哈勃拍下了星际彗星掠过地球时的快照

哈勃拍下了星际彗星掠过地球时的快照

NASA's Hubble Space Telescope took snapshots of 2I/Borisov, which you can see in the video above provided by Goddard Space Flight Center. It's the sharpest view of the comet to date.

美国宇航局的哈勃太空望远镜拍摄了2I/Borisov的快照，你可以在戈达德太空飞行中心提供的视频中看到。这是迄今为止最清晰的彗星图片。

Hubble captured comet 2I/Borisov streaking through our solar system about three weeks before it reached its closest point to the sun. (Photo: NASA, ESA, and D. Jewitt (UCLA))

An amateur astronomer from Crimea named Gennady Borisov first spotted the fast-moving fleck in the night sky in August. Soon after, several telescopes confirmed a trajectory that would take it within 190 million miles of our sun. The photo above was taken as the comet was traveling at 175,000 kilometres per hour (roughly 109,000 miles per hour) as it was headed for a rendezvous with the sun.

来自克里米亚的业余天文学家根纳季·鲍里索夫于今年8月首次在夜空中发现了快速移动的斑点。不久之后，几架望远镜确认了一条轨迹，该轨迹将把它带到距离太阳1.9亿英里以内的地方。这张照片拍摄于彗星以每小时175000公里(大约每小时109000英里)的速度与太阳会合的时候。

The photos are significant because while this comet won't be staying with us long, it still reveal clues about the solar system it came from.

这些照片意义重大，因为虽然这颗彗星不会在我们身边停留太久，但它仍然揭示了它来自太阳系的一些线索。

2I/Borisov was known as C/2019 Q4 before it became official. (Photo: Gemini Observatory/NSF/AURA)

The Gemini Observatory snapped an earlier full-color picture of the celestial body as it streaked through the heavens. Its woolly white halo and telltale tail were the first hints that we were entertaining our first interstellar comet.

双子座天文台早些时候拍摄了一张天体划过天空的全彩照片。它毛茸茸的白色光晕和尾巴是我们招待第一颗星际彗星的第一个线索。

Scientists at the International Astronomers Union (IAU) concurred with their findings, designating it the second interstellar object; it was crowned 2I/Borisov to honor that status.

国际天文学家联盟(IAU)的科学家们同意他们的发现，把它指定为第二个星际物体;它被命名为2I/Borisov以纪念这一地位。

From another world

来自另一个世界

It's only the second time we've detected an interstellar object. (In fact those first few letters of its official name stand for second interstellar.) The comets that typically blaze through our neighborhood hail from within the solar system — either from that icy outermost region known as the Oort Cloud or the Kuiper Belt, a veritable comet factory just beyond Neptune's orbit.

这是我们第二次探测到星际物体。(事实上，它的官方名称的前几个字母代表着第二部《星际穿越》。)通常在我们周围闪耀的彗星来自太阳系内部——要么来自被称为奥尔特云的冰冷的最外层区域，要么来自海王星轨道外的柯伊伯带——一个名副其实的彗星工厂。

Artist's impression of the first known interstellar asteroid, 'Oumuamua. (Photo: M. Kornmesser/ESO)

Strangely enough, this is the second time we've had an interstellar visitor in as many years. In 2017, a very strange object known as 'Oumuamua graced our solar system. Its unwieldy, cigar-like dimensions, unknown origin point and blazing speed sparked a frenzy of scientific speculation. While some scientists suggested it's a hobbled, tail-less comet that has been wandering the galaxy for billions of years, others just came right out and said what many of us were thinking: alien spaceship.

奇怪的是，这是这么多年来我们第二次迎来星际访客。2017年，一颗名为“Oumuamua”的奇怪天体为我们的太阳系增添了光彩。它笨拙的，雪茄一样的尺寸，未知的起源点和惊人的速度引发了疯狂的科学推测。虽然一些科学家认为这是一颗步履蹒跚、没有尾巴的彗星，在银河系中徘徊了数十亿年，但也有一些科学家直接走出来，说出了我们许多人所想的:外星飞船。

2I/Borisov is a little less ambiguous. Even though it was born in an incomprehensibly foreign space, it bears all the telltale trappings of comethood — specifically a lustrous tail of glitter likely caused by outgassing from its ice-cold heart.

2I/Borisov就不那么模糊了。尽管它出生在一个不可思议的陌生空间，但它身上却有着所有能说明问题的特质——特别是一条闪闪发亮的尾巴，很可能是由它冰冷的心脏释放出的气体造成的。

"Whereas 'Oumuamua appeared to be a rock, Borisov is really active, more like a normal comet. It's a puzzle why these two are so different," said Jewitt.

“虽然Oumuamua看起来像是一块岩石，但Borisov确实很活跃，更像是一颗普通的彗星。为什么这两个如此不同是一个谜。”Jewitt说。