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SilverCougar

Primordial Organic Matter Found in Meteorite

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Life on Earth may have started with the help of tiny hollow spheres that formed in the cold depths of space, a new study suggests. The analysis of carbon bubbles found in a meteorite shows they are not Earth contaminants and must have formed in temperatures near absolute zero.

The bubbles, called globules, were discovered in 2002 in pieces of a meteorite that had landed on the frozen surface of Tagish Lake in British Columbia, Canada, in 2000 (see Hydrocarbon bubbles discovered in meteorite).

Although the meteorite is a fragile type called a carbonaceous chondrite, many pieces of it have been remarkably well preserved because they were collected as early as a week after landing on Earth, so did not have much time to weather.

Researchers were excited to find the globules because they could have provided the raw organic chemicals needed for life as well as protective pockets to foster early organisms.

But despite the relatively pristine nature of the meteorite fragments, there was no proof that the globules were originally present in the meteorite, and were not the result of Earthly contamination.

Now, analysis of atomic isotopes shows that the globules could not have come from Earth and must have formed in very cold conditions, possibly before the Sun was born. The research was led by Keiko Nakamura-Messenger of NASA's Johnson Space Center in Houston, Texas, US.

Cold gas cloud

The globules are enriched in heavy forms of hydrogen and nitrogen, called deuterium and nitrogen-15, respectively, ruling out their formation on Earth. The relative amounts of these isotopes is characteristic of formation in a very cold environment: between 10 and 20 Kelvin above absolute zero.

This means that the globules may predate our Sun, since temperatures like these would have prevailed in the cold cloud of gas from which our Sun formed and ignited. Alternatively, the globules might have formed after the Sun but while the planets were still developing.

The right temperatures would also have existed in the outer reaches of the developing solar system where the comets are thought to have formed. Intriguingly, comets are known to contain particles of organic material of roughly the same size, although the shape of these particles is not known.

Membrane-like structures

Either way, the globules are extremely old, says team member Scott Messenger, also of the Johnson Space Center. "We're looking at the original structures of organic objects that formed long before the Earth formed," he told New Scientist.

Nakamura-Messenger's team says the globules could have been important for the origin of life by providing the raw materials and membrane-like structures needed. Some scientists think that the presence of some sort of container that could separate an organism's internal chemistry from its environment was a crucial stage in the evolution of life.

"It's sort of reminiscent of membrane type structures," agrees Larry Nittler, at the Carnegie Institution of Washington in Washington DC, US. But as for whether the structures could have kick-started life on Earth, "I think that’s highly speculative at this point," he says.

Journal reference: Science (vol 314, p 1439)

Another peice to the evolutionary puzzle. See what I mean when I say it's ever growing, changing, and refineing. You can't expect everyone who works on the evolutionary theory to know the answers right off. Not when there is so much out there to find, explore, and explain.

So this seems to be the theorized answer to how life started on earth.

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NASA Scientists Find Primordial Organic Matter in Meteorite


The IPB Image Johnson Space Center press release is reproduced below:

11.30.06

William Jeffs
Johnson Space Center, Houston
281-483-5111

RELEASE: J06-103

NASA Scientists Find Primordial Organic Matter in Meteorite


NASA researchers at Johnson Space Center, Houston have found organic materials that formed in the most distant reaches of the early Solar System preserved in a unique meteorite. The study was performed on the Tagish Lake carbonaceous chondrite, a rare type of meteorite that is rich in organic (carbon-bearing) compounds.

Organic matter in meteorites is a subject of intense interest because this material formed at the dawn of the Solar System and may have seeded the early Earth with the building blocks of life. The Tagish Lake meteorite is especially valuable for this work because much of it was collected immediately after its fall over Canada in 2000 and has been maintained in a frozen state, minimizing terrestrial contamination. The collection and curation of the meteorite samples preserved its pristine state.

In a paper published in the Dec. 1 issue of the journal Science, the team, headed by NASA space scientist Keiko Nakamura-Messenger, reports that the Tagish Lake meteorite contains numerous submicrometer hollow organic globules.

“Similar objects have been reported from several meteorites since the 60’s. Some scientists believed these were space organisms, but others thought they were just terrestrial contamination,” said Nakamura-Messenger. The same bubble-like organic globules appeared in this freshest meteorite ever received from space. “But in the past, there was no way to determine for sure where these organic globules came from because they were simply too small. They are only 1/10,000 inch in size or less.”

In 2005, two powerful new nano-technology instruments were installed in the scientists' laboratory at Johnson Space Center. The organic globules were first found in ultrathin slices of the meteorite with a new JEOL transmission electron microscope. It provided detailed structural and chemical information about the globules. The organic globules were then analyzed for their isotopic compositions with a new mass spectrometer, the Cameca NanoSIMS, the first instrument of its kind capable of making this key measurement on such small objects.

The organic globules in the Tagish Lake meteorites were found to have very unusual hydrogen and nitrogen isotopic compositions, proving that the globules did not come from Earth.

“The isotopic ratios in these globules show that they formed at temperatures of about -260° C, near absolute zero,” said Scott Messenger, NASA space scientist and co-author of the paper. “The organic globules most likely originated in the cold molecular cloud that gave birth to our Solar System, or at the outermost reaches of the early Solar System.”

The type of meteorite in which the globules were found is also so fragile that it generally breaks up into dust during its entry into Earth's atmosphere, scattering its organic contents across a wide swath. "If, as we suspect, this type of meteorite has been falling onto Earth throughout its entire history, then the Earth was seeded with these organic globules at the same time life was first forming here." said Mike Zolensky, NASA cosmic mineralogist and co-author of the paper.

The origin of life is one of the fundamental unsolved problems in natural sciences. Some biologists think that making a bubble-shape is the first step on the path to biotic life. “We may be a step closer to knowing where our ancestors came from,” Nakamura-Messenger said.

- end -

--------------------------------------------------------------------------------


Source: NASA/JSC Press Release J06-103

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Very interesting, although still quite a way from anything resembling life.

Is there any information regarding the composition of the compounds?

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It's about time a sensible theory has come around regarding how life originated.

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It's about time a sensible theory has come around regarding how life originated.

This theory has actually been around for a long time, although as far as I know, it's only now that some of the theorized compounds have been found.

See what I mean when I say it's ever growing, changing, and refineing. You can't expect everyone who works on the evolutionary theory to know the answers right off. Not when there is so much out there to find, explore, and explain.

I agree, however I wouldn't consider this to be related to evolution.

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Raptor is correct, the theory that complex organic compounds were brought to Earth on meteorites (especially comets) has been around for a long time. It gained ground in 1986 when spacecraft examining Halley's comet discovered it was coated in organic material.

A variation of this theory, albeit far more controversial, is the theory of panspermia. This puts forward the argument that simple life actually started in space and that the Earth and other planets were then seeded by impacts. There is no real evidence that panspermia is correct.

Evolution explains how life changed once it got started it does not explain how it started in the first place.

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Yes, this is not 'evolution', but chemoevolution.

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what this says is all the planets in this system were bombarded by organic material.

The inner planets were the most likely to have life start on them. Earth and Mars were the two likely candidates to sustain and foster life. Earth was the haven, but I think Mars was also a haven in it's youth.

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Earth and Mars were the two likely candidates to sustain and foster life. Earth was the haven, but I think Mars was also a haven in it's youth.

Very true. There is, of course, a difference between having the correct raw materials and having life itself. If the panspermia hypothesis turns out to be correct then it is highly likely that life will exist on every world (or at least most) in the solar system where is is possible for it to exist.

As well as Mars and Earth there are those that believe that Venus was once a hospitable world (maybe more so than Earth). It is not impossible that life started there, only to be extinguished by the runaway greenhouse effect that has turned Venus into a real life hell.

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