ESA/Hubble & NASA, L. C. Ho, D. Thilker
Today’s rather aquatic-themed NASA/ESA Hubble Space Telescope image features the spiral galaxy Messier 77, also known as the Squid Galaxy, which sits 45 million light-years away in the constellation Cetus (The Whale).
The designation Messier 77 comes from the galaxy’s place in the famous catalog compiled by the French astronomer Charles Messier. Another French astronomer, Pierre Méchain, discovered the galaxy in 1780. Both Messier and Méchain were comet hunters who cataloged nebulous objects that could be mistaken for comets.
Messier, Méchain, and other astronomers of their time mistook the Squid Galaxy for either a spiral nebula or a star cluster. This mischaracterization isn’t surprising. More than a century would pass between the discovery of the Squid Galaxy and the realization that the ‘spiral nebulae’ scattered across the sky were not part of our galaxy but were in fact separate galaxies millions of light-years away. The Squid Galaxy’s appearance through a small telescope — an intensely bright center surrounded by a fuzzy cloud — closely resembles one or more stars wreathed in a nebula.
The name ‘Squid Galaxy’ is recent, and stems from the extended, filamentary structure that curls around the galaxy’s disk like the tentacles of a squid. The Squid Galaxy is a great example of how advances in technology and scientific understanding can completely change our perception of an astronomical object — and even what we call it!
Hubble previously released an image of M77 in 2013. This new image incorporates recent observations made with different filters and updated image processing techniques which allow astronomers to see the galaxy in more detail.
影像来源: ESA/Hubble & NASA, L. C. Ho, D. Thilker
这是一张具有浓厚海洋风格的图像，由欧洲航天局/哈勃太空望远镜和美国国家航空航天局拍摄，展示的是螺旋星系梅西耶77（Messier 77），也被称为鱿鱼星系。该星系距离地球约4500万光年，位于鲸鱼座。
梅西耶77这一名称源自法国天文学家查尔斯·梅西耶（Charles Messier）编撰的著名天体目录。实际上，该星系是由另一位法国天文学家皮埃尔·梅尚（Pierre Méchain）于1780年首次发现。梅西耶与梅尚都是当时专注于搜寻彗星的天文学家，他们编录了可能被误认为是彗星的各种模糊天体。
在那个时代，梅西耶、梅尚以及他们的同行曾一度误将鱿鱼星系当作螺旋星云或恒星团，这种误判在当时并不罕见。直到一个多世纪后，科学家才逐步认识到这些分布在夜空中的“螺旋星云”其实并非银河系的一部分，而是距离我们数百万光年之外的独立星系。通过小型望远镜观察时，鱿鱼星系表现为一个明亮的中心区域，周围环绕着模糊光晕，非常像被星云包裹的一团星光。
“鱿鱼星系”这一名字是近年才被提出的，灵感来源于其盘面外围缠绕的细丝状结构，看起来宛如鱿鱼的触须。这一命名体现了天文技术和科学认知的进步如何改变我们对宇宙中天体的认识，甚至连我们对它们的称呼都可能随之更新。
哈勃望远镜曾在2013年公布过M77的图像。而这张新图则基于近期使用多种滤光器所获得的新观测数据，并结合了更先进的图像处理技术，使天文学家得以更清晰、更深入地观察该星系的结构细节。
