by A.C.B. Lovell, O.B.E., F.R.S., Professor of Radio Astronomy in the University of Manchester and Director of the Jodrell Bank Experimental Station.

For three centuries after Galileo the growth of astronomical knowledge was associated with the use of bigger and better telescopes. But even the largest optical telescope has its limitations. It cannot give the astronomer all the information he seeks.
Out of the technical developments stimulated by the last world war have come two new and exciting instruments of astronomical research. They are the artificial satellite and the radio telescope. From his study of the radio waves which reach the earth from outer space, the radio astronomer is now adding new and sometimes unexpected features to our picture of the universe.

Next week: Astronomy and the State
These lectures will be printed in 'The Listener'