"Biomorphs" found on meteorites traced to Mars have been proposed as evidence that life has existed on the Red Planet
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 ...
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.
or
2. What are the chances of a rock, sitting on earth for millions of years, not being contaminated with fossils from life on earth?
From NASA.gov:
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.[1]”
http://en.wikipedia.org/wiki/Radiocarbon_dating
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 ...
Huh?
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.
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