NASA·APOD每日天文一图2022.6.6 [超高清]

银河系会与仙女座星系发生碰撞吗？会！

Will our Milky Way Galaxy collide one day with its larger neighbor, the Andromeda Galaxy? Most likely, yes. Careful plotting of slight displacements of M31's stars relative to background galaxies on recent Hubble Space Telescope images indicate that the center of M31 could be on a direct collision course with the center of our home galaxy. Still, the errors in sideways velocity appear sufficiently large to admit a good chance that the central parts of the two galaxies will miss, slightly, but will become close enough for their outer halos to become gravitationally entangled. Once that happens, the two galaxies will become bound, dance around, and eventually merge to become one large elliptical galaxy -- over the next few billion years. Pictured here is a combination of images depicting the sky of a world (Earth?) in the distant future when the outer parts of each galaxy begin to collide. The exact future of our Milky Way and the entire surrounding Local Group of Galaxies is likely to remain an active topic of research for years to come. 

我们的银河系有一天会与其更大的邻居仙女座星系发生碰撞吗？很可能是的。在哈勃太空望远镜最近拍摄的图像上，仔细绘制了M31恒星相对于背景星系的轻微位移图，表明M31的中心可能与我们所在星系的中心发生直接碰撞。尽管如此，横向速度的误差似乎足够大，这两个星系的中心部分很有可能会稍微偏离，但会变得足够近，使它们的外晕在重力作用下纠缠在一起。一旦发生这种情况，这两个星系将结合在一起，跳舞，最终合并成一个巨大的椭圆星系——在接下来的数十亿年里。这里的图片是一组描绘世界天空（地球？）在遥远的将来，当每个星系的外部开始碰撞时。我们银河系和周围整个星系群的确切未来可能在未来几年内仍然是一个活跃的研究课题。