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Earth's alter ego

作者:马嗖    发布时间:2019-03-08 01:01:00    

ASTRONOMERS have spotted two more new planets orbiting Sun-like stars, and both are important firsts. One planet is about as far from its parent star as the Earth is from the Sun. Other recently discovered planets were either much closer or much more distant. “We had been a little puzzled why we hadn’t found any planets with an orbital distance similar to the Earth,” says Geoff Marcy of San Francisco State University. The new planet, which has at least 1.2 times the mass of Jupiter, orbits its star in 437 of our days. Its orbit is far more eccentric than the Earth’s, and would range between the orbits of Venus and Mars in our Solar System. The second planet is the closest ever found to a star, speeding around it in only 3.1 of our days. At least half the mass of Jupiter, it is a mere six million kilometres from its sun, giving it a torrid surface temperature of more than 1100 °C. That’s “hot enough to cook a chicken in a millisecond”,

 

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