68 
When J/ = mass of the nebula, 1 == mass of the planet, then by 
making use of: 
M=trRe y m= sar,’ o', 
we may write: 
Mm 9S 
zee PI) 
A* 4oo'r, 
The pressure of radiation experienced by the planet when it 
absorbs all the radiation received, is again calculated with the 
formula : 
A 
D=—. 
C 
The Newtonian attraction must be diminished by this amount in 
order to find the resulting force K. 
This becomes therefore: 
Mm 9S 
ee = 
5 A | 4fcoor, 
Can this diminution be great enough to bring about appreciable 
disturbances ? 
To investigate this, the following hypothetical case may be con- 
sidered : 
We assume that the solar nebula, after the formation of Neptune, 
has withdrawn to within the orbit of Uranus. We suppose Neptune 
itself to be still gaseous, though considerably denser than the. solar 
nebula, and with a radius a 100-times larger than at present. 
We further disregard the fact that the solar nebula in all proba- 
bility must have had already a pretty great central condensation, 
a circumstance which has an unfavourable influence on a possible 
effect of pressure of radiation. 
We base our calculation on the following numerical values: 
(}.P-1 P-3 4 P-%e—P 4 ol (6) 
Radius of Uranus orbit R = 2,868 . 104 (em). 
Present solar radius BR, — 6:96 10% (om; 
5 solar density 6, = 14: 
cA Neptune radius ie 10° (em). 
3 density of Neptune pd. 
Gravitation constant Fr 6,0 40S. 
Absorption exponent *) u = 0.0002: 
Thus we find: 
3 Mm 
1) Cf.: Eupen, ,Gaskugeln”, p. 285. 
