SSS 2008-03-13

（单词翻译）

This is Scientific American's 60-Second Science. I'm Steve Mursky. Got a minute?

 Orbiting around stars far far away is sand. Astronomers¹ have found sandy particles circling a pair of stars about 2,400 light years from us. And they think they might be seeing the very beginnings of the formation of an earth-like planet. The researchers reported their findings online in the journal Nature. The sandy stuff is orbiting the stars at about the same distance from them as the earth orbits around the sun. The stars are babies themselves. They are called KH-15D and there are only 3 million years old compared with our sun's mature 4.5 billion years. They are in the constellation² Monoceros in the Cone³ Nebula⁴. Other studies of particles around distant stars relied on infrared⁵ heat data. But astronomers in this research were able to observe reflected light from the sand itself. Study co-author  Christopher Johns-Krull from Rice University said precisely⁶ how and when planets form is an open question,we believe the disc shaped clowds of dust around newly formed stars condense forming microscopic⁷ grains of sand that eventually go on to become pebbles⁸, boulders⁹ and whole planets.

Thanks for the minute, for Scientific American's 60-second Science,I'm Steve Mursky.