在银河系中心发现的奇怪物体与银河系中的其他物体完全不同
There's something really weird in the centre of the Milky Way.
银河系的中心有个很奇怪的东西。
The vicinity of a supermassive black hole is a pretty weird place to start with, but astronomers have found six objects orbiting Sagittarius A* that are unlike anything in the galaxy. They are so peculiar that they have been assigned a brand-new class - what astronomers are calling G objects.
一开始，超大质量黑洞附近是一个相当怪异的地方，但天文学家已经发现了六个环绕人马座a *运行的天体，它们与银河系中的任何天体都不同。它们是如此特别，以至于被赋予了一个全新的类别——天文学家们称之为G类天体。
The original two objects - named G1 and G2 - first caught the eye of astronomers nearly two decades ago, with their orbits and odd natures gradually pieced together over subsequent years. They seemed to be giant gas clouds 100 astronomical units across, stretching out longer when they got close to the black hole, with gas and dust emission spectra.
最初的两个天体——G1和G2——在近20年前首次引起天文学家的注意，它们的轨道和古怪的性质在随后的几年里逐渐拼凑在一起。它们似乎是巨大的气体云，直径为100个天文单位，当它们靠近黑洞时，随着气体和尘埃发射光谱的出现，它们被拉长了。
But G1 and G2 weren't behaving like gas clouds.
但G1和G2的表现并不像气体云。
These objects look like gas but behave like stars, said physicist and astronomer Andrea Ghez of the University of California, Los Angeles.
加州大学洛杉矶分校的物理学家和天文学家Andrea Ghez说:“这些物体看起来像气体，但实际上却像恒星。”
Ghez and her colleagues have been studying the galactic centre for over 20 years. Now, based on that data, a team of astronomers led by UCLA astronomer Anna Ciurlo have identified four more of these objects: G3, G4, G5 and G6.
Ghez和她的同事已经研究银河系中心超过20年了。现在，根据这些数据，一个由加州大学洛杉矶分校的天文学家Anna Ciurlo领导的天文学家小组已经确定了另外四个这样的天体:G3、G4、G5和G6。
And they're on wildly different orbits from G1 and G2 (pictured above); all together, the G objects have orbital periods that range from 170 years to 1,600 years.
它们的运行轨道与G1和G2截然不同(见上图);总的来说，G星的轨道周期从170年到1600年不等。
It's unclear exactly what they are, but G2's intact emergence from periapsis in 2014 - that is, the closest point in its orbit to the black hole - was, Ghez believes, a big clue.
目前还不清楚它们到底是什么，但是G2在2014年完整地从periapsis(即其轨道上距离黑洞最近的点)的出现，Ghez相信，是一个重要的线索。
The research has been published in Nature.
这项研究发表在《自然》杂志上。
