唐门暗器排行:出乎意料的小行星——灶神星(图)

来源:百度文库 编辑:中财网 时间:2024/04/29 19:32:29

 Asteroid Vesta Exceeds Expectations

by Richard A. Kerr   胡德良

 The 529-kilometer-diameter asteroid Vesta is revealing even more geologic diversity than scientists had expected. They knew that a collision with another asteroid had splashed off three kinds of rock that still land on Earth as meteorites. And Vesta's overall spectral color, as returned by NASA's orbiting Dawn spacecraft, matches that of these Vesta meteorites, Dawn team members reported today at a planetary science meeting in Nantes, France. But rather than a monotonously uniform surface homogenized by impact cratering over the eons, the first up-close look at the asteroid reveals a full palette of mineral "colors" (mapped here in false color reflecting the wide range of rock compositions). Researchers will now have to sort out how more than 4 billion years of impacts—including one at the south pole that nearly destroyed the asteroid—reshaped Vesta after it developed a crust, mantle, and core much like Earth's.  直径为529公里的小行星——灶神星正在显示出更加丰富的地质多样性,这种多样性是科学家们以前没有料到的。科学家们知道,灶神星曾经跟另外一颗小行星发生碰撞,撞飞的三种岩石目前仍然以陨石的形式降落在地球上。今天,在法国南特举行的行星科学会议上,“黎明”号太空船研究小组报道:NASA的轨道卫星“黎明”号太空船返回的资料表明,灶神星整体的光谱色跟这些灶神星陨石的光谱色相符。由于无数代的陨石碰撞,灶神星并没有形成单调一致、质地均匀的表面。近距离乍一看,这颗小行星显示出一整套“矿物色”(图中描绘的并不是灶神星的真颜色,而是反映出其岩石构成的多样性)。现在,研究人员必须要解决这个问题:灶神星形成了在很大程度上类似于地球的地壳、地幔和地核之后,经历了40多亿年的碰撞,包括那次差一点儿毁灭这颗小行星的南极碰撞……这些碰撞又是如何重新塑造灶神星的呢?

   

译自:美国《科学》杂志网站(3 October 2011, 2:01 PM)