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Are meteorites responsible for life on Earth?
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Sugar from space could have sweetened the earliest forms of life on Earth. Scientists have found a range of sugar-like substances in two carbon-rich lumps of space rock dating back to the beginning of the Solar System.
Such compounds, collectively called polyols, are vital to life, providing components of DNA and cell membranes, and acting as energy sources. They are used commercially today as sugar-free sweeteners such as sorbitol. But although organic compounds are known to have arrived on Earth from space, until now there has been no sign of extraterrestrial polyols.
Dr George Cooper and his team based at Nasa's Ames Research Centre in California, announced the discovery of polyols in two asteroid fragments which landed on the Earth as meteorites. One was found at Lake Murray in Oklahoma, in the United States, in 1933. The other, known as the Murchison meteorite, fell on Victoria, Australia, in 1969. Dr Cooper says "there has been no conclusive evidence for the existence of polyols in meteorites, leaving a gap in our understanding of the origins of biologically-important organic compounds on Earth." The compounds possessed chemical features that pointed to them being extraterrestrial in origin, and not the result of contamination on Earth. It was thought they may have first formed in the clouds of dust and gas which drift between the stars. Starlight would have triggered chemical reactions within the clouds that eventually led to simple sugar-like substances. Later, a small dense core inside one of these interstellar clouds collapsed to form a rotating disc which evolved into the Solar System - the Sun, planets and asteroids.
LINKS
- www.touchanotherworld.com/
CurrentPhoto/CPcarbonaceous.htm
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