A hole in Mars

I think this article might well explain what it is. Neat for axis tilt as well. www.spacedaily.com/news/mars-water-00b.html

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Stoat
I think this article might well explain what it is. www.spacedaily.com/news/mars-water-00b.html

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Some exerpts from cited article:

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">It is typical for circular depressions to form within glacier ice in response to melting from below. In Iceland the accumulation of seasonal new ice "heals" such depressions, whereas on Mars they would be left as permanent "holes" in the ice shield in absence a water rich atmosphere

The melt water can carry a high concentration of rapidly quenched magma, that will eventually burst out on the surface to rest in a distal location away from the higher reaches of the volcano. The scarcity of vent-like openings within the caldera suggests that this is where the ice thickness reaches a maximum.

A new $4 million NASA research investigation headed by professor Don Gurnett of the University of Iowa was recently contracted to search for Martian water through the use of low-frequency radar signal that will penetrate to a depth of five kilometres.

This study, which is part of the European Space Agency's (ESA) Mars Express spacecraft to be launched in 2003, may be pivotal in the search for the lost Martian water. If technically successful, the project is likely to provide a wealth of information on the ideas presented above for the Tharsis water/ice budget. [Johann Helgason]
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So, is the author saying the distal surface area around the volcanos is ice, or at least frozen volcanic dust with water ice underneath? I'ts not clear to me.

In Iceland there are places where volcanic flood water leaves a layer of rock debris over ice. Then a new melt causes a sudden sink hole to appear in this. Now the guy is saying that the ice is very thick, yet it's on the equator. It could be because of the height of the volcano, or it could be that the ice started off at the poles and was carried round to the equator when the planet's axis tilted. I don't know, how long did this flip take to occur?

I don't think the idea of lots of water being buried in old glacier courses on Mars is that novel.

If this were a hydrocarbon pool, the ultraviolet light, etc, would turn the surface to carbon black. <b>And that is black.</b>The problem is that it would be a dry surface and it would become coated with "dust" from the winds over time. That would make it much brighter. However, Dr. Van Flandern's observation that this could be due to high contrast in the picture taking is the sinplest answer. This factor has to be resolved prior to "higher" theories.


Gregg Wilson

Perhaps we should wait untill an hdri image is put together but glaciers are still the favourite.

I did a google search for glaciers on mars and downloaded the second one which is a pdf, worth a read.

This article is also worth a read. They turned back the clock 5.5 million years and flipped the axis of the planet to explain the formation of glaciers at the equator. Bet your bottom dollar they never looked at Tom's work on this [] www.spaceflightnow.com/news/n0601/20marsglaciers/

(Edited) A couple of questions for Tom. Ages ago I did a little animation of a map of Mars rotating round about 90 degrees with one revolution of the planet. I did this so that the flip starts off slowly then builds up rapidly. The surface does an S shaped little shimmy. Now that would do horrible things to the planets surface.

The question is, how long did this flip take? If we are talking about polar ice, of several kilometres thick, moving round in some time period, the flip has to be fairly fast but not so fast that tectonic stress melts it. Does that sound right?

One thing about glaciers. When they go down a slope, they can meet another upward slope. The mass centre of the ice profile can clear the top of this hill and the ice below it digs out a hole. So, fiords and Scotish lochs' bottoms can be thousands of feet below sea level. If the glacier ice is only a few hundred metres thick on this volcano, the "hole" could still be much deeper than the average.

Still, a study of Martian glaciers might be a useful tool in working out the time period for the planets flip.

The previously discussed “hole in Mars” was reimaged. We can read what the HiRISE team said about the imaging at: hirise.lpl.arizona.edu/PSP_004847_1745

And also what was said originally at: hirise.lpl.arizona.edu/PSP_003647_1745

What interests me right now is that everybody, both on the official side of the inquiry and also the speculation here and elsewhere (mentioned in this thread above), missed the obvious answer as to why we could not see anything in the hole in the first imaging. The HiRISE team seems to have missed the obvious yet again. First here are the two images:

First image.



Second image.



Here briefly what I think is now fairly clear:
The hole is on the east slope of Arsia Mons. The first image, 3647, was taken at 3:27 PM (Local time), the sun’s incidence angle from the horizon was 38°. The second image, 4847, was taken at 2:34 PM, with an incidence angle of 49° from the horizon.

The reason the hole is all black in the first image is that the eastern slope of the mountain adds to the oblique angle of the sun (whatever it is) resulting in a very small incidence angle to the sun. In effect, the sun is about to set on that side of the mountain—and so the inside of the hole is in the dark, that’s all.

The second image is taken a little earlier in the day and we can easily see light shining on the side sloping in on the east side of the hole, and the shadow of the side sloping in on the west side of the hole. Judging from what we can now see, the “trench” or lava tube inside, may not be much deeper than the famous “T” on the east side on Olympus Mons.

We will need to see the hole at around noon sometime during southern spring (it’s located at 5.5°S) when the sun is directly overhead, to be sure.

[edited 8/30/07]

Neil DeRosa