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backtotheland76 t1_iwvrj41 wrote

I've always wondered if Mars once had a lot of water wouldn't that weigh a lot. Enough to increase it's gravity to the point of retaining all that water? Doesn't that go against current theories about how Mars lost its water. Or would all that water not really add up to much compared to the overall size of the planet.

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Sea-Obligation-1700 t1_iww0xd1 wrote

300m of water vs thousands of kilometres of rock. It's a rounding error of mass.

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dustofdeath t1_iwwvqwj wrote

Take an egg. Paint it blue. That layer of paint is thicker than that in comparison.

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