[X] My Assistant

[Alex]

Hi guys,

I just registered because I would like to know if anybody has got explanations for certain features appearing in the Mars surface and visible with Google Mars...

Can anybody tell me why the lower regions (in blue) are clearly less cratered than the higher ones (orange-red)?

Is it possible that those lower regions were filled up long time ago with water and therefore the craters were eroded?

What about some features that seem to be rivers? ... does anybody know if there is any scientific explanation for that? Does anybody know what does the scientific community have to say for the same?

Thanks in advance for your responses and regards.

[mcaplinger]

Can anybody tell me why the lower regions (in blue) are clearly less cratered than the higher ones (orange-red)?

Is it possible that those lower regions were filled up long time ago with water and therefore the craters were eroded?

What about some features that seem to be rivers? ... does anybody know if there is any scientific explanation for that? Does anybody know what does the scientific community have to say for the same?

http://www.msss.com/http/ps/intro.html may answer some of your questions.

To summarize: it's generally thought that the less-cratered areas of Mars were resurfaced by lava towards the end of the period of heavy bombardment when most craters were formed. One need not invoke an ocean to account for this "global dichotomy" -- see http://www.msss.com/http/ps/di.html and http://www.msss.com/http/ps/age2.html

The "rivers" are generally considered to be, well, rivers, formed in a period when Mars was wetter, although such features can be formed by more subtle but still water-related action, such as sapping -- see http://www.msss.com/http/ps/channels/channels.html