向太陽系外第一顆已知的彗星問好

向太陽系外第一顆已知的彗星問好

Our solar system is getting another visitor from a faraway galaxy.

我們的太陽系迎來了另一位來自遙遠(yuǎn)星系的訪客。

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

An amateur astronomer from Crimea named Gennady Borisov first spotted the fast-moving fleck in the night sky last month. Since then, both Hawaii's Gemini Observatory and Spain's William Herschel Telescope have confirmed a trajectory that could take it within 190 million miles of our sun.

一位來自克里米亞的業(yè)余天文學(xué)家Gennady Borisov上個月首次在夜空中發(fā)現(xiàn)了這個快速移動的斑點。從那以后，夏威夷的雙子座天文臺和西班牙的威廉·赫歇爾望遠(yuǎn)鏡都證實了這條軌道可以把它帶到離太陽1.9億英里以內(nèi)的地方。

The Gemini Observatory even managed to snap a startling full-color picture of the celestial body as it streaked through the heavens.

雙子座天文臺甚至成功地拍下了一幅令人吃驚的天體在天空中劃過時的全彩照片。

And, judging by its woolly white halo and telltale tail, it looks like we're entertaining our first interstellar comet.

而且，從它毛茸茸的白色光環(huán)和能說明問題的尾巴判斷，它看起來像是在款待我們的第一顆星際彗星。

Publishing their findings this month in the journal ArXiv, the Polish researchers who analyzed the data have dubbed the visitor C/2019 Q4 (Borisov).

本月，波蘭研究人員在《ArXiv》雜志上發(fā)表了他們的研究成果，他們分析了這些數(shù)據(jù)，并將其命名為游客C/2019 Q4 (Borisov)。

"Both orbital and morphological properties of this body show that this is the first certain case of an interstellar comet," the authors note in the study.

“這個天體的軌道和形態(tài)特征都表明，這是第一顆星際彗星，”作者在研究中指出。

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

國際天文學(xué)家聯(lián)盟(IAU)的科學(xué)家們同意他們的發(fā)現(xiàn)，將它命名為第二個星際物體——這意味著波里索夫現(xiàn)在被命名為2I/波里索夫以紀(jì)念這一地位。

"The orbit is now sufficiently well known, and the object is unambiguously interstellar in origin," according to a release by the IAU.

國際天文學(xué)聯(lián)合會發(fā)布的一份新聞稿稱:“這顆行星的軌道現(xiàn)在已經(jīng)足夠為人所知，而且它的起源也很明確，是星際間的。”

From another world

從另一個世界

It's only the second time we've detected an interstellar object. 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.

這是我們第二次探測到星際物體。通常在我們周圍燃燒的彗星來自太陽系內(nèi)部——要么來自被稱為奧爾特云(Oort Cloud)的最外層結(jié)冰區(qū)域，要么來自柯伊伯帶(Kuiper Belt)，這是海王星軌道之外一個名副其實的彗星工廠。

And while some of these celestial objects don't come around here very often — Comet West, for example, has an orbital period of about 250,000 years — they all call our solar neighborhood home. In all, there are likely more than 6,000 comets sailing around our space, all eventually brought to heel by our sun's gravitational leash.

雖然這些天體中有一些并不經(jīng)常出現(xiàn)在這里——例如，慧星韋斯特的軌道周期約為25萬年——但它們都把我們的太陽鄰居稱為家?？傊赡苡谐^6000顆彗星在我們的太空中航行，最終都被太陽的引力牽引著。

But 2I/Borisov has made the longest journey of all. Researchers say it won't loop around our sun, like its domestic counterparts. It's also traveling at a torrid 93,000 miles per hour — a speed that's far faster than any of the local spaceballs could muster. At that pace, not even the sun will be able to reel it in.

但是2I/Borisov的旅程卻是最長的。研究人員表示，它不會像國內(nèi)的太陽那樣環(huán)繞太陽運行。它還以每小時93000英里的驚人速度飛行——這一速度遠(yuǎn)遠(yuǎn)超過了當(dāng)?shù)厝魏我粋€太空球的速度。以這樣的速度，連太陽都無法把它卷進(jìn)去。

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，這是這么多年來我們第二次迎來星際訪客。2017年，一個名為“Oumuamua”的非常奇怪的天體出現(xiàn)在我們的太陽系中。它笨重的雪茄狀外形、未知的起源點和驚人的速度引發(fā)了一場瘋狂的科學(xué)猜測。雖然一些科學(xué)家認(rèn)為這是一顆步履蹣跚、沒有尾巴的彗星，已經(jīng)在銀河系中游蕩了數(shù)十億年，但另一些科學(xué)家卻直截了當(dāng)?shù)卣f出了我們許多人的想法:外星人的宇宙飛船。

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就不那么模棱兩可了。盡管它出生在一個難以理解的陌生空間，但它身上卻有著所有能說明問題的喜劇特征——特別是一條閃閃發(fā)亮的尾巴，很可能是由它冰冷的心臟釋放出的氣體造成的。

In any case, we'll get a chance to scrutinize 2I/Borisov a lot more closely as it brightens our doorstep over the coming weeks. While 'Oumuamua didn't stick around long enough for us to unfurl the "Welcome to Earth" banner, Borisov should make its nearest pass to Earth in December. It won't be quite as intimate as 'Oumuamua's visit, which scraped within 180 million miles of Earth. But it will light up the night sky a lot longer. The flyby will be closest to Earth on Dec. 8 — when the comet will be 190 million miles away — but will be present through April, when it finally bids our solar system a fond farewell.

無論如何，我們將有機(jī)會更仔細(xì)地觀察2I/Borisov，因為它將在未來幾周照亮我們的大門。雖然Oumuamua沒有停留足夠長的時間讓我們展開“歡迎來到地球”的橫幅，但是Borisov應(yīng)該在12月到達(dá)最近的地球。這次訪問不會像“Oumuamua的訪問”那么親密，“Oumuamua的訪問”距離地球不到1.8億英里。但它將照亮夜空更長的時間。這次飛越將在12月8日離地球最近——屆時彗星將在1.9億英里之外——但將持續(xù)到4月，屆時它將與我們的太陽系告別。