Talk:Valles Marineris

From Wikipedia, the free encyclopedia

	This article is part of WikiProject Mars, an attempt to improve and standardise articles related to Mars. If you would like to participate, you can edit the article attached to this page, or visit the project page, where you can join the project and/or contribute to the discussion.
B	This article has been rated as B-Class on the quality scale.
Top	This article has been rated as Top-importance on the importance scale.

[edit] Astrobleme theory

Is Valles Marineris an astrobleme? I'm not an expert, but I look at the map of Mars over my desk and wonder whether researchers are unanimous in agreeing that the extremely long, extremely straight feature, as well as numerous parallel features which also are extremely straight, as well as parallel crater chains, as well as the long straight colored region extending from the end of the valley... all has geologic origin. Many other straight features are crater-chains from tidally disrupted meteors. A re-entering moon, or a de-orbiting planetary ring would be expected to create something like Valles Marineris. It would be expected to align roughly with the equator (align roughly with the plane of the solar system where moon orbits lie.) Am I alone in thinking that the current version cannot explain the straightness nor the parallel straight features? --Wjbeaty 01:54, 16 September 2005 (UTC)

If you are thinking that maybe this is a low angle almost scrape the planet resulting in a giant trough, well, anything is possible, but I'd have to disagree. I'm of the opinion that the Valles is more of a rift valley akin to the East-African Rift valley. Basically, the building of Olympus Mons created a huge on one side of the planet. The planet want's to reach isostatic equilibrium and the valles is a result of that. More of a radial fracture than a series of impact craters aligned. That's just my humble opinion and I have been wrong before. --John Boone

Not a series of impact craters, but a single very oblong pattern. Any "low angle almost-scrape" would most probably be caused by a moon falling from orbit, and not by a impactor which just happened to strike the planet's limb. The many parallel features would be caused by separate material accompanying the moon, or perhaps the gradually-approaching moon would be disrupted by force gradients from atmospheric drag and atmospheric heating. Speaking of atmospheric heating, the present article mentions a massive expulsion of subsurface CO2. A glancing meteor strike heats surfaces by radiation and can fuse rock and sand, as with huge regions of green glass found in deserts in Libya and Australia. If Valles Marineris is an astrobleme, and if incandescent impactors tend to liquify entire deserts, it wouldn't be unexpected that Valles Marineris would be accompanied by a large region of collapse caused by CO2. Also, the Valles Marineris region contains several examples of rows of pits, with the rows aligned parallel to the valley. Online material discussing the region's geology say that these pits are from faults and sand collapse. But Mars also features many crater chains caused by the impact of tidally-disrupted objects. If later Mars exploration shows that these pits along Valles Marineris are actually crater chains and not associated with faults, then Valles Marineris is almost certainly a large impact crater. Additionally, I can imagine that the material creating such crater chains would not be tidally disrupted, but instead would be "atmospherically sorted" as the impactors of various sectional areas would experience various amounts of atmospheric drag for significant time, and an original tight cluster would spread out into a stream of objects. (Such things would rarely happen with impactors entering atmosphere near-vertically.) Small objects would produce crater-chains. Large objects would dig out an entire valley-shaped crater.

But why do I, a total amateur, dare to question the mass opinion of Mars geologists? It's because Earth geology has a long history of intolerance of dissenting opinion, of texts written with dry authority as if all controversies had been long settled, and of experts missing things which were obvious to crackpots and fringe scientists. Science includes instances paradigm-blindness or "Emperor's Clothes" effect, where the entire community supports a concept which is foolish in hindsight, and were only outsiders are able to see what's very obvious. I suspect that Valles Marineris is an example of this. There are so many little converging threads of evidence that, the more I look at it, the stronger my confidence. But I could be wrong, and I just haven't yet seen a particular critique of the idea which deals it a death-blow. --Wjbeaty 19:51, 3 December 2005 (UTC)

I agree with you on the foolish hindsight, just look at all the explinations for plate tectonic features that were proposed before the theory took hold in the scientific communtity. I cannot deal the "death-blow" to your theory, therefore I suggest that you include it in the article. I don't suppose we'll find out the real answer until we land a robot or human in the Valles to have a look around and gather more evidence, even then we still could be wrong. --John Boone 6 January 2006

I found an article about this on Tom Van Flandern's site. It seems quite plausible, and it does look like it was formed west to east, as any impacting moon would have to do. The only difficulty is that one would think most moons would tidally break up before impacting. The way, the truth, and the light 18:31, 3 May 2007 (UTC)

[edit] Time of discovery

When exactly did Mariner 9 discover the canyons? —Ævar Arnfjörð Bjarmason 13:41, 26 October 2005 (UTC)

[edit] Possible Citation?

Ok, I'm new here & citing sources isn't something I have experience in yet, but I *may* have found something! What do you all think? In the opening section, the statement of the dimensions of this ol' valley has a Citation Needed flag. Today an article came out in the online version of The Guardian [1] which states essentially the same dimensions (the depth being even greater than our data shows!) Is this article an acceptable source that could be cited for this information? If so, I'll defer to someone who knows how to do that, because I don't (yet)! Thanks! ~~Newbie Mpwrmnt 10:59, 16 February 2007 (UTC)