What is Radio Astronomy?
The fact that radio waves are arriving on earth and can be detected and studied, was first recognized by K.G. Jansky in 1932. He was working at the Bell Laboratories in New Jersey, U.S.A. and exploring radio-frequency-disturbances in the atmosphere. During his work he realized that some of the noises his instruments were picking up were coming from outer space. He observed a steady arrival of 14.6-m waves from a certain fixed direction in space. The maximum intensity was received from the direction of the center of the Milky Way – our own spiral galaxy of stars.
This discovery led to a new branch of astronomy – radio astronomy. By using sophisticated special types of antennae different radiations are picked up. Some of these are thermal radiations – the radiations that any heated body emits in radia frequency waves. Scientists have done radio studies of the moon, sun and many other objects that are found in space.
Scientists also send signals in the outer space towards objects like the moon and the meteors which are reflected back to the earth and are then studied.
Radio waves are similar to light waves but have bigger wavelength. Radio waves easily penetrate the opaque planetary atmosphere and interstellar dust clouds. But they cannot penetrate the optically transparent ionized gases enveloping the sun and other stars.
Powerful radio telescopes can detect signals from almost trillions of miles away places. Scientists believe that if there is life somewhere in the outer space, and if someone wants to tell others of their existence, they would probably send some signals which could be understood by us.