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Author
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Topic: How do they know?
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Dr Jack
Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: 07-14-2003
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Message 1 of 35 (123892)
07-12-2004 6:22 AM
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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?
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arachnophilia
Member (Idle past 1663 days) Posts: 9069 From: god's waiting room Joined: 05-21-2004
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Message 2 of 35 (123898)
07-12-2004 7:38 AM
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Reply to: Message 1 by Dr Jack
07-12-2004 6:22 AM
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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.
| This message is a reply to: | | | Message 1 by Dr Jack, posted 07-12-2004 6:22 AM | | Dr Jack has replied |
| Replies to this message: | | | Message 3 by Dr Jack, posted 07-12-2004 7:44 AM | | arachnophilia has replied |
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Dr Jack
Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: 07-14-2003
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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.
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arachnophilia
Member (Idle past 1663 days) Posts: 9069 From: god's waiting room Joined: 05-21-2004
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Message 4 of 35 (123901)
07-12-2004 8:05 AM
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Reply to: Message 3 by Dr Jack
07-12-2004 7:44 AM
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oh, well, i don't know then.
| This message is a reply to: | | | Message 3 by Dr Jack, posted 07-12-2004 7:44 AM | | Dr Jack has not replied |
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RAZD
Member (Idle past 1724 days) Posts: 20714 From: the other end of the sidewalk Joined: 03-14-2004
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Message 5 of 35 (123911)
07-12-2004 9:59 AM
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calculation
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
Rebel AAmerican .Zen [Deist
{{{Buddha walks off laughing with joy}}}
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Dr Jack
Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: 07-14-2003
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Message 6 of 35 (124197)
07-13-2004 6:19 AM
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Reply to: Message 1 by Dr Jack
07-12-2004 6:22 AM
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*Bump* in the hope that one of our geologist friends can sate my curiosity...
| This message is a reply to: | | | Message 1 by Dr Jack, posted 07-12-2004 6:22 AM | | Dr Jack has not replied |
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arachnophilia
Member (Idle past 1663 days) Posts: 9069 From: god's waiting room Joined: 05-21-2004
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Message 7 of 35 (124199)
07-13-2004 6:23 AM
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Reply to: Message 6 by Dr Jack
07-13-2004 6:19 AM
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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.
| This message is a reply to: | | | Message 6 by Dr Jack, posted 07-13-2004 6:19 AM | | Dr Jack has replied |
| Replies to this message: | | | Message 8 by Dr Jack, posted 07-13-2004 9:05 AM | | arachnophilia has replied |
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Dr Jack
Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: 07-14-2003
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Cheers!
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arachnophilia
Member (Idle past 1663 days) Posts: 9069 From: god's waiting room Joined: 05-21-2004
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Message 9 of 35 (124313)
07-13-2004 10:35 PM
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Reply to: Message 8 by Dr Jack
07-13-2004 9:05 AM
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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.
| This message is a reply to: | | | Message 8 by Dr Jack, posted 07-13-2004 9:05 AM | | Dr Jack has replied |
| Replies to this message: | | | Message 11 by Dr Jack, posted 07-15-2004 9:28 AM | | arachnophilia has not replied |
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Chiroptera
Inactive Member
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Message 10 of 35 (124507)
07-14-2004 3:09 PM
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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.
| Replies to this message: | | | Message 12 by Dr Jack, posted 07-15-2004 9:29 AM | | Chiroptera has not replied |
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Dr Jack
Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: 07-14-2003
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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
| This message is a reply to: | | | Message 9 by arachnophilia, posted 07-13-2004 10:35 PM | | arachnophilia has not replied |
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Dr Jack
Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: 07-14-2003
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Dude - they can't even predict the weather accurately five days in advance, how could we trust a two million year model?
| This message is a reply to: | | | Message 10 by Chiroptera, posted 07-14-2004 3:09 PM | | Chiroptera has not replied |
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One_Charred_Wing
Member (Idle past 6475 days) Posts: 690 From: USA West Coast Joined: 11-21-2003
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Message 13 of 35 (124834)
07-15-2004 9:46 PM
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Reply to: Message 5 by RAZD
07-12-2004 9:59 AM
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Re: calculation
Of course it is just a guess: mathematical models are not reality. 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...
| This message is a reply to: | | | Message 5 by RAZD, posted 07-12-2004 9:59 AM | | RAZD has replied |
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coffee_addict
Member (Idle past 186 days) Posts: 3645 From: Indianapolis, IN Joined: 03-29-2004
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Re: calculation
B2P writes: 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
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One_Charred_Wing
Member (Idle past 6475 days) Posts: 690 From: USA West Coast Joined: 11-21-2003
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Re: calculation
Curious Lam writes: Did you fail the class? Of course, that's why I'm taking it again. I'm not exactly a star student.
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