This is an image focusing on two galaxies. NGC 1316 on the left is large and messy. NGC 1317 on the right is smaller and neat. Which one is the serial killer?
Apparently the universe plays to the dramatically obviously, because the killer is the hulking, disheveled NGC 1316, which is hulking and disheveled because it has a habit of violently eating other galaxies. It’s a little more Leatherface than Hannibal Lecter.
According to Astronomy Magazine:
Several clues in the structure of NGC 1316 reveal that its past was turbulent. For instance, it has some unusual dust lanes embedded within a much larger envelope of stars and a population of unusually small globular star clusters. These suggest that it may have already swallowed a dust-rich spiral galaxy about 3 billion years ago.
Also seen around the galaxy are faint tidal tails — wisps and shells of stars that have been torn from their original locations and flung into intergalactic space. Complex gravitational effects on the orbits of stars produce these features when another galaxy comes too close. All of these signs point to a violent past during which NGC 1316 annexed other galaxies and suggest that the disruptive behavior is continuing.
NGC 1316 is located about 60 million light-years away from Earth in the southern constellation Fornax the Furnace. The image was captured from the MPG/ESO 2.2-meter telescope at the European Southern Observatory’s (ESO) La Silla Observatory in Chile and is a composite of several images from its archive.