New Evidence Presented For Ancient Fossils In Mars Rocks

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."

Comments

Skeptical

[Foobar of Borg]

If any fossilized life they find their has the same four nucleotides in its dna sequence (assuming anything like DNA can be recovered), then it is far more likely that the fossils are from Earth and have contaminated the sample. If, however, some sort of dna material can be obtained and there are different base nucleotides, then we have a winner.

Re:Skeptical

[Misanthrope]

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

Re:Skeptical

[sznupi]

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 random chance similar to our current "model"...

Re:Skeptical

[VanGarrett]

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.

Re:Skeptical

[Cyberax]

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).

Re:Skeptical

[lena_10326]

then it is far more likely that the fossils are from Earth and have contaminated the sample

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 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 meteor from erosion.) Third, the structure and size of the possible organisms do not match known Earth organisms. How do you explain that?

I invoke Occam's Razor. The simplest explanation is these meteors landed on Earth after travelling from Mars through space. The determination that these contain samples of fossilized life is a separate matter.

Re:Skeptical

[Clueless Nick]

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 information in present-day genes of surviving species, to form a bit of a speculative idea about the genetic makeup of its ancestor of millions of years ago.

If probably you mean that one day, we may find active microbial life on Mars, that indeed would be a great breakthrough, as it will allow us to compare its origin and evolution with ours, and thereby provide us better tools to understand how it arises in the first place. You know, the spark that ignited it all.

still has the same problems

[khallow]

There's no smoking gun, that is, some direct evidence of these organisms. And frankly, I don't find the current claim of relatively pure magnetite to be compelling. This is part of why I've bet against the discovery of alien life by 2050 since 1996.

Re:still has the same problems

[khallow]

Earth gets disintegrated to make way for a galactic hyperbypass.

Consequences of discovery

[Larson2042]

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.

Re:Consequences of discovery

[khallow]

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 Earth).

Re:Consequences of discovery

[Thinboy00]

What are you talking about? The prime directive was the Vulcans' idea, not ours.

Re:Consequences of discovery

[Anonymous Coward]

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.

I would suggest that we should enact our own panspermia missions. We can drop our own organisms on planets and moons. Imagine in only a few hundred years that Mars could have large areas covered with many varieties of lichens, including those nifty ones that blow around in the wind. We could start with extremophiles, and work our way up from there. I would guess that the lunar missions left human biological material on the moon as they would want to reduce weight as much as possible before returning to Earth. What is NASA's answer to this? And now ice has been found on the surface of the moon. My high school science teacher lied to me, I was told it was impossible due to sublimation.

Re:Consequences of discovery

[kurt555gs]

Thoats, callots' mad zitidars, what do you mean there is no life on Mars?

Re:Consequences of discovery

[ChatHuant]

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 chemical composition, a certain gravity, certain temperature ranges and so on. With panspermia that's not the case any more - it vastly expands the range of environments, processes, time frames and resources available for life to arise.

Re:Consequences of discovery

[Ginger Unicorn]

Vulcans and the Prime Directive are both human ideas.

Wash Post Flame Wars

[poena.dare]

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

Life from Earth

[PineHall]

It is my understanding that bacteria could survive a trip through space from Earth to Mars (or vice versa). I wonder if a chunk of earth made it to Mars and seeded Mars with bacterial life. That could mean that the bacterial life on Mars could have the same characteristics as bacterial life on Earth because they originated from Earth. It makes the contamination issue a little more complex.

Panspermia

[sdo1]

If it's true, it's actually not a huge deal. I could mean that life spontaneously started on both Earth and Mars (Panspermia). But it's probably more likely (Occam's razor and such) that life started on either Earth or Mars and was transported via meteor to the other planet. I would be very cool if life on Earth actually started on Mars, but it's not clear to me how we could prove which came first. -S

Damn them scientist...

[3seas]

... sic them politicians on them scientist... that'll prove they (the scientist) are wrong.

I reject the notion that man isn't a cosmic entity

[mykos]

I feel that this notion ingrained in to our environmental education that anything and everything human beings do is bad and/or unnatural is just wrong.
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.