Front Cover
Black holes are an important consequence of Einstein’s theory
of gravitation. Astronomers believe that some strong sources of
X-rays consist of a normal star and a black hole orbiting around
each other. Note that the black hole, on the right, is itself invisible
but surrounded by a swirling disc of hot gas which falls into it
from the companion star.
Back Cover
Albert Einstein
( 1879 – 1955 )
( Illustration by Prema Iyer )
