File:Hubble Sees Plunging Galaxy Losing Its Gas.png

English: Two's company and three's a crowd. But thousands are a mosh pit. That's the case in the giant Coma cluster of more than 1,000 galaxies.

Hubble spotted a wayward spiral galaxy losing its gas as it plunges toward the center of the massive cluster and is roughed up as it plows through the intergalactic medium. Telltale evidence lies in a long, thin streamer of material that is stretching like taffy from the galaxy's core and on into intergalactic space. Gas is the lifeblood of a galaxy, fueling the birth of new stars. Once it is stripped of all of its gas, the galaxy, named D100, will enter retirement and shine only by the feeble glow of its aging, red stars.

D100 is being stripped of its gas because of the gravitational tug of a grouping of giant "bully" galaxies in the crowded cluster. Their combined gravity is pulling the beleaguered galaxy toward the cluster's center. As D100 falls toward the core, the galaxy barrels through material. This action forces gas from the galaxy.

The gas-stripping process in D100 began roughly 300 million years ago. In the massive Coma cluster this violent gas-loss process occurs in many galaxies. But D100 is unique in several ways. Its long, thin tail is its most unusual feature extending nearly 200,000 light-years. But the pencil-like structure is comparatively narrow, only 7,000 light-years wide. Thankfully, our Milky Way galaxy lives in a sparsely populated small corner of the universe, with only one other big galaxy as a companion.