 elem5ts f\nd 9 ! comet's head--t is to say1 x pu%es !m away1 & t z ! head approa*es ! sun1 ^! elem5ts are driv5 out ( x away f ! sun 9 vap\r4 ,?is action may h some?+ to d ) electricity1 :i* is yet little und]/ood2 anyway1 ! effect is t1 in/ead ( attract+ ! matt] t[>d itself1 9 :i* case we %\ld see ! comet's tails /ret*+ t[>d ! sun1 ! sun drives x away6 ,9 ! *apt] on ! sun we _h to imag9e some?+ ( ! same k9d to acc\nt = ! corona1 & ! corona & ! comet's tails may be really ak9 to ea* o!r1 & c\ld p]haps be expla9$ 9 ! same way4 ,n[ we come to a /rang] fact /ill4 ,"s comets g "r ?r\gh ! sun's corona1 & yet d n seem to be influ5c$ by x 9 ! smalle/ degree4 ,?is may n seem v wond]ful at fir/ p]haps1 b if y rememb] t a da% ?r\gh any?+ s d5se z our atmosph]e1 at a pace mu* less ?an t at :i* a comet goes1 is en\gh to heat iron to a :ite heat1 & !n make x fly (f 9 vap\r1 we get a glimpse ( ! extreme f95ess ( ! mat]ials :i* make ! corona4 ,"h is ,h]s*el's acc\nt ( a comet t w5t v ne> ! sun3 ',! comet's di/ance f ! sun's c5tre 0 ab\t ! #afj? "p ( our di/ance f x4 ,all ! heat we enjoy on ?is e>? comes f ! sun4 ,imag9e ! heat we %\ld h to endure if ! sun 7 to approa* u1 or we ! sun1 to "o #afj? "p ( its pres5t di/ance4 ,x w\ld n be m]ely z if #afj suns 7 %9+ on u all at once1 b1 #afj times #afj1 accord+ to a rule :i* is well kn[n to all :o are conv]sant ) su* matt]s4 ,n[1 t is #be1fjj4 ,only imag9e a gl>e #be1fjj times fi]c] ?an t ( ! equatorial sun%9e at noon day ) ! sun v]tical4 ,9 su* a heat !re is no sub/ance we "k ( :i* w\ld n run l wat]1 boil1 & be conv]t$ into smoke or vap\r4 ,no wond] ! comet gave evid5ce ( viol5t excitem5t1 com+ f ! cold region outside ! planet>y sy/em torpid & ice-b\nd4 ,already :5 arriv$ ev5 9 our temp]ate region x began to %[ signs ( int]nal activity2 ! head _h begun to develop1 & ! tail to elongate1 till ! comet 0 = a "t lo/ sight (--n = days aft]w>ds 0 x se52 & its tail1 ^: direction 0 rev]s$1 & :i* c\ld n possibly be ! same tail x _h be=e1 _h already l5g!n$ to an ext5t ( ab\t n9ety millions ( miles1 s t x mu/ h be5 %ot out ) imm5se =ce 9 a direction away f ! sun4' ,we rememb] t comets h sometimes m ?an "o tail1 & a !ory has be5 advanc$ to acc\nt = ?is too4 ,x is suppos$ t p]haps diff]5t elem5ts are ?ru/ away by ! sun at diff]5t angles1 & "o tail may be due to "o elem5t & ano!r to ano!r4 ,b if ! comet goes on tail-mak+ to a l>ge ext5t e "t x returns to ! sun1 :at happ5s ev5tually8 ,d ! tails fall back aga9 into ! head :5 out ( rea* ( ! sun's action8 ,su* an idea is inconceivable2 b if n1 !n e "t a comet approa*es ! sun he loses some?+1 & t some?+ is made up ( ! elem5ts :i* 7 =m]ly 9 ! head & h be5 viol5tly eject$4 ,if ?is be s we may well expect to see comets :i* h return$ _m times to ! sun )\t tails at all1 = all ! tail-mak+ /uff t 0 9 ! head w h be5 us$ up1 & z ?is is exactly :at we d see1 ! !ory is probably true4 ,:]e d ! comets come f8 ,t also is a v l>ge "q4 ,x us$ to be suppos$ !y 7 m]ely w&]]s 9 space :o happ5$ to h be5 attract$ by our sun & drawn into 8 sy/em1 b !re are facts :i* g v /rongly aga9/ ?is1 & a/ronom]s n[ g5]ally believe t comets really belong to ! sol> sy/em1 t _! prop] orbits are ellipses1 & t 9 ! case ( ^? :i* fly (f at su* an angle t !y c nev] return !y mu/ at "s "t h be5 pull$ out ( _! orig9al orbit by ! influ5ce ( "o ( ! planets4 ,illu/ration3 ,royal ,obs]vatory1 ,cape ( ,good ,hope4 ,a ,,great ,,comet4 ,to get a good idea ( a really f9e comet1 until we h ! opportunity ( see+ "o = ourselves1 we _c d bett] ?an look at ?is picture ( a comet photograph$ 9 #aija at ! ,cape ( ,good ,hope4 ,x is only comp>atively rec5tly t photography has be5 appli$ to comets4 ,:5 ,halley's comet appe>$ la/ "t su* a ?+ 0 n ?\ght (1 b :5 he comes aga9 numb]s ( cam]as1 fitt$ up ) all ! late/ sci5tific appliances1 w be wait+ to get good impressions ( him4 ,,*apt] ,,ix ,,%oot+ ,,/>s ,,& ,,fi]y ,,balls ,all ! sub/ances :i* we are accu/om$ to see & h&le 9 our daily lives belong to our _w4 ,!re are vegetables :i* gr[ 9 ! e>?1 m9]als :i* are dug out ( x1 & elem5t>y ?+s1 su* z air & wat]1 :i* h always made up a "p ( ?is planet s9ce man knew x4 ,^! are obvi\s1 b !re are o!r ?+s n q s obvi\s :i* also help to =m our _w4 ,among ^! we may class all ! elem5ts kn[n to *emi/s1 _m ( :i* h difficult names1 su* z oxyg5 & hydrog54 ,^! two are ! elem5ts :i* make up wat]1 & oxyg5 is an important elem5t 9 air1 :i* has nitrog5 9 x too4 ,!re are numb]s & numb]s ( o!r elem5ts p]fectly famili> to *emi/s1 ( :i* _m p nev] ev5 he> ! names4 ,we live 9 ! mid/ ( ^! ?+s1 & we take !m = grant$ & pay little att5tion to !m2 b :5 we beg9 to le>n ab\t o!r worlds we at once want to "k if ^! sub/ances & elem5ts :i* ent] s l>gely into our daily lives are to be f\nd else:]e 9 ! univ]se or are q peculi> to our own _w4 ,?is "q might be answ]$ 9 sev]al ways1 b "o ( ! mo/ practical te/s w\ld be if we c\ld get hold ( some?+ :i* _h n be5 always on ! e>?1 b _h fall5 ^u x f space4 ,!n1 if ?is body 7 made up ( elem5ts correspond+ ) ^? we f9d "h1 we might judge t ^! elem5ts are v g5]ally diffus$ ?r\gh\t ! bodies 9 ! sol> sy/em4 ,x s\nds 9 ! highe/ degree improbable t any?+ %\ld come hurl+ ?r\gh ! air & alight on our little planet1 :i* we "k is a m]e speck 9 a great ocean ( space2 b we mu/ n =get t ! p[] ( gravity increases ! *ances greatly1 = any?+ com+ )9 a c]ta9 range ( ! e>?1 any?+ small en\gh1 t is1 & n travell+ at too great a pace1 is b\nd to fall on to x4 ,&1 h[ev] improbable x seems1 x is und\bt$ly true t masses ( matt] d cra% d[n ^u ! e>? f "t to "t1 & ^! are call$ meteorites4 ,:5 we ?9k ( ! great expanse ( ! oceans1 ( ! ice r\nd ! poles1 & ( ! des]t wa/es1 we "k t = e "o ( su* bodies se5 to fall _m m mu/ h fall5 unse5 by any human be+4 ,meteors l>ge en\gh to rea* ! e>? are n v frequ5t1 :i* is p]haps z well1 & z yet !re is no record ( anyone's hav+ be5 kill$ by !m4 ,mo/ ( !m consi/ ( masses ( /one1 & a few are ( iron1 :ile v>i\s sub/ances resembl+ ^? t we "k "h h be5 f\nd 9 !m4 ,*emi/s 9 analyz+ !m h also come across c]ta9 elem5ts s f> unkn[n ^u e>?1 ?\gh ( c\rse !re is no say+ t ^! may n exi/ at dep?s to :i* man has n p5etrat$4 ,a really l>ge meteor is a gr& sight4 ,if x is se5 at night x appe>s z a r$ />1 gr[+ rapidly bigg] & leav+ a trail ( lum9\s vap\r beh9d z x passes across ! sky4 ,9 ! daytime ?is vap\r looks l a cl\d4 ,z ! meteor hurls itself along !re may be a deep cont9u\s ro>1 end+ 9 "o supreme explosion1 or p]haps 9 sev]al explosions1 & f9ally ! meteor may come to ! e>? 9 "o mass1 ) a =ce s great t x buries itself "s feet deep 9 ! soil1 or x may bur/ into numb]s ( t9y fragm5ts1 :i* are scatt]$ ov] a l>ge area4 ,:5 a meteor is f\nd soon aft] its fall x is v hot1 & all its surface has 'run1' hav+ be5 fus$ by heat4 ,! heat is caus$ by ! friction ( our atmosph]e4 ,! meteor gets entangl$ 9 ! atmosph]e1 &1 be+ drawn by ! attraction ( ! e>?1 da%es ?r\gh x4 ,"p ( ! en]gy ( its motion is turn$ to heat1 :i* gr[s great] & great] z ! d5s] air ne>] to ! e>? is enc\nt]$2 s t 9 "t all ! surface ( ! meteor runs l liquid1 & ?is liquid1 ris+ to a /ill high] temp]ature1 is bl[n (f 9 vap\r1 leav+ a new surface expos$4 ,! vap\r makes ! trail ( fire or cl\d se5 to foll[ ! meteor4 ,if ! process w5t on = long ! meteor w\ld be all dissipat$ 9 vap\r1 & 9 any case x mu/ rea* ! e>? consid]ably r$uc$ 9 size4 ,numb]s & numb]s ( comp>atively small ones disappe>1 & = e "o t manages to come to e>? !re mu/ be hundr$s se5 only z %oot+ />s1 :i* vani% & 'leave n a wrack beh9d4' ,:5 a meteor is se5 to fall x is trac$1 &1 :5ev] possible1 x is f\nd & plac$ 9 a museum4 ,m5 h sometimes come across l>ge masses ( /one & iron ) _! surfaces fus$ ) heat4 ,^! are 9 e way l ! recogniz$ meteorites1 except t no eye has not$ _! adv5t4 ,z !re c be no reasonable d\bt t !y are ( ! same orig9 z ! o!rs1 !y too are collect$ & plac$ 9 museums1 & 9 any l>ge museum y w\ld be able to see bo? k9ds--^? :i* h be5 se5 to come to e>? & ^? :i* h be5 f\nd accid5tally4 ,! meteors :i* appe> v brilliant 9 _! c\rse across ! sky are sometimes call$ fire-balls1 :i* is only ano!r "n = ! same ?+4 ,"s ( ^! are bright] ?an ! full moon1 s bright t !y cause objects on e>? to ca/ a %ad[4 ,9 #ahjc a fi]y ball 0 notic$ above a small t[n 9 ,norm&y2 x bur/ & scatt]$ /ones f> & wide1 b luckily no "o 0 hurt4 ,! l>ge/ meteorites t h be5 f\nd on ! e>? are a ton or m 9 weight2 o!rs are m]e /ones2 & o!rs aga9 j du/ t floats ab\t 9 ! atmosph]e be=e g5tly settl+4 ,( c\rse1 meteors ( ?is la/ k9d c\ld n be se5 to fall l ! l>g] ones1 yet !y d fall 9 su* numb]s t calculations h be5 made %[+ t ! e>? mu/ cat* ab\t a hundr$ millions ( meteors daily1 hav+ altoge!r a total weight ( ab\t a hundr$ tons4 ,?is s\nds enorm\s1 b comp>$ ) ! weight ( ! e>? x is v small inde$4 ,n[ t we h arriv$ at ! fact t /range bodies d come hurtl+ d[n ^u u out ( space1 & t we c actually h&le & exam9e !m1 ! next "q is1 ,:]e d !y come f8 ,at "o "t x 0 ?\ght t !y 7 fragm5ts :i* _h be5 flung (f by ! e>? h]self :5 %e 0 subject to viol5t explosions1 & t !y _h be5 ?r[n f> en\gh to resi/ ! impulse to drop d[n ^u h] aga91 & _h be5 circl+ r\nd ! sun ev] s9ce1 until ! e>? came 9 contact ) !m aga9 & !y _h fall5 back ^u h]4 ,x is n difficult to imag9e a =ce :i* w\ld be p[]ful en\gh to a*ieve ! feat ( spe$+ some?+ (f at su* a velocity t x pass$ beyond ! e>?'s p[] to pull x back1 b no?+ t we h on e>? w\ld be ne>ly /rong en\gh to a*ieve su* a feat4 ,imag9ative writ]s h pictur$ a projectile hurl$ f a cannon's m\? ) su* trem5d\s =ce t x n only pass$ beyond ! range ( ! e>?'s p[] to pull x back1 b s t x fell )9 ! influ5ce ( ! moon & 0 precipitat$ on to h] surface6 ,su* ?+s mu/ rema9 a*ievem5ts 9 imag9ation only2 x is n possible = !m to be c>ri$ out4 ,o!r ideas z to ! orig9 ( meteors 7 t !y _h be5 expell$ f ! moon or f ! sun4 ,x w\ld ne$ a mu* less =ce to s5d a projectile away f ! moon ?an f ! e>? on acc\nt ( its small] size & less d5sity1 b ! di/ance f ! e>? to ! moon is n v great1 & any projectile hurl$ =? f ! moon w\ld cross x 9 a comp>atively %ort "t4 ,!re=e if ! meteorites come f ! moon1 ! moon mu/ be expell+ !m /ill1 & we might expect to see "s evid5ce ( x2 b we "k t ! moon is a dead _w1 s ?is explanation is n possible4 ,! sun1 = its "p1 is torn by su* gigantic di/urbances t1 not)/&+ its va/ size1 !re is no d\bt suffici5t =ce !re to s5d meteors ev5 s f> z ! e>?1 b ! *ances ( _! enc\nt]+ ! e>? w\ld be small4 ,bo? ^! !ories are n[ disc>d$4 ,x is believ$ t ! meteors are m]ely less] fragm5ts ( ! same k9d ( mat]ials z ! planets1 circl+ indep5d5tly r\nd ! sun2 & a pro( ( ?is is t f> m meteorites fall on t "p ( ! e>? :i* is fac+ =w>d 9 its j\rney ?an on t beh9d1 & ?is is :at we %\ld expect if ! meteors 7 scatt]$ indep5d5tly ?r\gh space & x 0 by reason ( our movem5ts t we came 9 contact ) !m4 ,!re is no ne$ to expla9 ?is fur!r4 ,ev]yone kn[s t 9 cycl+ or driv+ along a road :]e !re is a good deal ( traffic bo? ways ! p we meet are m 9 numb] ?an ^? :o ov]take u1 & ! same result w\ld foll[ ) ! meteors2 t is to say1 9 travell+ ?r\gh space :]e !y 7 fairly ev5ly di/ribut$ we %\ld meet m ?an we %\ld be ov]tak5 by4 ,y rememb] t x 0 sugge/$ ! sun's fuel might be obta9$ f meteors1 & ?is 0 prov$ to be n possible1 ev5 ?\gh !re are no d\bt unkn[n millions ( ^! /range bodies circl+ ?r\gh\t ! sol> sy/em4 ,!re are s _m names = ^! fla%+ bodies t we may get a little confus$3 :5 !y are se5 9 ! sky !y are meteors1 or fire-balls2 :5 !y rea* ! e>? !y are call$ meteorites1 & also a]olites4 ,!n !re is ano!r class ( ! same bodies call$ %oot+ />s1 & ^! are 9 reality only meteors on a small] scale2 b !re ought to be no confusion 9 our ?\ghts1 = all ^! objects are small bodies travell+ r\nd ! sun1 & caught by ! e>?'s influ5ce4 ,:5 y wat* ! sky = "s "t on a cle> night1 y w seldom fail to see at lea/ "o /> fla% out sudd5ly 9 a pa? ( ?rill+ light & disappe>1 & y _c be c]ta9 :e!r t /> _h be5 %9+ 9 ! sky a m9ute be=e1 or if x _h appe>$ sudd5ly only 9 ord] to g out4 ,! la/ idea is "r4 ,we mu/ get rid at once ( ! notion t x w\ld be possible = any fix$ /> to behave 9 ?is mann]4 ,to beg9 )1 ! fix$ />s are _m ( !m actually travell+ at a great velocity at pres5t1 yet s immeasurably di/ant are !y t _! movem5t makes no p]ceptible diff]5ce to u4 ,= "o ( !m to appe> to da% across ! heav5s z a meteor does w\ld mean a velocity entirely unkn[n to u1 ev5 comp>+ x ) ! spe$ ( light4 ,no1 ^! %oot+ />s are n />s at all1 ?\gh !y 7 s nam$1 long be=e ! real motions ( ! fix$ />s 7 ev5 dimly guess$ at4 ,z we h se51 !y belong to ! same class z meteors4 ,i rememb] be+ told by a cl]gyman1 ye>s ago1 t "o night 9 ,novemb] he _h gone up to b$ v late1 & z he pull$ up 8 bl9d to look at ! sky1 to 8 amazem5t he saw a p]fect hail ( %oot+ />s1 "s appe>+ e m9ute1 & all d>t+ 9 vivid trails ( light1 long] or %ort]1 ?\gh all seem$ to come f "o po9t4 ,s m>vell\s 0 ! sight t he da%$ across ! village /reet1 unlock$ ! *ur* door1 & himself pull$ ! bell ) all 8 might4 ,! p 9 t quiet c\ntry village _h long be5 9 b$1 b !y huddl$ on _! clo!s & ran out ( _! pretty ?at*$ cottages1 ?9k+ !re mu/ be a great fire1 & :5 !y saw ! wond] 9 ! sky !y 7 amaz$ & cri$ out t ! _w mu/ be com+ to an end4 ,! cl]gyman knew bett] ?an t1 & 0 able to reassure !m1 & tell !m he _h only tak5 ! mo/ effectual means ( wak+ !m s t !y might n miss ! display1 = he 0 sure z long z !y liv$ !y w\ld nev] see su* ano!r sight4 ,a /> %[] ( ?is k9d is c]ta9ly well wor? gett+ up to see1 b ?\gh uncommon x is n unique4 ,!re are _m records ( su* %[]s hav+ occurr$ 9 times gone by1 & :5 m5 put toge!r & exam9$ ! records !y f\nd t ! %[]s came at regul> int]vals4 ,= in/ance1 e ye> ab\t ! same "t 9 ,novemb] !re is a /> %[]1 n comp>able1 x is true1 ) ! brilliant "o ! cl]gyman saw1 b /ill noticeable1 = m %oot+ />s are se5 !n ?an at o!r times1 & once 9 e ?irty-?ree ye>s !re is a specially f9e "o4 ,x happ5$ 9 fact to be "o ( ^! t ! village p 7 wak5$ up to see4 ,n all at once1 b gradually1 ! my/]y ( ^! %[] displays 0 solv$4 ,x 0 realiz$ t ! meteors ne$ n necess>ily come f "o fix$ place 9 ! sky because !y seem$ to u to d s1 = t 0 only an effect ( p]spective4 ,if y 7 look+ d[n a long1 p]fectly /raight av5ue ( tree-trunks1 ! av5ue w\ld seem to close 91 to get n>r[] & n>r[] at ! f> end until x became a po9t2 b x w\ld n really d s1 = y w\ld "k t ! trees at ! f> end 7 j ! same di/ance f ea* o!r z ^? betwe5 :i* y 7 /&+4 ,n[1 two meteors />t+ f ! same direction at a di/ance f ea* o!r1 & keep+ p>allel1 w\ld seem to u to />t f a po9t & to op5 out wid] & wid] z !y approa*$1 b !y w\ld n really d s2 x w\ld only be1 z 9 ! case ( ! av5ue1 an effect ( p]spective4 ,if a great _m meteors did ! same ?+1 !y w\ld appe> to u all to />t f "o po9t1 :]eas really !y w\ld be on p>allel l9es1 only z !y ru%$ to meet u or we ru%$ to meet !m ?is effect w\ld be produc$4 ,!re=e ! fir/ discov]y 0 t ^! meteors 7 ?\s&s & ?\s&s ( little bodies travell+ 9 l9es p>allel to ea* o!r1 l a sw>m ( little planets4 ,to judge t _! pa? 0 n a /raight l9e b a circle or ellipse 0 ! next /ep1 & ?is 0 f\nd to be ! case4 ,f tak+ exact measurem5ts ( _! pa?s 9 ! sky an a/ronom] comput$ !y 7 really travell+ r\nd ! sun 9 a l5g!n$ orbit1 an ellipse m l a comet's orbit ?an t ( a planet4 ,b next came ! puzzl+ "q1 ,:y did ! e>? app>5tly hit !m e ye> to "s ext5t1 & once 9 ?irty-?ree ye>s seem to run "r into ! middle ( !m8 ,?is also 0 answ]$4 ,"o has only to imag9e a sw>m ( su* meteors at fir/ ha/5+ busily along _! orbit1 a great clu/] all toge!r1 !n1 by ! ne> neighb\rhood ( "s planet1 or by "s o!r di/urb+ causes1 be+ drawn out1 leav+ /raggl]s lagg+ beh9d1 until at la/ !re might be "s all r\nd ! pa?1 b only ?9ly scatt]$1 :ile ! busy1 important clu/] t =m$ ! nucleus 0 /ill mu* ?ick] ?an any o!r "p4 ,n[1 if ! orbit t ! meteors foll[$ cut ! orbit or pa? ( ! e>? at "o po9t1 !n e "t ! e>? came to :at we may call ! level cross+ %e mu/ run into "s ( ! /raggl]s1 & if ! *ief "p ( ! sw>m took ?irty-?ree ye>s to get r\nd1 !n once 9 ab\t ?irty-?ree ye>s ! e>? mu/ /rike "r into x4 ,?is w\ld acc\nt = ! wond]ful display4 ,s long drawn-out is ! ?icke/ "p ( ! sw>m t x takes a ye> to pass ! po9ts at ! level cross+4 ,if ! e>? /rikes x ne> ! front "o ye>1 %e may come "r r\nd 9 "t to /rike into ! re> "p ( ! sw>m next ye>1 s t we may get f9e displays two ye>s runn+ ab\t e ?irty-?ree ye>s4 ,! la/ "t we pass$ ?r\gh ! sw>m 0 9 #ahii1 & !n ! %[ 0 v disappo9t+4 ,"h 9 ,engl& ?ick cl\ds prev5t$ our see+ mu*1 & !re w n be ano!r *ance = u to see x at its be/ until #aicb4 ,^! ,novemb] meteors are call$ ,leonids1 because !y seem to come f a gr\p ( />s nam$ ,leo1 & ?\gh ! mo/ noticeable !y are n ! only ones4 ,a %[] ( ! same k9d occurs 9 ,augu/ too1 b ! ,augu/ meteors1 call$ ,p]seids1 because !y seem to come f ,p]seus1 revolve 9 an orbit :i* takes a hundr$ & =ty-two ye>s to trav]se6 ,s t only e "o hundr$ & =ty-second ye> c\ld we hope to see a good display4 ,:5 all ^! facts _h be5 ga!r$ up1 x seem$ )\t d\bt t c]ta9 gr\ps ( meteors travell$ 9 company along an elliptical orbit4 ,b !re rema9$ /ill some?+ m--a bold & +5i\s !ory to be advanc$4 ,x 0 f\nd t a comet1 a small "o1 only to be se5 ) ! telescope1 revolv$ 9 exactly ! same orbit z ! ,novemb] meteors1 & ano!r "o1 l>g]1 9 exactly ! same orbit z ! ,augu/ ones2 h5ce x c\ld h>dly be d\bt$ t comets & meteors _h "s connection ) ea* o!r1 ?\gh :at t connection is exactly no "o kn[s4 ,anyway1 we c h no %ad[ ( d\bt :5 we f9d ! comet foll[+ a m>k$ pa?1 & ! meteors pursu+ ! same pa? 9 8 wake1 t ! two h "s my/]i\s aff9ity4 ,!re are o!r small] %[]s besides ^! ( ,novemb] & ,augu/1 & a rem>kable fact is kn[n ab\t "o ( !m4 ,?is p>ticul> /ream 0 f\nd to be connect$ ) a comet nam$ ,biela's ,comet1 t _h be5 _m times obs]v$1 & :i* return$ ab\t e sev5 ye>s to ! sun4 ,aft] x _h be5 se5 sev]al times1 ?is a/oni%+ comet split 9 two & appe>$ z two comets1 bo? ( :i* return$ at ! end ( ! next sev5 ye>s4 ,b on ! next two occasions :5 !y 7 expect$ !y nev] came at all1 & ! ?ird "t !re came in/ead a f9e display ( %oot+ />s1 s x really seem$ z if ^! meteors mu/ be ! fragm5ts ( ! lo/ comet4 ,x is v curi\s & int]e/+ to notice t 9 ^! /> %[]s !re is no c]ta9 record ( any l>ge meteorite rea*+ ! e>?2 !y seem to be made up ( su* small bodies t !y are all dissipat$ 9 vap\r z !y trav]se our air4 ,,*apt] ,x ,,! ,,glitt]+ ,,heav5s ,on a cle> moonless night ! />s appe> unc\ntable4 ,y see !m tw9kl+ ?r\gh ! leafless trees1 & cov]+ all ! sky f ! z5i?1 ! highe/ po9t above y\r head1 d[n to ! horizon4 ,x seems z if someone _h tak5 a gigantic pepp]-pot & scatt]$ !m f> & wide s t "s _h fall5 9 all directions4 ,if y 7 ask$ to make a guess z to h[ _m y c see at "o "t1 no d\bt y w\ld answ] ',millions6' ,b y w\ld be q wrong1 = ! numb] ( />s t c be se5 at once )\t a telescope does n exce$ two ?\s&1 & ?is1 aft] ! l>ge figures we h be5 deal+ )1 appe>s a m]e trifle4 ,) a telescope1 ev5 ( small p[]1 _m m are reveal$1 & e increase 9 ! size ( ! telescope %[s m /ill2 s t x might be suppos$ ! univ]se is inde$ illimitable1 & t we are only prev5t$ f see+ beyond a c]ta9 po9t by our limit$ res\rces4 ,b 9 reality we "k t ?is _c be s4 ,if ! :ole sky 7 "o mass ( />s1 z x mu/ be if ! numb] ( !m 7 inf9ite1 !n1 ev5 ?\gh we c\ld n di/+ui% ! sep>ate items1 we %\ld see x bright ) a p]vad+ & diffus$ light4 ,z ?is is n s1 we judge t ! univ]se is n un5d+1 ?\gh1 ) all our inv5tions1 we may nev] be able to probe to ! end ( x4 ,we ne$ n1 inde$1 cry = inf9ity1 = ! di/ances ( ! fix$ />s f u are s immeasurable t to atoms l ourselves !y may well seem unlimit$4 ,our sol> sy/em is set by itself1 l a little isl& 9 space1 & f>1 f> away on all sides are o!r great light-giv+ suns resembl+ our own m or less1 b dw9dl$ to ! size ( t9y />s1 by reason ( ! great void ( space ly+ betwe5 u & !m4 ,our sun is1 inde$1 j a />1 & by no means l>ge comp>$ ) ! av]age ( ! />s ei!r4 ,b1 !n1 he is our own2 he is comp>atively ne> to u1 & s to u he appe>s magnific5t & unique4 ,judg+ f ! sol> sy/em1 we might expect to f9d t ^! o!r great suns :i* we call />s h also planets circl+ r\nd !m1 look+ to !m = light & heat z we d to our sun4 ,!re is no reason to d\bt t 9 "s in/ances ! conjecture is "r1 & t !re may be o!r suns ) att5dant planets4 ,x is h[ev] a great mi/ake to suppose t because our p>ticul> family 9 ! sol> sy/em is built on c]ta9 l9es1 all ! o!r families mu/ be made on ! same patt]n4 ,:y1 ev5 9 our own sy/em we c see h[ v mu* ! planets diff] f ea* o!r3 !re are no two ! same size2 "s h moons & "s h n2 ,saturn's r+s are q peculi> to himself1 & ,uranus & ,neptune indulge 9 /range vag>ies4 ,s :y %\ld we expect o!r sy/ems to be less v>i$8 ,z sci5ce has advanc$1 ! idea t ^! f>away suns mu/ h planet>y att5dants z our sun has be5 disc>d$4 ,! m we "k ! m is disclos$ to u ! inf9ite v>iety ( ! univ]se4 ,= in/ance1 s mu* accu/om$ are we to a yell[ sun t we nev] ?9k ( ! possibility ( !re be+ "o ( ano!r col\r4 ,:at w\ld y say !n to a ruby sun1 or a blue "o2 or to two suns ( diff]5t col\rs1 p]haps r$ & gre51 circl+ r\nd ea* o!r2 or to two su* suns ea* go+ r\nd a d>k companion8 ,= !re are d>k bodies z well z %9+ bodies 9 ! sky4 ,^! are "s ( ! m>vels ( ! />ry sky1 m>vels q z absorb+ z any?+ we h f\nd 9 ! sol> sy/em4 ,x requires great c>e & pati5ce & inf9ite lab\r be=e ! v delicate obs]vations :i* alone c reveal to u any?+ ( ! nature ( ! fix$ />s c be accompli%$4 ,x is only s9ce ! improvem5t 9 l>ge telescopes t ?is k9d ( "w has become possible1 & s x is b rec5tly m5 h begun to /udy ! />s intimately1 & ev5 n[ !y are baffl$ by indescribable difficulties4 ,"o ( ^! is our inability to tell ! di/ance ( a ?+ by m]ely look+ at x unless we also "k its size4 ,on e>? we are us$ to see+ ?+s appe> small] ! fur!r !y are f u1 & by long habit c g5]ally tell ! real size2 b :5 we turn to ! />s1 :i* appe> s mu* alike1 h[ are we to judge h[ f> (f !y are8 ,two />s app>5tly ! same size & close toge!r 9 ! sky may really be z f> "o f ano!r z ! e>? is f ! ne>e/2 = if ! fur!r "o 7 v mu* l>g] ?an ! ne>]1 !y w\ld !n appe> ! same size4 ,at fir/ x 0 natural en\gh to suppose t ! big bright />s ( :at we call ! fir/ magnitude 7 ! ne>e/ to u1 & ! less bright ! next ne>e/1 & s on d[n to ! t9y ones1 only reveal$ by ! telescope1 :i* w\ld be ! fur!/ away ( all2 b rese>* has %[n t ?is is n correct4 ,"s ( ! brighte/ />s may be comp>atively ne>1 & "s ( ! smalle/ may be ne> also4 ,! size is no te/ ( di/ance4 ,s f> z we h be5 able to discov]1 ! /> :i* seems ne>e/ is a fir/ magnitude "o1 b "s ( ! o!rs :i* out%9e x mu/ be among ! inf9itely di/ant ones4 ,?us we lie 9 ! c5tre ( a jewell$ univ]se1 & _c tell ev5 ! size ( ! jewels :i* cov] its radiant robe4 ,i say 'lie1' b t is really n ! correct ^w4 ,s f> z we h be5 able to f9d out1 !re is no su* ?+ z absolute re/ 9 ! univ]se--9 fact1 x is impossible2 = ev5 suppos+ any body c\ld be motionless at fir/1 x w\ld be drawn by ! attraction ( its ne>e/ neighb\rs 9 space1 & gradually ga9 a great] & great] velocity z x fell t[>d !m4 ,ev5 ! />s we call 'fix$' are all hurry+ along at a great pace1 & ?\gh _! di/ance prev5ts u f see+ any *ange 9 _! positions1 x c be measur$ by suitable in/rum5ts4 ,our sun is no exception to ?is univ]sal rule4 ,l all 8 compe]s1 he is hurry+ busily along some:]e 9 ob$i5ce to "s impulse ( :i* we d n "k ! nature2 & z he goes he c>ries ) him 8 :ole cortge ( planets & _! satellites1 & ev5 ! comets4 ,yes1 we are rac+ ?r\gh space ) ano!r motion1 too1 besides ^? ( rotation & revolution1 = our e>? keeps up ) its ma/] attractor1 ! sun4 ,x is difficult1 no d\bt1 to foll[ ?is1 b if y ?9k = a mom5t y w rememb] t :5 y are 9 a railway-c>riage ev]y?+ 9 t c>riage is really travell+ along ) x1 ?\gh x does n appe> to move4 ,& ! :ole sol> sy/em may be look$ at z if x 7 "o block 9 movem5t4 ,z 9 a c>riage1 ! diff]5t bodies 9 x cont9ue _! own movem5ts all ! "t1 :ile %>+ 9 ! common movem5t4 ,y c get up & *ange y\r seat 9 ! tra91 & :5 y sit d[n aga9 y h n only mov$ t little way ( :i* y are consci\s1 b a great way ( :i* y are n consci\s unless y look out ( ! w9d[4 ,n[ 9 ! case ( ! e>?'s own motion we f\nd x necess>y to look = some?+ :i* does n %>e 9 t motion = purposes ( comp>ison1 & we f\nd t some?+ 9 ! sun1 :o %[s u v cle>ly we are turn+ on our axis4 ,b 9 ! case ( ! motion ( ! sol> sy/em ! sun is mov+ himself1 s we h to look beyond him aga9 & turn to ! />s = confirmation4 ,!n we f9d t ! />s h motions ( _! own1 s t x is v difficult to judge by !m at all4 ,x is z if y 7 bicycl+ swiftly t[>ds a numb] ( p all walk+ ab\t 9 diff]5t directions on a wide lawn4 ,!y h _! movem5ts1 b !y all also h an app>5t movem5t1 really caus$ by y z y advance t[>d !m2 & :at a/ronom]s _h to d 0 to sep>ate ! true movem5ts ( ! />s f ! false app>5t movem5t made by ! advance ( ! sun4 ,?is great problem 0 attack$ & ov]come1 & x is n[ kn[n ) tol]able c]ta9ty t ! sun is sweep+ onw>d at a pace ( ab\t twelve miles a second t[>d a fix$ po9t4 ,x really matt]s v little to u :]e he is go+1 = ! di/ances are s va/ t hundr$s ( ye>s mu/ elapse be=e 8 movem5t makes ! slighte/ diff]5ce 9 reg>d to ! />s4 ,b !re is "o ?+ :i* we c judge1 & t is t ?\gh 8 c\rse appe>s to be 9 a /raight l9e1 x is mo/ probably only a "p ( a great curve s huge t ! little bit we "k seems /raight4 ,:5 we speak ( ! />s1 we ought to keep q cle>ly 9 our m9ds ! fact t !y lie at su* an incr$ible di/ance f u t x is probable we %all nev] le>n a great deal ab\t !m4 ,:y1 m5 h n ev5 yet be5 able to communicate ) ! planet ,m>s1 at its ne>e/ only "s ?irty-five million miles f u1 & ?is is a m]e no?+ 9 measur+ ! space betwe5 u & ! />s4 ,to express ! di/ances ( ! />s 9 figures is really a wa/e ( "t1 s a/ronom]s h inv5t$ ano!r way4 ,y "k t light c g r\nd ! _w eight times 9 a second2 t is a spe$ q beyond our compreh5sion1 b we j accept x4 ,!n ?9k :at a di/ance x c\ld travel 9 an h\r1 9 a day2 & :at ab\t a ye>8 ,! di/ance t light c travel 9 a ye> is tak5 z a conv5i5t measure by a/ronom]s = s\nd+ ! dep?s ( space4 ,measur$ 9 ?is way light takes f\r ye>s & f\r mon?s to rea* u f ! ne>e/ /> we "k (1 & !re are o!rs s mu* m di/ant t hundr$s--nay1 ?\s&s--( ye>s w\ld h to be us$ to convey x4 ,light :i* has be5 travell+ along ) a velocity q beyond ?\ght1 sil5tly1 unre/+1 f ! "t :5 ! ,britons liv$ & ran half nak$ on ?is isl& ( ours1 has only rea*$ u n[1 & !re is no limit to ! "t we may g back 9 our imag9+s4 ,we see ! />s1 n z !y are1 b z !y 74 ,if "s gigantic conflagration _h happ5$ a hundr$ ye>s ago 9 "o ( !m situat$ a hundr$ light-ye>s away f u1 only n[ w\ld t mess5g]1 swift] ?an any mess5g] we "k1 h br\ght ! news ( x to u4 ,to put ! matt] 9 figures1 we are sure t no /> c lie ne>] to u ?an tw5ty-five billions ( miles4 ,a billion is a million millions1 & is repres5t$ by a figure ) twelve n\ghts beh9d x1 s--#a1jjj1jjj1jjj1jjj2 & tw5ty-five su* billions is ! lea/ di/ance )9 :i* any /> c lie4 ,h[ mu* f>!r away />s may be we "k n1 b x is some?+ to h f\nd out ev5 t4 ,on ! same scale z t we took 9 our fir/ example1 we might express x ?us3 ,if ! e>? 7 a gre5gage plum at a di/ance ( ab\t ?ree hundr$ ( y\r /eps f ! sun1 & ,neptune 71 on ! same scale1 ab\t ?ree miles away1 ! ne>e/ fix$ /> c\ld n be ne>] ?an ! di/ance measur$ r\nd ! :ole e>? at ! ,equator6 ,all ?is mu/ provoke ! "q1 ,h[ c anyone f9d out ^! ?+s8 ,well1 = a long "t ! problem ( ! di/ances ( ! />s 0 ?\ght to be too difficult = anyone to attempt to solve x1 b at la/ an +5i\s me?od 0 devis$1 a me?od :i* %[s once m ! triumph ( man's m9d ov] difficulties4 ,9 practice ?is me?od is extremely difficult to c>ry out1 = x is complicat$ by s _m o!r ?+s :i* mu/ be made all[ance =2 b 9 !ory1 r\ghly expla9$1 x is n too h>d = anyone to grasp4 ,! way ( x is ?is3 ,if y hold up y\r f+] s z to cov] exactly "s object a few feet di/ant f y1 & %ut fir/ "o eye & !n ! o!r1 y w f9d t ! f+] has app>5tly %ift$ v consid]ably aga9/ ! backgr\nd4 ,! f+] has n really mov$1 b z se5 f "o eye or ! o!r1 x is ?r[n on a diff]5t "p ( ! backgr\nd1 & s appe>s to jump2 !n if y draw two imag9>y l9es1 "o f ea* eye to ! f+]1 & ano!r betwe5 ! two eyes1 y w h made a triangle4 ,n[1 all ( y :o h done a little ,euclid "k t if y c asc]ta9 ! l5g? ( "o side ( a triangle1 & ! angles at ea* end ( x1 y c =m ! re/ ( ! triangle2 t is to say1 y c tell ! l5g? ( ! o!r two sides4 ,9 ?is in/ance ! base l9e1 z x is call$--t is to say ! l9e ly+ betwe5 ! two eyes--c easily be measur$1 & ! angles at ea* end c be f\nd by an in/rum5t call$ a sextant1 s t by simple calculation anyone c\ld f9d out :at di/ance ! f+] 0 f ! eye4 ,n[1 "s +5i\s man decid$ to apply ?is me?od to ! />s4 ,he knew t x is only objects q ne> to u t w appe> to %ift ) s small a base l9e z t betwe5 ! eyes1 & t ! fur!r away any?+ is ! long] mu/ ! base l9e be be=e x makes any diff]5ce4 ,b ?is clev] man ?\ght t if he c\ld only get a base l9e long en\gh he c\ld easily compute ! di/ance ( ! />s f ! am\nt t !y appe>$ to %ift aga9/ _! backgr\nd4 ,he knew t ! longe/ base l9e he c\ld get on e>? w\ld be ab\t eight ?\s& miles1 z t is ! diamet] ( ! e>? f "o side to ! o!r2 s he c>efully obs]v$ a /> f "o end ( ?is imm5se base l9e & !n f ! o!r1 q confid5t t ?is plan w\ld answ]4 ,b :at happ5$8 ,aft] c>eful obs]vations he discov]$ t no /> mov$ at all ) ?is base l9e1 & t x mu/ be ev] s mu* long] 9 ord] to make any impression4 ,!n inde$ ! case seem$ hopeless1 = "h we are ti$ to ! e>? & we _c get away into space4 ,b ! a/ronom] 0 no?+ daunt$4 ,he knew t 9 its j\rney r\nd ! sun ! e>? travels 9 an orbit :i* measures ab\t "o hundr$ & eighty-five millions ( miles across1 s he resolv$ to take obs]vations ( ! />s :5 ! e>? 0 at "o side ( ?is great circle1 & aga91 six mon?s lat]1 :5 %e _h travell$ to ! o!r side4 ,!n inde$ he w\ld h a magnific5t base l9e1 "o ( "o hundr$ & eighty-five millions ( miles 9 l5g?4 ,:at 0 ! result8 ,ev5 ) ?is mighty l9e ! />s are f\nd to be s di/ant t _m d n move at all1 n ev5 :5 measur$ ) ! f9e/ in/rum5ts1 & o!rs move1 x may be1 ! bread? ( a hair at a di/ance ( sev]al feet6 ,b ev5 ?is delicate measure1 a hair's-bread?1 tells its own tale2 x lays d[n a limit ( tw5ty-five billion miles )9 :i* no /> c lie6 ,?is sy/em :i* ,i h expla9$ to y is call$ f9d+ ! />'s p>allax1 & p]haps x is easi] to und]/& :5 we put x ! o!r way r\nd & say t ! hair's-bread? is :at ! :ole orbit ( ! e>? w\ld appe> to h %runk to if x 7 se5 f ! di/ance ( ^! />s6 ,_m1 _m />s h n[ be5 exam9$1 & ( !m all our ne>e/ neighb\r seems to be a bright /> se5 9 ! ,s\!rn ,hemisph]e4 ,x is 9 ! con/ellation or /> gr\p call$ ,c5taurus1 & is ! brighte/ /> 9 x4 ,9 ord] to designate ! />s :5 x is necess>y to ref] to !m1 a/ronom]s h inv5t$ a sy/em4 ,to only ! v brighte/ are prop] names atta*$2 o!rs are not$ accord+ to ! degree ( _! brightness1 & call$ aft] ! lett]s ( ! ,greek alphabet3 alpha1 beta1 gamma1 delta1 etc4 ,our own ^w 'alphabet' comes1 y "k1 f ! fir/ two lett]s ( ?is ,greek s]ies4 ,z ?is p>ticul> /> is ! brighte/ 9 ! con/ellation ,c5taurus1 x is call$ ,alpha ,c5tauri2 & if ev] y travel into ! ,s\!rn ,hemisph]e & see x1 y may greet x z our ne>e/ neighb\r 9 ! />ry univ]se1 s f> z we "k at pres5t4 ,,*apt] ,,xi ,,! ,,con/ellations ,f ! v e>lie/ times m5 h wat*$ ! />s1 felt _! my/]i\s influ5ce1 tri$ to discov] :at !y 71 & not$ _! ris+ & sett+4 ,!y classifi$ !m into gr\ps1 call$ con/ellations1 & gave su* gr\ps ! names ( figures & animals1 accord+ to ! positions ( ! />s compos+ !m4 ,"s ( ^! imag9>y figures seem to u s wildly ridicul\s t we _c conceive h[ anyone c\ld h gone s f> out ( _! way z to inv5t !m4 ,b !y h be5 long sanction$ by cu/om1 s n[1 ?\gh we f9d x difficult to recognize 9 scatt]$ gr\ps ( />s any lik5ess to a fi% or a ram or a be>2 we /ill call ! con/ellations by _! old names = conv5i5ce 9 ref]r+ to !m4 ,suppos+ ! axis ( ! e>? 7 q upright1 /raight up & d[n 9 reg>d to ! plane at :i* ! e>? goes r\nd ! sun1 !n we %\ld always see ! same set ( />s f ! ,nor!rn & ! same set ( />s f ! ,s\!rn ,hemisph]es all ! ye> r\nd4 ,b z ! axis is tilt$ slightly1 we c1 dur+ our nights 9 ! w9t] 9 ! ,nor!rn ,hemisph]e1 see m ( ! sky to ! s\? ?an we c 9 ! summ]2 & 9 ! ,s\!rn ,hemisph]e j ! rev]se is ! case1 f> m />s to ! nor? c be se5 9 ! w9t] ?an 9 ! summ]4 ,b always1 :e!r x is w9t] or summ]1 !re is "o fix$ po9t 9 ea* hemisph]e r\nd :i* all ! o!r />s seem to sw+1 & ?is is ! po9t imm$iately ov] ! ,nor? or ! ,s\? ,poles4 ,!re is1 luckily1 a bright /> almo/ at ! po9t at :i* ! ,nor? ,pole w\ld seem to /rike ! sky 7 x inf9itely l5g!n$4 ,?is is n "o ( ! brighte/ />s 9 ! sky1 b q bright en\gh to s]ve ! purpose1 & if we /& ) our faces t[>ds x1 we c be sure we are look+ due nor?4 ,h[ c we discov] ?is /> = ourselves 9 ! sky8 ,g out on any />light night :5 ! sky is cle>1 & see if y c f9d a v conspicu\s set ( sev5 />s call$ ! ,great ,be>4 ,i %all n describe ! ,great ,be>1 because e *ild ought to "k x already1 & if !y don't1 !y c ask ! fir/ gr[n-up p]son !y meet1 & !y w c]ta9ly be told4 7,see map47 ,illu/ration3 ,,con/ellations ,,ne> ,,! ,,pole ,,/>4 ,hav+ f\nd ! ,great ,be>1 y h only to draw an imag9>y l9e betwe5 ! two la/ />s =m+ ! squ>e on ! side away f ! tail1 & c>ry x on ab\t ?ree times z f> z ! di/ance betwe5 ^? two />s1 & y w come /raight to ! ,pole ,/>4 ,! two />s 9 ! ,great ,be> :i* help "o to f9d x are call$ ! ,po9t]s1 because !y po9t to x4 ,! ,great ,be> is "o ( ! con/ellations kn[n f ! olde/ times2 x is also sometimes call$ ,*>les's ,wa91 ! ,dipp]1 or ! ,pl\gh4 ,x is always easily se5 9 ,engl&1 & seems to sw+ r\nd ! ,pole ,/> z if held by an invisible rope ti$ to ! ,po9t]s4 ,besides ! ,great ,be> !re is1 n f> f x1 ! ,little ,be>1 :i* is really v l x1 only small] & h>d] to f9d4 ,! ,pole ,/> is ! la/ /> 9 its tail2 f x two small />s lead away p>allel to ! ,great ,be>1 & !y br+ ! eye to a small pair :i* =m "o side ( a squ>e j l t 9 ! ,great ,be>4 ,b ! :ole ( ! ,little ,be> is turn$ ! opposite way f ! ,great ,be>1 & ! tail po9ts 9 ! opposite direction4 ,& :5 y come to ?9k ( x1 x is v ridicul\s to h call$ ^! gr\ps ,be>s at all1 or to talk ab\t tails1 = be>s h no tails6 ,s x w\ld h be5 bett] to h call$ !m foxes or dogs1 or almo/ any o!r animal r ?an be>s4 ,n[1 if y look at ! sky on ! opposite side ( ! ,pole ,/> f ! ,great ,be>1 y w see a cle>ly m>k$ capital ,w made up ( five or six bright />s4 ,?is is call$ ,cassiopeia1 or ! ,lady's ,*air4 ,9 look+ at ,cassiopeia y _c help notic+ t !re is a zone or broad b& ( v _m />s1 "s exce$+ly small1 :i* app>5tly runs "r across ! sky l a ragg$ hoop1 & ,cassiopeia seems to be set 9 or on x4 ,?is b& is call$ ! ,milky ,way1 & crosses n only our nor!rn sky1 b ! s\!rn sky too1 ?us mak+ a broad girdle r\nd ! :ole univ]se4 ,x is v wond]ful1 & no "o has yet be5 able to expla9 x4 ,! belt is n uni=m & ev51 b x is "h & !re brok5 up into /ream]s & *ips1 hav+ ! same appe>ance z a piece ( ribbon :i* has be5 snipp$ ab\t by scissors 9 pure mis*ief2 or x may be comp>$ to a great riv] brok5 up into _m *annels by rocks & ob/acles 9 its c\rse4 ,! ,milky ,way is ma9ly made up ( ?\s&s & ?\s&s ( small />s1 & _m m are reveal$ by ! telescope2 b1 z we see 9 ,cassiopeia1 !re are l>ge bright />s 9 x too1 ?\gh1 ( c\rse1 ^! may be inf9itely ne>] to u1 & may only appe> to u to be 9 ! ,milky ,way because !y are betwe5 u & x4 ,n[1 besides ! few con/ellations t ,i h m5tion$1 !re are numb]s ( o!rs1 "s ( :i* are difficult to discov]1 z !y conta9 no bright />s4 ,b !re are c]ta9 con/ellations :i* e "o %\ld "k1 because 9 !m may be f\nd "s ( ! brighte/ />s1 ^? ( ! fir/ magnitude4 ,magnitude means size1 & x is really absurd = u to say a /> is ( ! fir/ magnitude simply because x appe>s to u to be l>ge1 =1 z ,i h expla9$ already1 a small /> comp>atively ne> to u might appe> l>g] ?an a great] "o fur!r away4 ,b ! ^w 'magnitude' 0 us$ :5 m5 really ?\ght />s 7 l>ge or small accord+ to _! appe>ance1 & s x is us$ to ?is day4 ,!y call$ ! bigge/ & brighte/ fir/ magnitude />s4 ,( ^! !re are n _m1 only "s tw5ty1 9 all ! sky4 ,! next brighte/--ab\t ! brightness ( ! ,pole ,/> & ! />s 9 ! ,great ,be>--are ( ! second magnitude1 & s on1 ea* magnitude conta9+ />s less & less bright4 ,:5 we come to />s ( ! six? magnitude we h rea*$ ! limit ( our sight1 = sev5? magnitude />s c only be se5 ) a telescope4 ,n[ t we und]/& :at is meant by ! magnitude1 we c g back to ! con/ellations & try to f9d "s m4 ,if y draw an imag9>y l9e across ! two />s =m+ ! backbone ( ! ,be>1 />t+ f ! end ne>e/ ! tail1 & cont9ue x onw>d = a good di/ance1 y w come to a v bright /> call$ ,capella1 :i* y w "k1 because ne> x are ?ree little ones 9 a triangle4 ,n[1 ,capella means a goat1 s ! small ones are call$ ! kids4 ,9 w9t] ,capella gets high up into ! sky1 & !n !re is to be se5 bel[ h] a little clu/] call$ ! ,pleiades4 ,!re is no?+ else l ?is 9 ! :ole sky4 ,x is =m$ ( six />s1 z x appe>s to p]sons ( ord9>y sight1 & ^! />s are ( ! six? magnitude1 ! l[e/ t c be se5 by ! nak$ eye4 ,b ?\gh small1 !y are set s close toge!r1 & appe> s brilliant1 tw9kl+ l diamonds1 t !y are "o ( ! mo/ noticeable objects 9 ! heav5s4 ,a leg5d tells t !re 7 once sev5 />s 9 ! ,pleiades cle>ly visible1 & t "o has n[ disappe>$4 ,?is is sometimes spok5 ( z '! lo/ ,pleiad1' b !re does n seem to be any f\ndation = ! /ory4 ,9 old days p atta*$ p>ticul> hol9ess or luck to ! numb] sev51 & possibly1 :5 !y f\nd t !re 7 only six />s 9 ?is wond]ful gr\p1 !y inv5t$ ! /ory ab\t ! sev5?4 ,z ! ,pleiades rise1 a beautiful r$di% /> ( ! fir/ magnitude rises b5ea? !m4 ,x is call$ ,aldeb>an1 & x1 z well z ! ,pleiades1 =ms a "p ( ! con/ellation ( ,taurus ! bull4 ,9 ,engl& we c see 9 w9t] bel[ ,aldeb>an ! :ole ( ! con/ellation ( ,orion1 "o ( ! f9e/ ( all ! con/ellations1 bo? = ! numb] ( ! bright />s x conta9s & = ! ext5t ( ! sky x cov]s4 ,f\r bright />s at wide di/ances enclose an irregul> f\r-sid$ space 9 :i* are set ?ree o!rs close toge!r & slant+ d[nw>ds4 ,bel[ ^!1 aga91 are ano!r ?ree :i* seem to fall f !m1 b are n s bright4 ,! figure ( ,orion z drawn 9 ! old repres5tations ( ! con/ellations is a v magnific5t "o4 ,! ?ree bright />s =m 8 belt1 & ! ?ree small] ones ! hilt ( 8 sword hang+ f x4 ,illu/ration3 ,,orion ,,& ,,8 ,,neighb\rs4 ,if y draw an imag9>y l9e ?r\gh ! />s =m+ ! belt & prolong x d[nw>ds slant+ly1 y w see1 9 ! v height ( w9t]1 ! brighte/ /> 9 all ! sky1 ei!r 9 ! ,nor!rn or ,s\!rn ,hemisph]e4 ,?is is ,sirius1 :o /&s 9 a class q by himself1 = he is _m times bright] ?an any o!r fir/ magnitude />4 ,he nev] rises v high above ! horizon "h1 b on crisp1 fro/y nights may be se5 gleam+ l a big diamond betwe5 ! leafless twigs & b\ghs ( ! rime-encru/$ trees4 ,sirius is ! ,dog ,/>1 & x is p]haps =tunate t1 z he is plac$1 he c be se5 sometimes 9 ! s\!rn & sometimes 9 ! nor!rn skies1 s t _m m p h a *ance ( look+ at 8 wond]ful brilliancy1 ?an if he _h be5 plac$ ne> ! ,pole />4 ,9 speak+ ( ! supreme brightness ( ,sirius among ! />s1 we mu/ rememb] t ,v5us & ,jupit]1 :i* outrival him1 are n />s1 b planets1 & t !y are mu* ne>] to u4 ,sirius is s di/ant t ! measures = p>allax make h>dly any impression on him1 b1 by repeat$ exp]im5ts1 x has n[ be5 prov$ t light takes m ?an eight ye>s to travel f him to u4 ,s t1 if y are eight ye>s old1 y are look+ at ,sirius z he 0 :5 y 7 a baby6 ,n f> f ! ,pleiades1 to ! left z y face !m1 are to be f\nd two bright />s ne>ly ! same size2 ^! are ! ,heav5ly ,tw9s1 or ,gem9i4 ,return+ n[ to ! ,great ,be>1 we f9d1 if we draw a l9e ?r\gh ! middle & la/ />s ( 8 tail1 & c>ry x on = a little di/ance1 we come fairly ne> to a clu/] ( />s 9 ! =m ( a horse%oe2 !re is only "o fairly bright "o 9 x1 & "s ( ! o!rs are q small1 b yet ! horse%oe is di/9ct & v beautiful to look at4 ,?is is ! ,nor!rn ,cr[n4 ,! v bright /> n f> f x is ano!r fir/-class /> call$ ,arcturus4 ,to ! left ( ! ,nor!rn ,cr[n lies ,h]cules1 :i* is only m5tion$ because ne> x is ! po9t to :i* ! sun ) all 8 sy/em appe>s at pres5t to be spe$+4 ,= o!r fasc9at+ con/ellations1 su* z ,leo or ! ,lion1 ,&rom$a & ,p]seus1 & ! ?ree bright />s by :i* we recognize ,aquila ! ,eagle1 y mu/ wait a:ile1 unless y c get "s "o to po9t !m out4 ,^? :i* y h not$ already are en\gh to lead y on to se>* = m4 ,p]haps "s ( y :o live 9 t[ns & c see only a little /rip ( sky f ! nurs]y or s*oolroom w9d[s h already f\nd ?is *apt] dull1 & if s y may skip ! re/ ( x & g on to ! next4 ,= ! o!rs1 h[ev]1 !re is "o m ?+ to "k be=e leav+ ! subject1 & t is ! names ( ! /r+ ( con/ellations =m+ :at is call$ ! ,zodiac4 ,y may h he>d ! rhyme3 ',! ,ram1 ! ,bull1 ! ,heav5ly ,tw9s1 ,& next ! ,crab1 ! ,lion %9es1 ,! ,virg9 & ! ,scales2 ,! ,scorpion1 ,ar*]1 & ,he-goat1 ,! ,man t holds ! wat]+-pot1 ,! ,fi% ) glitt]+ tails4' ,?is puts 9 a =m easy to rememb] ! signs ( ! con/ellations :i* lie 9 ! ,zodiac1 an imag9>y belt across ! :ole heav5s4 ,x is v difficult to expla9 ! ,zodiac1 b ,i mu/ try4 ,imag9e = a mom5t ! e>? mov+ r\nd its orbit ) ! sun 9 ! middle4 ,n[1 z ! e>? moves ! sun w be se5 cont9ually aga9/ a diff]5t backgr\nd--t is to say1 he w appe> to u to move n only across our sky 9 a day by reason ( our rotation1 b also along ! sky1 *ang+ 8 position among ! />s by reason ( our revolution4 ,y w say at once t we _c see ! />s :5 ! sun is !re1 & no m we c4 ,b ! />s are !re all ! same1 & e mon? ! sun seems to h mov$ on into a new con/ellation1 accord+ to a/ronom]s' reckon+4 ,if y c\nt up ! names ( ! con/ellations 9 ! rhyme1 y w f9d t !re are j twelve1 "o = ea* mon?1 & at ! end ( ! ye> ! sun has come r\nd to ! fir/ "o aga94 ,! fir/ "o is ,aries ! ,ram1 & ! sun is se5 project$ or ?r[n aga9/ t "p ( ! sky :]e ,aries is1 9 ,april1 :5 we beg9 spr+2 ?is is ! fir/ mon? to a/ronom]s1 & n ,janu>y1 z y might suppose4 ,p]haps y w le>n to recognize all ! con/ellations 9 ! ,zodiac "o day2 a few ( !m1 su* z ! ,bull & ! ,heav5ly ,tw9s1 y "k already if y h foll[$ ?is *apt]4 ,,*apt] ,,xii ,,:at ,,! ,,/>s ,,are ,,made ,,( ,h[ c we possibly tell :at ! />s are made (8 ,if we ?9k ( ! va/ oceans ( space ly+ betwe5 !m & u1 & realize t we c nev] cross ^? oceans1 = 9 !m !re is no air1 x w\ld seem to be a hopeless task to f9d out any?+ ab\t ! />s at all4 ,b ev5 ?\gh we _c trav]se space ourselves1 !re is a mess5g] t c1 a mess5g] t ne$s no air to su/a9 him1 t moves m swiftly ?an our feeble m9ds c compreh5d1 & ?is mess5g] br+s u tid+s ( ! />s--8 "n is ,light4 ,light tells u _m m>vell\s ?+s1 & n ! lea/ m>vell\s is ! news he gives u ( ! work+s ( ano!r =ce1 ! =ce ( gravitation4 ,9 "s ways gravitation is p]haps m wond]ful ?an light1 = ?\gh light spe$s across airless space1 x is /opp$ at once by any opaque sub/ance--t is to say1 any sub/ance n transp>5t1 z y "k v well by y\r own %ad[s1 :i* are caus$ by y\r bodies /opp+ ! light ( ! sun4 ,light /rik+ on "o side ( ! e>? does n p5etrate ?r\gh to ! o!r1 :]eas gravitation does4 ,y rememb]1 ( c\rse1 :at ! =ce ( gravitation is1 = we read ab\t t v e>ly 9 ?is book4 ,x is a my/]i\s attraction exi/+ betwe5 all matt]4 ,e atom pulls e o!r atom t[>ds itself1 m or less /rongly accord+ to di/ance4 ,n[1 solid matt] itself makes no diff]5ce to ! =ce ( gravitation1 :i* acts ?r\gh x z ?\gh x 7 n !re4 ,! sun is pull+ ! e>? t[>d itself1 & x pulls ! atoms on ! f> side ( ! e>? j z /rongly z x w\ld if !re 7 no?+ ly+ betwe5 x & !m4 ,!re=e1 unlike light1 gravitation takes no he$ ( ob/acles 9 ! way1 b acts 9 spite ( !m4 ,! gravitation ( ! e>? holds y d[n j ! same1 ?\gh y are on ! upp] floor ( a h\se1 ) _m lay]s ( wood & pla/] betwe5 y & x4 ,x _c pull y d[n1 = ! floor holds y up1 b x is gravitation t keeps y\r feet on ! gr\nd all ! same4 ,a clev] man made up a /ory ab\t "s "o :o inv5t$ a k9d ( /uff :i* /opp$ ! =ce ( gravitation go+ ?r\gh x1 j z a solid body /ops light2 :5 ?is /uff 0 made1 ( c\rse1 x w5t "r away (f into space1 c>ry+ ) x anyone :o /ood on x1 z !re 0 no?+ to hold x to ! e>?6 ,t 0 only a /ory1 & x is n likely anyone c\ld inv5t su* /uff1 b x s]ves to make cle> ! work+ ( gravitation4 ,^! two tireless =ces1 light & gravitation1 run ?r\gh\t ! :ole univ]se1 & c>ry messages ( trem5d\s importance = ^? :o h m9ds to grasp !m4 ,)\t light we c\ld "k no?+ ( ^! di/ant worlds1 & )\t und]/&+ ! laws ( gravity we %\ld n be able to int]pret mu* t light tells u4 ,to beg9 ) light1 :at c we le>n f x8 ,we turn at once to our own great light-giv]1 ! sun1 to :om we owe n only all life1 b also all ! col\r & beauty on e>?4 ,x is well kn[n to m5 ( sci5ce t col\r lies 9 ! light itself1 & n 9 any p>ticul> object4 ,t brilliant blue cloak ( y\rs is n blue ( itself1 b because ( ! light t falls on x4 ,if y _c believe ?is1 g into a room light$ only by gas1 & hey1 pre/o6 ! col\r is *ang$ z if x 7 a conjur+ trick4 ,y _c tell n[ by look+ at ! cloak :e!r x is blue or gre56 ,!re=e y mu/ admit t z ! col\r *anges ) ! *ange ( light x mu/ be due to light1 & n to any quality belong+ to ! mat]ial ( ! cloak4 ,b1 y may prote/1 if ! col\r is solely due to light1 & light falls on ev]y?+ alike1 :y are !re s _m col\rs8 ,t is a v fair "q4 ,if ! light t comes f ! sun 7 ( only "o col\r--say blue or r$--!n ev]y?+ w\ld be blue or r$ all ! _w ov]4 ,"s doors 9 h\ses are made ) a /rip ( r$ or blue glass runn+ d[n ! sides4 ,if y h "o 9 y\r h\se l t1 g & look ?r\gh x1 & y w see an a/oni%+ _w made up ( diff]5t tones ( ! same col\r4 ,ev]y?+ is r$ or blue1 accord+ to ! col\r ( ! glass1 & ! only diff]5ce 9 ! appe>ance ( objects lies 9 ! diff]5t %ades1 :e!r ?+s are light or d>k4 ,?is is a _w z x might appe> if ! sun's rays 7 only blue or only r$4 ,b ! sun's light is n ( "o col\r only1 =tunately = u2 x is ( all ! col\rs mix$ toge!r1 :i*1 se5 9 a mass1 make ! effect ( :ite light4 ,n[1 objects on e>? are only ei!r se5 by ! reflect$ light ( ! sun or by "s artificial light4 ,!y h no light ( _! own4 ,put !m 9 ! d>k & !y d n %9e at all2 y _c see !m4 ,x is ! sun's light /rik+ on !m t makes !m visible4 ,b all objects d n reflect ! light equally1 & ?is is because !y h ! p[] ( absorb+ "s ( ! rays t /rike on !m & n giv+ !m back at all1 & only ^? rays t are giv5 back %[ to ! eye4 ,a :ite ?+ gives back all ! rays1 & s looks :ite1 = we h ! :ole ( ! sun's light return$ to u aga94 ,b h[ ab\t a blue ?+8 ,x absorbs all ! rays except ! blue1 s t ! blue rays are ! only ones t come back or reb\nd f x aga9 to meet our eyes1 & ?is makes u see ! object blue2 & ?is is ! case ) all ! o!r col\rs4 ,a r$ object reta9s all rays except ! r$1 :i* x s5ds back to u2 a yell[ object gives back only ! yell[ rays1 & s on4 ,:at an extraord9>y & my/]i\s fact6 ,imag9e a brilliant fl[]-g>d5 9 autumn4 ,"h we h tall yell[ sunfl[]s ) velvety br[n c5tres1 clu/]+ p9k & crimson hollyhocks1 deep r$ & bright yell[ peonies1 sl5d] fairy-l ,japanese anemones1 great bun*es ( mauve ,mi*aelmas daisies1 & c\ntless o!rs1 & m+l$ ) all ^! are _m %ades ( gre54 ,yet x is ! light ( ! sun alone t fall+ on all ^! v>i$ objects1 makes t glori\s blaze ( col\r2 x seems incr$ible4 ,x may be difficult to believe1 b x is true beyond all d\bt4 ,ea* delicate velvety petal has "s quality 9 x :i* causes x to absorb c]ta9 ( ! sun's rays & s5d back ! o!rs1 & its col\r is det]m9$ by ^? x s5ds back4 ,well !n h[ inf9itely v>i$ mu/ be ! col\rs hidd5 9 ! sun's light1 col\rs :i*1 mix$ all toge!r1 make :ite light6 ,yes1 ?is is s1 = all col\rs t we "k are to be f\nd !re4 ,9 fact1 ! col\rs t make up sunlight are ! col\rs to be se5 9 ! ra9b[1 & !y run 9 ! same ord]4 ,h y ev] look$ c>efully at a ra9b[8 ,if n1 d s at ! next *ance4 ,y w see x beg9s by be+ d>k blue at "o end1 & passes ?r\gh all col\rs until x gets to r$ at ! o!r4 ,we _c see a ra9b[ e day j :5 we want to1 b we c see m9iature ra9b[s :i* conta9 j ! same col\rs z ! real ones 9 a numb] ( ?+s any "t ! sun %9es4 ,= in/ance1 9 ! cut-glass edge ( an ink/& or a decant]1 or 9 "o ( ^? old-fa%ion$ hang+ pieces ( cut-glass t dangle f ! *&eli] or c&le-brackets4 ,( c\rse y h (t5 se5 ^! col\rs reflect$ on ! wall1 & tri$ to get !m to %9e ^u y\r face4 ,or y h caught sight ( a brilliant pat* ( col\r on ! wall & look$ ar\nd to see :at caus$ x1 f9ally trac+ x to "s ?ick edge ( %9+ glass /&+ 9 ! sunlight4 ,n[1 ! cut-glass edge %[s ^! col\rs to y because x breaks up ! light t falls ^u x into ! col\rs x is made (1 & lets ea* "o come out sep>ately1 s t !y =m a b& ( bright col\rs in/ead ( j "o ray ( :ite light4 ,?is is p]haps a little difficult to und]/&1 b ,i w try to expla94 ,:5 a ray ( :ite light falls on su* a piece ( glass1 :i* is kn[n z a prism1 x goes 9 z :ite light at "o side1 b ! ?ree-corn]$ %ape ( ! glass breaks x up into ! col\rs x is made (1 & ea* col\r comes out sep>ately at ! o!r side--namely1 f blue to r$--l a little ra9b[1 & in/ead ( "o ray ( :ite light1 we h a broad b& ( all ! col\rs t light is made (4 ,:o w\ld ev] h ?\ght a pretty play?+ l ?is c\ld h told u :at we s mu* want$ to "k--namely1 :at ! sun & ! />s are made (8 ,x seems too m>vell\s to be true1 yet true x is t = ages & ages light has be5 c>ry+ its sil5t messages to our eyes1 & only rec5tly m5 h le>nt to int]pret !m4 ,x is z if "s telegraph op]ator _h be5 go+ /eadily on1 click1 click1 click1 = ye>s & ye>s1 & no "o _h notic$ him until someone le>nt ! code ( dot & da% 9 :i* he work$1 & !n all at once :at he 0 say+ became cle>4 ,! *ief in/rum5t 9 translat+ ! message t ! light br+s is simply a prism1 a ?ree-corn]$ w$ge ( glass1 j ! same z ^? hang+ lu/res belong+ to ! *&eli]s4 ,:5 a piece ( glass l ?is is fix$ 9 a telescope 9 su* a way t ! sun's rays fall on x1 !n !re is ?r[n on to a piece ( pap] or any o!r suitable backgr\nd a broad col\r$ b& ( lovely light l a little ra9b[1 & ?is is call$ ! sun's spectrum1 & ! in/rum5t by :i* x is se5 is call$ a spectroscope4 ,b ?is 9 itself c\ld tell u little2 ! message x br+s lies 9 ! fact t :5 x has pass$ ?r\gh ! telescope1 s t x is magnifi$1 x is cross$ by hundr$s ( m9ute black l9es1 n plac$ ev5ly at all1 b scatt]$ up & d[n4 ,!re may be two s close toge!r t !y look l "o1 & !n ?ree f> ap>t1 & !n "s m at diff]5t di/ances4 ,:5 ?is rem>kable appe>ance 0 exam9$ c>efully x 0 f\nd t 9 sunlight ! l9es t appe>$ 7 always exactly ! same1 9 ! same places1 & ?is seem$ s curi\s t m5 began to seek = an explanation4 ,someone ?\ght ( an exp]im5t :i* might tea* u some?+ ab\t ! matt]1 & in/ead ( lett+ sunlight fall on ! prism1 he made an artificial light by burn+ "s /uff call$ sodium1 & !n all[$ ! b& ( col\r$ light to pass ?r\gh ! telescope2 :5 he exam9$ ! spectrum t result$1 he f\nd t1 ?\gh numb]s ( l9es to be f\nd 9 ! sun's spectrum 7 miss+1 !re 7 a few l9es "h exactly mat*+ a few ( ! l9es 9 ! sun's spectrum2 & ?is c\ld n be ! result ( *ance only1 = ! l9es are s ma!matically exact1 & are 9 !mselves s peculi>ly di/ribut$1 t x c\ld only mean t !y 7 due to ! same cause4 ,:at c\ld ?is signify1 !n1 b t away up !re 9 ! sun1 among o!r ?+s1 /uff call$ sodium1 v well kn[n to *emi/s on e>?1 is burn+8 ,aft] ?is _m o!r sub/ances 7 heat$ :ite-hot s z to give out light1 9 ord] to discov] if ! l9es to be se5 9 _! spectra 7 also to be f\nd 9 ! sun's spectrum4 ,"o ( ^! 0 iron1 &1 a/oni%+ to say1 all ! _m little ?read-l l9es t appe>$ 9 its spectrum 7 reproduc$ to a hair's-bread?1 among o!rs1 9 ! sun's spectrum4 ,s we h f\nd out beyond all possibility ( d\bt "s ( ! mat]ials ( :i* ! sun is made4 ,we "k t iron1 sodium1 hydrog51 & num]\s o!r sub/ances & elem5ts1 are all burn+ away !re 9 a t]rific furnace1 to :i* any furnace we h on e>? is b z ! flick] ( a mat*4 ,x 0 n1 ( c\rse1 mu* use apply+ ?is me?od to ! planets1 = we "k t ! light :i* comes f !m to u is only reflect$ sunlight1 & ?is1 inde$1 0 prov$ by means ( ! spectroscope4 ,b ! />s %9e by _! own light1 & ?is op5$ up a wide field = inquiry4 ,! difficulty 01 ( c\rse1 to get ! light ( "o /> sep>at$ f all ! re/1 because ! light ( "o /> is v fa9t & feeble to ca/ a spectrum at all4 ,yet by inf9ite pati5ce difficulties 7 ov]come4 ,"o /> alone 0 all[$ to ?r[ its light into ! telescope2 ! light pass$ ?r\gh a prism1 & %[$ a fa9t b& ( _m col\rs1 ) ! expect$ little black l9es cutt+ across x m or less ?ickly4 ,exam9ations h ?us be5 made ( hundr$s ( />s4 ,9 ! c\rse ( !m "s sub/ances z yet unkn[n to u on e>? h be5 enc\nt]$1 & 9 "s />s "o elem5t--hydrog5--is mu* /rong] ?an 9 o!rs2 b1 on ! :ole1 speak+ broadly1 x has be5 satisfactorily %[n t ! />s are made on ! same pr9ciples z our own sun1 s t ! reason+ ( a/ronom]s :i* _h argu$ !m to be suns 0 prov$4 ,illu/ration3 ,,! ,,spectrum ,,( ,,! ,,sun ,,& ,,sirius4 ,we h "h 9 ! picture ! spectrum ( ! sun & ! spectrum ( ,arcturus4 ,y c see t ! l9es :i* appe> 9 ! b& ( light belong+ to ,sirius are also 9 ! b& ( light belong+ to ! sun1 toge!r ) _m o!rs4 ,?is means t ! sub/ances flam+ out & s5d+ u light f ! f> away /> are also giv+ out light f our own sun1 & t ! sun & ,sirius bo? conta9 ! same elem5ts 9 _! compositions4 ,?is1 inde$1 seems en\gh = ! spectroscope to h accompli%$2 x has int]pret$ = u ! message light br+s f ! />s1 s t we "k beyond all possibility ( mi/ake t ^! gl[+1 tw9kl+ po9ts ( light are brilliant suns 9 a /ate ( int5se heat1 & t 9 !m are burn+ elem5ts ) :i* we ourselves are q famili>4 ,b :5 ! spectroscope _h done t1 its "w 0 n f9i%$1 = x has n only told u :at ! />s are made (1 b ano!r ?+ :i* we c\ld nev] h kn[n )\t x--namely1 if !y are mov+ t[>d u or go+ away f u4 ,,*apt] ,,xiii ,,re/less ,,/>s ,y rememb] we h already rem>k$ ^u ! difficulty ( tell+ h[ f> "o /> lies beh9d ano!r1 z we d n "k _! sizes4 ,x is1 to take ano!r simil> case1 easy en\gh to tell if a /> moves to "o side or ! o!r1 b v difficult by ord9>y obs]vation to tell if x is advanc+ t[>d u or runn+ away f u1 = ! only means we h ( judg+ is if x gets l>g] or small]1 & at t enorm\s di/ance ! fact :e!r x advances or rec$es makes no diff]5ce 9 its size4 ,n[1 ! spectroscope has *ang$ all ?is1 & we c tell q z c]ta9ly if a /> is com+ t[>d u z we c if x moves to "o side4 ,i w try to expla9 ?is4 ,y "k1 p]haps1 t s\nd is caus$ by vibration 9 ! air4 ,! noise1 :atev] x is1 j>s ! air & ! vibrations /rike on our e>s4 ,x is r ! same ?+ z ! result ( ?r[+ a /one into a pond3 f ! c5tre ( ! spla% little wavelets run out 9 ev]-wid5+ circles2 s ?r\gh ! air run ev]-wid5+ vibrations f e s\nd4 ,! m vibrations !re are 9 a second ! %rill] is ! note !y make4 ,9 a high note ! air-vibrations foll[ "o ano!r fa/1 p\r+ into "o's e> at a t]rific spe$1 s t ! app>atus 9 ! e> :i* receives !m itself vibrates fi]cely & records a high note1 :ile a l[] note br+s few] & sl[] vibrations 9 a second1 & ! e> is n s mu* di/urb$4 ,h y ev] notic$ t if a railway eng9e is sweep+-t[>d y & scream+ all ! "t1 its note seems to get %rill] & %rill]8 ,t is because ! eng9e1 9 advanc+1 s5ds ! vibrations out ne>] to y1 s m ( !m come 9 a second1 & ?us !y are cr[d$ up clos] toge!r1 & are high] & high]4 ,n[1 light is also caus$ by waves1 b !y are n ! same z s\nd waves4 ,light travels )\t air1 :]eas s\nd we "k _c travel )\t air1 & is ev] s mu* sl[]1 & altoge!r a gross]1 clumsi] ?+ ?an light4 ,b yet ! waves or rays :i* make light correspond 9 "s ways to ! vibrations ( s\nd4 ,:at corresponds to ! treble on ! piano is ! blue end ( ! spectrum 9 light1 & ! bass is ! r$ end4 ,n[1 :5 we are look+ at ! spectrum ( any body :i* is advanc+ swiftly t[>d u1 some?+ ( ! same effect is obs]v$ z 9 ! case ( ! %riek+ eng9e4 ,take any /> & imag9e t t /> is ha/5+ t[>d u at a pace ( ?ree hundr$ miles a second1 :i* is n at all an unusual rate = a />2 !n1 if we exam9e ! b& ( light1 ! spectrum1 ( su* a />1 we %all obs]ve an extraord9>y fact--all ^! little l9es we h spok5 ( are %ov$ up t[>d ! treble or blue end ( ! spectrum4 ,!y /ill rema9 j ! same di/ances f ea* o!r1 & are 9 twos & ?rees or s+le1 s t ! :ole set ( l9es is unalt]$ z a set1 b ev]yone ( !m is %ift$ a t9y fraction up t[>d ! blue end ( ! spectrum1 j a little displac$4 ,n[ if1 in/ead ( advanc+ t[>d u1 ?is same /> _h be5 ru%+ away f u at a simil> pace1 all ^! l9es w\ld h be5 mov$ a t9y bit t[>d ! r$ or bass end ( ! spectrum4 ,?is is kn[n to be c]ta9ly true1 s t by means ( ! spectroscope we c tell t "s ( ^! great sun-/>s are advanc+ t[>d u & "s rec$+ f u1 accord+ to :e!r ! multitudes ( little l9es 9 ! spectrum are %ift$ slightly to ! blue or ! r$ end4 ,y rememb] t x has be5 surmis$ t ! pace ! sun moves ) 8 sy/em is ab\t twelve miles a second4 ,?is seems fa/ en\gh to u1 :o ?9k t "o mile a m9ute is good "t = an express tra91 b x is sl[ comp>$ ) ! pace ( _m ( ! />s4 ,z ,i h said1 "s are travell+ at a rate ( betwe5 two hundr$ & ?ree hundr$ miles a second2 & x is due to ! spectroscope t we "k n only :e!r a /> is advanc+ t[>d u or rec$+ f u1 b also :e!r ! pace is great or n2 x ev5 tells u :at ! pace is1 up to ab\t half a mile a second1 :i* is v m>vell\s4 ,x is a curi\s fact t _m ( ! small />s %[ great] movem5t ?an ! l>ge ones1 :i* mayor may n mean t !y are ne>] to u4 ,x may be tak5 z e/abli%$ t !re is no su* ?+ z absolute re/ 9 ! univ]se3 ev]y?+1 />s & nebul alike1 are mov+ some:]e2 9 an inf9ite v>iety ( directions1 ) an inf9ite v>iety ( spe$ !y ha/5 ?is way & t4 ,x w\ld be impossible = any to rema9 /ill1 = ev5 suppos+ x _h be5 s '9 ! beg9n+1' ! va/ =ces at "w 9 ! univ]se w\ld n let x rema9 s4 ,out ( space w\ld come ! p]si/5t call ( gravitation3 atoms w\ld cry sil5tly to atoms4 ,!re c\ld be no p]fect equality ( pull on all sides2 f "o side or ano!r ! pull w\ld be ! /rong]4 ,sl[ly ! in]t mass w\ld obey & beg9 fall+ t[>d x2 x might be an in* at a "t1 b ) rapid increase1 until at la/ x also 0 ha/5+ "s :i!r 9 ?is univ]se :i* appe>s to u to be inf9ite4 ,x mu/ be rememb]$ t ^! />s1 ev5 :5 mov+ at an enorm\s pace1 d n *ange _! places 9 ! sky :5 reg>d$ by ord9>y obs]v]s4 ,x w\ld take ?\s&s ( ye>s = any ( ! con/ellations to appe> at all diff]5t f :at !y are n[1 ev5 ?\gh ! />s t compose !m are mov+ 9 diff]5t directions ) a great velocity1 = a space ( _m millions ( miles1 at ! di/ance ( mo/ ( ! />s1 w\ld be b z ! bread? ( a f9e hair z se5 by u on e>?4 ,s ?\s&s ( ye>s ago m5 look$ up at ! ,great ,be>1 & saw x app>5tly ! same z we see x n[2 yet = all t l5g? ( "t ! />s compos+ x h be5 ru%+ 9 ?is direction & t at an enorm\s spe$1 b d n appe> to u on ! e>? to alt] _! positions 9 reg>d to ea* o!r4 ,i "k ( no?+ t gives "o a m ov]:elm+ s5se ( ! might9ess ( ! univ]se & ! smallness ( ourselves ?an ?is fact4 ,f age to age m5 look on *angeless heav5s1 yet ?is app>5tly /able univ]se is full] ( flux & reflux ?an is ! re/less ocean itself1 & ! v wavelets on ! sea are n m num]\s nor m re/less ?an ! />s t be/rew ! sky4 ,,*apt] ,,xiv ,,! ,,col\rs ,,( ,,! ,,/>s ,has x ev] occurr$ to y t ! />s are n all ( ! same col\r8 ,x is true t1 j glanc+ at !m casually1 y might say !y are all :ite2 b if y exam9e !m m c>efully y _c help see+ t "s %9e ) a /eely blue light1 :ile o!rs are r$di% or yell[i%4 ,^! col\rs are n easy to di/+ui% ) ! nak$ eye1 & might n attract any att5tion at all unless !y 7 po9t$ out2 yet :5 att5tion is drawn to ! fact1 x is impossible to d5y ! r$ness ( "s1 su* z ,aldeb>an4 ,b ?\gh we may admit ?is1 we might add t ! col\rs are s v fa9t & inconspicu\s1 t !y might be1 aft] all1 only ! result ( imag9ation4 ,to prove t ! col\rs are con/ant & real we mu/ use a telescope1 & !n we ne$ h no fur!r d\bt ( _! reality1 = in/ead ( disappe>+1 ! col\rs ( "s />s /& out q vividly beyond ! possibility ( mi/ake4 ,r$ />s are a bright r$1 & !y are ! mo/ easily se5 ( all1 ?\gh ! o!r col\rs1 blue & yell[ & gre51 are se5 v decid$ly by "s p4 ,! r$ />s h be5 describ$ by v>i\s obs]v]s z resembl+ 'a drop ( blood on a black field1' 'mo/ magnific5t copp]-r$1' 'mo/ int5se blood-r$1' & 'gl[+ l a live coal out ( ! d>kness ( space4' ,"s p see !m z a %9+ r$1 l t ( a gl[+ cl\d at sunset4 ,!re=e !re c be no d\bt t ! col\rs are g5u9e en\gh1 & are tell+ u "s message4 ,?is message we are able to read1 = we h begun to und]/& ! language ! />s speak to u by _! light s9ce ! inv5tion ( ! spectroscope4 ,! spectroscope tells u t ^! col\rs indicate diff]5t /ages 9 ! developm5t ( ! />s1 or diff]5ces ( con/itution--t is to say1 9 ! elem5ts ( :i* !y are made4 ,our own sun is a yell[ />1 & o!r yell[ />s are ak9 to him2 :ile r$ & blue & gre5 />s conta9 diff]5t elem5ts1 or elem5ts 9 diff]5t proportions4 ,/>s d n always rema9 ! same col\rs = an indef9ite "t2 "o /> may *ange sl[ly f yell[ to :ite1 & ano!r f r$ to yell[2 & !re are in/ances ( notable *anges1 su* z t ( ! brilliant :ite ,sirius1 :o 0 /at$ 9 old times by _m diff]5t obs]v]s to be a r$ />4 ,all ?is makes u ?9k1 & ye> by ye> ?\ght leads u on to k1 & k ab\t ^! di/ant suns increases4 ,b ?\gh we "k a good deal n[1 !re are /ill _m que/ions we %\ld l to ask :i* we _c expect to h answ]$ = a long "t yet1 if ev]4 ,! /> col\rs h "s mean+s :i* we _c ev5 guess2 we c only notice ! facts reg>d+ !m4 ,= in/ance1 blue />s are nev] kn[n to be solit>y--!y always h a companion1 b :y ?is %\ld be s passes our compreh5sion4 ,:at is x 9 ! con/itution ( a blue /> :i* holds or attracts ano!r8 ,:atev] x may be1 x is e/abli%$ by repeat$ in/ances t blue />s d n /& alone4 ,9 ! con/ellation ( ,cygnus !re are two />s1 a blue & a yell[ "o1 :i* are ne> en\gh to ea* o!r to be se5 9 ! same telescope at ! same "t1 & yet 9 reality are sep>at$ by an almo/ incr$ible numb] ( billions ( miles4 ,b z we "k t a blue /> is nev] se5 alone1 & t x has (t5 z its companion a yell[i% or r$di% />1 x is probable t ^! two1 situat$ at an enorm\s di/ance f "o ano!r1 are yet 9 "s my/]i\s way dep5d5t on ea* o!r1 & are n m]ely se5 toge!r because !y happ5 to fall 9 ! same field ( view4 ,_m d\ble />s %[ mo/ beautifully contra/$ col\rs3 among !m are pairs ( yell[ & rose-r$1 gold5 & azure1 orange & purple1 orange & lilac1 copp]-col\r & blue1 apple-gre5 & *]ry-r$1 & s on4 ,9 ! ,s\!rn ,hemisph]e !re is a clu/] conta9+ s _m />s ( brilliant col\rs t ,sir ,john ,h]s*el nam$ x '! ,jewell$ ,clu/]4' ,i expect mo/ ( y h se5 an adv]tisem5t ( ,pe>'s ,soap1 9 :i* y are ask$ to />e at "s r$ lett]s1 & !n look away to "s :ite surface1 su* z a ceil+1 :5 y w see ! same lett]s 9 gre54 ,?is is because gre5 is ! complem5t>y or contra/+ col\r to r$1 & ! same ?+ is ! case ) blue & yell[4 ,:5 any "o col\r ( ei!r ( ^! pairs is se51 x t5ds to make ! o!r appe> by reaction1 & if ! eye gaz$ h>d at blue in/ead ( r$1 x w\ld next see yell[1 & n gre54 ,n[1 _m p to :om ?is curi\s fact is kn[n argue t p]haps ! col\rs ( ! d\ble />s are n real1 b ! effect ( contra/ only2 = in/ance1 !y say a r$ /> ne> a companion :ite "o w\ld t5d to make ! companion appe> gre51 & s1 ( c\rse1 x w\ld4 ,b ?is does n acc\nt = ! /> col\rs1 :i* are really inh]5t 9 ! />s !mselves1 z may be prov$ by cutt+ (f ! light ( "o />1 & look+ only at ! o!r1 :5 its col\r /ill appe>s un*ang$4 ,ano!r argum5t equally /rong aga9/ ! contra/ !ory is t ! col\rs ( />s 9 pairs are by no means always ^? :i* w\ld appe> if ! effect 0 only due to complem5t>y col\rs4 ,x is n always blue & yell[ or r$ & gre5 pairs t we see1 ?\gh ^! are frequ5t1 b _m o!rs ( v>i\s k9ds1 su* z copp] & blue1 & ruddy & blue4 ,we h !re=e come to ! conclusion t !re are 9 ?is a/oni%+ univ]se numb]s ( glori\sly col\r$ suns1 "s ( :i* app>5tly lie close toge!r4 ,:at foll[s8 ,:y1 we want to "k1 ( c\rse1 if ^! />s are really pairs connect$ ) ea* o!r1 or if !y only appe> s by be+ 9 ! same l9e ( sight1 ?\gh "o is inf9itely m di/ant ?an ! o!r4 ,& t "q also has be5 answ]$4 ,!re are n[ kn[n ?\s&s ( cases 9 :i* />s1 hi!rto reg>d$ z s+le1 h be5 sep>at$ into two1 or ev5 m1 by ! use ( a telescope4 ,( ^! ?\s&s1 "s hundr$s h be5 c>efully inve/igat$1 & ! result is t1 ?\gh !re are und\bt$ly "s 9 :i* ! connexion is m]ely accid5tal1 yet 9 by f> ! great] numb] ( cases ! two />s ?us se5 toge!r h really "s connexion :i* b9ds !m to "o ano!r2 !y are dep5d5t on "o ano!r4 ,?is has be5 made kn[n to u by ! work+ ( ! wond]ful law ( gravitation1 :i* is obey$ ?r\gh\t ! :ole univ]se4 ,we "k t by ! op]ation ( ?is law two mighty suns w be drawn t[>d ea* o!r ) a c]ta9 pull1 j z surely z we "k t a /one let loose f ! h& w fall ^u ! e>?2 s by not+ ! effect ( two mighty suns ^u ea* o!r _m facts ab\t !m may be f\nd out4 ,by ! mo/ m9ute & c>eful measurem5ts1 by ! use ( ! spectroscope1 & by e res\rce kn[n to sci5ce1 a/ronom]s h1 inde$1 actually f\nd out ) a ne> approa* to exactness h[ f> "s ( ^! great suns lie f ea* o!r1 & h[ l>ge !y are 9 comp>ison ) "o ano!r4 ,! v fir/ d\ble /> ev] discov]$ 0 "o :i* y h already se51 ! middle "o 9 ! tail ( ! ,great ,be>4 ,if y look at x y w be delight$ to f9d t y c see a wee /> close to x1 & y w ?9k y are look+ at an example ( a d\ble /> ) y\r v own eyes2 b y w be wrong1 = t wee /> is sep>at$ by untold di/ances f ! l>ge "o to :i* x seems s ne>4 ,9 fact1 any />s :i* c be se5 to be sep>ate by ! nak$ eye mu/ lie immeasurably f> ap>t1 h[ev] t9y seems ! space betwe5 !m4 ,su* />s may possibly h "s connexion ) ea* o!r1 b1 at any rate 9 ?is case1 su* a connexion has n be5 prov$4 ,no1 ! l>g] /> itself is made up ( two o!rs1 :i* c only be se5 ap>t 9 a telescope4 ,s9ce ?is discov]y d\ble />s h be5 pl5tifully f\nd 9 e "p ( ! sky4 ,! av]age space betwe5 su* d\ble />s z se5 f our e>? is--:at d y ?9k8 ,x is ! wid? ( a s+le hair held up ?irty-six feet f our eyes6 ,?is c\ld n1 ( c\rse1 be se5 )\t ! use ( a telescope or op]a-glasses4 ,x s]ves to give "s impression ( /> di/ances :5 we ?9k t ! millions & millions ( miles ly+ betwe5 ^? />s h %runk to t hair's-bread? se5 f our po9t ( view4 ,tw9 />s circle toge!r r\nd a common c5tre ( gravity1 & are b\nd by ! laws ( gravitation j z ! planets are4 ,our sun is a solit>y />1 ) no companion1 & !re=e su* a /ate ( ?+s seems to u to be incr$ible4 ,fancy two gigantic suns1 "o topaz-yell[ & ! o!r azure-blue1 circl+ ar\nd 9 endless movem5t6 ,:]e 9 su* a sy/em w\ld !re be room = ! planets8 ,h[ c\ld planets exi/ "u ! pull ( two suns 9 opposite directions8 ,/ill m wond]s are unfold$ z ! inquiry proce$s4 ,c]ta9 irregul>ities 9 ! motions ( "s ( ^! tw9 sy/ems l$ a/ronom]s to inf] t !y 7 act$ ^u by ano!r body1 ?\gh ?is o!r body 0 n disc]nible4 ,9 fact1 ?\gh !y c\ld n see x1 !y knew x mu/ be !re1 j z ,adams & ,lev]ri] knew ( ! exi/5ce ( ,neptune1 be=e ev] !y _h se5 him1 by ! irregul>ities 9 ! movem5ts ( ,uranus4 ,z ! results %[$1 x 0 !re1 & 0 comp>able 9 size to ! tw9 suns x influ5c$1 & yet !y c\ld n see x4 ,s !y conclud$ ?is ?ird body mu/ be d>k1 n light-giv+ l its companions4 ,we are ?us l$ to ! /range conclusion t "s ( ^! sy/ems are v complicat$1 & are =m$ n only ( %9+ suns1 b ( huge d>k bodies :i* _c be call$ suns4 ,:at are !y1 !n8 ,c !y be imm5se planets8 ,is x possible t life may !re exi/8 ,no fairy tale c\ld /ir ! imag9ation s p[]fully z ! ?\ght ( su* sy/ems includ+ a planet>y body z l>ge or l>g] ?an its sun or suns4 ,if inde$ life exi/s !re1 :at a v>i$ sc5e mu/ be pres5t$ day by day6 ,at "o "t bo? suns m+l+ _! fla%+ rays may be toge!r 9 ! sky2 at ano!r "t only "o appe>s1 a yell[ or blue sun1 z ! case may be4 ,! surface ( su* planets mu/ und]go weird trans=mations1 ! foliage %[+ "o day gre51 ! next yell[1 & ! next blue2 %ad[s ( azure & orange w alt]nate6 ,b fasc9at+ z su* ?\ghts are1 we c get no fur!r along t pa?4 ,to turn f fancy to facts1 we f9d t telescope & spectroscope h suppli$ u ) q en\gh matt] = wond] )\t call+ ^u imag9ation4 ,we h discov]$ t _m ( ! />s :i* seem to %9e ) a pure s+le light are d\ble1 & _m m consi/ n only ( two />s1 b ( sev]al1 "s ( :i* may be d>k bodies4 ,! ,pole ,/> 0 long kn[n to be d\ble1 & is n[ discov]$ to h a ?ird memb] 9 its sy/em4 ,^! multiple sy/ems v>y f "o ano!r 9 almo/ e case4 ,"s are made up ( a mighty /> & a comp>atively small "o2 o!rs are compos$ ( />s equal 9 light-giv+ p[]--tw9 suns4 ,"s progress swiftly r\nd _! orbits1 "s g sl[ly2 inde$1 s sl[ly t dur+ ! c5tury !y h be5 "u obs]vation only ! v fa9te/ sign ( movem5t has be5 detect$2 & 9 o!r sy/ems1 :i* we are b\nd to suppose d\ble1 ! />s are s sl[ 9 _! movem5ts t no progress seems to h be5 made at all4 ,! /> we "k z ! ne>e/ to u 9 ! heav5s1 ,alpha ,c5tauri1 is compos$ ( two v bright p>tn]s1 :i* take ab\t eighty-sev5 ye>s to trav]se _! orbit4 ,!y sometimes come z ne> to ea* o!r z ,saturn is to ! sun4 ,9 ! case ( ,sirius a/ronom]s f\nd out t he _h a companion by reason ( 8 irregul>ities ( movem5t be=e !y discov]$ t companion1 :i* is app>5tly a v small />1 only to be disc]n$ ) good telescopes4 ,b "h1 aga91 x w\ld be unwise to judge only by :at we see4 ,?\gh ! /> appe>s small1 we "k by ! influ5ce x ex]cises on ,sirius t x is v ne>ly ! same size z he is4 ,?us we judge t x is poor 9 light-giv+ prop]ty2 9 fact1 its %9+ p[] is mu* less ?an t ( its companion1 ?\gh its size is s ne>ly equal4 ,?is is n wond]ful1 = ,sirius's m>vell\s light-giv+ p[] is "o ( ! wond]s ( ! univ]se2 he %9es z brilliantly z tw5ty-n9e or ?irty ( our suns6 ,9 "s cases ! d>k body :i* we _c see may ev5 be l>g] ?an ! %9+ "o1 ?r\gh :i* alone we c "k any?+ ( x4 ,"h we h a new idea1 a h9t t 9 "s ( ^! sy/ems !re may be a mighty e>? ) a small] sun go+ r\nd x1 z m5 imag9$ our sun w5t ar\nd ! e>? be=e ! real tru? 0 f\nd out4 ,s we see t1 :5 we speak ( ! />s z suns comp>able ) our sun1 we _c ?9k ( !m all z be+ exactly on ! same model4 ,!re are endless v>ieties 9 ! sy/ems2 !re are solit>y suns l ours :i* may h a numb] ( small planets go+ r\nd !m1 z 9 ! sol> sy/em2 b !re are also d\ble suns go+ r\nd ea* o!r1 suns ) mighty d>k bodies revolv+ r\nd !m :i* may be planets1 & huge d>k bodies ) small suns too4 ,e increase ( k op5s up new wond]s1 & ! _w 9 :i* we live is b "o k9d ( _w amid an inf9ite numb]4 ,9 ?is *apt] we h le>nt an altoge!r new fact--! fact t ! ho/s ( heav5 comprise n only ^? %9+ />s we are accu/om$ to see1 b also d>k bodies equally massive1 & probably equally num]\s1 :i* we _c see4 ,9 fact1 ! regions ( space may be /rewn ) su* d>k bodies1 & we c\ld h no possible means ( discov]+ !m unless !y 7 ne> en\gh to "s %9+ body to ex]t an influ5ce ^u x4 ,x is n ) 8 eyes alone1 or ) 8 s5ses1 man kn[s ( ! exi/5ce ( ^! great worlds1 b (t5 solely by ! use ( ! p[]s ( 8 m9d4 ,,*apt] ,,xv ,,tempor>y ,,& ,,v>iable ,,/>s ,x is a cle> night1 ne>ly all ! _w is asleep1 :5 an a/ronom] crosses 8 lawn on 8 way to 8 obs]vatory to sp5d ! d>k h\rs 9 mak+ inve/igations into pr(\nd space4 ,8 brilliant m9d1 foll[+ ! rays ( light :i* %oot f ! fur!/ />1 w trav]se immeasurable di/ances1 :ile ! body is =gott54 ,j be=e ent]+ ! obs]vatory he pauses & looks up2 8 eye cat*es sight ( some?+ t arre/s him1 & he /ops involunt>ily4 ,yet any /rang] /&+ beside him1 & gaz+ :]e he gazes1 w\ld see no?+ unusual4 ,!re is no fi]y comet ) its tail /ret*+ across f z5i? to horizon1 no flam+ meteor da%+ across ! d>k5$ sky4 ,b t !re is some?+ unusual to be se5 is evid5t1 = ! a/ronom] brea!s quickly1 & aft] ano!r e>ne/ scrut9y ( ! object :i* has attract$ him1 he ru%es into ! obs]vatory1 se>*es = a />-*>t1 & exam9es att5tively t "p ( ! sky at :i* he has be5 gaz+4 ,he runs 8 f+] ov] ! *>t3 "h & !re are ! well-kn[n />s t m>k t con/ellation1 b "h8 ,9 t "p !re is no /> m>k$1 yet he kn[s1 = 8 own eyes h told him b a few mom5ts ago1 t "h !re is actually blaz+ a />1 n l>ge1 p]haps1 b cle> en\gh to be se5 )\t a telescope--a />1 maybe1 :i* no eye b 8 has yet obs]v$6 ,he hurries to 8 telescope1 & adju/s x s z to br+ ! /rang] into ! field ( view4 ,a new />6 ,:5ce has x come8 ,:at does x mean8 ,by ! next day at ! late/ ! news has fl[n ov] ! wires1 & all ! sci5tific _w is aw>e t a new /> has be5 detect$ :]e no /> ev] 0 se5 be=e4 ,hundr$s ( telescopes are turn$ on to x2 its spectrum is not$1 & x /&s reveal$ z be+ 9 a /ate ( conflagration1 hav+ blaz$ up f obscurity to conspicu\sness4 ,night aft] night its brilliance gr[s1 until x ranks ) ! brighte/ />s 9 heav51 & !n x dies d[n & gr[s dim1 gradually s9k+--s9k+ into ! obscurity f :5ce x em]g$ s briefly1 & its place 9 ! sky kn[s x no m4 ,x may be !re /ill1 b s inf9itely fa9t & f> away t no p[] at our comm& c reveal x to u4 ,& ! amaz+ "p ( x is t ?is huge disa/]1 ?is mighty conflagration1 is n actually happ5+ z x is se51 b has happ5$ _m hundr$s ( ye>s ago1 ?\gh ! message br\ght by ! light c>ri] has b rea*$ u n[4 ,!re h n be5 a great _m su* outbur/s record$1 ?\gh _m may h tak5 place unrecord$1 = ev5 9 ^! days1 :5 tra9$ obs]v]s are ceaselessly wat*+ ! sky1 'new' />s are n always notic$ at once4 ,9 #ahib a new /> appe>$1 & %one = two mon?s be=e anyone notic$ x4 ,?is p>ticul> "o nev] rose to any v brilliant size4 ,i twas situat$ 9 ! con/ellation ( ,auriga1 & 0 notic$ on ,febru>y #a4 ,x rema9$ fairly bright until ,m>* #f1 :5 x began to die d[n2 b x has n[ sunk s l[ t x c only be se5 9 ! v l>ge/ telescopes4 ,photography has be5 mo/ useful 9 record+ ^! />s1 = :5 "o is notic$ x has sometimes be5 f\nd t x has be5 record$ on a photographic plate tak5 "s "t previ\sly1 & ?is %[s u h[ long x has be5 visible4 ,m & m photography becomes ! useful h&maid ( a/ronom]s1 = ! photographic prep>$ plate is m s5sitive to rays ( light ?an ! human eye1 &1 :at is m useful /ill1 su* plates reta9 ! rays t fall ^u !m1 & fix ! impression4 ,also on a plate ^! rays are cumulative--t is to say1 if a v fa9t /> %9es cont9u\sly on a plate1 ! long] ! plate is expos$1 )9 c]ta9 limits1 ! cle>] w ! image ( t /> become1 = ! light rays fall "o on ! top ( ! o!r1 & t5d to en=ce ea* o!r1 & s emphasize ! impression1 :]eas ) our eyes x is n ! same ?+ at all1 = if we d n see an object cle>ly because x is too fa9t1 we d n see x any bett]1 h[ev] mu* we may />e at ! place :]e x ought to be4 ,?is is because ea* light ray t rea*es our eye makes its own impression1 & passes on2 !y d n become heap$ on ea* o!r1 z !y d on a photographic plate4 ,"o v>iable /> 9 ,p]seus1 discov]$ 9 #aija1 rose to su* brilliancy t = "o night x 0 que5 ( ! ,nor!rn ,hemisph]e1 out%9+ all ! o!r fir/-class />s4 ,x rose into prom95ce ) wond]ful quickness1 & sank equally fa/4 ,at its height x out%one our sun eight ?\s& times6 ,?is /> 0 s f> f u t x 0 reckon$ its light mu/ take ab\t ?ree hundr$ ye>s to rea* u1 consequ5tly ! great conflagration1 or :atev] caus$ ! outbur/1 mu/ h tak5 place 9 ! reign ( ,james ,i41 ?\gh1 z x 0 only se5 "h 9 #aija1 x 0 call$ ! new /> ( ! new c5tury4 ,:5 ^! new />s die d[n !y sometimes cont9ue to %9e fa9tly = a long "t1 s t !y are visible ) a telescope1 b 9 o!r cases !y may die out altoge!r4 ,we "k v little ab\t !m1 & h b small opportunity = obs]v+ !m1 & s x is n safe to haz>d any !ories to acc\nt = _! peculi>ities4 ,at fir/ m5 suppos$ t ! great flame 0 made by a viol5t collision betwe5 two bodies com+ toge!r ) great velocity s t bo? fl>$ up1 b ?is speculation has be5 %[n by ! spectroscope to be improbable1 & n[ x is suppos$ by "s p t two />s j\rney+ ?r\gh space may pass ?r\gh a nebul\s region1 & ?us may fl>e up1 & su* a !ory is back$ up by ! fact t a v great numb] ( su* />s d seem to be mix$ up 9 "s /range way ) a nebul\s haze4 ,all ^! new />s t we h be5 discuss+ s f> h only blaz$ up once & !n di$ d[n1 b !re is ano!r class ( />s q z peculi>1 & ev5 m difficult to expla91 & ^! are call$ v>iable />s4 ,!y get bright] & bright] up to a c]ta9 po9t1 & !n die d[n1 only to become bright once m1 & ^! *anges occur ) ! utmo/ regul>ity1 s t !y are kn[n & c be pr$ict$ be=eh&4 ,?is is ev5 m unacc\ntable ?an a sudd5 & unrepeat$ outbur/1 = "o c und]/& a great fl>e-up1 b t a /> %\ld fl>e & die d[n ) regul>ity is almo/ beyond compreh5sion4 ,cle>ly we mu/ look fur!r ?an be=e = an explanation4 ,let u fir/ exam9e ! facts we "k4 ,v>iable />s diff] greatly f ea* o!r4 ,"s are g5]ally ( a l[ magnitude1 & only become bright = a %ort "t1 :ile o!rs are bright mo/ ( ! "t & die d[n only = a %ort "t4 ,o!rs become v bright1 !n s9k a little bit1 b n s l[ z at fir/2 !n !y become bright aga91 &1 la/ly1 g "r d[n to ! l[e/ po9t1 & !y keep on always ?r\gh ?is regul> cycle ( *anges4 ,"s g ?r\gh ! :ole ( ^! *anges 9 ?ree days1 & o!rs take mu* long]4 ,! p]iods1 z ! int]vals betwe5 ! complete r\nd ( *anges are call$1 v>y1 9 fact1 betwe5 ?ree days & six hundr$6 ,x may seem impossible t *anges cov]+ s long z six hundr$ days c\ld be kn[n & foll[$1 b !re is no?+ t ! pati5ce ( a/ronom]s w n compass4 ,"o v well-kn[n v>iable /> y c see = y\rselves1 & z an ounce ( obs]vation is wor? a p\nd ( he>say1 y might take a little tr\ble to f9d x4 ,g out on any cle> />light night & look4 ,n v f> f ,cassiopeia 7,w471 to ! left z y face x1 are ?ree bright />s runn+ d[n 9 a great curve4 ,^! are 9 ! con/ellation call$ ,p]seus1 & a little to ! "r ( ! middle & l[e/ "o is ! only v>iable /> we c see 9 ! sky )\t a telescope4 ,?is is ,algol4 ,= ! great] "p ( ?ree days he is a bright /> ( ab\t ! second magnitude1 !n he beg9s to fade1 & = f\r & a half h\rs gr[s /eadily dimm]4 ,at ! dimme/ he rema9s = ab\t tw5ty m9utes1 & !n rises aga9 to 8 ord9>y brightness 9 ?ree & a half h\rs4 ,h[ c we expla9 ?is8 ,y may possibly be able to sugge/ a reason4 ,:at d y say to a d>k body revolv+ r\nd ,algol1 or1 r1 revolv+ ) him r\nd a common c5tre ( gravity8 ,if su* a ?+ 7 inde$ true1 & if su* a body happ5$ to pass betwe5 u & ,algol at ea* revolution1 ! light ( ,algol w\ld be cut (f or eclips$ 9 proportion to ! size ( su* a body4 ,if ! d>k body 7 ! full size ( ,algol & pass$ "r betwe5 him & u1 x w\ld cut (f all ! light1 b if x 7 n q ! same size1 a little w\ld /ill be se54 ,& ?is is really ! explanation ( ! /range *anges 9 ! brightness ( ,algol1 = su* a d>k body z we are imag9+ does 9 reality exi/4 ,x is a l>ge d>k body1 v ne>ly z l>ge z ,algol himself1 & if1 z we may conjecture1 x is a mighty planet1 we h ! extraord9>y example ( a planet & its sun be+ ne>ly ! same size4 ,we h se5 t ! eclipse happ5s e ?ree days1 & ?is means1 ( c\rse1 t ! planet>y body mu/ g r\nd its sun 9 t "t1 s z to return aga9 to its position betwe5 u & him1 b ! ?+ is difficult to believe4 ,:y1 ! ne>e/ ( all our planets to ! sun1 ! wee ,m]cury1 takes eighty-sev5 days to complete its orbit1 & "h is a mighty body ha/5+ r\nd its sun 9 ?ree6 ,to d ?is 9 ! "t ! l>ge d>k planet mu/ be v ne> to ,algol2 inde$1 a/ronom]s h calculat$ t ! surfaces ( ! two bodies are n m ?an ab\t two million miles ap>t1 & ?is is a trifle :5 we consid] t we ourselves are m ?an =ty-six times z f> z t f ! sun4 ,at ?is di/ance ,algol1 z obs]v$ f ! planet1 w fill half ! sky1 & ! heat he gives out mu/ be some?+ /up5d\s4 ,also ! effects ( gravitation mu/ be que] inde$1 act+ on two su* huge bodies s close toge!r4 ,if any be+s live 9 su* a /range _w1 ! pull :i* draws !m to _! mighty sun mu/ be v ne>ly equal to ! pull :i* holds !m to _! own globe2 ! two toge!r may c\nt]act ea* o!r1 b ! effect mu/ be /range6 ,f irregul>ities 9 ! movem5ts ( ,algol x has be5 judg$ t !re may be also 9 ! same sy/em ano!r d>k body1 b ( x no?+ has be5 def9itely asc]ta9$4 ,b all v>iable />s ne$ n necess>ily be due to ! light be+ int]cept$ by a d>k body4 ,!re are cases :]e two bright />s 9 revolv+ r\nd ea* o!r produce ! same effect2 = :5 se5 side by side ! two />s give twice z mu* light z :5 "o is hidd5 beh9d ! o!r1 & z !y are se5 alt]nately side by side & 9 l9e1 !y seem to alt] regul>ly 9 lu/re4 ,,*apt] ,,xvi ,,/> ,,clu/]s ,,& ,,nebul ,c\ld y po9t out any /> clu/] 9 ! sky8 ,y c\ld if y w\ld only ?9k = a m9ute1 = "o has be5 m5tion$ already4 ,?is is ! clu/] kn[n z ! ,pleiades1 & x is s peculi> & s diff]5t f any?+ else1 t _m p recognize ! gr\p & "k :]e to look = x ev5 be=e !y "k ! ,great ,be>1 ! fav\rite con/ellation 9 ! nor!rn sky1 itself4 ,! ,pleiades is a real /> clu/]1 & ! *ief />s 9 x are at su* enorm\s di/ances f "o ano!r t !y c be se5 sep>ately by ! eye unaid$1 :]eas 9 mo/ clu/]s ! />s appe> to be s close toge!r t )\t a telescope !y make a m]e blur ( brightness4 ,= a long "t x 0 suppos$ t ! />s compos+ ! ,pleiades c\ld n really be connect$ because ( ! great di/ances betwe5 !m2 =1 z y "k1 ev5 a hair's-bread? app>5tly betwe5 />s signifies 9 reality _m millions ( miles4 ,light travell+ f ! ,pleiades to u1 at t incompreh5sible pace ( :i* y already "k1 takes a hundr$ & n9ety ye>s to rea* u6 ,at ?is incr$ibly remote di/ance lies ! ma9 "p ( ! clu/] f u2 b x is m m>vell\s /ill t we h e reason to believe t ! outly+ />s ( ?is clu/] are z f> f ! c5tral ones z ! ne>e/ /> we "k (1 ,alpha ,c5tauri1 is f u6 ,little wond] 0 x1 !n1 t m5 hesitat$ to ascribe to ! ,pleiades any real connection ) ea* o!r1 & suppos$ !m to be m]ely an assemblage ( />s :i* seem$ to u to lie toge!r4 ,) ! unaid$ eye we see comp>atively few />s 9 ! ,pleiades4 ,six is ! usual numb] to be c\nt$1 ?\gh p ) v good sight h made out f\rte54 ,view$ ?r\gh ! telescope1 h[ev]1 ! sc5e *anges3 into ?is "p ( space />s are cr[d$ 9 a/oni%+ pr(usion2 x is impossible to c\nt !m1 & ) e increase 9 ! p[] ( ! telescope /ill m are reveal$4 ,well ov] a ?\s& 9 ?is small space seems no exagg]at$ e/imate4 ,n[1 x is impossible to say h[ _m ( ^! really belong to ! gr\p1 & h[ _m are se5 !re accid5tally1 b obs]vations ( ! mo/ prom95t ones h %[n t !y are all mov+ 9 exactly ! same direction at ! same pace4 ,x w\ld be aga9/ probability to conceive t su* a ?+ c\ld be ! result ( m]e *ance1 consid]+ ! inf9ite v>iety ( /> movem5ts 9 g5]al1 & s we are b\nd to believe t ?is wond]ful collection ( />s is a real gr\p1 & n only an app>5t "o4 ,s spl5did are ! great suns t illum9ate ?is mighty sy/em1 t at lea/ fifty or sixty ( !m f> surpass our own sun 9 brilliancy4 ,!re=e :5 we look at t t9y sp>kl+ gr\p we mu/ 9 imag9ation picture x z a va/ clu/] ( mighty />s1 all controll$ & sway$ by "s dom9ant impulse1 ?\gh sep>at$ by spaces en\gh to make ! bra9 reel 9 ?9k+ ( !m4 ,if ^! suns possess also att5dant planets1 :at a galaxy ( worlds1 :at a univ]se )9 a univ]se is "h6 ,o!r /> clu/]s !re are1 n s conspicu\s z ! ,pleiades1 & mo/ ( ^! c only be se5 ?r\gh a telescope1 s we may be ?ankful t we h "o example s spl5did )9 our own vision4 ,!re are "s clu/]s s f> & fa9tly %9+ t !y 7 at fir/ ?\ght to be nebul1 & n />s at all2 b ! telescope gradually reveal$ ! fact t _m ( ^! are made up ( />s1 & s p began to ?9k t all fa9t %9+ pat*es ( nebul\s light 7 really /> clu/]s1 :i* w\ld be resolv$ into />s if only we _h bett] telescopes4 ,s9ce ! inv5tion ( ! spectroscope1 h[ev]1 fre% light has be5 ?r[n on ! matt]1 = ! spectrum :i* is %[n by "s ( ! nebul\s pat*es is n ! same z t %[n by />s1 & we "k t _m ( ^! /range appe>ances are n made up ( inf9itely di/ant />s4 ,we are talk+ "h q freely ab\t nebul because we h met "o long ago :5 we discuss$ ! gradual evolution ( our own sy/em1 & we "k q well t a nebula is compos$ ( lum9\s fa9tly-gl[+ gas ( extreme f95ess & ?9ness4 ,we see 9 ! sky at ! pres5t "t :at we may take to be object-lessons 9 our own hi/ory1 = we see nebul ( all sorts & sizes1 & 9 "s />s are mix$ up1 & 9 o!rs />s are b dimly se51 s t x does n require a great /ret* ( ! imag9ation to picture ^! />s z be+ born1 em]g+ f ! swaddl+ b&s ( filmy webs t h enwrapp$ !m2 & o!r nebul seem to be gas only1 ?9 & gl[+1 ) no />s at all to be f\nd 9 x4 ,we /ill "k v little ab\t ^! my/]i\s appe>ances1 b ! "w ( classify+ & resolv+ !m is go+ on apace4 ,nebul are divid$ into sev]al classes1 b ! easie/ di/9ction to rememb] is t betwe5 :ite nebul & gre5 nebul4 ,?is is n to say t we c see "s col\r$ gre51 b t gre5 appe>s 9 ! spectrum ( "s ( ! nebul1 :ile ! spectrum ( a :ite nebula is m l t ( a />4 ,x is =tunate = u t 9 ! sky we c see )\t a telescope "o in/ance ( ea* ( ! sev]al objects ( int]e/ t we h ref]r$ to4 ,we h be5 able to see "o v vivid example ( a v>iable />2 we h se5 "o v beautiful example ( a /> clu/]2 & x rema9s to look = "o v good example ( a :ite nebula4 ,j z 9 f9d+ ,algol y 7 do+ a little bit ( practical "w1 prov+ some?+ ( :i* y _h read1 s by see+ ?is nebula y w rememb] m ab\t nebul 9 g5]al ?an by read+ _m *apt]s on ! subject4 ,?is p>ticul> nebula is 9 ,&rom$a1 & is n f> f ,algol2 & x is n difficult to f9d4 ,x is ! only "o t c be well se5 )\t a telescope1 & 0 kn[n to ! anci5ts2 x is believ$ to h be5 m5tion$ 9 a book ( ! t5? c5tury6 ,if y take an imag9>y l9e d[n f ! two left-h& />s ( ,cassiopeia1 & foll[ x c>efully1 y w come be=e long to a r fa9t />1 & close to x is ! nebula4 ,:5 y cat* sight ( x y w1 p]haps1 at fir/ be disappo9t$1 = all y w see is a s(t blur ( :ite1 z if someone _h laid a dab ( lum9\s pa9t on ! sky ) a f+]2 b z y gaze at x night aft] night & realize its un*angeabl5ess1 realize also t x is a mass ( gl[+ gas1 an isl& 9 space1 inf9itely di/ant1 unsupport$ & inexplicable1 some?+ ( ! wond] ( x w creep ov] y4 ,illu/ration3 ,dr4 ,max ,wolf4 ,,! ,,great ,,nebula ,,9 ,,&rom$a4 ,?\s&s ( telescopic nebul are n[ kn[n1 & h be5 exam9$1 & !y are ( all %apes4 ,r\ghly1 !y h be5 divid$ up into sev]al classes--^? t seem to u to be r\nd & ^? t are long ovals1 l ?is "o 9 ,&rom$a2 b ^! may1 ( c\rse1 be only r\nd ones se5 edgewise by u2 o!rs are v irregul>1 & spread ov] an enorm\s "p ( ! sky4 ,! mo/ rem>kable ( ^! is t 9 ,orion1 & if y look v h>d at ! middle /> 9 ! sword-hilt ( ,orion1 y may be able to make out a fa9t mi/9ess4 ,?is1 :5 se5 ?r\gh a telescope1 becomes a wond]ful & f>-spread+ nebula1 ) bright] & d>k] p>ts l gulfs 9 x1 & d>k *annels4 ,x has be5 sometimes call$ ! ,fi%-m\? ,nebula1 f a fanciful idea z to its %ape4 ,inde$1 s extraord9>ily v>i$ are ^! curi\s /ructures1 t !y h be5 comp>$ ) numb]s ( diff]5t objects4 ,we h "s l bru%es1 o!rs resembl+ fans1 r+s1 sp9dles1 keyholes2 o!rs l animals--a fi%1 a crab1 an owl1 & s on2 b ^! sugge/ions are imag9ative1 & h no?+ to d ) ! real problem4 ,9 ,! ,sy/em ( ! ,/>s ,miss ,cl]ke says3 ',9 reg>d+ ^! s+ul> /ructures we seem to see surges & spray-flakes ( a nebul\s ocean1 bewit*$ into sudd5 immobility2 or a rack ( tempe/-driv5 cl\ds hang+ 9 ! sky1 mom5t>ily await+ ! trans=m+ viol5ce ( a fre% onset4 ,sometimes cont95ts ( pale light are sep>at$ by n>r[ /raits ( comp>ative d>kness2 else:]e obscure spaces are hemm$ 9 by lum9\s inlets & *annels4' ,"o curi\s po9t ab\t ! ,orion ,nebula is t ! /> :i* seems to be 9 ! mid/ ( x resolves itself "u ! telescope into n "o b six1 ( v>i\s sizes4 ,nebul are 9 mo/ cases too enorm\sly remote f ! e>? = u to h any possible means ( comput+ ! di/ance2 b we may take x t light mu/ j\rney at lea/ a ?\s& ye>s to rea* u f !m1 & 9 _m cases mu* m4 ,!re=e1 if at ! "t ( ! ,norman ,conque/ a nebula _h begun to gr[ dim & fade away1 x w\ld1 = all int5ts & purposes1 /ill be !re = u1 & = ^? t come aft] u = sev]al g5]ations1 ?\gh all t exi/$ ( x 9 reality w\ld be its pale image fleet+ onw>d ?r\gh space 9 all directions 9 ev]-wid5+ circles4 ,t nebul d sometimes *ange we h evid5ce3 !re are cases 9 :i* "s h gr[n indisputably bright] dur+ ! ye>s !y h be5 "u obs]vation1 & "s nebul t h be5 record$ by c>eful obs]v]s seem to h vani%$4 ,:5 we consid] t ^! /range bodies fill _m1 _m times ! area ( our :ole sol> sy/em to ! out]mo/ b\nds ( ,neptune's orbit1 x is difficult to imag9e :at =ce x is t acts on !m to revive or qu5* _! light4 ,t t light is n ! direct result ( heat has long be5 kn[n2 x is probably "s =m ( electric excitem5t caus+ lum9osity1 v mu* z x is caus$ 9 ! comets4 ,inde$1 _m p h be5 tempt$ to ?9k ( ! nebul z ! comets ( ! univ]se1 & 9 "s po9ts !re are1 no d\bt1 /rong resemblances betwe5 ! two4 ,bo? %9e 9 ! same way1 bo? are s fa9t & ?9 t />s c be se5 ?r\gh !m2 b ! spectroscope %[s u t to c>ry ! idea too f> w\ld be wrong1 z !re are _m diff]5ces 9 con/itution4 ,we h se5 t !re are d>k />s z well z light />s2 if s1 may !re n be d>k nebul z well z light ones8 ,x may v well be s4 ,we h se5 t !re are reasons = suppos+ our own sy/em to h be5 at fir/ a cool d>k nebula rotat+ sl[ly4 ,! heav5s may be full ( su* bodies1 b we c\ld n disc]n !m4 ,_! ?9ness w\ld prev5t _! hid+ any />s t happ5$ to be beh9d !m4 ,no evid5ce ( _! exi/5ce c\ld possibly be br\ght to u by any *annel t we "k4 ,x is true t1 besides ! d>k rifts 9 ! bright nebul1 :i* may !mselves be caus$ by a d>k] & non-lum9\s gas1 !re are also /range rifts 9 ! ,milky ,way1 :i* at "o "t 7 conjectur$ to be due to a d>k body int]v5+ betwe5 u & ! />ry backgr\nd4 ,?is idea is n[ q disc>d$2 :atev] may cause !m1 x is n t4 ,"o ( ! mo/ />tl+ ( ^! rifts is t call$ ! ,coal-,sack1 9 ! ,s\!rn ,hemisph]e1 & x occurs 9 a "p ( ! sky o!rwise s bright t x is ! m noticeable4 ,no possible explanation has yet be5 sugge/$ to acc\nt = x4 ,?us x may be se5 t1 ?\gh mu* has be5 discov]$1 mu* rema9s to be discov]$4 ,by ! pati5t "w ( g5]ations ( a/ronom]s we h ga9$ a cle> idea ( our own position 9 ! univ]se4 ,"h are we on a small globe1 sw++ r\nd a f> mighti] & a self-lum9\s globe1 9 company ) sev5 o!r planets1 _m ( :i*1 includ+ ourselves1 are att5d$ by satellites or moons4 ,betwe5 ! orbits ( ^! planets is a r+ or zone ( t9y bodies1 also go+ r\nd ! sun4 ,into ?is sy/em fla% e n[ & !n /range lum9\s bodies--"s com+ b once1 nev] to return2 o!rs return+ aga9 & aga94 ,f> out 9 space lies ?is isl& ( a sy/em1 & beyond ! gulfs ( space are o!r suns1 ) o!r sy/ems3 "s may be ak9 to ours & "s q diff]5t4 ,/rewn ab\t at inf9ite di/ances are /> clu/]s1 nebul1 & o!r my/]i\s objects4 ,! :ole implies design1 creation1 & ! work+ ( a mighty intellig5ce2 & yet !re are small1 weak creatures "h on ?is little globe :o refuse to believe 9 a ,god1 or :o1 :ile ackn[l$g+ ,him1 w\ld believe !mselves to "k bett] ?an ,he4 ,,! ,,end ,,bill+ ,,& ,,sons1 ,,ltd41 ,,pr9t]s1 ,,guild=d