Evidence grows on extraterrestrial origins of Earth life.

Still more compelling evidence:
Other than its unfortunate headline, “We’re all aliens… how humans began life in outer space“, this new article from Steve Connor at The Independent is a compendium of a few of the highlights of our favorite subject here at CosmicSeed.  Rather than being an announcement about 1 particular new discovery, it presents a well-rounded but all-to-brief overview of scientist’s opinions focusing on ammonia, nitrogen, and organic molecules from meteorites.

Charles Darwin solved the mystery of life’s wondrous diversity with his theory of natural selection. But even he was flummoxed by the ultimate mystery of mysteries: what led to the origin of life itself?

In trying to answer the problem, scientists have turned to the stars, or at least the “builders’ rubble” of meteorites and comets left over from the formation of our solar system some five billion years ago. These space rocks, they believe, could help to explain why life began here on Earth.

In fact, a growing body of evidence is now pointing to deep space as the possible source of the raw materials that formed the building blocks of life. The latest study, which focused on a class of meteorites that fell on to the Antarctic ice sheet, also suggests that life’s origins may have been extraterrestrial.

An analysis of the meteorites has revealed that these rocks can be induced, under high pressures and temperatures, to emit nitrogen-containing ammonia, a vital ingredient for the first self-replicating molecules that eventually led to DNA, the molecule at the heart of all life.

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It Came from Outer Space: “Comets Brought Building Blocks of Life to Earth”

Could life on Earth as we know it have come from outer space? New research from Lawrence Livermore National Laboratory scientists shows that comets that crashed into Earth millions of years ago could have produced amino acids – the building blocks of life. Amino acids are critical to life and serve as the building blocks of proteins, which are linear chains of amino acids.

“There’s a possibility that the production or delivery of prebiotic molecules came from extraterrestrial sources,” Goldman said. “On early Earth, we know that there was a heavy bombardment of comets and asteroids delivering up to several orders of magnitude greater mass of organics than what likely was already here.

Livermore’s Nir Goldman and colleagues found that simple molecules found within comets (such as water, ammonia, methylene and carbon dioxide) just might have been instigators of life on Earth as the sudden compression and heating of cometary ices crashing into the planet can produce complexes resembling the amino acid, glycine.

Origins of life research initially focused on the production of amino acids from organic materials already present on the planet. Further research showed that Earth’s atmospheric conditions consisted mainly of carbon dioxide, nitrogen and water. Shock-heating experiments and calculations eventually proved that synthesis of organic molecules necessary for amino acid production will not occur in this type of environment.”

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Did asteroids bring water and life to Earth?

September 3, 2010 | by Michael Anft
Space scientists have put several men on the moon, robotically explored the farthest reaches of the solar system, and calculated the age and composition of the universe. But they’ve had a hard time nailing down two of the most basic questions about life on Earth: How did the surface of the planet become mostly water? Especially since the massive collision that formed the moon 4.5 billion years ago would have vaporized any water then present? And how did Earth acquire the organic compounds that cooked up life? The common wisdom has been that comets, cooled by ultra-frosty temperatures beyond the solar system, smashed into Earth sometime after the moon’s creation, bringing water in the form of ice, possibly along with organic matter essential to the creation of life.

But a recent pair of studies, one led by Andrew Rivkin, a planetary astronomer at the Applied Physics Laboratory, questions this long-held notion. Using infrared telescopes in Hawaii to measure the reflected light of asteroids, Rivkin’s team has discovered substantial ice and evidence of prebiotic, carbonaceous compounds on one of them. The finding, detailed in the April 29 issue of Nature, puts hypotheses on the origins of life on Earth in a new light and blurs distinctions scientists have long made between asteroids (orbiting rocky bodies that formed within the solar system) and comets (which typically come from outside our planetary system). A separate experiment run by an astronomer at the University of Central Florida (UCF) recently confirmed the Rivkin team’s results.

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