Pulsars is a celestial object, thought to be a rapidly rotating neutron star,
that emits regular pulses of radio waves and other electromagnetic radiation
at rates of up to one thousand pulses per second.

  • a pulsar is a neutron star that spins rapidly, beaming out regular pulses of radio waves.
  • the first pulsar was detected by Cambridge astronomer, Jocelyn Bell Burnell.

Jocelyn Bell Burnell 
Born: 15th July 1943, Lurgan, North Ireland

  • at first, astronomers though the regular pulses might be signals from aliens, and pulsars were jokingly called LGMs (Little Green Men)
  • most pulsars send their radio pulse about once a second -the slowest pulse only every eight seconds, and the fastest every 1.4 milliseconds.
  • as it gets older, the pulse rate of a pulsar slows down.
  • the Messier 1, Crab pulsar slows by a millionth of a second a day.

This picture shows a time sequence for the pulsar in the Crab nebula,
shown in context against an image, also taken with the Kitt Peak 4-meter Mayall telescope.

In USA, the Arizona Kitt Peak 4-meter (158 inch) Mayall telescope
was one of the largest optical telescope in the world.

  • more than 1,500 pulsars are now known, but there may be 100,00 active in the Milky Way.
  • pulsars probably result from a supernova explosion – that is why most are found in flat disc of the Milky Way, where supernove occur.
  • pulsars are not found in the same place as supernove because they form after the debris from the explosion had spend into space.
  • with such rapid pulses, pulsars must be tiny neutron stars  – anything larger could not spin as fast.


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