潜伏在小行星当中的奇怪球体（图）   

 

被称为P/2010 A2的物体好象是小行星碰撞后形成的残余物。

Oddball Lurking Among the Asteroids

A peculiar object just discovered beyond the orbit of Mars could be the survivor of an asteroid collision. Researchers haven't yet confirmed the idea, but further studies should produce new clues about the composition and behavior of these tiny rocky bodies--information that someday could help prevent a catastrophic collision with Earth.	刚刚发现的一个奇怪物体位于火星的轨道之外，可能是一次小行星碰撞之后的残存物。研究人员尚未证实该观点，但是进一步研究应该能够提供新的线索，揭示这些小型岩石天体的构成和特性，有朝一日这些信息可能会有助于防止地球遭遇灾难性的撞击。
Billions of asteroids and comets are whirling around the sun, and they have their own distinct traffic patterns. Most asteroids, which are made of rock, confine themselves to a belt between the orbits of Mars and Jupiter. Most comets, which consist of water ice, linger at the far reaches of the solar system. A few comets have fallen into arcs that take them periodically close to the sun, where their spectacular tails form, as solar heat vaporizes some of their ice.	几十亿颗小行星和彗星在围绕着太阳旋转，它们有着自己独特的穿行模式。多数小行星是由岩石构成的，被限制在火星和木星轨道之间的一个带状区域里；而多数彗星是由水冰构成的，游荡在太阳系的边远区域。有些彗星遵循的轨道曲线使它们周期性地靠近太阳，靠近太阳时太阳的热量蒸发掉其中一些冰，形成壮观的慧尾。
Last month astronomers spotted something that didn't fit either category. The object, dubbed P/2010 A2, orbits the sun well within the main asteroid belt, according to observations taken as part of the Lincoln Near Earth Asteroid Research sky survey. Unlike its conventional rocky cousins, however, this object is sporting what looks like a tail.	上个月，天文学家们发现了一个不属于任何类别的物体，该物体被称为P/2010 A2。根据林肯近地小行星研究小组进行天空观测时所记录下来的观察资料，P/2010 A2在小行星带主带内部围绕着太阳旋转。然而跟平常的岩石小行星不一样，该物体显示出如同慧尾的部分。
To find out what was going on, a team trained the Hubble Space Telescope's camera on P/2010 A2 on 25 and 29 January. The results suggest that the object's tail is rubble from a crash with another asteroid, not the sign of a wayward comet. Unlike every other comet that's ever been observed, the object's 140-meter-wide nucleus sits off-center from the tail (see photo). The tail features an x-shaped pattern--again, something unknown among comets--and so far shows no signs of ice.	为了查明所发生的情况，一个研究小组分别于1月25日和29日两次将哈勃太空望远镜的摄像头对准P/2010 A2。观察结果显示，该物体的尾巴实际上是跟另外一颗小行星撞击后所产生的碎石，并没有表现出奇特的彗星迹象。跟所观察到的任何其他彗星都不相同，该物体140米宽的核心位于偏离尾巴中心的位置；尾巴的特点是有一个X形图案，据了解这在彗星中也是从未有过的情况；而且，到目前为止没有发现冰的迹象。
The tentative verdict is that this probably is the remnant of a recent asteroid collision, where a smaller body struck a larger object at a velocity of about 15,000 kilometer per hour. The team, led by astronomer and lead investigator David Jewitt of the University of California, Los Angeles, announced their conclusion yesterday.	对此，一个临时性的结论是：该物体是最近一次小行星碰撞所造成的残余物，在这次碰撞中一颗较小的天体以大约15,000公里的时速撞击了一颗较大的天体。昨天，一个研究小组在加州大学洛杉矶分校的天文学家、首要研究人员大卫·朱伊特带领下，宣布了他们得出的结论。
Astronomer Peter Brown of the University of Western Ontario in Canada agrees. "This is clearly something unusual and not typical of the sort of behavior we expect from a common comet," says Brown, who was not involved in the study. Astronomer William Bottke of the Southwest Research Institute in Boulder, Colorado, says the researchers need to collect more data about the object's composition, so they can "put the collision into context."	加拿大西安大略大学的天文学家彼得·布朗同意上述结论。“很明显，这是个不同寻常的物体，没有普通彗星所拥有的典型特点，”布朗说。布朗并没有参加这项研究。科罗拉多州博尔德市西南研究院的天文学家威廉·博特克说，研究人员应该搜集更多有关该物体构成成分的数据资料，以便将此次碰撞跟其所发生的背景联系起来。
If P/2010 A2 is the result of a collision, Jewitt says, further observations will improve understanding of the physics of the impact. And collecting real data, he says, might help scientists learn how to destroy an incoming asteroid that threatens Earth. "That's not why I care about the object," he says, "but this is a real connection."	朱伊特称，如果P/2010 A2是碰撞造成的，更多的观测将会使研究人员进一步了解这次撞击的物理过程。他说，收集实时数据资料可能会帮助科学家们了解如何摧毁飞进来威胁地球的小行星。“那并不是我关心该物体的目的所在，”他说，“然而，这两者确实有关联。”