﻿188 
  ANNUAL 
  EEPORT 
  SMITHSONIAN" 
  INSTITUTION, 
  1927 
  

  

  horster 
  and 
  von 
  Salis 
  have 
  found 
  that 
  its 
  intensity 
  varies 
  with 
  the 
  

   position 
  of 
  osmic 
  masses, 
  in 
  a 
  way 
  which 
  indicates 
  that 
  the 
  radia- 
  

   tion 
  is 
  received 
  largely 
  from 
  regions 
  near 
  the 
  Milky 
  Way, 
  especially 
  

   the 
  regions 
  of 
  Andromeda 
  and 
  Hercules. 
  

  

  I 
  have 
  calculated 
  that 
  the 
  total 
  amount 
  of 
  highly-penetrating 
  

   radiation 
  actually 
  received 
  is 
  of 
  the 
  order 
  of 
  twice 
  that 
  which 
  ought 
  

   to 
  be 
  received 
  from 
  the 
  Andromeda 
  nebula- 
  alone 
  (Nature, 
  December 
  

   12, 
  1925) 
  if 
  this 
  consisted 
  solely 
  of 
  matter 
  of 
  the 
  same 
  radiating 
  

   power 
  as 
  the 
  very 
  youngest 
  of 
  the 
  stars. 
  Clearly 
  the 
  total 
  amount 
  of 
  

   radiation 
  which 
  is 
  observed 
  to 
  be 
  received 
  on 
  earth 
  is 
  of 
  the 
  right 
  

   order 
  of 
  magnitude; 
  it 
  is, 
  moreover, 
  so 
  large 
  that 
  it 
  is 
  difficult 
  to 
  

   imagine 
  any 
  possible 
  origin 
  for 
  it 
  other 
  than 
  that 
  just 
  mentioned. 
  

   Its 
  penetrating 
  power 
  appears 
  to 
  be 
  rather 
  less 
  than 
  might 
  have 
  

   been 
  expected 
  if 
  it 
  originated 
  in 
  the 
  actual 
  annihilation 
  of 
  electrons 
  

   and 
  protons, 
  but 
  I 
  do 
  not 
  think 
  the 
  difficulty, 
  if 
  it 
  exists, 
  is 
  insuper- 
  

   able. 
  Quite 
  recently 
  Rosseland 
  (Astro. 
  Journ., 
  May 
  1926) 
  has 
  sug- 
  

   gested 
  that 
  bombardment 
  of 
  this 
  radiation 
  may 
  be 
  the 
  cause 
  of 
  

   the 
  observed 
  bright 
  lines 
  in 
  stellar 
  spectra; 
  I 
  had 
  previously 
  (Nature, 
  

   December 
  12, 
  1925) 
  suggested 
  a 
  similar 
  origin 
  for 
  the 
  luminosity 
  of 
  

   the 
  irregular 
  nebulae. 
  

  

  There 
  is 
  a 
  temptation 
  to 
  try 
  to 
  probe 
  still 
  further 
  into 
  the 
  physics 
  

   of 
  the 
  nebulte, 
  to 
  try 
  to 
  understand 
  the 
  properties 
  of 
  matter 
  in 
  its 
  

   still 
  earlier 
  forms, 
  perhaj^s 
  even 
  to 
  get 
  a 
  glimpse 
  of 
  it 
  in 
  the 
  actual 
  

   process 
  of 
  creation. 
  But 
  to 
  yield 
  to 
  this 
  temptation 
  would 
  carry 
  

   us 
  too 
  far 
  into 
  the 
  realms 
  of 
  conjecture 
  and 
  speculation. 
  So 
  far 
  the 
  

   course 
  of 
  our 
  argument 
  has 
  not 
  depended 
  on 
  either 
  conjecture 
  or 
  

   speculation. 
  Where 
  there 
  has 
  appeared 
  at 
  first 
  to 
  be 
  a 
  choice 
  of 
  

   ways, 
  all 
  ways 
  except 
  one 
  have 
  proved 
  on 
  further 
  examination 
  to 
  be 
  

   prohibited 
  either 
  by 
  observational 
  knowledge 
  or 
  by 
  well-established 
  

   principles 
  of 
  physics 
  or 
  dynamics 
  : 
  there 
  has 
  never 
  been 
  any 
  real 
  

   choice. 
  For 
  this 
  reason 
  the 
  conclusions 
  we 
  have 
  reached, 
  although 
  

   certainly 
  novel 
  and 
  perhaps 
  unexpected, 
  appear 
  to 
  me 
  to 
  be, 
  in 
  their 
  

   main 
  lines, 
  inevitable 
  ; 
  I 
  can 
  see 
  no 
  means 
  of 
  escape. 
  

  

  LIFE 
  AND 
  THE 
  UNIVERSE 
  

  

  A 
  general 
  survey 
  of 
  the 
  results 
  obtained 
  by 
  cosmical 
  physics 
  has 
  

   suggested 
  that 
  terrestrial 
  laboratory 
  physics 
  is 
  a 
  mere 
  tail-end 
  of 
  

   the 
  general 
  science 
  of 
  physics. 
  The 
  primary 
  physical 
  process 
  of 
  

   the 
  universe 
  is 
  the 
  conversion 
  of 
  matter 
  into 
  radiation, 
  a 
  process 
  

   which 
  did 
  not 
  come 
  within 
  our 
  terrestrial 
  purview 
  at 
  all 
  until 
  

   1904. 
  The 
  primary 
  matter 
  of 
  the 
  universe 
  consists 
  of 
  highly 
  dis- 
  

   sociated 
  atoms, 
  a 
  state 
  of 
  matter 
  which, 
  again, 
  was 
  not 
  contem- 
  

   plated 
  before 
  1917. 
  The 
  primary 
  radiation 
  of 
  the 
  universe 
  is 
  not 
  

   visible 
  light, 
  but 
  short-waA^e 
  radiation 
  of 
  a 
  hardness 
  which 
  would 
  

   have 
  seemed 
  incredible 
  at 
  the 
  beginning 
  of 
  the 
  present 
  century. 
  

  

  