Meteorites Showered Earth with Phosphorus
(From the November/December issue of StarDate magazine)
Meteorites may be responsible for bringing to Earth a chemical element vital to the creation of life, University of Arizona scientists say. Phosphorus, said to be the fifth most important element to life, would have been concentrated on iron-based meteorites that struck this planet during its formation.
Graduate student Matthew Pasek and planetary scientist Dante Lauretta theorized that phosphorus could form on meteorites. Their experiments showed that a mineral called schreibersite, which is common in iron-based meteorites, produces a biochemically useful form of phosphate when mixed with water.
Pasek noted that while phosphorus performs a variety of functions in the human body, it is not common on Earth. “Because phosphorus is much rarer in the environment than in life, understanding the behavior of phosphorus on early Earth gives clues to life’s origin,” he said.
One of the most fascinating aspects of the discovery, Lauretta said, is that because iron meteorites are essential to the formation of a planet teeming with life, and because only Jupiter has enough mass to direct them to the inner solar system, star systems without a Jupiter-sized object will have a tough time sprouting life. DF
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