NGC 4650A

NGC 4650A appears to be two galaxies in one. A rare type of galaxy known as a Polar Ring, NGC 4650A is composed of an old central group of stars and a young ring of stars rotating farther out. What creates Polar Ring Galaxies is still being researched, but a leading theory is the collision of two distinct galaxies in the distant past. An unknown type of dark matter is implied because the ring typically rotates too fast to be held together by only the visible stars.