 | Anisotropy in the cosmic microwave background radiation. |
Since 1964, when cosmic microwave background radiation was first discovered, scientists have searched the skies for evidence of temperature variations that might reflect the origins of the universe. In 1977, a team led by astrophysicist George Smoot of Lawrence Berkeley National Laboratory reported the first measurements of temperature variations in the microwave sky, but this irregularity was attributed to the motion of the Earth's galaxy in space. Smoot and colleagues already had begun developing a highly sensitive radiometer for detecting ancient microwaves, and it finally was launched aboard a satellite in 1989. Since then, Lawrence Berkeley scientists have used radiometers and powerful computers and algorithms to observe hot and cold ripples in the microwave radiation afterglow of the Big Bang. Today, this anisotropy is thought to be the primordial seed from which, over billions of years, the galaxies and large structures of the present-day universe grew.
Scientific Impact: The temperature and size of the spots detected are in agreement with theories suggesting that up to 90 percent of the universe consists of mysterious "dark matter," the existence of which is inferred only because its gravity influences the motion of ordinary matter. Understanding of microwave background radiation, when combined with the eventual discovery of dark matter, will unify physics on the largest and smallest scales, fusing together the fields of cosmology and particle physics.
Social Impact: The patterns observed in microwave sky are like footprints left by the Earth's ancestors 15 billion years ago, only these footprints are gravitational effects. Thus, this work expands human understanding of how the universe evolved and contributes to science education.
Reference: "Structure in the COBE DMR First Year Maps," G.F. Smoot et al., Astrophys. J. 396:L1-L5 (1992).
URL: http://www.nersc.gov/research/annrep98/smoot.html
Technical Contact: Dr. George Smoot, gfsmoot@lbl.gov
Press Contact: Jeff Sherwood, DOE Office of Public Affairs, 202-586-5806
SC-Funding Office: Office of High Energy and Nuclear Physics
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