Pulsar Facts



  • A pulsar is a neutron star that spins rapidly, beaming out regular pulses of radio waves — rather like an invisible cosmic lighthouse.
  • The first pulsar was detected by a Cambridge astronomer called Jocelyn Bell Burnell in 1967.
  • At first astronomers thought the regular pulses might be signals from aliens, and pulsars were jokingly called LGMs (short for Little Green Men).
  • Most pulsars send their radio pulse about once a second. The slowest pulse only every four seconds and the fastest every 1.6 milliseconds.
  • The pulse rate of a pulsar slows down as it gets older.
  • The Crab pulsar slows by a millionth each day.
  • More than 650 pulsars are now known, but there may be 100,000 active in our galaxy.
  • Pulsars probably result from a supernova explosion — that is why most are found in the flat disc of the Milky Way, where supernovae occur.
  • Pulsars are not found in the same place as supernovae because they form after the debris from the explosion has spread into space.
  • We know they come from tiny neutron stars often less than 10 km across, because they pulse so fast.
  • The Crab nebula contains a pulsar also known as NP0532. It is the youngest pulsar yet discovered and it probably formed after the supernova explosion seen in the Crab nebula in AD 1054. It has a rotation period of 76 0.0331 seconds, but it is gradually slowing down.