Word: pulsars
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...months since British astronomers announced the discovery of pulsars, scientists have done a brilliant detective job of piecing together the nature of the strange, regularly beeping radio sources. Their effort has been all the more remarkable because they have never actually seen a pulsar; all of their clues come from radio signals picked up by giant radio telescopes...
...avenue of investigation has opened in the skies. Three University of Arizona astronomers have spotted a visible star that is located precisely where radio telescopes had detected a pulsar and is flashing at a rate identical to the pulsar's beeps. In all likelihood, they say, the flashing star is actually a pulsar...
Good Reasons. In setting out to make a visual sighting of a pulsar, Astronomers John Cocke, Michael Disney and Donald Taylor defied the beliefs of more experienced astronomers who were certain that the strange objects would be too small and distant to be seen through terrestrial telescopes. Undaunted, they pointed the 36-in. telescope at Arizona's Steward Observatory toward a small star in the Crab nebula, the glowing, cloudlike remnant of a supernova (stellar explosion) that was first witnessed from earth...
...Arizona astronomers had three good reasons for picking their target: 1) most scientists now believe that pulsars are neutron stars, small and incredibly dense spheres that are residues of exploded stars like the one that formed the Crab nebula; 2) a pulsar had recently been detected in the Crab by radio telescopes and 3) the Crab pulsar, or neutron star, beeps faster than any discovered to date. Thus it is presumably younger, hotter and brighter, and could be seen more easily than any other...
...first inkling that pulsars might not be reliable timepieces came after Cornell University astronomers at Arecibo, Puerto Rico, trained their 1,000-ft. radio telescope on a newly discovered pulsar in the Crab Nebula, the glowing remnant of a supernova-or stellar explosion-that was seen from earth in A.D. 1054. Unlike most other pulsars, which have relatively low repetition rates (between one and four per second), the new find was ticking about 30 times per second. Carefully measuring the pulse rate in October and then again in November, the astronomers found that it was slowing down by about...