特殊星系Arp 273
Peculiar Galaxies of Arp 273
Image Credit & Copyright: Jason Guenzel
Explanation: The spiky stars in the foreground of this backyard telescopic frame are well within our own Milky Way Galaxy. But the two eye-catching galaxies lie far beyond the Milky Way, at a distance of over 300 million light-years. Their distorted appearance is due to gravitational tides as the pair engage in close encounters. Cataloged as Arp 273 (also as UGC 1810), the galaxies do look peculiar, but interacting galaxies are now understood to be common in the universe. Nearby, the large spiral Andromeda Galaxy is known to be some 2 million light-years away and approaching the Milky Way. The peculiar galaxies of Arp 273 may offer an analog of their far future encounter. Repeated galaxy encounters on a cosmic timescale can ultimately result in a merger into a single galaxy of stars. From our perspective, the bright cores of the Arp 273 galaxies are separated by only a little over 100,000 light-years.
Tomorrow’s picture: aurora over white dome
特殊星系Arp 273
影像提供与版权: Jason Guenzel
说明: 在这幅摄于住家后院的望远镜影像里，带芒的恒星近在我们银河系之内。而这两个很吸睛的星系，则座落在银河系后方3亿多光年远处。它们扭曲的外观，源自这对星系彼此接近时的引力潮汐效应。编录号为Arp 273 （亦称UGC 1810）的这对星系，外观诚然很特殊，但这种相互作用星系，目前认为在宇宙其实很常见。例如：离我们约2百万光年远的仙女座星系，就不停地往银河系靠，因此，Arp 273可能是未来互扰事件的告示牌。在长长的宇宙时间尺度期间，如果星系重覆接近，它们最后会合拼成单一星系。从地球看出去，星系对Arp 273的明亮星系核相隔约100,000光年。
明日的图片: aurora over white dome
