setUoYouRPROFILE's blog: "tufui"

Some of the water that covers much of the Earth may have been carried here by comets from beyond Neptune, new evidence suggests. The water in a comet called 103P/Hartley 2 is chemically very similar to water on Earth, suggesting that some of Earth's water comes from the same comet family, reports an international study led by Paul Hartogh at the Max-Planck-Institut fur Sonnensystemforschung and published Wednesday in Nature. 103P/Hartley 2 is believed to come from the Kuiper belt beyond the orbit of Neptune. "Our results...suggest that comets could have played a major role in bringing vast amounts of water to an early Earth," said Dariusz Lis, senior research associate in physics at the California Institute of Technology in Pasadena and co-author of the paper. Most of the Earth is very similar in composition to meteorites called enstatite chondrites,burberry outlet cheap which suggests that it similarly started off very dry. Scientists think asteroids and comets may have subsequently crashed into the Earth, transporting water in the process. Water is made of hydrogen and oxygen molecules, and hydrogen comes in both a lighter and heavier form called deuterium. The ratio of the two forms on Earth is very distinctive. Six comets analyzed in the past had water with deuterium-to-hydrogen ratios twice as larg