More evidence of a lumpy universe.Bunched into giant walls or packed along spidery filaments, galaxies a few hundred million light-years from Earth display a decidedly lumpy pattern. Several models suggest that this cosmic architecture formed relatively recently. They predict that as astronomers map the distribution of galaxies deeper in space-equivalent to looking further back in time-they should see the lumpiness smooth out rapidly. Now, a new study suggests that lumpiness in the universe may have arisen earlier and persisted longer than many theorists have asserted. To study the distribution of distant galaxies, Judith G. Cohen cohen or kohen (Hebrew: “priest”) Jewish priest descended from Zadok (a descendant of Aaron), priest at the First Temple of Jerusalem. The biblical priesthood was hereditary and male. and her colleagues at the California Institute of Technology California Institute of Technology, at Pasadena, Calif.; originally for men, became coeducational in 1970; founded 1891 as Throop Polytechnic Institute; called Throop College of Technology, 1913–20. in Pasadena used the world's largest optical telescope, the W.M. Keck atop Hawaii's Mauna Kea Mauna Kea (mou`nə kā`ə), dormant volcano, 13,796 ft (4,205 m) high, in the south central part of the island of Hawaii. It is the loftiest peak in the Hawaiian Islands and the highest island mountain in the world, rising c. . The team measured the recession velocities, or redshifts, of 106 faint galaxies in a small patch of sky. Because the universe is expanding, more distant galaxies recede re·cede 1 intr.v. re·ced·ed, re·ced·ing, re·cedes 1. To move back or away from a limit, point, or mark: waited for the floodwaters to recede. 2. from Earth faster than nearby ones, and their light is correspondingly shifted to longer, or redder, wavelengths. Some of the galaxies in this infrared survey lie halfway to the edge of the visible universe-several billion light-years from Earth. The redshifts reveal that 64 of the 106 galaxies aren't spread out evenly, but cluster together in five groupings, notes Cohen. No similar survey has "found as much strong redshift redshift Displacement of the spectrum of an astronomical object toward longer wavelengths (visible light shifts toward the red end of the spectrum). In 1929 Edwin Hubble reported that distant galaxies had redshifts proportionate to their distances (see clustering as is presented here," she and her colleagues, David W. Hogg, Michael A. Pahre, and Roger Blandford Roger Blandford is an astronomer and astrophysicist. He is[1] a Fellow of the Royal Society and Fellow of the American Academy of Arts and Sciences. He is currently Pehong and Adele Chen director of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), , will report in the May 1 Astrophysical Journal Letters. Richard E. Griffiths of Johns Hopkins University Johns Hopkins University, mainly at Baltimore, Md. Johns Hopkins in 1867 had a group of his associates incorporated as the trustees of a university and a hospital, endowing each with $3.5 million. Daniel C. in Baltimore cautions that the number of galaxies in any one grouping is small. Nonetheless, he adds, "there may be a lot more clumping than we otherwise thought at large distances. Models of structure formation are going to have to take [this] into account." To determine whether her team has truly seen clustering, Cohen plans to examine whether galaxies in adjacent patches of sky congregate in a similar fashion. This larger study may also reveal whether the galaxies have bunched into isolated groups or organized into extended walls-a more complex pattern. Theorists who favor recent formation of large-scale structure will have an even harder time accounting for the early development of walls. |
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