How do they know?

I've heard a couple of times lately that the driest place on earth is part of antarctica where it has not rained in two million years. I'm at a loss though: how on earth can they know this?

ice core samples.dry is kind of misleading. there's lots of water there -- it's just solid. technically it's a desert, just one made of h2o.

I don't think so. This says that the 'Dry Valleys' contain no moisture at all - including ice or snow. Which matches with what I've heard before. If there's no ice there then there can't be any ice cores either.

oh, well, i don't know then.

I would guess that it would be a calculation based on current rate of drying (100 mph Katabatic down winds) and the amount of moisture found in certain rocks and the time it would take to depress it to that extent.Of course it is just a guess: mathematical models are not reality.

---

we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

*Bump* in the hope that one of our geologist friends can sate my curiosity...

tell you what, i have earth science class later tonight, i'll ask my prof the question.i can't guarantee an answer of course, as he's an astrophysicist who got stuck teaching the class and not a geologist, and i tend to know more on the subject than he does, but you never know.

Cheers!

the best answer we could come with was lack of rock formations that use water as a catalyst in formation, lack of permafrost, lack or evidence of chemical reactions to water, etc.

My guess was going to be that there is no precipitation observed now, and that current climate models suggest that this has been the climate for the past so many million years.

See that's what I thought. What I can't figure out is how they could tell 'hasn't rained in two million years' from 'rained once, or thrice, in two million years'.Thanks for asking, anyway.This message has been edited by Mr Jack, 07-15-2004 08:28 AM

Dude - they can't even predict the weather accurately five days in advance, how could we trust a two million year model?

Thank you! At least somebody will admit that math is not the ABSOLUTE TRUTHTELLER! Now if only I could've convinced my algebra teacher of just that then maybe I wouldn't be taking the class again...

Did you fail the class?

---

The Laminator

​

Of course, that's why I'm taking it again. I'm not exactly a star student.