,A ZEPTOSECOND "<SYMBOL ZS"> IS "O
SEXTILLION? ( A SECOND  #AJ_< SECONDS1 A
"O FOLL[$ BY TW5TY-"O Z]OES WOR? ( "T4
,X IS ! %ORTE/ UNIT ( "T T PHYSICI/S H
"E ACTUALLY M1SUR$ "S?+ 93 9 #BJBJ1 A
T1M 9 ,FRANKFURT "TD A PHOTON CROSS+ A
HYDROG5 MOLECULE AT #BDG ZEPTOSECONDS1
SETT+ ! RECORD = ! FA/E/ PROCESS "E
OBS]V$4 ,2L ! ZEPTOSECOND LIES ONLY "O
%ORT] "ND ,,SI 9T]VAL  ! YOCTOSECOND
"<#AJ_<;T ;S">  & 2Y BO?1 ! ,PLANCK "T
"<@9#E4D  #AJ_<TT ;S">1 ": PHYSICS XF
MAY /OP MAK+ S5SE4
,! LADD] ( SMALL "T
,"T GETS SMALL FA/4 ,EA* "ND /EP IS A
?\S& "TS %ORT] ?AN ! LA/3
NANOSECOND  #AJ_<;Y  ;S  LI<T TRAVELS
@9#CJ CM "<"O FOOT">  PICOSECOND  #AJ_<
;S  *EMICAL BOND VIBRA;NS  FEMTOSECOND
#AJ_<;U ;S  FA/E/ *EMICAL REAC;NS
"<,NOBEL #AIII">  ATTOSECOND  #AJ_<;X ;S
ELECTRON MO;N "<,NOBEL #BJBC"> 
ZEPTOSECOND #AJ_< ;S  PHOTON CROSS+ A
MOLECULE2 NUCLE> PHOTONS  YOCTOSECOND
#AJ_<;T ;S  QU>K-GLUON PLASMA FLA%ES2
HYPO!TICAL PHYSICS  ,PLANCK "T #AJ_<TT
;S  2L ?1 8"T0 MAY N EXI/
,TO FEEL ! SCALE3 A ZEPTOSECOND IS TO "O
SECOND Z "O SECOND IS TO AB #CA4G
TRILLION YE>S  R\<LY #B1CJJ "TS ! CURR5T
AGE ( ! UNIV]SE4 ,LI<T1 ! FA/E/ ?+ "!
IS1 TRAVELS B>ELY A ?IRD ( A NANOMETRE 
AB ! WID? ( A SMALL VIRUS  9 "O
ZEPTOSECOND4
,H[ D Y EV5 "T #BDG ZEPTOSECONDS8
,NO CLOCK TICKS T FA/  ! M1SURE;T IS
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EXP]I;T1 ,RE9H>D ;,DRN]'S GR\P AT ,GOE!
,UNIV]S;Y ,FRANKFURT FIR$ AN ;,X-RAY
PHOTON AT A HYDROG5 MOLECULE & M1SUR$ :
( ! TWO ATOMS ! PHOTON HIT F/ BY WAT*+ !
9T]F];E PATT]N ( ! EJECT$ ELECTRONS4 ,!
DI6];E 2T ! TWO >RIVAL R1D+S  H[ L;G !
PHOTON TOOK TO CROSS ! MOLECULE  CAME \
TO #BDG ZEPTOSECONDS ON AV]AGE4 ,X
REMA9S ! %ORTE/ "T 9T]VAL "E M1SUR$4
,! TE*NIQUE DESC5DS F ATTOSECOND SCI;E1
! FIELD T WON ! #BJBC ,NOBEL ,PRIZE 9
,PHYSICS  ,ANNE ,L',HUILLI]1 ,PI]RE
,AGO/9I & ,F]5C ,KRAUSZ %[$ H[ TO G5]ATE
& USE LI<T PULSES LA/+ ATTOSECONDS
"<#AJ_<;X ;S"> TO PHOTOGRAPH ELECTRONS 9
MO;N4 ,ZEPTOSECOND M1SURE;TS PU% ! SAME
IDEA ?REE ORD]S ( MAGNITUDE FUR!R4
,": ZEPTOSECONDS LIVE 9 NATURE
"9 ,LI<T CROSS+ A SMALL MOLECULE 
@9#AJJ#EJJ ZS "9 ,FLUORESC;E ( A PHOTON
9SIDE A NUCLEUS  NUCLE> GAMMA EMIS.N "TS
C R1* ! ATTOSECOND-TO-ZEPTOSECOND RANGE
"9 ,QU>K-GLUON PLASMA  ! 8S\P0 ( FREE
QU>KS PRODUC$ 9 H1VY-ION COLLI.NS LIVES
& DIES ON "TSCALES ( @9#AJ_<#AJ_<;T ;S 
DEEP YOCTOSECOND T]RITORY  ,! ZEPTOV]SE 
! NEWLY OP5$ R1LM ( PHYSICS AT #AJ_<
METRES"93 A PHOTON CROSSES A ZEPTOMETRE
9 AB ?REE BILLION?S ( A ZEPTOSECOND1 & !
R>E DECAYS T PROBE T R1LM UNFOLD OV]
FEMTOSECOND-TO-PICOSECOND B1UTY-"PICLE
LIFE"TS
,UNITS SMALL] ?AN ?
,ONLY ! YOCTOSECOND "<#AJ_<;T ;S"> IS
SMALL] AM;G "ND ,,SI UNITS  9VOK$ = !
FLEET+ LIFE"T ( QU>K-GLUON PLASMA /ATES4
,2L "ND UNITS 5TIRELY SITS ! ,PLANCK "T1
@9#E4D  #AJ_<TT ;S  ! "T LI<T TAKES TO
CROSS "O ,PLANCK L5G?  : _M PHYSICI/S
SUSPECT IS N A SMALL QUANT;Y S M* Z A
B.D>Y3 ! PO9T ": 82F0 & 8AF0 MAY /OP 2+
M1N+;L 3CEPTS4 ,NO?+ %ORT] ?AN A ,PLANCK
"T IS M1SURABLE EV5 9 PR9CIPLE "U CURR5T
PHYSICS4
,SEE AL
"9 ZEPTOV]SE  ! R1LM AT #AJ_< METRES "9
SMALLE/ ?+S "E M1SUR$  ! FULL GALL]Y (
T9Y RECORDS "9 SCI5TIFIC NOTA;N "9
HI/ORY ( PHYSICS
,REF];ES
- ,GRUNDMANN1 ,S5FTLEB5 ET ;AL4 
8,ZEPTOSECOND BIR? "T DELAY 9 MOLECUL>
PHOTOIONIZA;N10 ,SCI;E #CGJ3#CCI "<#AF
,OCTOB] #BJBJ"> - ,NOBEL ,PRIZE 9
,PHYSICS #BJBC  ATTOSECOND LI<T PULSES
"<,L',HUILLI]1 ,AGO/9I1 ,KRAUSZ"> -
,,BIPM  ,,SI ,BRO*URE1 DECIMAL PREFIXES
"<ZEPTO- & YOCTO- ADOPT$ #AIIA"> -
,,ALICE COLLABORA;N  QU>K-GLUON PLASMA
LIFE"T M1SURE;TS1 ,,C]N