http://blogs.discovermagazine.com/loom/2009/10/23/podcast-the-cave-dwellers/ A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer. Tue, 24 Nov 2009 16:41:26 -0600 http://wordpress.org/?v=2.8.4 hourly 1 http://blogs.discovermagazine.com/loom/2009/10/23/podcast-the-cave-dwellers/comment-page-1/#comment-26782 Mark Siddall Sun, 25 Oct 2009 01:22:05 +0000 http://blogs.discovermagazine.com/loom/?p=1957#comment-26782 Just to clarify... I did not mean Carl was self-serving. I meant spelunking microbiologists who claim they are researching a model for finding life on Mars are. And to be fair, this was just the tail end of an otherwise informative podcast. Glad you're over the flu Carl. Just to clarify… I did not mean Carl was self-serving. I meant spelunking microbiologists who claim they are researching a model for finding life on Mars are. And to be fair, this was just the tail end of an otherwise informative podcast. Glad you’re over the flu Carl.

]]> http://blogs.discovermagazine.com/loom/2009/10/23/podcast-the-cave-dwellers/comment-page-1/#comment-26776 Charles Schmidt Fri, 23 Oct 2009 21:15:17 +0000 http://blogs.discovermagazine.com/loom/?p=1957#comment-26776 Thank you Mark well said. Thank you Mark well said.

]]> http://blogs.discovermagazine.com/loom/2009/10/23/podcast-the-cave-dwellers/comment-page-1/#comment-26775 Mark Siddall Fri, 23 Oct 2009 19:13:56 +0000 http://blogs.discovermagazine.com/loom/?p=1957#comment-26775 Um... Carl... Fact Check? This premises associated with looking for Martian-like critters in Earth caves is more than just a little self-serving. The premise says that microbes on Mars, if they exist, might be deep underground to avoid cosmic rays and UV radiation from the Sun. The lack of a martian atmosphere results in lethal doses of UV light. The relative lack of a Martian magnetic field also means many more cosmic rays will hit Mars. Does this really mean that cave-dwelling microbes are a sensible model? NO!!! Why? Because even terrestrial cave dwelling microbes require liquid water! There is no evidence of liquid water on Mars. The surface of Mars is far too cold for liquid water to trickle down. Magmatic heat from deep inside is less likely to reach up high enough to liquify water on Mars that it is even on Earth (where it is not likely to contribute much anyway). Geothermal activity on Earth relies mostly on the results of plate tectonics. Mars is no longer tectonically active. So, please, can we get beyond the notion that earthly wet caves have anything to do with the possibility of life on Mars underground? No heat, no flowing liquid water on Mars. The premises are false. Um… Carl… Fact Check?
This premises associated with looking for Martian-like critters in Earth caves is more than just a little self-serving. The premise says that microbes on Mars, if they exist, might be deep underground to avoid cosmic rays and UV radiation from the Sun. The lack of a martian atmosphere results in lethal doses of UV light. The relative lack of a Martian magnetic field also means many more cosmic rays will hit Mars. Does this really mean that cave-dwelling microbes are a sensible model? NO!!! Why? Because even terrestrial cave dwelling microbes require liquid water! There is no evidence of liquid water on Mars. The surface of Mars is far too cold for liquid water to trickle down. Magmatic heat from deep inside is less likely to reach up high enough to liquify water on Mars that it is even on Earth (where it is not likely to contribute much anyway). Geothermal activity on Earth relies mostly on the results of plate tectonics. Mars is no longer tectonically active. So, please, can we get beyond the notion that earthly wet caves have anything to do with the possibility of life on Mars underground? No heat, no flowing liquid water on Mars. The premises are false.

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