Aug 8 1978
From The Space Library
NASA announced that data returned by the American-British European international ultraviolet explorer (IUE) satellite had suggested the existence of a massive black hole at the center of globular clusters in earth's galaxy. A group of scientists headed by Dr. Herbert Gursky and Dr. Andrea Dupree, both of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass., had examined six clusters, three of them x-ray sources.
NASA, in cooperation with ESA and the British Science Research Council, had launched IUE in Jan. 1978 into a modified near-equatorial synchronous orbit to study a wide range of celestial objects in the ultraviolet region of the electromagnetic spectrum. Dr. Gursky said the onboard UV instruments had delivered unexpected information when they penetrated the background denseness of the clusters, which were like miniature galaxies 15 000 light-yr away, to observe the cluster core. What they saw, according to Gursky, was probably radiation from a group of 10 to 20 bright-blue stars orbiting the core: "These stars may well be orbiting a massive black hole the size or mass of one thousand solar systems," he said. However, existence of a black hole was not certain, as rotation of the stars in relation to the center of the million-star cluster had to be studied first. If the stars were indeed orbiting a massive black hole, Gursky believed they were right on the edge or, if not, might be providing their own gravitational equilibrium.
What surprised the observation team, Gursky said, was the ability of the short-wavelength instrumentation to cut clearly through the million star cluster. "For the first time we are seeing in a clean way the center or core of those globular clusters, and we were surprised. You can see the clusters in visible light, there are lots of red giant stars there, which mask what is going on in the center. Now we have a tool, the IUE's shortwave ultraviolet, capable of going for the first time right to the core through the whole cluster," said Gursky. Although the team would continue to observe the six globular clusters, Gursky doubted their findings could be definite until NASA put the space telescope in orbit from the Space Shuttle in 1983. That telescope, using much more powerful instrumentation including short-wavelength ultraviolet, could study the blue stars in more detail. (NASA Release 78-122)
In a report on Soviet space activities, Defense/Space Business Daily said Progress 2 had crashed into the Pacific Aug. 4, 2da after it had undocked from the Salyut station where it had been for 25da. This Progress resupply spacecraft (a modified Soyuz) had not been designed as a recoverable reentry and descent vehicle.
The Soviets had orbited Cosmos 1028, believed to be another in a series of long-duration high-resolution reconnaissance/surveillance satellites; orbit was 182/272km, 67.l° inclination, 88.7min period. Another in the series, Cosmos 905, launched Apr. 26, 1977, had remained in orbit 30da and was recovered. Others in the series had been Cosmos 758, in orbit for 20da after launch Sept. 3, 1975; Cosmos 805, in orbit for 20da after launch Feb. 20, 1976; and Cosmos 844, in orbit 39da after launch July 22, 1976. (DISD, Aug 8/78, 171)
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