NGC 1316: After Galaxies Collide

Explanation: Astronomers turn detectives when trying to figure out the cause of unusual sites like NGC 1316 . A preliminary inspection indicates that NGC 1316 is an enormous elliptical galaxy that started devouring a smaller spiral galaxy neighbor about 100 million years ago. Supporting evidence includes the dark dust lanes uniquely indicative of a spiral . What remains unexplained are the unusually small globular star clusters , visible as faint dots on the above photograph . Most elliptical galaxies have more and brighter globular clusters than evident in NGC 1316 . Yet the observed globulars are too old to have been created by the recent spiral collision . One hypothesis therefore holds that these globulars survive from an even earlier galaxy that was subsumed into NGC 1316.