Extraction of Energy from a Black Hole

"A black hole is a general relativistic object whose gravitational pull is so great that


nothing, not even light, can escape after having fallen past its event horizon.


Despite its interior being invisible, a black hole may reveal its presence by playing


the role of energy supplier in such astrophysical phenomena as AGN, quasars and


gamma-ray bursts. In this talk, I willexplain characteristic features of black holes


and discuss some mechanisms by which energy can be extracted from them."