Meteorites reveal extended deep-freeze on Mars

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Also here http://news.bbc.co.uk/2/hi/science/nature/4703055.stm

Pretty contradictory to what we have been hearing the past couple of years. Oh well, these reports seem to be changing quite often.

One of the scientists at the MRO briefing was asked about this, and his response was basically, "Well, we're still arguing about this because there's evidence on both sides."

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Greetings!

I couldn't take it for long, but Richard Hoagland was on C2C last night and was pretty livid about this subject. Probably because it would totally contradict his assertion that Mars was an inhabited moon of a larger planet that once occupied the orbit of the asteroid belt and was destroyed in some sort of hyperdimensional explosion.

:roll:

Regards, tbm

I was pretty livid, listening. He called the scientists who put forth their argon results "turkeys", and led Noory on the path to: Caltech scientists -> JPL -> former JPL oversight committee head Admiral Inman -> CIA. So the dastardly CIA wants to make us to believe that Mars was always cold.

He's entertained me for one moment, though. I laughed at his fumbling mixed metaphor: NASA's facts are like the thread in a knitted shawl his grandmother used to talk about -- pull one thread and the whole ball of wax falls apart. Huh?

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I was struck by the claim that because these 8 rocks were likely buried on Mars, they wouldn't have been affected by short warm periods at the surface. Presumably Mars still has a molten core, and heat is moving up from it. Has anyone managed to make any estimates of temperature versus depth on the red planet?

Many images we have of Mars show signs of past water (river beds,basins etc). Wouldn't these features, after billions of years have vanished mostly by erosion,wind?


What I read is that temperatures near the equator rise up to +25°C.

couldn't there still have been liquid water under the ice during those 4 billion years?

Wouldn't a layer of ice on top actually *protect* the liquid water from potentially not thick enough atmosphere?

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If I'm reading the article correctly, these findings do not suggest that Mars has been continuously cold for billions of years, just that it has not been warm over any very long interval in the past few billion years. And that's on a geological timescale:
That means it could have risen above freezing for up to a million years in the time since it formed, perhaps even very recently. So this finding does not conflict with the marks of liquid water we've found on the surface. The question now is, how long does it take for life to emerge?

Keep in mind that "warm" is relative. Regardless of warming periods and possible water under ice, underground water, occasional flows from impacts, and so forth, Mars still would have been very cold and had limited liquid surface water over much of its later history. Especially with Hoagland types, I've seen folks translate "wet Mars" to mean "covered with oceans." Not too likely for billions of years.

Most of Mars is volcanic rock covered with dust. And has been pretty much consistent for a really long time, even a long time geologically speaking. Pretty boring, and there is really a lot of it.

The interesting bits though (the rest of the planet), are really interesting!

Mars has had a complex enough history that anyone who claims to know what has happened over the entire planet and over the entire history at this point is just fooling themselves. It's like the blind men and the elephant.

I think we're beginning to close in on an accurate pitcture of the grophysical history of Mars - one of a perpetually cold and frozen planet, punctuated by occasional rapid warning for geologically brief periods of time. This can explain much of the body of evidence that has been accumulated to date.

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I'll wait until I have read the paper but what I have seen demonsrates the utter arogance and shortsightedness of tying to 1) reconstruct the global history of Mars from two contextless random samples and 2) thinking you have achieved it.

You have to intergrate all the data - geomorphology, mineralogy, GCMs -and place them in context, not just geochemistry. You need to consider terrestrial examples - there are many areas on earth that have escaped significanct heating since they formed a billion years ago or more. However geochemists are known for this sort of thing. They need to get out into the real world more, it is much more complex than their simple models. Unfortunately, geochemists tend to do this sort of thing all the time.

The evidence for long periods (millions of years) with water activity over large areas of Mars is overwhelming, despite these wild extrapolations.

Jon

It would seem to me that if the rocks came from the polar regions, they could have been cold, while the rest of the planet may have been warm.

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I think shallow polar rocks would be warmed periodically. Mars' obliquity is estimated 15-35 degrees, some even say 0-60 degrees, and the polar regions would often be exposed to direct sunlight for half a martian year at a time. (The moon is credited for keeping Earth's obliquity much more constant.)

The Status of Mars Climate Change Modeling

Deeper polar rocks would tend towards being kept at the average temperature of deep rocks planet-wide.

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As a geologist and paleontologists I can assure you that we have a hard enough time determining the past temperatures on Earth. From a strictly 'geologic' perspective the evidence is all over the place. It's the biologic (paleontological) evidence that gives some type of rational perspective. Without a biological record to go on any statements on Mars' past temperatures are educated speculation. Mars, although not quite as large as the Earth is still BIG. A couple of non-biologic rock samples here and there don't mean a lot. What we can sample 'on' the planet today doesn't much indicate what was happening 'on' the planet a couple billion years ago. It's not easy trying to speculate on past surface and atmospheric temperatures from any non-biologic rocks studied today.

Best to keep an open mind because nobody could know what temperatures used to be like on Mars. Theories are interesting on past Mars geology and climate if some perspective is kept.