Round Thing Near South Pole Options

[antoniseb]

Here is an image which I think is from Mars Odyssey, but I'm not certain. It is from one of the orbiters. Thanks to a friend in another forum for pointing it out.

It shows a dark, very close to circular, ring near the extremities of the polar cap.

http://www.msss.com/moc_gallery/e13_e18/me...14/E1401276.jpg
http://www.msss.com/moc_gallery/e13_e18/im...4/E1401276.html

It may be that this feature has already been discussed here, if so can someone please point me to the discussion. Otherwise, I am curious to know what you think may have caused this.

[Guest_Myran_*]

Richard Trigaux said: it is impossible to freeze a wave.

I never suggested anything such either.
When water freeze its expands somewhat. On larger areas of water this creates ice ridges since the small expansion are multiplied many times over and you get a stress so large that sheats of ice piles up in long lines.
As a child I often crawled into the triagular cages that they have within, a magical kingdom with a very special light perfect for my childhood fantasies.
But back to the question at hand here, if we start with one perfectly round lake
caused by one meteor impact or volcanic heat doesnt actually matter, the pushing action of the freezing water would push against the hard shore of frozen ice that surrounds it on all sides.
Since it started out with a round shape from the very start it would tend to freeze towards the center with circles within circles.
A more important question is why it have a dark edge, im unable to answer that.

[RNeuhaus]

A more important question is why it have a dark edge, im unable to answer that.

The dark land is due to ,maybe, the fact that the land is wet so it appear to be darker than a dry land.

Rodolfo

P.D.The only thing that can make a perfect circle is the water waves after an impact.