Wet, warm Mars Options

[dvandorn]

Back in the Paolo's Plunge thread, someone recently made a statement to the effect that the idea of an early wet, warm Mars has gone from a proposition to a belief. The statement made it clear that this was a bad thing -- that the concept of an early wet, warm Mars is keeping us from seeing how the planet's histopry has actually played out.

I'm responding to that statement here since I don't want to continue to hijack the other thread. But I feel the following two points must be made:

1) Mars was once warm enough (and had a thick enough atmosphere) to support flowing liquid water on its surface.

2) Mars was once wet enough for that liquid water to form well-developed river drainage systems and for enormous floods to scour thousands of square kilometers of its surface.

Those two statements aren't theoretical. Observed landforms verify them with primary, empirical evidence of river channels and catastrophic flood plains.

Those are statements of fact, not belief. My own feeling is that we must proceed from that point and not continually try and postulate a Martian history which cannot account for these proven facts.

Also, to the comment made several times that the LHB was responsible for the stripping of Mars' atmosphere, I must point out that several reputable studies have shown that the interaction between the solar wind and Mars' upper atmosphere is sufficient to have reduced an atmosphere as dense as Earth's to what we see today over the course of three billion years. And that neither Venus nor Earth seem to have had their atmospheres stripped during the LHB.

Just a few points I felt needed to be made at this juncture.

-the other Doug

[Juramike]

OK...I'll bite.

Scenario A has an early Mars with a long-lived warm and wet climate with really big storms and outflows happening all the time (as part of the natural climate variation).

Scenario B has an early Mars that's pretty much icy-dry and cold, but punctuated by sporadic post-impact wet periods with catastrophic floods during transient post-big impact greenhouse climates.


(And there is the whole spectrum of possibilities varying from Scenario A to B as well as changing through time as well. e.g. from A to B or even B to A)


What observational evidence would allow differentiation of periods of Scenario A or periods of Scenario B?
(BTW, Mars not the only body for which this question seems relevant)

- Mike