26 April 1985
Vol 228, Issue 4698

About The Cover

The color image represents a cross section of a spiraling gas flow near a black hole. The colors represent the gas density in every zone on the computational grid; density decreases in spectral order from red to blue. The underlying grid can be seen as the small squares at the outer edges of the image. The red stripes that “pinch in” at the equator (horizontal plane) are shock waves. The heart-shaped region is a fat disk orbiting the black hole. See page 403. [Computation by John Hawley and Larry L. Smarr, Department of Astronomy, University of Illinois. Calculations were performed on the Cray-1 supercomputer, Max-Planck Institut f&uumlaut;r Physik und Astrophysik, Garching, Federal Republic of Germany]