But whether or not the idea of a trail of gas makes you giggle, it should definitely make you feel tiny: At around 250,000 light years long, the tail alone is more than twice the diameter of the Milky Way.
The tail, which is described in a paper published recently in Astronomy and Astrophysics, is probably made of gas stripped away from the galaxy it seems to stream from. The galaxy is part of a cluster of galaxies, which are held together by gravity and have hot intergalactic gas between them. The pressure exerted on a galaxy as it crashes through this external gas could pull its own gas out into space. The 10 million degree gas glows bright blue in the above image, captured in X-rays.
The "head" of the ribbon is its brightest point, and researchers believe this spot may be made of cooler gas than the rest of the stream. It may also contain heavier elements than the end of the tail. These heavier elements might be used to form new stars -- ones that would trail out behind the original galaxy. That may be the galaxy's best hope for new stars: Calculations suggest that the source galaxy was once one of the cluster's most active star factories, but has ceased making new stars. That might be because all of the galaxy's star-making materials have been drawn out into intergalactic space.
In addition to being the longest tail of this nature ever spotted before, the newly discovered feature seems to be unusually far away from its source galaxy.