Astronomers Find A Galaxy Of Unusual Size (G.O.U.S.), And Discover Why It Exists
“At 800,000 light-years across and with some 4 trillion stars inside, this is one of the largest spiral galaxies ever discovered: a true cosmic outlier. At just 230 million light-years away, it’s also close enough that we can image and identify its globular clusters and star formation rate. The fact that a galaxy this large and massive is so regularly shaped, with such low levels of star formation and so few globular clusters (1600) for its incredible size really does make this a cosmic unicorn.
This galaxy of unusual size really is a first-of-its-kind, and not just for being so beautifully symmetric and quiet, but for growing to this enormous magnitude without a single major disruptive event throughout its history. In all the Universe, there may not be another like it, but the odds are far better that this is just the first discovery of a new type of spiral galaxy: a G.O.U.S.”
How big can a spiral galaxy gets? While most of them are only tens of thousands of light-years across, larger ones like the Milky Way and Andromeda are common, and a small fraction are even bigger. But the newest record-holder, UGC 2885 or Rubin’s galaxy, is truly unusual: it looks like it’s never had a major or even a mid-sized merger before.