Saturday, June 14, 2008
We are Made of Star Stuff.
London (UK) - Scientists from the Imperial College of London claim to have found evidence that life on our planet did not originate from Earth itself. For the first time, the scientists say, it is confirmed that an important component of early genetic material found in meteorite fragments is of extraterrestrial origin.
We had a lot of space and alien stories lately, with one particular interesting making even the Larry King show. But any of that material could be considered insignificant, if Zita Martins’ claims, a research associate at the Department of Earth Science and Engineering of the Imperial College, are in fact correct. According to the researcher, at least parts of the raw material that are believed to have been required to create the first molecules of DNA and RNA may be of extraterrestrial origin.
Martins and her colleagues said they discovered uracil and xanthine, which are precursors to the molecules that make up DNA and RNA and are known as nucleobases in rock fragments of the Murchison meteorite, which crashed in Australia in 1969. She explained that “early life may have adopted nucleobases from meteoritic fragments for use in genetic coding which enabled them to pass on their successful features to subsequent generations."
Apparently, the researchers were successful in proving that the molecules came from space and were not a result of contamination when the meteorite landed on Earth. What supports Martins claims is the fact that meteor showers are believed to have been common several billions of years ago on Earth: “Between 3.8 to 4.5 billion years ago large numbers of rocks similar to the Murchison meteorite rained down on Earth at the time when primitive life was forming,” the press release from the Imperial College reads. “The heavy bombardment would have dropped large amounts of meteorite material to the surface on planets like Earth and Mars.”
Mark Sephton, also of Imperial's Department of Earth Science and Engineering, believes this research is an important step in understanding how early life might have evolved. "Because meteorites represent left over materials from the formation of the solar system, the key components for life - including nucleobases - could be widespread in the cosmos,” he said. “As more and more of life's raw materials are discovered in objects from space, the possibility of life springing forth wherever the right chemistry is present becomes more likely."
The findings are published in the journal Earth and Planetary Science Letters.