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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May 5 2009, 01:38 AM
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Merciless Robot Group: Admin Posts: 8789 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
That's an interesting observation about Jupiter & Saturn, Mike. Shooting from the hip, I wonder if the fact that both planets probably have had a significant amount of small stuff orbiting in their equatorial planes (the ring systems being mere tattered remnants of the originals) has contributed greatly to erosion of large impact features on their moons, which would presumably tend to form more infrequently and therefore also generally be older.
FWIW, I think you're spot on assuming that Earth, Venus & Mars wipe out really big craters pretty fast, although Argyre & Hellas are proportionately huge. Plate tectonics cleans up Earth rather well, and even the largest expanse of old terrain (the Canadian Shield) preserves only a few hefty ancient craters. Venus' surface looks a little like warm taffy at macroscales, and I bet that it's pretty malleable as silicate planetary crusts go over short geological timescales. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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