A crystal found in a meteorite from Mars could only have been formed by a microbe and may be evidence of the oldest life form ever found, researchers say.
So, where were all the new stories back in 2001? Where was all of the coverage? George W. Bush waxing poetic on one more mystery of the universe being solved?
Good question. Further research in July of 2003 finds several articles that don't take the AP article's "proof" as absolute enough. Apparently, they would like to see little green men with laser pistols asking to be taken to our leader...
The original AP article is long gone from CNN.com where it was posted back in February of 2001. But you can click on "more" below to read it.
But you can still read the BBC News coverage of this historic discovery.
Read about a Caltech student who made the same findings in 1997 and won a huge award for it.
From the Associated Press and CNN.com:
Study: Crystal proves life existed on Mars
February 27, 2001
Web posted at: 12:48 p.m. EST (1748 GMT)
WASHINGTON (AP) -- A crystal found in a meteorite from Mars could only have been formed by a microbe and may be evidence of the oldest life form ever found, researchers say.
Scientists at the Johnson Space Center in Houston say that a crystallized magnetic mineral, called magnetite, found in a Martian meteorite is similar to crystals formed on Earth by bacteria.
"I am convinced that this is supporting evidence for the presence of ancient life on Mars," said Kathie Thomas-Keprta, an astrobiologist at the space center and the first author of a study appearing Tuesday in the Proceedings of the National Academy of Sciences.
Thomas-Keprta said there is no report of such magnetites being formed by any but biologic means.
Earlier claim of life on Mars dismissed by researchers
The magnetite crystal was found in a Mars meteorite called Allen Hills 84001, or ALH84001. Researchers at the Johnson Space Center in 1996 announced that the space rock contained microscopic evidence of life, but their claim has been dismissed by most other researchers.
Thomas-Keprta said the new study strongly supports the original claim and may even suggest that there is still microscopic life on Mars.
"If it existed there at one time, we would expect it to exist today," said Thomas-Keprta.
The new finding is supported by a second paper in Proceedings.
E. Imre Friedmann, a biologist at NASA's Ames Research Center in Moffett Field, California, said an electron microscope examination of ALH840001 had produced evidence of magnetite crystals formed in chains.
Friedmann said that on Earth the bacteria that make magnetite forms the material in chains and that these chains are surrounded by a membrane. Under the electron microscope, fossilized images of both the chains and the membrane can be seen, he said.
"We see chains that could have been formed only biologically," said Friedmann. "There is no way you could come up with a non-biological explanation."
On Earth, some bacteria that live on the bottom of lakes produce magnetite as a navigation aide. The magnetic crystals act as a sort of compass to allow the bacteria to orient itself as it moves along the lake bottom.
Friedmann said the bacteria require an environment that is low in oxygen. The built-in compass "helps them navigate in the proper oxygen levels," he said.
Thomas-Keprta said the magnetite is "a bacteria fossil, sort of like dinosaur bones."
She said magnetite could not come from Earth organisms because it was encased inside the meteorite in a carbonate mineral that has been age-dated at 3.9 billion years old.
Because of this age, said Thomas-Keprta, "this is evidence of the oldest life form ever found."
Mars now has neither standing water nor a magnetic field, which would prompt bacteria to make magnetite. But experts believe that the planet once had oceans, an atmosphere and a magnetic field. Thomas-Keprta said it was during this period, billions of years ago, that the bacteria lived and made the magnetite found in ALH84001.
Some scientists still skeptical
Some researchers who rejected the 1996 study by the Johnson Space Center scientists said they are not convinced by the new evidence.
Ralph P. Harvey, a geologist who has studied ALH84001, said the new conclusions are "hasty" and should not be accepted without further study.
"I don't think this report should be considered as proof" that life ever existed on Mars, said Harvey, but he did not totally reject the Thomas-Keprta interpretation.
"The door is still open until further evidence is rolled out," said Harvey.
He said he is troubled that Thomas-Keprta and her co-authors found many crystals of magnetite in the meteorite, but are reporting only on those crystals that they believe could have come from bacteria.
"All of the rest of the magnetites say 'No' to life," said Harvey. "They are focusing only a minority of magnetites in this rock."
Also, said Harvey, the researchers are concluding that the selected crystals could be formed only by a life process when there is little research to support this.
"Their support for these magnetite crystals is that they have never been found in a non-biological setting," he said. "It is in my mind hasty to rule out another origin."
At 4.6 billion years, ALH84001 is the oldest of 16 meteorites found on Earth and identified chemically as originating from Mars. Scientists believe that an asteroid smashed into Mars 13 to 16 million years ago and catapulted the Martian chunk into orbit. It wandered in space for millions of years and finally fell to Earth about 13,000 years ago. It was found on the Allen Hills ice field in Antarctica in 1984 and has been intensely studied since.
Copyright 2001 The Associated Press.
From BBC News:
'Conclusive evidence' for Martian life
By BBC News Online's Ivan Noble
Scientists have published what they claim is "conclusive evidence" that bacteria once lived on Mars.
The study is a follow-up to the famous 1996 research that purported to show ancient bacterial forms in a meteorite from Mars. Critics at the time said the evidence was too thin to prove anything.
Now, a Nasa-backed team from the US, Spain and Germany has published further work which it says strengthens the earlier claims.
But some British experts, at least, are still sceptical, arguing the latest study falls short of absolute proof.
The argument centres on tiny crystals found in a potato-sized meteorite picked up in Antarctica in 1984.
The international team says the crystals are the same as those deposited by earthly microorganisms known as magnetotactic bacteria.
Since the meteorite is from Mars, it can only be assumed that the same bacteria must have lived on Mars as well, the team says.
Signature of life
The crystals in question are made of magnetite, a compound of iron and oxygen. The team's aim was to show that they must have been deposited by living organisms, rather than a simpler chemical process.
Magnetite crystals deposited by bacteria on Earth show six key features that distinguish them from crystals of non-biological origin. This biosignature is what researchers have been looking for.
Last year, another group of researchers announced that it had found some, but not all, of the six key features.
Now, in a paper published in the journal Proceedings of the National Academy of Sciences (PNAS), Imre Friedmann, Jacek Wierzchos, Carmen Ascaso and Michael Winklhofer say they have found the missing sixth element.
Crystal chain clue
The final clue was the arrangement of the crystals in the meteorite. Crystals left behind by bacteria on Earth form characteristic chains.
Dr Imre Friedmann of Nasa's Ames Research Center says his team used a new method of electron microscopy to show that the Martian crystals are in chains, too.
"These crystals match all the criteria for biologically-formed chains, and as far as I'm concerned it's conclusive evidence that Martian bacteria were in this meteorite.
"I cannot guess how my colleagues will react, but in my opinion no reasonable person can doubt it any more. The evidence is so strong.
"When you put all the elements together there can be no other explanation," Dr Friedmann says.
Mission to Mars
Professor Colin Pillinger, lead scientist on the British-led Beagle 2 effort to land on Mars in 2003, describes the Nasa-backed study as very interesting, but says it falls short of absolute proof.
"The bigger the claim, the more perfect the evidence has to be," he told BBC News Online. "This doesn't actually prove that the evidence in the meteorite is for life on Mars.
"We cannot say absolutely, hand on heart, that this is something which happened on Mars until we find organic matter in a genuine Martian sample. We have to go to Mars and if there is doubt we will have to bring samples back. If there is still doubt, we will have to send a person there to carry out the experiments in situ.
"Our Mars mission experiments are designed to test for organic matter and isotopic fractionation - the best measure I know to detect organic life."
Rock origins
One major objection to the claims has always been that the magnetite crystals could have come from bacteria which infiltrated the rock after it landed on Earth.
But Dr Friedmann says the crystals are undoubtedly from Mars because they are inside other globules of rock whose origin is uncontested.
The Viking missions to Mars in the 1970s analysed Martian rock and the Martian atmosphere.
These measurements allow scientists to work out whether a meteorite bears the chemical signature of something formed on Mars.
The meteorite in this study - known as ALH84001 - was found in Antarctica in 1984 but no-one realised it was a Martian meteorite until 1993. There 15 meteorites now known to be of Martian origin.
From PasadenaStarNews.Com:
Meteorite helps Caltech student prove his thesis
Rocky road to success
By Becky Oskin, Staff Writer
PASADENA -- Six years ago, Ben Weiss spent all night slicing the oldest rock on Earth into pieces the size of a child's fingernail.
The precious slivers of dark brown meteorite offered Weiss, then a first-year Caltech graduate student, a chance to delve into the most hotly contested debate in geology: whether a potato-size piece of Mars blasted from the red planet 15 million years ago carried remnants of Martian life to Earth.
"All night long we kept laughing out of excitement and disbelief as we played with not only an invaluable rock from Mars but the oldest known rock from any planet!' Weiss, 29, wrote in his thesis.
From those bits of 4-billion- year-old Mars rock, Weiss proved the meteorite took a cool trip to Earth, never reaching sterilizing temperatures that could kill life forms hitching a ride. He also found evidence Mars had a magnetic field protecting a thick atmosphere in its early history conditions conducive for evolution of the simplest microbes.
For these discoveries, this year Caltech awarded Weiss its highest honor for graduates, the Clauser prize. Given annually to a doctoral student whose research exhibits potential for opening up new avenues of human thought and endeavor, as well as by the ingenuity with which it has been carried out, the award validated Weiss' choice to follow his love of a science he says was even more crackpot six years ago than it is today.
"The field I'm in is definitely not a traditional kind of science. It's a historical science. It's hard to really prove something. You have to be careful not to drown in speculation and stick to the facts,' Weiss said.
Weiss originally set out to study the planets as an astronomer, earning a physics degree from Amherst University in Massachusetts, not too far from his home in upstate New York. After a stint as an exchange student in Singapore, he enrolled at Harvard University as a graduate student interested in cosmological lensing, the deflection of light by gravity.
That was also the year Pathfinder arrived at Mars and captured the public's interest with stunning pictures of the planet's surface. Mars science and its connection to life on Earth found a captive audience in Weiss, and he transferred to Caltech to work with geobiologist Joe Kirschvink, who had samples of the Martian meteorite ALH84001.
It was a risky decision, Weiss said. "It could have been a disaster' if nothing interesting came of his investigations, leaving him without a thesis.
Instead, Weiss ended up with what Kirschvink calls a slam dunk win proof that Mars could have hosted life and perhaps even seeded Earth.
"Ben's thesis work has doubled the problem of the origin of life,' Kirschvink said.
The proof that fractured rock ALH84001 could have transported simple Martian life forms to Earth comes from many different areas of geology, but Weiss focused on magnetization.
Kirschvink's lab specializes in paleomagnetism, the remnant alignment of iron grains within a rock. Weiss figured out a way to apply the most sensitive magnetic field detector in the world to examine the meteorite and query its history.
One of his first results showed that grains of the iron-bearing mineral magnetite, hidden with carbonates stuck in fractures criss-crossing the meteorite, were aligned magnetically when the rock was heated to about 100 degrees Fahrenheit.
The results meant that even when ALH84001 was blasted off Mars and burned its way through Earth's atmosphere, those magnetite grains were never exposed to temperatures warmer than the average summer day in Southern California.
And if one rock can travel to Earth at temperatures hospitable to life, maybe some of the billions of tons of rocks kicked off the surface of Mars over the eons could have brought Martian life here.
Weiss and Kirschvink call it panspermia: we could all be descended from Martians.
It's worth noting that a standing joke among Weiss' Caltech colleagues is that he's a Martian who has invaded a human body.
"He's just off the wall, or maybe he's just an absent-minded professor,' Kirschvink said.
The panspermia theory is what some scientists call crackpot, but Weiss' other results from the Martian meteorite have revolutionized understanding of the planet's early history.
Stripping away the meteorite's magnetization revealed Mars once had a planetary magnetic field. Mars does not have a field today.
"The magnetic field has really important implications for Mars' core, and also may be tied to the evolution of the Martian climate,' Weiss said.
Gas trapped in the meteorite's minerals does not match the ratio of gases of Mar's modern, thin atmosphere. Younger Martian meteorites do match.
The implication: "We have a sample of 4-billion-year-old Martian atmosphere,' Weiss said.
If Mars once had a magnetic field like Earth, it would protect the planet's atmosphere from bleeding off into space. But if the magnetic field turned off when the interior of Mars cooled, ending the rotation that produced the field, then the decline of the magnetic field might be linked to Mars' vanished atmosphere.
This transition seemed to happen about 4 billion years ago, when ALH84001 was fractured on Mars during a heavy bombardment of meteorites. Earth's moon also was pounded by space rocks during the period, hinting at some systemwide cataclysm.
"This rock was severely busted up 4 billion years ago,' Weiss said. "The first half-billion years was a really violent time on Mars, and this rock records that,' he said.
Now that Weiss has graduated from Caltech, he appears ready to leave Mars behind. His future plans include trying to figure out when Earth's magnetic field first turned on, and analyzing interplanetary dust particles to learn more about the earliest magnetic fields in the solar system. MIT will build Weiss, who has accepted a professorship there, one of the most sensitive magnetometers ever.
"It's so sensitive that anything I think of to study will be interesting,' Weiss said.
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