New Evidence Presented For Ancient Fossils In Mars Rocks 91
azoblue passes along a story in the Washington Post, which begins:
"NASA's Mars Meteorite Research Team reopened a 14-year-old controversy on extraterrestrial life last week, reaffirming and offering support for its widely challenged assertion that a 4-billion-year-old meteorite that landed thousands of years ago on Antarctica shows evidence of microscopic life on Mars. In addition to presenting research that they said disproved some of their critics, the scientists reported that additional Martian meteorites appear to house distinct and identifiable microbial fossils that point even more strongly to the existence of life. 'We feel more confident than ever that Mars probably once was, and maybe still is, home to life,' team leader David McKay said at a NASA-sponsored conference on astrobiology."
Skeptical (Score:3, Interesting)
Re:Skeptical (Score:4, Interesting)
Actually I'd be a little surprised if the nucleotides were different, current studies seem to suggest that the nucleotides had selective pressure. Here's a video that summarizes some current work on abiogenesis by Dr. Jack Szostak. http://www.youtube.com/watch?v=U6QYDdgP9eg [youtube.com]
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It's quite possible that the Martian life used different nucleotids. For example, even on Earth uracil is used instead of thymine in RNA. Also, parts of DNA can be methylated.
And it's certainly conceivable that some other substances can be used for genetic information. Maybe even from non-organic elements (metals, for example).
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Hard to believe there's not someplace on Earth where the same nucleotide variations would have been advantageous.
Yeah, and it's quite plausible that at the dawn of primitive life, there were several variations, but only this one survived. Life probably got nearly wiped out many times back then, considering all the meteorities, volcanic activity, probably not-yet-quite-stable sun... So our current encoding is probably the one that was best in an environment that didn't get sterilized when everything else got sterilized at some point.
But once the encoding sets in, once there's actual xNA with information, changing encod
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How could a fossil that is few billion years old be of Earth origin, if the meteorite is here for only a very short time?
Anyway, if we would rely mostly on comparing things like nucleotides (not that they actually can)...well, that bit of information doesn't have to provide us with definite answer at all. With life that is so old, we aren't certain at all that Earth life relied on "the same four nucleotides" back then. Heck, it might have been that, while Earth life was different, the one on Mars was by a r
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Beyond that, if they are the same, then it may not be coincidence at all. One planet's life may have been seeded by the other, or both come from another common origin, whether deliberately by intelligent beings, or indeliberately by chance.
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Picture a cartoon coyote, opening a box labeled "ACME". He takes out a large firework with "6,000 years" written on the side. He then proceeds to light the fuse and retires to a safe distance...
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I wasn't even touching on this subject. Sure, there is a considerable debate if those are really fossil bacteria.
But determining how old those structures are is considerably easier. Likewise - determining from where the meteorite, in which they are embedded, came from and how long it has been on Earth.
There is very little uncertainty that those structures are Martian, which was what GP poster doubts.
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First, meteors are easily identifiable as coming from outer space due to the structure of the rock i.e. melted exterior but not interior, material composition matching Mars, and carbon dating. Second, this particular meteor [wikipedia.org] was found embedded in ice in Antarctica as many meteors are found. How did it get there? (Antarctica is a great place find intact meteors because the ice buffers the landing and then protects the
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I almost posted a critical comment as I had misread your statements, especially about Occam's Razor.
Luckily, I read your post again. You are very correct!
Where did that bit about the structure and size of the possible organisms come from? I could not find it when I did RTFA. It talks about magnetites.
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They can't carbon date stuff from Mars, because carbon dating has to be done on things that formerly were alive. Heck, it depends on the properties of our atmosphere -- the fact that the carbon there has a certain isotope makeup, and that we know how this makeup has been changing over history. The carbon dating calibration curves describe history of Earth's atmosphere, not some other random atmosphere.
They can date stuff from Mars using other isotopes that have longer half-lives, and are somehow related to
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That's not incorrect, but not because things the you are going to date with carbon dating need to have been alive. They need to have been in equilibrium with the atmospheric carbon pool before they went out of equilibrium - which a living thing does by dieing, but a non-living thing could do, for example, by being buried in sediment.
The ultimate constraint on carbon dating (and any dating system)
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The featured article talks about magnetite possibly formed by microbes. There is no mention of nucleotides. How can organic molecules from microbes survive fossilization for billions of years, form part of a meteorite, survive its journey through our atmosphere and yet be analyzed?
After all, it would be an extremely rare chance to find surviving DNA from even dinosaur fossils here on earth. The scientific method followed for studying genetic evolution happens mostly by triangulation of molecular informatio
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"...then it is far more likely that the fossils are from Earth and have contaminated the sample."
Or that they maybe are the original seed of earth life.
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Well, again, no
Contamination (at least some of it) has been ruled out when the fossils were found 'inside' (pockets in) the rock
And I guess there's no recoverable DNA there.
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Also, if we some day find microorganisms on Mars that share the genetic code of Earth's life, that doesn't prove it's not native Mars live; panspermia and selection both could reasonably explain it. Finding a different code, however, would be excellent evidence for unique origin or long, indpendent evolutionary histo
OK ... (Score:1)
still has the same problems (Score:3, Insightful)
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What happens in 2051?
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The world has been destroyed for 39 years.
Re:still has the same problems (Score:5, Funny)
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Otherwise we might have to lie infront of bulldozers or something.
Consequences of discovery (Score:5, Interesting)
While it may be cool to find life on Mars, it would present some additional problems for future colonization (or even just future missions, robotic or otherwise). If we do find life, do we quarantine Mars so that we don't contaminate the native life there? Do we bar ourselves from any terraforming efforts whatsoever so that we don't disrupt possible existing life? You all must realize that that would be the position of at least some people; what percentage of the public that might be, and the influence they would have is another question.
Generally, I think it would be much simpler if we never found life on Mars, and could in fact say with a fair amount of certainty that it is completely dead. That would remove a (possibly significant) reason to oppose human colonization and terraforming.
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If we do find life, do we quarantine Mars so that we don't contaminate the native life there? Do we bar ourselves from any terraforming efforts whatsoever so that we don't disrupt possible existing life?
I say "damn those Martians, full speed ahead!"
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While it may be cool to find life on Mars, it would present some additional problems for future colonization (or even just future missions, robotic or otherwise). If we do find life, do we quarantine Mars so that we don't contaminate the native life there? Do we bar ourselves from any terraforming efforts whatsoever so that we don't disrupt possible existing life? You all must realize that that would be the position of at least some people; what percentage of the public that might be, and the influence they would have is another question.
I think here that we'll just have to take it as the universe gives it to us. If there is life on Mars, we will probably establish some sort of barrier so that Earth life doesn't necessarily contaminate Mars life and vice versa. Even if Mars colonization turns out to be obstructed by regulation or other means to prevent contamination, the obstacles will be reasonable or someone will find a way to get around the regulations in question (say by totally ignoring them and deliberately contaminating Mars and/or E
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Re:Consequences of discovery (Score:4, Interesting)
What are you talking about? The prime directive was the Vulcans' idea, not ours.
Re:Consequences of discovery (Score:4, Insightful)
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Frack the Vulcans.
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it might be cheaper to scoop the gas off titan
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How many trips would that take?
What kind of volume are we talking about here?
What kind of time frame are we looking at?
We need some calculations so that we can make our
Titan gas hauler large enough to get the job done
in a reasonable amount of time. Is there enough
metal in our solar system to make a space craft large enough
to haul that much gas in a reasonable amount of time?
I think human made space stations are probably a better bet.
Terraforming is a fantasy that doesn't add up.
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I used to be naive and idealistic like you, then I learned about panspermia. It is fairly certain by now that all planets are being bombarded by asteroids filled with random organisms. Earth and Mars have almost certainly been recipients of foreign material. Any bacteria, etc. that we might transfer to Mars should cause us no worries. Organisms from Earth should be just as valid as random organisms from panspermia. In fact the very organisms that we might take there could have been derived from our own expo
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I used to be naive and idealistic like you, then I learned about panspermia. It is fairly certain by now that all planets are being bombarded by asteroids filled with random organisms. Earth and Mars have almost certainly been recipients of foreign material. Any bacteria, etc. that we might transfer to Mars should cause us no worries. Organisms from Earth should be just as valid as random organisms from panspermia. In fact the very organisms that we might take there could have been derived from our own exposure to panspermia.
Speaking of smoking guns, where's the asteroid or comet with life on it? For panspermia to be valid, there need to be evidence of life in space. We haven't observed that yet (aside from some bacteria spores in the upper atmosphere, which might become cast off from Earth). Further, just because Mars and Earth might have organisms from the same common source, doesn't mean that they'll live peacefully together. On Earth, we have plenty of examples of invader species that upend an ecosystem in which they have n
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Panspermia doesn't really answer where life comes from. It just sort of shifts the question off of Earth.
It's true, it doesn't answer where life comes from, but it's more than turtles all the way down. Shifting the question off Earth changes the question, because off Earth the conditions are different! Panspermia removes all objections related to the specific conditions of primeval Earth. If you postulate that life has appeared on Earth, your theory has to explain it given a lot of constraints: a certain c
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Any bacteria, etc. that we might transfer to Mars should cause us no worries.
Oh yeah. Because these organisms might have the same origins, we shouldn't concern ourselves with the consequences of introducing earth bacteria.
Just like introducing species into new ecosystems on earth, because hey all the life came from earth, is something you can do willy-nilly with no care since it never has negative consequences.
So okay, what happens when we figure out that life on Mars and earth did have a common ancestor,
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We kill them all and take what's theirs and hear the lamentations of the women, etc. That is clear.
Truly, if there is life on Mars I think that will cause us to go there and rape it even sooner than otherwise.
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Truly, if there is life on Mars I think that will cause us to go there and rape it even sooner than otherwise.
Please, tell me you meant raze.
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Truly, if there is life on Mars I think that will cause us to go there and rape it even sooner than otherwise.
Please, tell me you meant raze.
Please, tell me you meant raise.
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If we do find life, do we quarantine Mars so that we don't contaminate the native life there?
Well... that depends on if we've invented the Prime Directive by then.
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Thoats, callots' mad zitidars, what do you mean there is no life on Mars?
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[...] If we do find life, do we quarantine Mars so that we don't contaminate the native life there?[...]
Depends on the means used to find that life form and the motivation to go to Mars. If (say) China decides to colonise Mars as a means to ensure that human life goes on even if the Earth becomes uninhabitable, I do not think that other countries would shoot down their colony ships on the basis of preserving a pristine state of the Martian nature. I'm sure there are international treaties about space exploration and ethics in space, but if there's an emergency or a huge amount of money waiting for a very limi
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"do we quarantine Mars so that we don't contaminate the native life there?"
Of course not. Are you nucking PHUTTS? If there's life on Mars, or anywhere else, we'll CULTIVATE it and EAT IT!! Do you know what nutrients those Martian slugs need? Mine aren't doing so well, right now. Maybe a little acetic acid?
The universe has lots of microbes.... (Score:1)
People really need to *Get Over* the whole Star Trek thing and worrying about every
bacillus/eucaryot and rock as if it were some precious message from an all knowing spaghetti-monster.
"Oh my god, I moved a rock!!!!!"
Mars is the house next door. If it's on Mars, it's probably here already too, and vice versa.
The main proponents of staying in Earth are those who would lose a great deal of social
control over the masses. Protecting microbes
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As for terraforming Mars, Venus is a better bet. Gravity is similar, it's inside the
temperate zone and it's atmosphere has the makings of water.
Mars has a CO2 atmosphere for a reason. It's gravity is too low to keep oxygen
from blowing away in the solar wind.
Actually Venus has lost most of its hydrogen so doesn't have much in the way of water makings.
And Mars has a CO2 atmosphere for the same reason as Venus. Oxygen is reactive and combines with hydrogen or carbon (usually) rather then existing as an elementary element.
The only reason that the Earth has free oxygen is due to life.
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Yes, but I think you're disregarding the points about terraforming.
!Just add water!
Terraforming could rectify the missing hydrogen (water).
There are a few icy comets that we could re-orbit around Venus.
Heck, we only need 1.1475x10^18 metric tonnes of water to get the job done. :)
(And some sulfur-loving algae)
Total mass of comets represent 2% of solar (3.9782x10^25)
The number of comets required to do this would be a rather daunting though
since the average comet is only 1 km or less. We would require 1.3
Wash Post Flame Wars (Score:4, Insightful)
Y'know /. is pretty damn cool. Our flame wars are a joy to behold compared to the Wash Post flaming attached to the article.
http://www.washingtonpost.com/wp-dyn/content/article/2010/04/30/AR2010043002000_Comments.html [washingtonpost.com]
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Haha, that's amazing, there are actually people there claiming that the scientists have invented the whole thing to get more research funding. It's worse than youtube comments.
That kind of thing could never happen on slashdot! [slashdot.org]
Life from Earth (Score:3, Interesting)
I'd rather life here, didn't start on Mars... (Score:1)
Panspermia (Score:5, Interesting)
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Damn them scientist... (Score:3, Funny)
... sic them politicians on them scientist... that'll prove they (the scientist) are wrong.
Another McKay (Score:2)
...Stirring up trouble with crazy theories about aliens...
I reject the notion that man isn't a cosmic entity (Score:4, Insightful)
The universe is a vast place. And in the big picture, we are all part of it. Nothing we could possibly do is out of the bounds of nature on a universal scale. We have as much right to explore, seed, and shape the cosmos as any other creature in the universe. If we disturb the habitat of any other planet, so be it. It's the laws of the universe at work.
To paraphrase Carl Sagan... The cosmos is within all of us. We are made of star stuff.
Re:I reject the notion that man isn't a cosmic ent (Score:2)
"We are made of star stuff."
Big balls of gas?
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Seldom h
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How would we feel about extra-terrestrial creatures coming to Earth and seeding it with THEIR kind of life, which might be actually harmful to us?
If there is life on extra-solar planets, or even other planets in our solar system, it may have arisen uniquely, taken different biochemical routes, evolved differently.
Considering the question from the viewpoint of the golden rule, should we be really polluting other systems just to push our own biological agenda?
Other extraterrestrial civilizations may also evol
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How would we feel about extra-terrestrial creatures coming to Earth and seeding it with THEIR kind of life, which might be actually harmful to us?
That would still be entirely natural.
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..and I reject the notion that my urinating on your doorstep is in any way unnatural.
Its called having respect for something that isn't yours. Get some, and stop whining that other people might actually hold you accountable for the consequences of your actions, since you are apparently too selfish or short-sighted to consider them on your own.
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Easy to say when you're not on the receiving end. What if some alien civilization decided Earth looked like a good place to hang out when we were still crawling out of the ocean?
Sounds like you're saying it's alright to take what you want if you have the power and no one can stop you. Nazis and Poland, Europeans and the New World, Sky People and Pandora... just take what you want. I think we should tread carefully. We may destroy something irreplaceable before we recognize its value.
Proof positive (Score:1)
http://www.telegraph.co.uk/culture/3655398/A-dishwasher-on-Mars.html [telegraph.co.uk]
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(probability that life exists on Mars)
s/exists/ever existed/.
Unknowable given our current state of science, but some theories would place it quite high.
x (probability a comet hits Mars and expels some rocks with bacteria inside)
Given that life existed, this is almost certain to have happened, probably many times. We know that rocks have been expelled via such a mechanism. We know that in a biosphere like Earth's, it is almost impossible to find surface-level rocks that don't have any signs of life. We wo