The last image puts it all in perspective.
Compared to what we find in our Solar System, galaxies are truly enormous.
The smallest known galaxy is Segue 2, with only about ~1000 stars inside.
These stars are spread out over ~500 light-years: billions of times the physical size of any individual star.
Galaxies can get much larger, but many “relative size” depictions are inaccurate.
Our own Milky Way, typical of modern spirals, is slightly over 100,000 light-years across.
Andromeda’s diameter is roughly double ours: 220,000 light-years.
But interacting galaxies can become tidally disrupted, vastly increasing their extent.
The Tadpole galaxy’s tail alone is 280,000 light-years long.
Meanwhile, UGC 2885 is our largest spiral: 832,000 light-years in extent.
Elliptical galaxies, however, are the largest galaxies of all.
Messier 87, the Virgo supercluster’s largest galaxy, is 980,000 light-years across.
The Coma Cluster’s biggest, NGC 4889, spans 1,300,000 light-years in diameter.
Meanwhile, the Phoenix Cluster’s brightest central galaxy measures 2.2 million light-years across.
But the biggest one of all? That’s IC 1101.
Half the light is contained within a 2 million light-year central radius.
Its full span is 5.5 million light-years across: nearly double the Local Group’s full extent.
The true relative size differences highlight galactic diversity.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
Starts With A Bang is written by Ethan Siegel, Ph.D., author of Beyond The Galaxy, and Treknology: The Science of Star Trek from Tricorders to Warp Drive.