Skip to comments.NASA team cites new evidence that meteorites from Mars contain ancient fossils
Posted on 05/04/2010 12:55:53 AM PDT by Palter
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.
The researchers' presentations were not met with any of the excited frenzy that greeted the original 1996 announcement about the meteorite -- which led to a televised statement by President Bill Clinton in which he announced a "space summit," the formation of a commission to examine its implications and the birth of a NASA-funded astrobiology program.
Fourteen years of relentless criticism have turned many scientists against the McKay results, and the Mars meteorite "discovery" has remained an unresolved and somewhat awkward issue. This has continued even though the team's central finding -- that Mars once had living creatures -- has gained broad acceptance among the biologists, chemists, geologists, astronomers and other scientists who make up the astrobiology community.
"Biomorphs" found on meteorites traced to Mars have been proposed as evidence that life has existed on the Red Planet
(Excerpt) Read more at washingtonpost.com ...
NASA PR flacks have already denounced this release. Too many of the geologists and “earth” science types at JPL would be put out of a job if this news got corroborated.
For that matter, could Obama and company withstand the likely public pressure for a manned expedition to investigate life on Mars if it ever appeared that such a thing was likely? Even their Defense Dept. budget eviscerations would have to be put on hold in such an event.
With all the evidence that Mars was once covered with flowing water. Its very ignorant for any scientist to say there is no life on mars, there never was or ever will be.
Just ask Helen. She saw it land.
How many scientists throughout history have proclaimed things to be impossible only to be punked later on? Too many to count.
OK, **IF** it is possible that ejecta from Mars made it to earth (and I see that as REMOTE) HOW can one establish that this particular piece of ejecta/meteorite came from MARS since there is no other sample to confirm/compare/verify? That this meteorite came from MARS is pure speculation, not science.
Doesn’t mean it’s not possible. But come on.
Also if ejecta from MARS could make it to earth, then the reverse is also true. Perhaps early life from earth colonized early MARS via ejecta. A plausible pan-spermism theory if you like those.
Clearly, the science is settled, so why do we continue the discussions?
The Viking Mission to Mars back in the 70s conducted remote tests on rocks there and did an isotope analysis. Some meteorites on Earth match up identically to them chemically. It is like a DNA match.
OK we have a decent correlation. Would not call it proof or even conclusive. IT is fun to speculate though.
I’m not sure if the NASA Viking mission did remote testing of Martian rocks. It may have only analyzed its atmosphere remotely and then matched it chemically to gases trapped within meteorites found on Earth.
“...unheralded measurement by the two NASA Viking spacecraft that landed on Mars in 1976. Although sent to conduct experiments to detect extant life in Martian soil (which they did not), the Viking landers gained redemption of sorts because the instruments measured the amounts of different gases in the thin Martian atmosphere. Those same gases were first found in 1983 by Donald Bogard and Pratt Johnson in very small amounts (but in the exact same proportions) trapped within shock glass veins and pockets in shergottite Elephant Moraine 79001, and now in at least five other Martian meteorites [on Earth].”
“Why are they from Mars?
The 31 meteorites are unusual igneous meteorites (SNC achondrites named Shergotty, Nakhla, Chassigny are type examples). Most martian meteorites are 1.3 billion years old or less, much younger than typical igneous meteorites from asteroids which are 4.5 billion years old. They also have higher contents of volatiles than igneous meteorites. The conclusive evidence that the SNC meteorites originated on Mars comes from the measurement of gases trapped in one meteorite’s interior. The trapped gases match those that Viking measured in the martian atmosphere.”
OK, here’s where they reach a shaky conclusion: “The conclusive evidence that the SNC meteorites originated on Mars comes from the measurement of gases trapped in one meteorites interior. The trapped gases match those that Viking measured in the martian atmosphere.
That only “proves” the gases match. For ONE meteorite. hmmm is THAT good science?
It enables a fun hypothesis, NOT a conclusion.
Still it would be nice to GO to MARS and prove/dis-prove all this.
From my first link:
“and now in at least five other Martian meteorites [on Earth].”
From NASA, Nov 2009:
New Study Adds to Finding of Ancient Life Signs in Mars Meteorite
HOUSTON Using more advanced analytical instruments now available, a Johnson Space Center research team has reexamined the 1996 finding that a meteorite contains strong evidence that life may have existed on ancient Mars.
The new research focused on investigating alternate proposals for the creation of materials thought to be signs of ancient life found in the meteorite. The new study argues that ancient life remains the most plausible explanation for the materials and structures found in the meteorite. ...”
This proves there has been life on Mars. Afterall someone was throwing those rocks at us.
“In 1983 it was suggested by Smith et al.  that meteorites in the so called SNC group (Shergottites, Nakhlites, Chassignites) originated from Mars, from evidence from an instrumental and radiochemical neutron activation analysis of the meteorites. They found that the SNC meteorites possess chemical, isotopic, and petrologic features consistent with data available from Mars at the time, findings further confirmed by Treiman et al.  a few years later, by similar methods. Then in late 1983, Bogard et al.  showed that the isotopic concentrations of various noble gases of some of the shergottites were consistent with the observations of the atmosphere of Mars made by the Viking spacecraft in the mid-to-late 1970s.
In 2000, an article by Treiman, Gleason and Bogard gave a survey of all the arguments used to conclude the SNC meteorites (of which 14 had been found at the time) were from Mars. They wrote, “There seems little likelihood that the SNCs are not from Mars. If they were from another planetary body, it would have to be substantially identical to Mars as it now is understood.”
33 of the 34 Mars meteorites are divided into three rare groups of achondritic (stony) meteorites: shergottites (24), nakhlites (7), and chassignites (2), with the oddball meteorite ALH 84001 not usually placed in a group. Consequently, Mars meteorites as a whole are sometimes referred to as the SNC group. They have isotope ratios that are said to be consistent with each other and inconsistent with the Earth. The names derive from the location of where the first meteorite of their type was discovered.”
Ok I should have caught that. ;-)
But, the ‘scientist’ still concludes/presumes that the meteorites under study are definitively Martian ejecta.
It could be true. No doubt.
I still say that’s thin science to CONCLUDE those rocks ARE Martian surface ejecta.
I worked in the Life Sciences, not the planet sciences, so this is an honest question — do ‘scientists’ have lots of examples of ejecta from other planets?
Scientists on both sides of the debate (as to whether the sample contains evidence of past life on Mars) agree the rock in question came from Mars.
"The meteorite, called ALH84001, was found in 1984 in Allan Hills ice field, Antarctica, by an annual expedition of the National Science Foundation's Antarctic Meteorite Program. It was preserved for study in JSC's Meteorite Processing Laboratory and its possible Martian origin was not recognized until 1993. It is one of only 12 meteorites identified so far that match the unique Martian chemistry measured by the Viking spacecraft that landed on Mars in 1976. ALH84001 is by far the oldest of the 12 Martian meteorites, more than three times as old as any other.
Many of the team's findings were made possible only because of very recent technological advances in high- resolution scanning electron microscopy and laser mass spectrometry. Only a few years ago, many of the features that they report were undetectable. Although past studies of this meteorite and others of Martian origin failed to detect evidence of past life, they were generally performed using lower levels of magnification, without the benefit of the technology used in this research. The recent discovery of extremely small bacteria on Earth, called nanobacteria, prompted the team to perform this work at a much finer scale than past efforts. "
Alright then, for those of us less astute, please explain how a meteorite broke off of mars and came to earth. Did the planet feel playful and toss a few rocks at Earth hoping to start a game of catch? How could a fully formed planet shed meteorites? Just askin’.
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In addition, what is the likelihood that these meteorites, if they really are from Mars, happened to be ejecta from near the surface where life would presumable be? Any event large enough to blow pieces of Mars away at velocities in excess of escape velocity would consist almost entirely of interior material and a minuscule proportion that was close to the surface. This "science" appears to be little more than a convenient fund raising trick to appropriate more tax money.
Agreed. This has GRANT APPLICATION written all over it :-)
Planetary meteorites are fragments that were blasted off their planets by large impacts and sent into space.
...and occasionally get caught in the gravitational fields of other planets.
The science behind identifying some meteorites as being pieces of Mars is pretty solid. Most are identified with specific impacts, in fact.
Yes, the chances of any one rock getting to Earth is slim, but there are lots of them around the Solar System. Some make it, and a few of those get found and identified.
What’s controversial is identifying the “fossils” as evidence of life. The origin of the meteorite isn’t scientifically controversial, though it may be hard to believe if you’re not acquainted with meteorites and the science around them.
We’ve got pieces of meteorite on Earth associated with specific asteroids in the asteroid belt, too, with good reason, though we haven’t even sent robots there. And a piece of a small body like Vesta seems even more unlikely to make it to Earth, yet so far as we can tell that’s not only happened, but is far more common than Martian meteorites.
I, too, am suspicious of the “gas match” in a 4 billion year old rock. Earth’s atmosphere has gone between 0 and 35 percent oxygen over the last 4 billion years. No way would an earth rock on Mars match today’s earth’s atmosphere, so why would a rock from Mars’s distant past match today’s Martian atmosphere, and if it did, how could there have been a living microbe in the area to get trapped in the same rock with it?
You raise a good question about the ancient gases trapped within the rock chemically matching those of Mars’ *recent* atmosphere. The rock is believed to have been blasted off of Mars roughly 16 million years ago by an impact. So even if they have dated the gases to 16 million years ago (I have no idea what age they have for the gases), the atmosphere could have changed since then, although there really hasn’t been much going on on Mars for its atmosphere to have changed very much, especially within the past 20 million years or so. Earth’s atmosphere changes due to the huge amount of biologic, volcanic and other complex activity we have here. Our atmosphere is also much denser than Mars’ thin and comparatively simple one.
So that would explain Helen Thomas...
Two possible view:
1. God didn’t create a dead universe.
2. What are the chances of a rock, sitting on earth for millions of years, not being contaminated with fossils from life on earth?
1. The original igneous rock solidified within Mars about 4.5 billion years ago, about 100 million years after the formation of the planet. (Based on isotope ages of the igneous component of the meteorite)
2. Between 3.6 and 4 billion years ago the rock was fractured, presumably by meteorite impacts. Water then permeated the cracks, depositing carbonate minerals and allowing primitive bacteria to live in the fractures.
3. About 3.6 billion years ago, the bacteria and their by-products became fossilized in the fractures. (Based on isotope ages of the minerals in the fractures)
4. 16 million years ago, a large meteorite struck Mars, dislodging a large chunk of this rock and ejecting it into space. (Based on the cosmic ray exposure age of the meteorite)
5. 13,000 years ago, the meteorite landed in Antarctica.
6. The meteorite, ALH84001, was discovered in 1984 in the Allan Hills region of Antarctica.
There's no way to gauge the age of Martian fossil. They must "assume" carbon 12 dating is identical on another planet. That's a big assumption.
They wouldn't use Carbon-12 methods for dating such ancient material. Carbon-12 is only good for about 60,000 to 80,000 years in the past.
"3. About 3.6 billion years ago, the bacteria and their by-products became fossilized in the fractures. (Based on isotope ages of the minerals in the fractures)"
Borg L.E., Connelly J.N., Nyquist L.E., Shih C.-Y., Wisemann H., and Reese Y. (1999) The age of the carbonates in Martian meteorite ALH84001. Science 286, 90-94.
The carbonate globules in ALH84001 (hosts to putative signs of ancient Martian life) formed 3.90±0.04 billion years ago. The Rb-Sr and U-Pb radioactive isotope chronometers give this same age, a time when the surface of Mars was rich in water (or ice) and was frequently hit by large asteroids. The age of the globules and the age of the largest asteroid impact onto ALH84001 are the same (within 300 million years), so the globules could have been formed by (or during) that impact.
To obtain the age when the carbonate globules in ALH84001 formed, Borg and colleagues analyzed isotope abundances of rubidium (Rb), strontium (Sr), uranium (U) and lead (Pb) as they dissolved carbonate globules in successively stronger and stronger acids. The weakest acids dissolved Earth contaminants, which had the common Earth lead. The stronger acids dissolved first Ca-Mg-Fe-rich carbonate (the ankerite/dolomite) and then the more magnesium-rich carbonate of the globules. The isotope ratios of Rb, Sr, U, and Pb in these various dissolved carbonates were analyzed to get ages. By Rb/Sr, the carbonates formed 3.90±0.04 billion years ago; by U-Pb, the carbonates formed 4.04±0.10 billion years ago. These two ages are the same within analytical uncertainties, and so are probably real and believable.
This age, when the carbonate globules formed, is also within error of the potassium-argon (K-Ar) age of the whole meteorite ALH84001, ~3.8-4.3 billion years ago. The K-Ar ages (actually Ar-Ar) represents the time when the whole rock was last heated enough to lose its trapped argon, likely above about 500°C. The similarity of the times of heating and carbonate formation suggests that the two events are related - perhaps that the carbonates formed because of the heat from an asteroid impact (Harvey and McSween, 1996; Scott et al., 1997, 1998). However, the uncertainties in the ages, ±40 million years for the carbonates and ±150 million years for the heating, leave time for nearly any mode of carbonate formation.
This paper is a superb, excruciatingly careful, study, and seems to leave little room for other possible ages. Given the rarity of carbonate in ALH84001, it may be difficult to get more precise ages than these. A possible weakness in the paper is the necessary assumption that all the carbonates started out with the same initial ratios of Sr isotopes (87Sr/86Sr) and of Pb (206Pb/204Pb). It is possible that the carbonates formed from mixtures of fluids with different chemical and isotopic compositions (Valley et al., 1997; Golden et al. 2000a), and that the "ages" here represent fluid mixing, not a date.
The similarity between the age of the carbonates and the heating event is intriguing, but perhaps not very significant given the uncertainties in the ages . Identical ages would fit the carbonate formation theories of Harvey and McSween (1996), and Scott et al. (1997, 1998), and also the possibility that the carbonates formed from hot water generated by the impact. However, the uncertainty in the time of the heating event, a few hundred million years, leaves a lot of time for the carbonates to have formed by nearly any other mechanism imaginable.
Perhaps you should do a little research in carbon 12 dating and then you will understand why your post is not relevant.
BTW: It would actually be Carbon-14 dating, not Carbon-12. 12 is regular Carbon: 12 protons, 12 neutrons. Carbon-14 is an isotope of Carbon-12, having 2 extra neutrons.
“Radiocarbon dating, or carbon dating, is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to determine the age of carbonaceous materials up to about 58,000 to 62,000 years.”
Ugh!! Make that regular Carbon (Carbon 12) has SIX protons and SIX neutrons, while Carbon-14 has 6 protons and 8 neutrons.
NASA is so desperate, with every announcement and turn of the page they claim “life” on other planets hoping so despareately to get more funding from the left in hopes to prove there is no God, and no judgement coming for them ...
Oh, you mean the left hopes that NASA’s findings will “prove” there is no god? I thought you meant that was NASA’s aim.
I remember that. Clinton was, as usual, jammed up about something and events were reaching a critical stage. The thought was he and NASA made a point about it to distract attention from the grifter's problem.
Don't you just love funding motivated science?
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