Word: geller
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Dates: during 1980-1989
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...collection of galaxies, as the textbooks have long assumed, the cosmos seems to be organized into immense bubbles, each of them about 150 million light-years across. The walls of the bubbles are galaxies, and the interiors appear to be virtually empty. Most surprising of all is a feature Geller and Huchra call the "Great Wall" -- a sheet of galaxies at least 200 million light-years wide, 500 million long and perhaps 15 million thick. It looks like a single structure, but the scientists say it may instead be made up of the walls of adjacent bubbles. Says Geller: "Because...
...various elements in and around the galaxy's stars. These lines appear to be shifted toward the red end of the spectrum, depending on how fast the galaxy is moving and thus how far away from earth it is. By carefully measuring the degree of red shift, Huchra and Geller calculated the relative positions of the galaxies...
...particular, some scientists speculate that cold dark matter caused galaxies to form into the kind of bubbles Geller and Huchra have found. The process supposedly got under way 10 billion to 20 billion years ago, when the universe began with the Big Bang and the energy from that explosion started to condense into matter. Since then, ordinary visible matter, by itself, has probably not had time to gather into enormous structures. But cold dark matter may have condensed first, and its gravitational force could have helped pull visible matter into bubbles and galaxies. In fact, recent computer simulations at Princeton...
...meantime, the CfA study will go on, and other mapping efforts are in the works. "Big as it is," Geller explains, "our survey area compared with the visible universe is like Rhode Island compared with the surface of the earth." The bubbles and walls could be isolated phenomena. But, notes Geller: "Every survey ever done has contained structures as big as the survey could contain." If that trend continues, then there are larger objects yet to be found, which will give theorists even worse headaches. "These surveys test in the most acute way our conceptions of how structure developed...
CREDIT: M.J. GELLER, J.P. HUCHRA, E. FALCO, R.K. MCMAHAN...