would help distinguish these approaches—and confirm or disprove the theory itself.

One critical source of information would be provided by new observations of the CMB’s profile. From the time of Penzias and Wilson until the end of the 1980s, the only features known about that radiation were its average temperature, spectral distribution, and overall isotropy. Experiments also accounted for a small discrepancy in the radiation’s temperature in opposite directions of the sky due to Doppler shifting caused by the Milky Way’s motion through space. Researchers, though, believed that a more precise examination would yield evidence for the seeds of structure formation in the universe. These seeds would be minute anisotropies due to slight differences in the early distribution of matter. Because inflationary theorists aspired to explain the process of structure formation in terms of stretched-out quantum fluctuations, they hoped such anisotropies would soon be found. Conversely, if no such bumps existed, advocates of any variation of the Big Bang model would have a hard time explaining how galaxies and other structures emerged.

CRINKLES IN THE FABRIC

On November 18, 1989, NASA launched the Cosmic Background Explorer (COBE) satellite, designed to take an unprecedented look at the primordial radiation bathing the cosmos. It carried several instruments, including a differential microwave radiometer, able to discern anisotropies in the background spectrum as tiny as a few parts per million. A team led by George Smoot of Lawrence Berkeley Laboratories (LBL) analyzed and interpreted the data. Physicists nervously awaited the experiment’s results. Would it confirm the Big Bang picture of a fiery beginning? Would it detect the minute raisins in the tapioca pudding of uniformity?

Tension mounted as months passed by with no wrinkles to be



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