Re: [meteorite-list] Alien Microbes Could Survive Crash-Landing
Dear List, Back in 1999 it seemed to me that in order for there to be no life having ever existed on Mars one of two conjectures, or both, must be true. 1. It is absolutely impossible for viable spores to be transported by any natural process from the Earth to Mars (No Free Ride Conjecture). 2. There was never any environment on Mars that could have supported a positive growth rate for such organisms if they did get there. (Killer Mars Conjecture) Since 1999, recently, the Mars rovers have shown that the Killer Mars Conjecture is false. And the work of Burchell et al as described is evidence that the first conjecture is false also. Even if Burchell's mechanism is improbable, that won't do, as there have been billions of times matter has been exchanged between the planets due to impacts. There are plenty of chances in 4 billion years. The odds need to be vanishingly small. I'm leaning toward the minority who think that ALH 84001 has biomarkers. Although most of the biosignal in ALH 84001 can be produced abiologically, it can also be produced biologically, and in light of the two conjectures above being false that interpretation seems more reasonable. Comments? Francis Graham --- Ron Baalke [EMAIL PROTECTED] wrote: http://www.nature.com/news/2004/040830/full/040830-10.html Alien microbes could survive crash-landing Philip Ball Nature September 2, 2004 Tough bugs make interplanetary wanderings more plausible. Bacteria could survive crash-landing on other planets, a British team has found. The result supports to the idea that Martian organisms could have fallen to Earth in meteorites and seeded life. Bugs inside lumps of rock can survive impacts at speeds of more than 11 kilometres per second, say the researchers [1]. The work also shows that bacteria could survive crashing into icy surfaces such as Jupiter's moons Europa and Ganymede. The possibility that Earth's first life came here inside space rocks - the panspermia hypothesis - was proposed in 1903 by the Swedish chemist Svante Arrhenius. But the painful landing has always been a stumbling block. Mark Burchell and his colleagues at the University of Kent, Canterbury, have put panspermia to the test by firing lumps of porous ceramic infiltrated with bacteria into targets. During impact, the bacteria are crushed by up to a million times atmospheric pressure. A few years ago everyone said we were crazy, says Burchell. They knew it wouldn't work. But in 2001 he and his colleagues showed that soil bacteria can survive a high-speed impact into soft gel [2]. Most of the microbes died, but enough survived to make panspermia possible, provided that the bugs don't have to travel too far: they would probably be sterilized by cosmic rays and UV radiation during a journey from another solar system. Crushing blow But the researchers didn't know whether the pressures generated in their experiment were comparable to those of a meteorite impact. Nor did they know how different microbial species would fare. To find out, the team used a gas-powered gun to fire bits of ceramic, between 0.1 and 2 millimetres across, into targets of gel or ice. The projectiles were loaded with cells or spores of the soil bacteria Rhodococcus erythropolis or Bacillus subtilis. At similar pressures to those that would be suffered inside a meteorite as it crashed, around one in every ten million R. erythropolis cells and a few in every hundred thousand B. subtilis survived when they hit the gel. A gram of terrestrial soil typically contains a billion bacterial cells. The survival rate for an ice target was about ten times higher, so Burchell and colleagues think that it's not just Earth and Mars that could have swapped life. The icy moons of Jupiter, for instance, at least one of which, Europa, has a sub-surface ocean of water, could seed one another. Or a planet could re-seed itself if, as some have suggested might have happened on the early Earth, a massive impact wiped out all life. References 1.. Burchell M. J., Mann J. R. Bunch A. W. Monthly Notices of the Royal Astronomical Society , 352. 1273 - 1278 (2004). 2.. Burchell M. J., Mann J. R., Bunch A. W. Brandao P. F. B. Icarus, 154. 545 - 547 (2001). __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list __ Do you Yahoo!? Yahoo! Mail is new and improved - Check it out! http://promotions.yahoo.com/new_mail __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Alien Microbes Could Survive Crash-Landing
My contention is NOT that such a transfer is impossible, especially over billions of Earth years. But I think it extraordinarily unlikely that the infant Mars could---in the first 300 to 500 million years of solar system formation---evolve a hearty population of anaerobic bacteria (capable of surving for millions of years in the hostile extremes of space migration) and then seed life on Earth by whatever means, while our planet was still an infant, as well. I think the evolutionary window is just too small for all this conjecture. On the other hand, it DOES seem that life appeared on this planet fairly suddenly---contaminating Earth, as it were, like a particularly nasty swimmer diving into a sterile swimming pool. To me, anyway, it would seem more likely that our entire young solar system may have been contaminated with older and more complex organic materials from an extrasolar source---in other words, all life seeded pretty much simultaneously, IF indeed we find evidence of life elsewhere in this system. Just two cents worth. In a message dated 9/18/2004 4:31:44 PM Eastern Daylight Time, Francis Graham [EMAIL PROTECTED] writes: Dear List, Back in 1999 it seemed to me that in order for there to be no life having ever existed on Mars one of two conjectures, or both, must be true. 1. It is absolutely impossible for viable spores to be transported by any natural process from the Earth to Mars (No Free Ride Conjecture). 2. There was never any environment on Mars that could have supported a positive growth rate for such organisms if they did get there. (Killer Mars Conjecture) Since 1999, recently, the Mars rovers have shown that the Killer Mars Conjecture is false. And the work of Burchell et al as described is evidence that the first conjecture is false also. Even if Burchell's mechanism is improbable, that won't do, as there have been billions of times matter has been exchanged between the planets due to impacts. There are plenty of chances in 4 billion years. The odds need to be vanishingly small. I'm leaning toward the minority who think that ALH 84001 has biomarkers. Although most of the biosignal in ALH 84001 can be produced abiologically, it can also be produced biologically, and in light of the two conjectures above being false that interpretation seems more reasonable. Comments? Francis Graham --- Ron Baalke [EMAIL PROTECTED] wrote: http://www.nature.com/news/2004/040830/full/040830-10.html Alien microbes could survive crash-landing Philip Ball Nature September 2, 2004 Tough bugs make interplanetary wanderings more plausible. Bacteria could survive crash-landing on other planets, a British team has found. The result supports to the idea that Martian organisms could have fallen to Earth in meteorites and seeded life. Bugs inside lumps of rock can survive impacts at speeds of more than 11 kilometres per second, say the researchers [1]. The work also shows that bacteria could survive crashing into icy surfaces such as Jupiter's moons Europa and Ganymede. The possibility that Earth's first life came here inside space rocks - the panspermia hypothesis - was proposed in 1903 by the Swedish chemist Svante Arrhenius. But the painful landing has always been a stumbling block. Mark Burchell and his colleagues at the University of Kent, Canterbury, have put panspermia to the test by firing lumps of porous ceramic infiltrated with bacteria into targets. During impact, the bacteria are crushed by up to a million times atmospheric pressure. A few years ago everyone said we were crazy, says Burchell. They knew it wouldn't work. But in 2001 he and his colleagues showed that soil bacteria can survive a high-speed impact into soft gel [2]. Most of the microbes died, but enough survived to make panspermia possible, provided that the bugs don't have to travel too far: they would probably be sterilized by cosmic rays and UV radiation during a journey from another solar system. Crushing blow But the researchers didn't know whether the pressures generated in their experiment were comparable to those of a meteorite impact. Nor did they know how different microbial species would fare. To find out, the team used a gas-powered gun to fire bits of ceramic, between 0.1 and 2 millimetres across, into targets of gel or ice. The projectiles were loaded with cells or spores of the soil bacteria Rhodococcus erythropolis or Bacillus subtilis. At similar pressures to those that would be suffered inside a meteorite as it crashed, around one in every ten million R. erythropolis cells and a few in every hundred thousand B. subtilis survived when they hit the gel. A gram of terrestrial soil typically contains a billion bacterial cells. The survival rate for an ice target was about ten times higher, so Burchell and colleagues think that it's not just Earth and Mars that could
RE: [meteorite-list] Alien Microbes Could Survive Crash-Landing
.. Snip ... Bacteria could survive crash-landing on other planets, a British team has found. Interesting, but they appear to have kinda missed out the 'extreme cosmic radiation' and the heat/cold bit, that would likely kill the little suckers... Best, Mark Ford __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
RE: [meteorite-list] Alien Microbes Could Survive Crash-Landing
The life from Mars fanatics make several leaps of faith in imagining Martian space seeds, full of viable bacteria, raining down from our skies. If we accept that the solar planets are all basically the same age, and life first appeared here a few hundred million years after Earth's formation (the planet was still hot at the time), then this is a pretty small window for a LOT of activity. The infant Mars would have to evolve a hearty bacterial population, suffer a catastrophic impact that ejected bacteria-laden stones back into solar orbit, and those infected Martian rocks would require several million more years of space migration to the Earth---and all of this would transpire in the solar system's first few hundred million years of existence? I'm not saying it's impossible; rather, I'm saying that this is a scenario that is supported by not one shred of evidence. In a message dated 9/14/2004 3:48:18 AM Eastern Daylight Time, mark ford [EMAIL PROTECTED] writes: .. Snip ... Bacteria could survive crash-landing on other planets, a British team has found. Interesting, but they appear to have kinda missed out the 'extreme cosmic radiation' and the heat/cold bit, that would likely kill the little suckers... Best, Mark Ford __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Alien Microbes Could Survive Crash-Landing
Yikees - Original Message - From: Ron Baalke [EMAIL PROTECTED] To: Meteorite Mailing List [EMAIL PROTECTED] Sent: Monday, September 13, 2004 6:54 PM Subject: [meteorite-list] Alien Microbes Could Survive Crash-Landing http://www.nature.com/news/2004/040830/full/040830-10.html Alien microbes could survive crash-landing Philip Ball Nature September 2, 2004 Tough bugs make interplanetary wanderings more plausible. Bacteria could survive crash-landing on other planets, a British team has found. The result supports to the idea that Martian organisms could have fallen to Earth in meteorites and seeded life. Bugs inside lumps of rock can survive impacts at speeds of more than 11 kilometres per second, say the researchers [1]. The work also shows that bacteria could survive crashing into icy surfaces such as Jupiter's moons Europa and Ganymede. The possibility that Earth's first life came here inside space rocks - the panspermia hypothesis - was proposed in 1903 by the Swedish chemist Svante Arrhenius. But the painful landing has always been a stumbling block. Mark Burchell and his colleagues at the University of Kent, Canterbury, have put panspermia to the test by firing lumps of porous ceramic infiltrated with bacteria into targets. During impact, the bacteria are crushed by up to a million times atmospheric pressure. A few years ago everyone said we were crazy, says Burchell. They knew it wouldn't work. But in 2001 he and his colleagues showed that soil bacteria can survive a high-speed impact into soft gel [2]. Most of the microbes died, but enough survived to make panspermia possible, provided that the bugs don't have to travel too far: they would probably be sterilized by cosmic rays and UV radiation during a journey from another solar system. Crushing blow But the researchers didn't know whether the pressures generated in their experiment were comparable to those of a meteorite impact. Nor did they know how different microbial species would fare. To find out, the team used a gas-powered gun to fire bits of ceramic, between 0.1 and 2 millimetres across, into targets of gel or ice. The projectiles were loaded with cells or spores of the soil bacteria Rhodococcus erythropolis or Bacillus subtilis. At similar pressures to those that would be suffered inside a meteorite as it crashed, around one in every ten million R. erythropolis cells and a few in every hundred thousand B. subtilis survived when they hit the gel. A gram of terrestrial soil typically contains a billion bacterial cells. The survival rate for an ice target was about ten times higher, so Burchell and colleagues think that it's not just Earth and Mars that could have swapped life. The icy moons of Jupiter, for instance, at least one of which, Europa, has a sub-surface ocean of water, could seed one another. Or a planet could re-seed itself if, as some have suggested might have happened on the early Earth, a massive impact wiped out all life. References 1.. Burchell M. J., Mann J. R. Bunch A. W. Monthly Notices of the Royal Astronomical Society , 352. 1273 - 1278 (2004). 2.. Burchell M. J., Mann J. R., Bunch A. W. Brandao P. F. B. Icarus, 154. 545 - 547 (2001). __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Alien Microbes Could Survive Crash-Landing
I think their survival would depend if the planet the bacteria came from had a helmet law Sorry- list needs to smile a bit! Everyone have a good night. Mike Groetz (Seriously, this was a very interesting article- Thank You Ron). --- Ron Baalke [EMAIL PROTECTED] wrote: http://www.nature.com/news/2004/040830/full/040830-10.html Alien microbes could survive crash-landing Philip Ball Nature September 2, 2004 Tough bugs make interplanetary wanderings more plausible. Bacteria could survive crash-landing on other planets, a British team has found. The result supports to the idea that Martian organisms could have fallen to Earth in meteorites and seeded life. Bugs inside lumps of rock can survive impacts at speeds of more than 11 kilometres per second, say the researchers [1]. The work also shows that bacteria could survive crashing into icy surfaces such as Jupiter's moons Europa and Ganymede. The possibility that Earth's first life came here inside space rocks - the panspermia hypothesis - was proposed in 1903 by the Swedish chemist Svante Arrhenius. But the painful landing has always been a stumbling block. Mark Burchell and his colleagues at the University of Kent, Canterbury, have put panspermia to the test by firing lumps of porous ceramic infiltrated with bacteria into targets. During impact, the bacteria are crushed by up to a million times atmospheric pressure. A few years ago everyone said we were crazy, says Burchell. They knew it wouldn't work. But in 2001 he and his colleagues showed that soil bacteria can survive a high-speed impact into soft gel [2]. Most of the microbes died, but enough survived to make panspermia possible, provided that the bugs don't have to travel too far: they would probably be sterilized by cosmic rays and UV radiation during a journey from another solar system. Crushing blow But the researchers didn't know whether the pressures generated in their experiment were comparable to those of a meteorite impact. Nor did they know how different microbial species would fare. To find out, the team used a gas-powered gun to fire bits of ceramic, between 0.1 and 2 millimetres across, into targets of gel or ice. The projectiles were loaded with cells or spores of the soil bacteria Rhodococcus erythropolis or Bacillus subtilis. At similar pressures to those that would be suffered inside a meteorite as it crashed, around one in every ten million R. erythropolis cells and a few in every hundred thousand B. subtilis survived when they hit the gel. A gram of terrestrial soil typically contains a billion bacterial cells. The survival rate for an ice target was about ten times higher, so Burchell and colleagues think that it's not just Earth and Mars that could have swapped life. The icy moons of Jupiter, for instance, at least one of which, Europa, has a sub-surface ocean of water, could seed one another. Or a planet could re-seed itself if, as some have suggested might have happened on the early Earth, a massive impact wiped out all life. References 1.. Burchell M. J., Mann J. R. Bunch A. W. Monthly Notices of the Royal Astronomical Society , 352. 1273 - 1278 (2004). 2.. Burchell M. J., Mann J. R., Bunch A. W. Brandao P. F. B. Icarus, 154. 545 - 547 (2001). __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list ___ Do you Yahoo!? Declare Yourself - Register online to vote today! http://vote.yahoo.com __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Alien Microbes Could Survive Crash-Landing
Has someone been going though their old SF and re-read The Andromeda Strain? Tracy Latimer From: Mike Groetz [EMAIL PROTECTED] To: Meteorite Mailing List [EMAIL PROTECTED] Subject: Re: [meteorite-list] Alien Microbes Could Survive Crash-Landing Date: Mon, 13 Sep 2004 18:10:38 -0700 (PDT) I think their survival would depend if the planet the bacteria came from had a helmet law Sorry- list needs to smile a bit! Everyone have a good night. Mike Groetz (Seriously, this was a very interesting article- Thank You Ron). --- Ron Baalke [EMAIL PROTECTED] wrote: http://www.nature.com/news/2004/040830/full/040830-10.html Alien microbes could survive crash-landing Philip Ball Nature September 2, 2004 _ Check out Election 2004 for up-to-date election news, plus voter tools and more! http://special.msn.com/msn/election2004.armx __ Meteorite-list mailing list [EMAIL PROTECTED] http://six.pairlist.net/mailman/listinfo/meteorite-list
