Margaret Joan Geller

(b. 1947)

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(1947–) American astronomer

The daughter of a crystallographer from Ithaca, New York State, Geller was encouraged as a small child to study science and mathematics. She was educated at the University of California, Berkeley, and at Princeton where she obtained her PhD in 1975. After a period at the Institute of Astronomy, Cambridge, England, Geller moved to Harvard in 1980 and was appointed professor of astronomy in 1988. She is also a staff member of the Smithsonian Astrophysical Observatory.

Since the early 1980s Geller and her coworkers have been carrying out for the Center for Astrophysics (CfA) a red-shift survey of some 15,000 galaxies. The intention is to map all galaxies above a certain brightness, out to about 650 million light years, in a particular sector of the heavens. They were aware that to some observers the sky lacked the uniformity predicted by the big-bang theory. In 1981, for example, a 100-million-light-year gap had been discovered in the constellation Bootes. Geller considered the possibility that this was a local phenomenon, and that the predicted homogeneity would become more apparent on a much larger scale. Further investigations were expected to show a uniform distribution of galaxies.

But when they came to plot the distribution of galaxies they saw neither a uniform spread, nor a random scattering of galaxies, but large-scale clusters grouped into enormous structures. The largest of these, dubbed the Great Wall, stretches for more than 500 million light-years. It was difficult to see how anything as massive could have been formed within the context of current cosmological theory; when Geller reported the initial results of the CfA survey in 1989 she noted, “Something fundamental is missing in our models.”

Subjects: Science and Mathematics.

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