2020 May 15


Galaxy Wars: M81 and M82
Image Credit & Copyright:
Dietmar Hager, Torsten Grossmann

Explanation: These two galaxies are far far away, 12 million light-years distant toward the northern constellation of the Great Bear. On the left, with grand spiral arms and bright yellow core is spiral galaxy M81, some 100,000 light-years across. On the right marked by red gas and dust clouds, is irregular galaxy M82. The pair have been locked in gravitational combat for a billion years. Gravity from each galaxy has profoundly affected the other during a series of cosmic close encounters. Their last go-round lasted about 100 million years and likely raised density waves rippling around M81, resulting in the richness of M81’s spiral arms. M82 was left with violent star forming regions and colliding gas clouds so energetic the galaxy glows in X-rays. In the next few billion years, their continuing gravitational encounters will result in a merger, and a single galaxy will remain.

Tomorrow’s picture: light-weekend

Dietmar Hager, Torsten Grossmann

说明: 这二个星系,位在北天的大熊座方向约1千2百万光年远之处。影像左方的星系,是拥有壮丽螺旋臂和泛黄核心,宽约100,000光年的M81。右方罩着泛红气体及尘埃的天体,则是不规则星系M82。在过去的十亿年之中,这两个星系不停透过重力进行缠斗。在一系列的近距离接近里,它们的重力对彼此都有很重大的影响。在最近一回合持续约1亿年的缠斗里,重力互扰在M81的星系盘上,触发盘旋不息的密度波,并造就了M81壮观的螺旋臂。而在M82里,则出现快速产生大量恒星的剧烈恒星形成区,以及气体剧烈碰撞因而让星系发出明亮的X射线。在接下来的数十亿年之中,它们永不停歇的重力互扰,最后会让它们合并成一个更大的星系。

明日的图片: light-weekend

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