Expert: Jayendra Upadhye - 11/17/2004

Question
Hi, i have 2 statements, I need to know if they are true or false, and if false, I need to know why, thanks for any input

1) the mass of the Sun compared to the mass of all the planets combined is like the mass of an elephant compared to the mass of a cat

2) the weather conditions on Mars today are much different than they were in the distant past.

Answer
Hi jonny,
1 - That is because the total mass of the solar system is almost all of it in the sun!
less than 10 % of the total mass of the solar system is in the planets!
So it would be apt if we compared a rat with the elephant actually..
2 - That is true, as there is evidence of gealogically eroded river valley systems as well as ancient shore lines on mars. That implies that flowing water an a high pressure atmosphere was existent on mars in its early days.
Carl sagan in his COSMOS says that martian gravity could not hold onto the high pressure atmosphere and soon lost the water to attrition to space! Later on its core froze solid, and it lost the protective magnetosphere.(sustained by convecting liquid mantle).
The ionising radiation of the sun thus further added to the misery and soon all water except subterranean reserves was lost. (the magnetosphere generally traps the solar wind into the van allen belts).

Pls do rate this answer.
Jayen