Quote:
Originally Posted by OutOfTheCube
I think the big question is, if there was that much water there, what happened to it? Does a planet just randomly lose it's ability to sustain water/life?
|
there's a show called Naked Science on Discovery and they did an episode called Mars Waterworld that talks about just that. basically Mars is too small to sustain an atmosphere. it had one for a brief time (universally speaking) when it first cooled and liquid water was present on the surface. but because the gravity is so weak on Mars it couldn't hold it's atmosphere and the sun's solar wind eventually blew it away, then the water just boiled off and disappeared with nothing to protect it
when they were first formed, Mars and Earth were virtually identical. Earth however was fortunate in a sense to be impacted by another planet early in the solar systems life, adding more mass to Earth and creating our moon. and that extra mass is what allows us to keep our atmosphere and the water within it