A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of the galactic disk.

极环星系是种稀有的星系类型，它们有着几乎和银盘平面垂直，呈环形公转的大量的恒星、气体和星尘。

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At times, enough gas builds up for the dwarf to collapse, leading its carbon to fuse nearly instantly and the dwarf to explode in a Type I supernova, which can outshine a galaxy for a few months.

有时，足够的气体会积累起来导致这颗矮星发生坍缩，使得它的碳原子几乎能立即聚合，而爆炸成为I类超新星，它在几个月内的亮度能超过一个星系。

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A small, irregular galaxy, the SMC represents a type of galaxy more common in the early Universe.

作为一个小而不规则的星系，小麦哲伦星系呈现出早期宇宙星系的普遍类型。

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While red dwarfs are the most common type of star in the Milky Way galaxy, they often do not show up in astronomical surveys because they are too dim in visible light.

MSN: 'Impossible' stars found in our galaxy - Technology & science - Space - Space.com | NBC News

" He adds a bit later: "That we live in a large spiral galaxy with very little central stellar bulge and a modest central black hole may be a clue to the type of galaxies best suited to life: ones that did not spend their pasts building colossal black holes and fighting the demons unleashed in the process.

WSJ: Book Review: Gravity's Engines