2019 November 20
Explanation: What’s happening to these spiral galaxies? Although details remain uncertain, there sure seems to be a titanic battle going on. The upper galaxy is labelled UGC 1810 by itself, but together with its collisional partners is known as Arp 273. The overall shape of the UGC 1810 — in particular its blue outer ring — is likely a result of wild and violent gravitational interactions. The blue color of the outer ring at the top is caused by massive stars that are blue hot and have formed only in the past few million years. The inner part of the upper galaxy — itself an older spiral galaxy — appears redder and threaded with cool filamentary dust. A few bright stars appear well in the foreground, unrelated to colliding galaxies, while several far-distant galaxies are visible in the background. Arp 273 lies about 300 million light years away toward the constellation of Andromeda. Quite likely, UGC 1810 will devour its galactic sidekicks over the next billion years and settle into a classic spiral form.
说明：这些旋涡星系发生了什么？尽管详细情况仍不确定，但似乎肯定正在进行一场激烈的战斗。影像上方的星系单独被称为UGC 1810，但与其发生碰撞的星系伙伴合起来被称为Arp 273。UGC 1810的整体形状（特别是它的蓝色外环）很可能是狂暴的引力相互作用的结果。星系外环的蓝色色泽是由炽热的蓝色大质量恒星造成的，这些恒星仅形成于过去数百万年。上方星系的内部本身是一个较古老的旋涡星系，它看起来更红，并交织着冰冷的丝状尘埃。一些明亮的恒星在前景中清晰可见，它与发生碰撞的星系无关，而在背景中还可以看到几个遥远的星系。Arp 273位于仙女座方向，距离我们约3亿光年远。UGC 1810很可能将在未来10亿年吞噬它的星系伙伴，最终形成一个经典的旋涡星系。