这次双重晦气已引起人们对小行星威胁的关注。长久以来天文学家们就清楚这种实实在在的威胁,但一旦在实验室外提起就会引来哄堂大笑。
Some politicians have nevertheless taken action.
不过还是有些政客们采取了行动。
In 1998 America s Congress ordered NASA to begin cataloguing the very largest, planet killerasteroids-defined as those more than a kilometer across.
美国国会在1998年下令NASA将那些大型的行星杀手级别的小行星编入目录,直径超过1公里的都归入其中。
The agency reckons it has accounted for more than 90% of them.
NASA认为超过90%的这类小行星都已记录在案。
But as the impact from such a beast would be catastrophic, the few undiscovered rocksstill represent a threat.
但是由于这种怪兽可能带来灾难性的撞击,少部分未被发现的此类岩石仍然是个威胁。
Deep impact
深度撞击
These days, a mix of national organizations and universities run an alphabet soup ofdetectors.
目前,一群来自不同国家组织和大学的研究人员开始了初步的探测。
But the field is still a bit of backwater, and budgets are tight.
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