As a result, the system requires 13 sets of sophisticated data acquisition systems, one for each beam, which were largely developed and built by the UK group. It has already added more than 580 new pulsars to the nearly 800 known when the survey began about three years ago. A pulsar is the collapsed core of a massive star that has ended its life in a supernova explosion. Weighing more than our Sun, yet only 20 kilometres across, these incredibly dense objects produce beams of radio waves which sweep round the sky like a lighthouse, often hundreds of times a second. Radio telescopes receive a regular train of pulses as the beam repeatedly crosses the Earth so the objects are observed as a pulsating radio signal.
Pulsars make exceptional clocks, which enable a number of unique astronomical experiments.
Very precise timing observations of systems in which a pulsar is in orbit around another neutron star have been able to prove the existence of gravitational radiation as predicted by Albert Einstein and have provided very sensitive tests of his theory of General Relativity - the theory of gravitation which supplanted that of Isaac Newton.