Lost Space

摘要

The amount of energy collected from space by all the radio telescopes ever used to explore the sky would not light a single lightbulb. This fact, oft stated by radio astronomers, points out the Achilles' heel of their endeavor. Radio astronomy tracks cosmic events by tuning into weak radio waves that identify the molecules in stars and other celestial bodies. Stronger signals, either from space or earthly sources, can easily overwhelm even the most sophisticated radio telescopes. Today, the sky buzzes with the signals of cell telephones, television and radio broadcasts, military radar, air-traffic-control chatter, and satellites involved in communications, navigation, and meteorology.