银河系的质量相当于8900亿个太阳

银河系的质量相当于8900亿个太阳

The Milky Way has a mass that’s 890 billion times the mass of our sun.

银河系的质量是太阳的8900亿倍。

That figure, as Live Science reports, is 3.9 tredecillion pounds — or the number 1 followed by 42 zeros. The mass is also equal to about 6 billion billion billion elephants, the science outlet reports.

据《生活科学》报道，这个数字是3.9万亿磅，也就是1后面跟42个0。据《科学出口》报道，大象的重量也相当于60亿亿亿头大象。

It’s challenging to measure the mass of a galaxy that we occupy, however.

然而，测量我们所在星系的质量是一项挑战。

Researchers tend to “weigh” them by examining the movements of stars inside the galaxies, which can demonstrate how the galaxy’s gravity is impacting those stars.

研究人员倾向于通过观察星系内恒星的运动来“衡量”它们，这可以证明星系的引力是如何影响这些恒星的。

“The disk of our galaxy is spinning but not uniformly,” study co-author Fabio Iocco, an astrophysicist at Imperial College London, told Live Science. “Objects at different distances from the center of the galaxy go around that center at different speeds.”

伦敦帝国理工学院的天体物理学家Fabio Iocco是这项研究的共同作者，他告诉Live Science:“我们星系的圆盘在旋转，但是并不均匀。”“距离星系中心不同距离的物体以不同的速度围绕该中心旋转。”

The researchers reportedly compared their findings with previous work in this area and found that they lined up. Their paper was made available Monday in the arXiv database.

据报道，研究人员将他们的发现与之前在这一领域的研究结果进行了比较，发现结果是一致的。他们的论文于周一发布在arXiv数据库中。

“If you do it for different distances, from the center until very far away, you get an estimate of the mass enclosed at increasing distances. So you can draw not only a total mass, but a mass distribution,” Iocco told Live Science.

“如果你从中心到很远的地方，从不同的距离计算，你会得到距离增加时的质量估计值。所以你不仅可以画出总质量，还可以画出质量分布。”