Black holes and the universe

Modern physics has shown us the immense power of black holes superstrong gravitational fields. The force of gravity warps space and time, crushing stars and perhaps galaxies too, until they fall in on themselves to form a black hole. Igor Novikov, a distinguished astrophysicist and skilled writer, explains the cosmic importance of black holes. He accounts for the physical environment of a black hole, explains how astronomers search for them, and places them in the context of the expanding universe.