Black Holes

Physical theory predicts black holes. Are they there?

M > 3 M_sun.
small size.

There is evidence for the existence of such an object. The best case is an xray source called Cygnus X1. Cygnus X1 appears to be a black hole with a mass of about 7 solar masses that is part of a binary system. The other star in the binary system is a B class supergiant star. We will discuss the evidence in more detail later.

Davison E. Soper, Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA soper@bovine.uoregon.edu