Quote:
|
Originally Posted by Sporally
And i have anyother question i just thought of this morning:
All planets (with the exception of Pluto) beyond Jupiter are gasplanets. One thing i don't understand is why only the planets are made of gas while the moons are solid. Actually i would have considered it to be the total opporsite since i know a great pressure makes things more solid while low pressure makes it harder to keep the molecules static (more or less). I see the point of low pressure and high pressure, but i don't see why e.g. Titan is solid and Saturn is not.
|
I think it's due to gravity. The gas-giants gravity is strong enough to hold onto the lighter elements like hydrogen and helium. The satellites on the other hand have much weaker gravity and would have lost the lighter elements to space over time. Still they are made up of a higher porpotion of lighter elements than planets and moons in the inner solar system.