﻿PHYSICS 
  OF 
  THE 
  UNIVERSE 
  JEANS 
  179 
  

  

  sions 
  are 
  a 
  certain 
  amount 
  of 
  space 
  and 
  a 
  certain 
  amount 
  of 
  time; 
  

   the 
  protons 
  and 
  electrons 
  are 
  the 
  streaks 
  of 
  paint 
  which 
  define 
  the 
  

   picture 
  against 
  its 
  space-time 
  background. 
  Traveling 
  as 
  far 
  back 
  

   in 
  time 
  as 
  we 
  can 
  brings 
  us 
  not 
  to 
  the 
  creation 
  of 
  the 
  picture, 
  but 
  

   to 
  its 
  edge, 
  and 
  the 
  origin 
  of 
  the 
  picture 
  lies 
  as 
  much 
  outside 
  the 
  pic- 
  

   ture 
  as 
  the 
  artist 
  is 
  outside 
  his 
  canvas. 
  On 
  this 
  view, 
  discussing 
  

   the 
  creation 
  of 
  the 
  universe 
  in 
  terms 
  of 
  time 
  and 
  space 
  is 
  like 
  trying 
  

   to 
  discover 
  the 
  artist 
  and 
  the 
  action 
  of 
  painting 
  by 
  going 
  to 
  the 
  

   edge 
  of 
  the 
  picture. 
  This 
  brings 
  us 
  very 
  near 
  to 
  those 
  philosophical 
  

   systems 
  which 
  regard 
  the 
  universe 
  as 
  a 
  thought 
  in 
  the 
  mind 
  of 
  its 
  

   Creator, 
  and 
  so 
  reduce 
  all 
  discussion 
  of 
  material 
  creation 
  to 
  futility. 
  

  

  Both 
  these 
  points 
  of 
  view 
  are 
  impregnable, 
  but 
  so 
  also 
  is 
  that 
  of 
  

   the 
  plain 
  man 
  who, 
  recognizing 
  that 
  it 
  is 
  impossible 
  for 
  the 
  human 
  

   mind 
  to 
  comprehend 
  the 
  full 
  plan 
  of 
  the 
  universe, 
  decides 
  that 
  his 
  

   own 
  efforts 
  shall 
  stop 
  this 
  side 
  of 
  the 
  creation 
  of 
  matter. 
  

   ATOMIC 
  TRANSFORMATIONS 
  

  

  The 
  transformation 
  of 
  uranium 
  into 
  lead 
  and 
  helium 
  involves 
  a 
  

   drop 
  of 
  energy, 
  but 
  in 
  the 
  lighter 
  elements 
  the 
  energy-change 
  is 
  in 
  

   the 
  reverse 
  direction. 
  Four 
  atoms 
  of 
  hydrogen 
  are 
  more, 
  not 
  less, 
  

   massive 
  than 
  an 
  atom 
  of 
  helium, 
  so 
  that 
  their 
  energy-content 
  is 
  

   greater. 
  Thus 
  helium 
  can 
  never 
  disintegrate 
  spontaneously 
  into 
  

   hydrogen, 
  although 
  four 
  atoms 
  of 
  hydrogen 
  might 
  spontaneously 
  

   unite 
  to 
  form 
  an 
  atom 
  of 
  helium. 
  They 
  could 
  not 
  unite 
  other 
  than 
  

   spontaneously, 
  except 
  possibly 
  as 
  a 
  rare 
  accident, 
  since 
  the 
  tempera- 
  

   ture 
  of 
  transformation, 
  64,000,000,000°, 
  is 
  higher 
  than 
  occurs 
  in 
  the 
  

   universe. 
  Whether 
  they 
  ever 
  unite 
  even 
  spontaneously 
  remains 
  an 
  

   open 
  question 
  on 
  which 
  opinions 
  differ. 
  Millikan 
  at 
  one 
  time 
  

   suggested 
  this 
  process 
  as 
  the 
  origin 
  of 
  the 
  highly 
  penetrating 
  radiation 
  

   which 
  bombards 
  the 
  earth 
  from 
  outer 
  space, 
  but 
  recent 
  observations 
  

   rule 
  this 
  interpretation 
  out; 
  the 
  observed 
  wave 
  length 
  of 
  the 
  radiation 
  

   is 
  too 
  short, 
  so 
  that 
  the 
  radiation 
  must 
  originate 
  in 
  something 
  more 
  

   fundamental 
  even 
  than 
  the 
  transformation 
  of 
  hydrogen 
  into 
  helium. 
  

   Whether 
  any 
  such 
  process 
  can 
  be 
  found, 
  short 
  of 
  the 
  complete 
  

   annihilation 
  of 
  matter, 
  remains 
  to 
  be 
  seen; 
  personally, 
  I 
  feel 
  doubtful. 
  

  

  [Added 
  October 
  7, 
  1929. 
  Since 
  the 
  foregoing 
  was 
  written, 
  Klein 
  and 
  Nishina 
  

   have 
  worked 
  out 
  a 
  very 
  complete 
  mathematical 
  theory 
  of 
  the 
  absorption 
  of 
  

   radiation. 
  According 
  to 
  this 
  theory, 
  the 
  observed 
  absorption 
  of 
  the 
  highly- 
  

   penetrating 
  radiation 
  indicates 
  a 
  wave-length 
  of 
  almost 
  exactly 
  1.3X10 
  — 
  ^^ 
  cms. 
  

   for 
  its 
  most 
  penetrating 
  part. 
  Thus 
  this 
  part, 
  at 
  least, 
  would 
  seem 
  to 
  originate 
  

   directly 
  in 
  the 
  annihilation 
  of 
  protons 
  and 
  their 
  accompanying 
  electrons.] 
  

  

  {Added 
  January 
  29, 
  1930. 
  The 
  theory 
  of 
  Klein 
  and 
  Nishina 
  has 
  now 
  been 
  tested 
  

   by 
  Gray, 
  Stoner 
  and 
  others, 
  and 
  is 
  found 
  to 
  fit 
  observation 
  almost 
  exactly. 
  In 
  

   view 
  of 
  this, 
  it 
  is 
  exceedingly 
  difficult 
  to 
  attribute 
  the 
  most 
  penetrating 
  radiation 
  

   to 
  any 
  other 
  source 
  than 
  annihilation 
  of 
  protons 
  and 
  electrons.] 
  

  

  Millikan 
  has 
  recently 
  suggested 
  that 
  this 
  radiation 
  may 
  result 
  

   from 
  electrons 
  and 
  protons 
  falling 
  together 
  and 
  forming 
  atoms 
  in 
  

   82322—30 
  13 
  

  

  