Number 180 (Story #1), May 27, 1994 by Phillip F. Schewe and Ben Stein THE EXISTENCE OF BLACK HOLES is now established observationally about as well as is possible with the release of new Hubble Space Telescope (HST) pictures of fast gas near the core of galaxy M87. Black holes have been adduced to explain a variety of high-energy phenomena, from quasars to the creation of positrons at the center of the Milky Way. Images of the cores of some galaxies had shown a pileup of stellar light, suggestive of the presence of a massive object, but many skeptical astronomers held out for stronger evidence; they insisted on tracking the movement of matter---in the case of M87 a disk of gas---orbiting the presumed black hole. The gas, which at a distance of only 60 light years out from the center of M87 could only have been resolved by HST, moves at a velocity of more than a million mph. This in turn suggests the presence of 1-2 billion-solar-mass black hole. (The New York Times, The Washington Post, and other papers, 26 May.)