What is a Pulsar?

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A huge star, several times bigger than our Sun, sometimes becomes so hot that it explodes and for a few days gives out as much energy as a whole galaxy would give, is called a Supernova.
Such a star is known to become a supernova. After a supernova explosion, all that is left is a very hot ball of matter, a few kilometers across. It spins at tremendous rate and sends out a beam of light and radio waves like a revolving searchlight.

The beam seems to 'pulse' on and off, so it is called a pulsar. Most pulsars are too faint to be seen except with a very large telescope, but they give out very powerful radio waves.

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