﻿COSMICAL 
  PHYSICS 
  JEAN'S 
  181 
  

  

  Each 
  proton 
  or 
  atom, 
  as 
  it 
  is 
  annihilated, 
  malves 
  a 
  splash 
  of 
  radi- 
  

   ant 
  energy 
  which 
  travels 
  through 
  the 
  star 
  until, 
  after 
  innumerable 
  

   absorptions 
  and 
  reemissions, 
  it 
  reaches 
  the 
  star's 
  surface 
  and 
  wanders 
  

   off 
  into 
  space. 
  Each 
  splash 
  is 
  similar 
  to 
  the 
  splashes 
  produced 
  by 
  

   radioactive 
  material 
  in 
  the 
  spinthariscope, 
  except 
  for 
  being 
  many 
  

   thousands 
  of 
  times 
  more 
  powerful. 
  The 
  great 
  energy 
  of 
  the 
  splashes 
  

   is 
  to 
  some 
  extent 
  counterbalanced 
  by 
  their 
  rarity. 
  In 
  the 
  sun, 
  for 
  

   example, 
  only 
  about 
  1 
  atom 
  in 
  every 
  10 
  ^^ 
  annihilates 
  itself 
  each 
  

   hour. 
  A 
  cubic 
  centimeter 
  of 
  the 
  sun's 
  mass 
  contains, 
  let 
  us 
  say, 
  10 
  -^ 
  

   atoms, 
  and 
  of 
  these 
  about 
  100,000 
  are 
  annihilated 
  every 
  hour. 
  The 
  

   energy 
  produced 
  in 
  a 
  cubic 
  centimeter 
  of 
  the 
  sun's 
  mass 
  is 
  thus 
  not 
  

   very 
  great, 
  averaging 
  about 
  9,400 
  ergs 
  or 
  0.00022 
  calorie 
  per 
  hour; 
  

   the 
  enormous 
  flow 
  of 
  energy 
  from 
  the 
  sun's 
  surface 
  results 
  from 
  the 
  

   fact 
  that 
  all 
  the 
  energy 
  produced 
  in 
  a 
  cone 
  433,000 
  miles 
  in 
  depth 
  

   has 
  to 
  stream 
  out 
  through 
  the 
  mouth 
  of 
  this 
  cone. 
  

  

  Such, 
  in 
  brief, 
  is 
  the 
  mechanism 
  by 
  which 
  stellar 
  energy 
  is 
  gener- 
  

   ated. 
  The 
  question 
  immediately 
  before 
  us 
  is 
  whether 
  this 
  genera- 
  

   tion 
  of 
  energy 
  proceeds 
  more 
  merrily, 
  whether 
  the 
  electrons 
  and 
  

   protons 
  fall 
  into 
  one 
  another 
  more 
  frequently, 
  when 
  the 
  stellar 
  mat- 
  

   ter 
  is 
  in 
  a 
  state 
  of 
  high 
  temperature 
  and 
  high 
  density. 
  

  

  It 
  is 
  a 
  matter 
  of 
  direct 
  observation 
  that 
  ordinary 
  radioactive 
  proc- 
  

   esses 
  can 
  not 
  be 
  either 
  inhibited 
  or 
  intensified 
  by 
  such 
  temperatures 
  

   as 
  are 
  available 
  in 
  the 
  laboratory; 
  the 
  quantum 
  theory 
  provides 
  the 
  

   reason. 
  Einstein 
  has 
  shown 
  how 
  a 
  subatomic 
  generation 
  of 
  radia- 
  

   tion 
  can 
  occur 
  in 
  either 
  of 
  two 
  ways, 
  spontaneously 
  or 
  through 
  the 
  

   stimulus 
  of 
  incident 
  radiation, 
  and 
  it 
  is 
  easy 
  to 
  calculate 
  the 
  tem- 
  

   perature 
  at 
  which 
  the 
  second 
  process 
  becomes 
  operative. 
  It 
  is 
  found 
  

   that 
  the 
  quantum 
  of 
  radiation 
  at 
  this 
  temperature 
  must 
  have 
  energy 
  

   equal 
  to 
  the 
  energy 
  set 
  free 
  by 
  the 
  subatomic 
  change 
  in 
  question. 
  

   The 
  temperature 
  necessary 
  to 
  expedite 
  the 
  disintegration 
  of 
  uranium 
  

   is 
  in 
  this 
  way 
  found 
  to 
  be 
  of 
  the 
  order 
  of 
  120,000,000,000 
  degrees, 
  and 
  

   it 
  at 
  once 
  becomes 
  clear 
  why 
  warming 
  up 
  uranium 
  in 
  the 
  laboratory 
  

   can 
  not 
  speed 
  up 
  its 
  disintegration. 
  A 
  simihir 
  calculation 
  shows 
  that 
  

   the 
  temperature 
  necessary 
  to 
  influence 
  the 
  rate 
  of 
  subatomic 
  anni- 
  

   hilation 
  of 
  matter 
  is 
  of 
  the 
  order 
  of 
  7,500,000,000,000 
  degrees. 
  It 
  

   may 
  be 
  argued 
  that 
  a 
  lower 
  temperature, 
  although 
  not 
  adequate 
  to 
  

   bring 
  about 
  the 
  actual 
  annihilation 
  of 
  matter, 
  might 
  set 
  up 
  sub- 
  

   atomic 
  processes 
  of 
  adequate 
  intensity. 
  This 
  is 
  true 
  as 
  regards 
  a 
  

   star's 
  momentary 
  radiation, 
  but 
  such 
  processes 
  can 
  not 
  provide 
  an 
  

   adequate 
  duration 
  for 
  the 
  radiation. 
  All 
  processes 
  which 
  are 
  af- 
  

   fected 
  by 
  temperatures 
  of 
  less 
  than 
  about 
  7,500,000,000,000 
  degrees 
  

   leave 
  the 
  total 
  number 
  of 
  electrons 
  and 
  the 
  total 
  number 
  of 
  protons 
  

   in 
  a 
  star 
  unaltered, 
  whereas 
  the 
  whole 
  evidence 
  of 
  astronomy 
  is 
  that 
  

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