研究表明，銀河系在數(shù)十億年前吞并了另一個(gè)星系。

研究表明，銀河系在數(shù)十億年前吞并了另一個(gè)星系

For astronomers, discovering new worlds, stars and even entire galaxies is really only half the battle. Once discovered, explaining how new features of space formed and where they came from, often means extensive research and a bit of guesswork. A new research effort aimed at uncovering some of the secrets of how our home galaxy, the Milky Way, formed, astronomers believe they’ve found evidence of an ancient collision.

對(duì)于天文學(xué)家來說，發(fā)現(xiàn)新的世界、恒星甚至整個(gè)星系實(shí)際上只是戰(zhàn)斗的一半。一旦發(fā)現(xiàn)，要解釋空間的新特征是如何形成的以及它們來自何處，將意味著廣泛的研究和設(shè)想。現(xiàn)在，在一項(xiàng)新的、旨在揭示我們銀河系是如何形成的研究中，發(fā)現(xiàn)了古代碰撞的證據(jù)。

A new paper published in Nature Astronomy suggests that the Milky Way slammed into a smaller “dwarf” galaxy long ago, swallowing up a huge amount of mass and using it as fuel to churn out new stars for billions of years afterward.

一篇發(fā)表在《自然天文學(xué)》上的新論文表明，銀河系很久以前撞上了一個(gè)較小的“矮”星系，吞沒了大量的質(zhì)量，并在隨后的數(shù)十億年里用它作為燃料大量產(chǎn)生新的恒星。

The research, which was made possible thanks to the high-powered Gaia space telescope, is based on the exact location and status of approximately a million stars in the Milky Way.

這項(xiàng)研究是基于銀河系中大約100萬顆恒星的確切位置和狀態(tài)，多虧了高性能的蓋亞太空望遠(yuǎn)鏡才得以實(shí)現(xiàn)。

The scientists noted that the stars surveyed fall into one of two groups, one of which appears to be the result of an “accretion event,” which is believed to be evidence of a galaxy collision.

科學(xué)家們指出，被調(diào)查的恒星分為兩組，其中一組似乎是“吸積事件”的結(jié)果，這被認(rèn)為是星系碰撞的證據(jù)。

Being able to determine the ages of the stars using the Gaia telescope allowed the researchers to better simulate the early life of the Milky Way, supporting the theory that our galaxy swallowed up a smaller one.

利用蓋亞望遠(yuǎn)鏡能夠確定恒星的年齡，使得研究人員能夠更好地模擬銀河系的早期生命，支持了我們的星系吞噬了一個(gè)較小星系的理論。

“The novelty of our work is that we have been able to assign precise ages to the stars that belong to the galaxies that merged and, by knowing these ages, when the merger took place,” Carme Gallart, lead author of the work, told AFP.

這項(xiàng)研究的主要作者Carme Gallart告訴法新社說:“我們的工作的新奇之處在于，我們已經(jīng)能夠確定合并星系的恒星的確切年齡，通過了解這些年齡，就可以確定合并發(fā)生的時(shí)間。”

“It’s a very gradual process—it’s not something like a car crash—it’s something that has an effect on the galaxy as a whole. It’s very massive so it happens slowly in human terms, not so slowly in cosmic time.”

“這是一個(gè)非常漸進(jìn)的過程，它不像汽車碰撞，而是對(duì)整個(gè)銀河系產(chǎn)生影響。而是對(duì)整個(gè)銀河系產(chǎn)生影響的過程。它非常巨大，所以從人類的角度來看，它發(fā)生的很慢，而從宇宙的角度來看，就沒那么慢了。”

It’s worth noting that this ancient collision isn’t the only one the Milky Way will experience, as astronomers already know that our galaxy is headed for a merger with the nearby Andromeda galaxy.

值得注意的是，這場(chǎng)古老的碰撞并不是銀河系將經(jīng)歷的唯一一次碰撞，因?yàn)樘煳膶W(xué)家已經(jīng)知道，我們的星系正朝著與鄰近的仙女座星系合并的方向前進(jìn)。

Thankfully that’s not expected to happen for another 4.5 billion years or so, so I wouldn’t worry too much about it.

值得慶幸的是，這在未來45億年左右都不會(huì)發(fā)生，所以我們不必太擔(dān)心。