Earthlike Mars? |
Earthlike Mars? |
Apr 1 2009, 02:28 AM
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Member Group: Members Posts: 233 Joined: 21-April 05 Member No.: 328 |
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. |
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Apr 6 2009, 05:48 AM
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Member Group: Members Posts: 236 Joined: 5-June 08 From: Udon Thani Member No.: 4185 |
A very interesting picture and discussion.
However, how much evidence is there really that all of the water was liquid at the same time? Would it not be possible that the effects were more local, resulting from various causes and not one 'tropical period'. Lacking a large moon, precession, nutation, and polar motion of Mars rotational axis will probably be larger then on Earth, resulting in several cycle's of 'super seasons' imposed on the existing seasons (which are already stronger then on earth due to Mars more elliptical orbit). Area's with exposed ice around the poles might receive more solar heating due to this, resulting in the ice sublimating (increasing air pressure) or possible become liquid for a short while, however at the same time other area's might 'cool down' due to the same effect, and ice might start building up again on these area's (reducing air pressure again). So the ice would more or less shift from one area to the other and this might even be possible without a liquid phase in between?? Local effects might be vulcanism (volcanic heat might rapidly heat a layer of ice, resulting in the ice sublimating and possible a short local liquid period if the air pressure rises sufficiently locally during a short period) or impacts (same effects, local heating). So you might have local 'flood-waves' during short periods without the need for a planet-wide 'tropical period'. How much prove do we have that we are looking at a planet-wide 'tropical period' instead of just a series of (more or less unrelated) local events? |
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