If the satellite reaches its planned orbit aboard a Delta rocket, the so-called Cosmic Background Explorer (COBE) is designed to probe for local variations in the background microwave radio hiss that seems to come from every corner of the sky. Although the observations of the three instruments on board—averaged over a year of readings—may turn Out to be bland, that blandness will be very challenging because of the problem of accounting for something so smooth in a universe that is lumpy.
This radio noise is thought to be a now-cool signal from once-hot matter on the very edge of the visible universe, a signal that has taken virtually the entire life of the universe to reach us.
In the view of physicists like Philip Morrison of MIT, the signals from matter that are receding from us at nearly the speed of light represent an event at least 10 billion years...