﻿IS 
  THE 
  EARTH 
  GROWING 
  OLD? 
  POMPECKJ 
  257 
  

  

  substratum 
  could 
  have 
  been 
  formed 
  upon 
  which 
  was 
  laid 
  the 
  first 
  

   sedimentary 
  stratum. 
  By 
  the 
  manner 
  and 
  means 
  of 
  its 
  occurrence, 
  

   one 
  type 
  of 
  rocks 
  always 
  requires 
  the 
  existence 
  of 
  the 
  other. 
  It 
  is 
  

   therefore 
  impossible 
  that 
  the 
  oldest 
  known 
  rocks 
  were 
  the 
  first 
  

   formed. 
  

  

  Now 
  let 
  us 
  postulate, 
  instead 
  of 
  the 
  more 
  generally 
  known 
  Kant- 
  

   Laplace 
  hypothesis, 
  the 
  Chamberlin-Moulton 
  planetesimal 
  theory. 
  

   The 
  latter 
  surely 
  more 
  readily 
  explains 
  many 
  phenomena 
  of 
  the 
  

   solar 
  planetary 
  system 
  than 
  does 
  the 
  older 
  hypothesis. 
  With 
  Cham- 
  

   berlin 
  and 
  Moulton 
  we 
  see 
  the 
  earth 
  increasing 
  in 
  mass 
  through 
  

   the 
  accretion 
  of 
  those 
  small 
  cosmic 
  bodies, 
  the 
  planetessimals. 
  The 
  

   earth 
  is 
  thus 
  increasing 
  even 
  at 
  the 
  present, 
  although, 
  indeed, 
  in 
  

   comparatively 
  small 
  amount, 
  through 
  its 
  encounters 
  with 
  meteors 
  

   and 
  shooting 
  stars.* 
  According 
  to 
  Chamberlin 
  the 
  earth 
  could 
  

   support 
  organic 
  life 
  by 
  the 
  time 
  it 
  had 
  reached 
  the 
  diameter 
  of 
  Mars 
  ; 
  

   that 
  is, 
  with 
  a 
  volume 
  of 
  only 
  one-ninth 
  of 
  its 
  present 
  amount. 
  Be 
  

   that 
  so, 
  the 
  earth, 
  in 
  order 
  to 
  sustain 
  life, 
  must 
  then 
  already 
  have 
  had 
  

   a 
  rocky 
  crust 
  and 
  pressing 
  upon 
  this 
  a 
  hydrosphere 
  and 
  an 
  atmos- 
  

   phere. 
  The 
  formation 
  of 
  sediments 
  would 
  then 
  have 
  taken 
  place, 
  

   and 
  since 
  that 
  time 
  the 
  earth's 
  crust, 
  in 
  round 
  numbers, 
  must 
  have 
  

   increased 
  in 
  thickness 
  some 
  3,000 
  kilometers. 
  How 
  very 
  decidedly 
  

   thin 
  is 
  the 
  earth's 
  shell, 
  which 
  we 
  know, 
  in 
  comparison 
  with 
  this 
  

   great 
  thickness 
  ! 
  

  

  Compared 
  with 
  the 
  great 
  size 
  of 
  the 
  earth 
  itself, 
  that 
  part 
  of 
  its 
  

   crust 
  which 
  is 
  known 
  to 
  us 
  is 
  indeed 
  very 
  petty 
  and 
  the 
  lapse 
  of 
  

   time 
  necessary 
  for 
  its 
  formation 
  surely 
  vanishingly 
  small 
  compared 
  

   with 
  the 
  eons 
  which 
  have 
  passed 
  since 
  the 
  birtlii 
  of 
  the 
  globe 
  itself. 
  

  

  Since 
  the 
  arbitrary 
  appraising 
  of 
  the 
  complete 
  age 
  of 
  the 
  earth 
  

   by 
  Buffon, 
  now 
  more 
  than 
  150 
  years 
  ago, 
  as 
  74,600 
  years, 
  repeated 
  

   researches 
  have 
  been 
  undertaken 
  to 
  evaluate 
  the 
  lapse 
  of 
  time 
  re- 
  

   quired 
  not 
  only 
  for 
  the 
  formation 
  of 
  the 
  earth's 
  crust 
  but 
  also 
  for 
  

   the 
  formation 
  of 
  the 
  various 
  rock 
  strata 
  which 
  make 
  up 
  that 
  crust. 
  

   The 
  various 
  estimates 
  differ 
  greatly. 
  The 
  various 
  premises 
  lead 
  to 
  

   divergent 
  results. 
  

  

  Figures 
  for 
  the 
  length 
  of 
  time 
  which 
  must 
  have 
  elapsed 
  to 
  ac- 
  

   count 
  for 
  the 
  formation 
  and 
  accumulation 
  of 
  the 
  sedimentary 
  de- 
  

   posits 
  known 
  within 
  the 
  earth's 
  crust 
  have 
  been 
  obtained 
  from 
  the 
  

   abrasive 
  effects 
  of 
  the 
  surface 
  waters, 
  from 
  the 
  amount 
  of 
  the 
  

   newly 
  accumulated 
  sediments, 
  and 
  from 
  the 
  extent 
  of 
  the 
  geo- 
  

   logical 
  changes 
  at 
  the 
  earth's 
  surface. 
  The 
  resulting 
  values 
  for 
  

  

  * 
  An 
  unpublished 
  computation 
  made 
  by 
  my 
  esteemed 
  friend, 
  E. 
  A. 
  Wuelflng, 
  indicates 
  a 
  

   total 
  of 
  some 
  3,650,000,000 
  shooting 
  stars 
  which 
  the 
  earth 
  annually 
  encounters. 
  Their 
  

   mass 
  could 
  easily 
  amount 
  to 
  a 
  resnectable 
  number 
  of 
  tons. 
  

  

  