War has been declared between two galaxies, and the future doesn’t look good for the underdog: The larger galaxy’s powerful jet of high-energy radiation and matter is hitting its helpless neighbor. Ambulance-chasing astronomers hope to take advantage of this cosmic drive-by shooting to learn more about the nature of such jets, which usually spurt into empty space.
The two galaxies, together called 3C321, lie 20,000 light-years apart but will eventually merge. Like most galaxies, both harbor supermassive black holes, strong centers of gravity that suck in any nearby matter. But only the larger galaxy produces a jet, a beam of energetic particles and radiation generated as matter swirls in toward the black hole.