Earthlike Mars? Options

[glennwsmith]

All, I know this isn't the right place for this post, but I've looked around and can't find an appropriate, current UMSF forum (Doug, perhaps you could give me some guidance on establishing such) -- so here goes: I think a [the] new paradigm for Martian geology is rapidly coalescing, namely, that Mars is very much like the Earth in terms of the preponderance of water -- except that it is all frozen, and covered under a thin layer of dust/regolith! See, for example, this article:

http://www.skyandtelescope.com/news/41995902.html

Hence the "seepages" found in crater walls; hence the evidence of catastophic flooding -- the result of volcanism melting huge pockets of ice. And I am going to add my own wrinkle (probably not original): that the differentiation of Mars into a rougher southern hemisphere and smoother northern hemsphere represents something like Earth's Pangea stage, ie, the northern hemisphere is a vast frozen sea covered with a thin layer of ice.

[marsbug]

Some more modelling on the idea of early mars being cold and wet.

[serpens]

"]Some more modelling [/url]on the idea of early mars being cold and wet.

I have some difficulty with the concept that the current temperature conditions (cold) applied to Mars in the beginning. To put this in perspective Earth was apparently warm, then we had the snowball earth followed by continuous warmth (always areas above freezing regardless of cyclical swings) . Lots of speculation on sun activity levels, interstellar dust, tectonics etc but no definite explanation for this. So why do we think Mars has always been stable at sub zero temperatures and pass off the clear evidence of major liquid water effects as brines or short term impact phenomona?

Given the evidence of large impactors (including the one that formed Earth's moon) these, and near misses would have caused variations in orbits of the inner planets, particularly for Mars given its size in comparison to Earth and Venus. If we can accept that a Mars sized planetoid collided with Earth then we should accept that there is a possibility that it also had a close encounter with Mars which at that time had an orbit closer to the sun. Potentially such an encounter moving Mars away from the warmth and setting the other body on a collision course for Earth.

Flight of fantasy perhaps. But no more so than trying to explain the water features on Mars purely in terms of impact or brines