一块小陨石撞击月球

景一

On January 21， 2019， something smacked1 into the moon， creating a flash of light. Things hit the moon all the time. But this time one thing was different. Thousands of people were watching. The impact took place during a total lunar eclipse2. And there are pictures to prove it.

2019年1月21日，有东西撞上了月球，形成了一道闪光。总是有物体撞击到月球上，但这次有一件事是不同的。有成千上万的人正在看着。这次的撞击发生在月全食期间。还有一些照片可以证明这一点。

Astronomers3 are using the pictures to gauge4 the size of the rock that hit the moon. Jorge Zuluaga is one of them. He works at the University of Antioquia in Medellín， Colombia. He and his colleagues gathered images from amateur5 astronomers in Colombia and the Dominican Republic. Those two countries are in South America and the Caribbean. There was also a video livestreamed6 on TimeAndDate.com from an observatory7 in Morocco.

天文学家正在利用这些图片来估算撞击月球的陨石的大小。豪尔赫·苏卢阿加就是其中之一。他在哥伦比亚梅德伦的安提奥奎亚大学工作。他和他的同事从哥伦比亚和多米尼加共和国的业余天文学家那里收集图像。这两个国家分别在南美洲和加勒比地区。摩洛哥的一个天文台也在TimeAndDate.com上直播了一段视频。

With these data， Zuluagas team calculated characteristics of the impact. For instance， it likely released the energy equivalent of about half a ton of TNT. That means the rock that hit the moon was somewhere between the size of a softball and a basketball. It probably had the mass of a few cans of paint—7 to 40 kilograms. The astronomers also calculate that the object smacked into the moon at 13.8 kilometers per second.

有了这些数据，苏卢阿加的团队计算出了撞击的特征。例如，它可能释放出相当于约半吨TNT的能量。这意味着撞击月球的陨石大小介于垒球和篮球之间。它的质量可能只有几罐油漆的重量——7到40公斤。天文学家们还计算出这个物体以每秒13.8公里的速度撞击了月球。

Their results appear in a paper posted January 28 at arXiv.org.

他们的研究结果于1月28日发表在了arxiv.org上。

Heres how Zuluaga remembers the story. He couldnt see the eclipse because it was cloudy. But the next day， he saw reports on Twitter. Some observers had reported a bright flash. People assumed it was a meteorite8 strike. Zuluaga contacted amateur astronomers he had worked with before and found several who had photographed the impact.

以下是苏卢阿加对故事的回忆。那天他看不到月食，因为天阴。但第二天，他在推特上看到了报道。一些观察者说有一道明亮的闪光。人们认为那是一次陨石撞击。苏卢阿加联系了他以前合作过的业余天文学家，找到了几个拍摄到撞击的人。

The researchers then estimated that the impact probably left a crater on the moon between 5 and 10 meters wide. That scar could be spotted9 with a current or future lunar orbiter10.

研究人员随后估计，撞击可能会在月球上留下一个5到10米宽的陨石坑。这个疤痕可能会被目前或未来的月球轨道飞行器发现。

That the impact happened during a lunar eclipse is important， Zuluaga says. It supports the idea that the moon is hit with meteorites almost constantly. Scientists estimate something hits the moon once an hour， on average.

苏卢阿加说，月食期间发生的撞击很重要。它证明了月球几乎总是被陨石撞击的观点。科学家估计平均每小时就有一个物体撞上月球。

The event also highlights the potential for discovery when amateur and professional astronomers work together. “A lunar eclipse is not as interesting for professionals as for amateur astronomers，” Zuluaga says. “But when you have these kinds of surprises， it is a blessing to have amateurs as friends.”

這件事也同样突出了当业余天文学家和专业天文学家一起合作时能够有所发现的潜力。苏卢阿加说：“对于专业人士来说，月食不像业余天文学家认为的那么有趣。但是当有这样的惊喜时，有业余爱好者做朋友是件好事。”