M31：仙女星系
(原标题: M31: The Andromeda Galaxy)
2022-01-19
浏览次数: 13
肉眼能轻易看到的最遥远的天体是M31，大仙女座星系。即使在大约250万光年远的地方，这个巨大的螺旋星系——跨度超过20万光年——也是可见的，尽管它是仙女座中一团微弱的星云。相比之下，明亮的黄色核心，黑暗的缠绕尘埃带，点缀着蓝色星团和红色星云的膨胀旋臂，在这张令人惊叹的望远镜图像中被记录下来，这张图像结合了轨道哈勃和斯巴鲁和梅奥尔的地面图像。在大约50亿年后，仙女座星系可能会更容易看到——因为它可能会横跨整个夜空——就在它与我们的银河系合并之前。
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The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy. Even at some two and a half million light-years distant, this immense spiral galaxy -- spanning over 200,000 light years -- is visible, although as a faint, nebulous cloud in the constellation Andromeda. In contrast, a bright yellow nucleus, dark winding dust lanes, and expansive spiral arms dotted with blue star clusters and red nebulae, are recorded in this stunning telescopic image which combines data from orbiting Hubble with ground-based images from Subaru and Mayall. In only about 5 billion years, the Andromeda galaxy may be even easier to see -- as it will likely span the entire night sky -- just before it merges with our Milky Way Galaxy.
© R. Gendler & R. Croman