data on X-ray sources, especially galactic clusters
and candidate black holes. In 1989, the Cosmic
Background Explorer (COBE) was launched to map
variations in the universe’s cosmic microwave back-
ground radiation.
On earth, meanwhile, the Very Large Array,
twenty-seven radio telescopes near Socorro, New
Mexico, became operational in 1980, and the fifteen-
meter-wide James Clerk Maxwell telescope atop
Mauna Kea, Hawaii, began detecting light from far
infrared to microwave frequencies in 1987.
Impact Several of the astronomical observations
made in the 1980’s had significant implications.
Supernovas, for example, can provide means of
measuring intergalactic distances and of testing cos-
mological theories, and SN 1987a served these func-
tions in two ways. First, neutrinos emitted by the
supernova were detected on Earth, providing the
first empirical evidence that gravity affects matter,
antimatter, and photons in similar ways. Second,
geometrical measurements of light sent out by SN
1987a confirmed the value of the Hubble constant, a
crucial component of astronomical theory.
The large-scale clumping and massive voids discov-
ered in the universe’s structure were also important.
These structures—including the Great Attractor, the
Boötes void, and the Great Wall—suggested that early
fluctuations had occurred in the expansion rate of
the universe. These fluctuations, predicted by Guth’s
inflationary model, were confirmed in 1990 by data
that the COBE satellite gathered. These data indi-
cated that the universe went through a period of ex-
ponential growth soon after the big bang; their col-
lection is widely regarded as constituting the most
significant astronomical observation made during
the late twentieth century.
Further Reading
Hartmann, William K.Moons and Planets. 3d ed.
Belmont, Calif.: Wadsworth, 1992. This classic
text is a moderately technical survey of planetary
science; includes discoveries during the 1980’s
from space-based and ground telescopes, as well
as many photographs and illustrations.
Leverington, David.A Histor y of Astronomy from 1890
to the Present. New York: Springer, 1995. Lever-
ington provides a highly detailed, mostly non-
technical account of modern astronomy, empha-
sizing the great changes in technology and theory.
With illustrations.
North, John.The Norton Histor y of Astronomy and Cos-
mology. New York: W. W. Norton, 1995. Surveys the
scientific history of astronomy and places its con-
cepts in the larger Western intellectual tradition.
The final chapter briefly recounts advances made
in astrophysics, black hole theory, and cosmology
during the 1980’s.
Schorn, Ronald A.Planetar y Astronomy from Ancient
Times to the Third Millennium. College Station:
Texas A&M University Press, 1998. Provides a
thorough, nontechnical survey of the history of
astronomy as a science. The last chapter discusses
the Voyager flybys of Jupiter, Saturn, Uranus, and
Neptune and the discoveries made as a result.
Sheehan, William.Worlds in the Sky: Planetar y Discov-
er y from Earliest Times Through Voyager and Magel-
lan. Tucson: University of Arizona Press, 1992.
This agreeably written, nontechnical narrative
provides basic historical background to the prog-
ress in astronomy during the 1980’s.
Roger SmithSee also Science and technology; SETI Institute;
Space exploration; Space shuttle program.AT&T breakup
The Event Forced fragmentation of a telephone
company’s monopoly
Date Settlement made on January 8, 1982
AT&T, a government-regulated monopoly providing local
and long-distance telephone service in the United States,
settled a long-running government antitrust suit by agree-
ing to divide itself into seven independently owned regional
local telephone companies and an unregulated national
long-distance company. The new national company would
also be free to enter emerging communications and com-
puter markets.
By the mid-1970’s, American Telephone and Tele-
graph (AT&T) was the sole provider of telephone
service and equipment for most consumers in the
United States. Early in the twentieth century, the
company had eliminated its independent competi-
tors in the telephone industry by refusing to offer
long-distance service or equipment to the local inde-
pendent phone companies, which at the time collec-
tively controlled one-half of the U.S. market. As a
result, the independent companies were either de-78 AT&T breakup The Eighties in America