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Baltimore MD (SPX) Aug 02, 2006 NASA has named a Johns Hopkins University astrophysicist the principal investigator of a proposal, accepted Tuesday, to design a space mission to determine the properties of the mysterious dark energy that is causing the expansion rate of the universe to speed up. Called the Advanced Dark Energy Physics Telescope, the mission promises to determine the precise location of 100-million galaxies. It would be the most comprehensive survey of the universe ever undertaken, according to team leader Charles L. Bennett, of the JHU Department of Physics and Astronomy. ADEPT also promises to discover about 1,000 new supernovae. ADEPT is "based on experimental breakthroughs that have occurred in just the last three years," Bennett said. "The (NASA) reviewers also recognized that the mission is practical, and that we have a top-notch and highly experienced team. We believe that ADEPT's results are likely to be of extraordinary importance to science." Dark energy is the term used to describe a new form of energy that is thought to permeate all of space. Unlike ordinary gravity, which is an attractive force, dark energy is repulsive. Cosmologists know something is driving an accelerated expansion of the universe - something that is acting like an anti-gravity force. Because this energy has never been directly seen and its identity is as yet unknown, it is called dark energy. "Is the physical nature of dark energy constant, or does it evolve with time?" Bennett asked. "To answer this question, we must look back in time, and for astronomers, that means looking at distant objects." The original discovery of dark energy came from observing a special kind of supernova. Astronomer and physicist Adam Riess, who also is a member of the ADEPT team, discovered dark energy in this way with his colleagues. "ADEPT will measure these supernovae, but its real advance lies in a new, more powerful technique," Bennett said. "Patterns in temperature of the very young universe provide a 'standard ruler' that is imprinted on the pattern of galaxies across the sky. ADEPT aims to map these through space and time." ADEPT promises to provide the galaxy positions needed to follow the historical development of the universe, so astronomers can determine the role played by the dark energy. Bennett said the ADEPT mission will help answer many questions about the role played by dark energy in both fundamental physics and cosmology. Community Email This Article Comment On This Article Related Links Stellar Chemistry, The Universe And All Within It Stellar Chemistry, The Universe And All Within It
![]() ![]() U.S. astronomers say a survey of galaxies observed along the sight lines to quasars and gamma-ray bursts creates a cosmic conundrum -- odd galaxy distribution. The survey revealed a puzzling inconsistency: Galaxies appear to be four times more common in the direction of gamma-ray bursts than in the direction of quasars. |
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