﻿PHYSICS 
  OF 
  THE 
  UNIVERSE 
  JEANS 
  167 
  

  

  Table 
  I. 
  — 
  Equipartition 
  of 
  energy 
  in 
  stellar 
  motions 
  

  

  This 
  final 
  law 
  of 
  distribution 
  of 
  eccentricity 
  of 
  orbit 
  is 
  independent 
  

   of 
  the 
  size 
  of 
  the 
  orbit, 
  but 
  the 
  time 
  of 
  relaxation 
  which 
  measures 
  the 
  

   rate 
  of 
  approach 
  to 
  this 
  final 
  state 
  is 
  not. 
  For 
  the 
  eccentricity 
  of 
  

   orbit 
  is 
  a 
  differential 
  effect, 
  arising 
  from 
  the 
  difference 
  of 
  the 
  gravita- 
  

   tional 
  pulls 
  of 
  a 
  passing 
  star 
  on 
  the 
  two 
  components 
  of 
  the 
  binary, 
  and 
  

   when 
  these 
  components 
  are 
  close 
  together 
  the 
  passing 
  star 
  can 
  get 
  no 
  

   grip 
  on 
  the 
  orbit. 
  For 
  visual 
  binaries, 
  in 
  which 
  the 
  components 
  are 
  

   usually 
  hundreds 
  of 
  millions 
  of 
  miles 
  apart, 
  the 
  "time 
  of 
  relaxation" 
  is 
  

   again 
  millions 
  of 
  millions 
  of 
  years, 
  but 
  it 
  is 
  a 
  hundred 
  times 
  as 
  great 
  as 
  

   this 
  for 
  the 
  far 
  more 
  compact 
  spectroscopic 
  binaries. 
  

  

  The 
  following 
  table, 
  compiled 
  from 
  material 
  given 
  by 
  Aitken, 
  

   shows 
  the 
  observed 
  distribution 
  of 
  eccentricities: 
  

  

  Table 
  II. 
  — 
  The 
  approach 
  to 
  equipartition 
  of 
  energy 
  in 
  binary 
  orbits 
  

  

  As 
  we 
  should 
  anticipate, 
  the 
  spectroscopic 
  binaries 
  show 
  no 
  

   approach 
  to 
  the 
  final 
  state; 
  most 
  of 
  them 
  retain 
  the 
  low 
  eccentricit}'^ 
  

   of 
  orbit 
  with 
  which 
  they 
  start 
  life. 
  The 
  visual 
  binaries 
  show 
  a 
  good 
  

   approach 
  up 
  to 
  an 
  eccentricity 
  of 
  about 
  0.6, 
  but 
  not 
  beyond. 
  The 
  

   deficiency 
  of 
  orbits 
  of 
  high 
  eccentricity 
  may 
  mean 
  that 
  gravitational 
  

   forces 
  have 
  not 
  had 
  sufficient 
  time 
  to 
  produce 
  the 
  highest 
  eccentricities 
  

   of 
  all, 
  but 
  part, 
  and 
  perhaps 
  all, 
  of 
  the 
  deficiency 
  must 
  be 
  ascribed 
  to 
  

   the 
  observational 
  difficulty 
  of 
  detecting 
  orbits 
  of 
  high 
  eccentricity. 
  

  

  Clearly, 
  however, 
  the 
  study 
  both 
  of 
  orbital 
  motions 
  and 
  of 
  motions 
  

   through 
  space 
  points 
  to 
  gravitational 
  action 
  extending 
  over 
  millions 
  

  

  