A kugelblitz (German: [ˈkuːɡl̩ˌblɪt͡s] ) is a theoretical astrophysical object predicted by general relativity. It is a concentration of heat, light or radiation so intense that its energy forms an event horizon and becomes self-trapped. In other words, if enough radiation is aimed into a region of space, the concentration of energy can warp spacetime so much that it creates a black hole. This would be a black hole whose original mass–energy was in the form of radiant energy rather than matter, however, there is currently no uniformly accepted method of distinguishing black holes by origin.