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 BurnellÂ
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 starsÂ – anything larger could not spin as fast.