Word: pulsars
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Dates: during 1960-1969
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Most scientists believe that pulsars emit their pulses by spinning rapidly. The time between pulses has been believed to be constant, but Drake has found that it is increasing very slightly. The energy the pulsar loses in rotation is given off as radiation; the energy loss of a pulsar is 100,000 times the energy loss...
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...
...electronic device that made 12,000 separate light-intensity measurements every second. They quickly discovered that the starlight increased to a peak about 30 times per second, a variation too rapid to be detected by the human eye. The flashes corresponded exactly to the radio pulses from the Crab pulsar, strongly suggesting that the target was indeed the pulsar. Unlike an earlier and apparently erroneous sighting of a flashing pulsar (TIME, May 31), this discovery was confirmed by the McDonald Observatory in Texas and Arizona's Kitt Peak National Observatory...
Astronomers do not yet know why the Crab pulsar flashes, but some suspect that its bursts of light are generated by charged particles in its intense magnetic field. Now that they have seen the light, scientists are attempting to take a clear spectrograph of the pulsar and to determine if the light itself is polarized. They are investigating a new report by astronomers at an observatory on Malta, who saw strange "ghost" flashes about 3° to either side of both the Crab pulsar and another nearby pulsar. With these new clues, scientists hope to be able to learn more...