Though there have been so many claims and counter claims but the first pulsar was discovered in 1967, quite accidentally, by Anthony Hewish and his co-workers notable, Miss J. Bell, at Cambridge. Hewish and his fellow workers were engaged in studying interplanetary scintillation exhibited by radio sources of small angular size (usually less than 1” of arc) with a new radio telescope at Cambridge operating at a frequency of 81.5 MHz, that was set for the purpose. It is known that changes inter planetary scintillation, when a radio source is observed at various angles with respect to the Sun, give information about the angular size of such source. While carrying out the program, Hewish and his co-workers came across an invisible object in the sky emitting sharp pulses of radio waves at exactly spaced intervals of time. Careful search revealed soon after, the presence of a few more such objects in the sky. They were subsequently given the name pulsar, of which the first to be discovered was Cp 1919 (meaning Cambridge pulsar at R.A. 19th 19m). So exact was the periodicity of emitted pulses from these objects that some astronomers could not resist the temptation of thinking that these pulses might possibly be-transmitted into space by intelligent beings on other planetary systems.
Keywords: Pulsar, Black holes, Neutron star.
Dr. Shobha Lal