Radio Astronomy

The availability of radio telescopes has made possible a number of exciting discoveries about our own solar system, about galaxies, about star-like objects, and about the interstellar medium. The solar system discoveries are based on the fact that the planets and their satellites do not emit visible light themselves (they only reflect visible light), although they do emit radio waves. Thus, astronomers can collect information about the planets using radio telescopes that was unavailable to them with optical telescopes.

As an example, astronomers at the Naval Research Laboratory decided in 1955 to look for radio waves in the direction of the planet Venus. They discovered the presence of such waves and found them considerably more intense than had been predicted earlier. The intensity of the radio waves emitted by the planet allowed astronomers to make an estimate of its surface temperature, in excess of 600°F (316°C).

At about the same time as the Venus studies were being carried out, radio waves from the planet Jupiter were also discovered. Astronomers found that the planet emits different types of radio radiation, some consisting of short wavelengths produced continuously from the planet's surface and some consisting of longer wavelengths emitted in short bursts from the surface.