[meteorite-list] Dig Deeply to Seek Life on Mars
http://www.agu.org/sci_soc/prrl/2007-03.html Dig deeply to seek life on Mars AGU Release No. 07-03 29 January 2007 American Geophysical Union University College London Joint Release AGU Contact: Peter Weiss Public Information Manager Phone: +1-202-777-7507 E-mail: [EMAIL PROTECTED] UCL Contact: Alexandra Brew Phone: +44-(0)20-7679-9726 E-mail: [EMAIL PROTECTED] WASHINGTON - Probes seeking life on Mars must dig deeply into young craters, gullies, or recently exposed ice to have a chance of finding any living cells that were not annihilated by radiation, researchers report in a new study. One promising place to look for them is within the ice at Elysium, site of a recently discovered frozen sea, they say. Current probes designed to find life on Mars cannot drill deeply enough to find living cells that may exist well below the surface, according to the study. Although these drills may yet find signs that life once existed on Mars, the researchers say, cellular life could not survive incoming radiation within several meters [yards] of the surface. This puts any living cells beyond the reach of todayâs best drills. The study, to be published 30 January in the journal Geophysical Research Letters, maps cosmic radiation levels at various depths, taking into account surface conditions in various areas of Mars. The lead author, Lewis Dartnell of University College London, said: Finding hints that life once existed - proteins, DNA fragments, or fossils - would be a major discovery in itself, but the Holy Grail for astrobiologists is finding a living cell that we can warm up, feed nutrients, and reawaken for studying. Finding life on Mars depends on liquid water surfacing on Mars, Dartnell added, but the last time liquid water was widespread on Mars was billions of years ago. Even the hardiest cells we know of could not possibly survive the cosmic radiation levels near the surface of Mars for that long. Unlike Earth, Mars is not protected by a global magnetic field or thick atmosphere, and for billions of years it has been open to radiation from space. The researchers developed a radiation dose model and quantified variations in solar and galactic radiation that penetrates the thin Martian atmosphere down to the surface and underground. They tested three surface soil scenarios and calculated particle energies and radiation doses both on the surface and at various depths underground, allowing them to estimate the survival times of any cells. The team found that the best places to look for living cells on Mars would be within the ice at Elysium, because the frozen sea is relatively recent - it is thought to have surfaced in the last five million years - and so has been exposed to radiation for a relatively short period of time. Even here, though, any surviving cells would be out of the reach of current drills. Other ideal sites include young craters, because the recently impacted surface has been exposed to less radiation, and gullies recently discovered in the sides of craters. Those channels may have flowed with water in the last five years and brought cells to the surface from deep underground. The study was funded by the United Kingdom's Engineering and Physical Sciences Research Council (EPSRC), the Swiss National Science Foundation, and the Swiss State Secretariat for Education and Research. Notes for Journalists Journalists and public information officers of educational and scientific institutions (only) can receive a PDF copy of this paper (a pre-publication copy subject to final editing of any article listed as in press) by sending a message to Jonathan Lifland at [EMAIL PROTECTED] . Please provide your name, the name of your publication, and your phone number. Members of the public can read the abstract of any published paper by clicking on the doi link in the source section, at the end of the highlight. The full scientific article is available for purchase through a link in the abstract. The paper and this press release are not under embargo. Title: Modelling the surface and subsurface Martian radiation environment: Implications for astrobiology Authors: Lewis Dartnell: Centre for Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London, United Kingdom; L. Desorgher: Physikalisches Institut, University of Bern, Bern, Switzerland;J. M. Ward: Department of Biochemistry and Molecular Biology, University College London, London, United Kingdom; A. J. Coates: Mullard Space Science Laboratory, University College London, Dorking,United Kingdom. Citation: Dartnell, L. R., L. Desorgher, J. M. Ward, and A. J. Coates (2007), Modelling the surface and subsurface Martian radiation environment: Implications for astrobiology, Geophys. Res. Lett., 34, L02207, doi:10.1029/2006GL027494, in press. Contact information for
Re: [meteorite-list] Dig Deeply to Seek Life on Mars
environment. They thrive, and some life gets pushed to a further, drier, colder, more radiative edge of the aquifer. Again, they adapt. They get good at handling THAT new environment. Finally, some life gets pushed right up out of the ground onto Oh No! NOT... The Surface! Ya know, there's a lot of elbow room up here. And with all this light, I can use my photosensitive spots to navigate. And, look! Here's something to eat! They adapt. THAT is how Life works. Mars has had four billion years, just like we have. IF Mars had ANY life, it would not have gone for four billion years without changing, without adapting, without the fundamental and deadly necessity of evolution having been at work. Evolution is not a choice. You can't say No, thank you, I'll just stay here in my nice cozy aquifer and multiply immortally my primitive genome just the way it is. No changes for me, please. It's not an option. So, the Principal Life Detection Instrument Package on the Mars Exploration SUV is a video camera on every corner to see if any Thing comes up to take a bite out of your (possibly edible) butt. How are they going to know if you're edible without having a nip? And, if that doesn't happen, then there won't be any microbes in the dirt, primitive organisms in the rocks and nobody living the Good Aquiferian Life for four billion years. Sterling K. Webb - - Original Message - From: Ron Baalke [EMAIL PROTECTED] To: Meteorite Mailing List meteorite-list@meteoritecentral.com Sent: Monday, January 29, 2007 1:14 PM Subject: [meteorite-list] Dig Deeply to Seek Life on Mars http://www.agu.org/sci_soc/prrl/2007-03.html Dig deeply to seek life on Mars AGU Release No. 07-03 29 January 2007 American Geophysical Union University College London Joint Release AGU Contact: Peter Weiss Public Information Manager Phone: +1-202-777-7507 E-mail: [EMAIL PROTECTED] UCL Contact: Alexandra Brew Phone: +44-(0)20-7679-9726 E-mail: [EMAIL PROTECTED] WASHINGTON - Probes seeking life on Mars must dig deeply into young craters, gullies, or recently exposed ice to have a chance of finding any living cells that were not annihilated by radiation, researchers report in a new study. One promising place to look for them is within the ice at Elysium, site of a recently discovered frozen sea, they say. Current probes designed to find life on Mars cannot drill deeply enough to find living cells that may exist well below the surface, according to the study. Although these drills may yet find signs that life once existed on Mars, the researchers say, cellular life could not survive incoming radiation within several meters [yards] of the surface. This puts any living cells beyond the reach of todayâ?Ts best drills. The study, to be published 30 January in the journal Geophysical Research Letters, maps cosmic radiation levels at various depths, taking into account surface conditions in various areas of Mars. The lead author, Lewis Dartnell of University College London, said: Finding hints that life once existed - proteins, DNA fragments, or fossils - would be a major discovery in itself, but the Holy Grail for astrobiologists is finding a living cell that we can warm up, feed nutrients, and reawaken for studying. Finding life on Mars depends on liquid water surfacing on Mars, Dartnell added, but the last time liquid water was widespread on Mars was billions of years ago. Even the hardiest cells we know of could not possibly survive the cosmic radiation levels near the surface of Mars for that long. Unlike Earth, Mars is not protected by a global magnetic field or thick atmosphere, and for billions of years it has been open to radiation from space. The researchers developed a radiation dose model and quantified variations in solar and galactic radiation that penetrates the thin Martian atmosphere down to the surface and underground. They tested three surface soil scenarios and calculated particle energies and radiation doses both on the surface and at various depths underground, allowing them to estimate the survival times of any cells. The team found that the best places to look for living cells on Mars would be within the ice at Elysium, because the frozen sea is relatively recent - it is thought to have surfaced in the last five million years - and so has been exposed to radiation for a relatively short period of time. Even here, though, any surviving cells would be out of the reach of current drills. Other ideal sites include young craters, because the recently impacted surface has been exposed to less radiation, and gullies recently discovered in the sides of craters. Those channels may have flowed with water in the last five years and brought cells to the surface from deep underground. The study was funded by the United Kingdom's Engineering and Physical Sciences Research Council (EPSRC), the Swiss National Science Foundation, and the Swiss State
