This process of removing energy from a rotating black hole was proposed by the mathematician Roger Penrose in 1969 and is called the Penrose process. The maximal amount of energy gain possible for a single particle via this process is 20.7% in terms of its mass equivalence, and if this process is repeated by the same mass, the theoretical maximal energy gain approaches 29% of its original mass-energy equivalent. As this energy is removed, the black hole loses angular momentum, and thus the limit of zero rotation is approached as spacetime dragging is reduced. In the limit, the ergosphere no longer exists. This process is considered a possible explanation for a source of energy of such energetic phenomena as gamma-ray bursts. Results from computer models show that the Penrose process is capable of producing the high-energy particles that are observed being emitted from quasars and other active galactic nuclei.