Word: huchra
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Dates: during 1980-1989
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...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 it runs...
...study is not the first to see dark voids and large conglomerations of galaxies, but it is by far the most comprehensive. The reason no one had done such a search earlier, says Huchra, is that galaxy mapping is extremely time consuming. Their survey of 4,000 galaxies took about 1,000 hours of telescope time...
...Huchra, who made the telescopic observations for the Harvard-Smithsonian team, used an instrument called a spectrograph to break down each galaxy's light into its constituent colors. Within the spectrum he could see lines representing 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...
CREDIT: M.J. GELLER, J.P. HUCHRA, E. FALCO, R.K. MCMAHAN...