Friday, August 24, 2012
Does the meteorite that brought the instructions for life on Earth?
Some think that meteorites brought indispensable materials for the beginning of life. A meteorite discovered in Antarctica would give strength to the argument that life on Earth may have started due to a boost from space, scientists say. The analysis shows that the meteorite is rich in the gas ammonia. Contain the element nitrogen, found in proteins and DNA that form the basis of the life as we know.
Researchers say meteorites as these may have come to Earth to supply the ingredients that were necessary for life. Details of the study published by researchers at Arizona State University and the University of California, Santa Cruz, are published in the journal Proceedings of the National Academy of Sciences. The new study is based on analysis of about 4 grams of powder extracted from a meteorite called Grave Nunataks 95229, discovered in 1995. It showed that the powder contained large amounts of ammonia, among other substances.
Professor Sandra Pizzarello, who led the research, said the study "shows that there are asteroids out there that when fragmented and became meteorites, may have come to Earth with an attractive mix of components, including a large amount of ammonia." Meteorites like this could have supplied Earth enough nitrogen in the right form to arise primitive forms of life, he says. Much of the evidence shows that there was not much ammonia on the early Earth, so where do they come?
Caroline Smith, Natural History Museum of London
Previous studies have focused on the meteorite "Murchison", who came to Australia in 1969 and which was found to be rich in organic compounds. The professor says that some of the molecules found there correspond to later times in the history of life. She believes that these compounds are too complex to have played a role in life on Earth.
The theory that the planet was fertilized by a comet or asteroid arises partly from the belief that the original Earth could not have offered a full inventory of simple molecules needed for the process that led to primitive life. The suggestion is that the asteroid belt between Mars and Jupiter, away from heat and pressure forming planets, could have been a better place for that process.
Caroline Smith, a meteorite expert at the Natural History Museum of London agrees that the important factor in the new study is the nitrogen, but would like to see similar results repeated in other meteorites. there are asteroids out there that when fragmented and became meteorites, may have come to Earth with an attractive mix of components, including a large amount of ammonia
"One of the problems with early biology on the early Earth is you need a lot of nitrogen for all these processes occur prebiologicos and of course there nitrogen in ammonia. "Much of the evidence shows that there was not much ammonia on the early Earth, so where do they come?" He asks. Still do not know what specifically what led to life on Earth began.
Pizzarello has hypothesized that a meteorite material may have interacted with environments on Earth such as volcanoes, but these are assumptions. "You find these extraterrestrial materials (in meteorites) which have what you need," he says, "but the how and the when, how and by what mechanism atmosphere really do not know."
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