[moklianne]

Mars and Venus could have been Earths of the distant past.

If you look at them now, which path are we currently on? Will Earth become Mars or Venus in another couple of thousand years of humankind on it? I don't see this correlation with other objects in the solar system.

I forget the movie, but the end really struck me. It was a typical exploring Mars movie. In the end, they found a holographic chamber that told the story on how the Earth was first seeded. Mars was dying and civilization left, but a pod stayed behind to seed Earth.


"If it wasn't for the runaway greenhouse effect of its 96% carbon dioxide atmosphere, Venus would be able to support life, although you'd feel like living in the Sahara. The only problem then would be if there would be enough nutrients to support Earth life (including water).

With Mars the problem is serious in the other way. It's too cold and its atmosphere is too thin. Even if you'd pump greenhouse gases into it, it would require some heavy molecules so that they wouldn't reach escape velocity even when heating up the planet. "

The Earth, Mars, and Venus are all roughly 4.5B years old. Intelligent life could have evolved and died out on Venus and Mars long before it even started on the Earth.

Mars could have lost its protective EM field from a nasty blast from the sun. Or perhaps something happened to its core to weaken its EM field. Maybe Venus' civilizations changed their climate too much and it couldn't recover. Its fun to speculate. I hope we continue to explore Mars and our other close neighbors often.