Pulsars
A
pulsar
is a rapidly spinning neutron star that has a mechanism to beam light, much like a lighthouse.
This mechanism is only partially understood, but is connected with very strong magnetic fields
spinning with the star.
If the beam of the pulsar sweeps over the Earth as the neutron star rotates, the light from the pulsar
appears to pulse on and off. More than 550 pulsars are now
known, with periods ranging from seconds
to milliseconds.
The first pulsar was
found by Anthony Hewish and Jocelyn Bell at the Cambridge
radio astronomy observatory in 1967. The most famous pulsar was discovered shortly after that.
It lies in the
Crab Nebula
(M1), which is about 7000 light years away in the constellation Taurus
(see adjacent image).
The Crab Pulsar rotates about 30 times
a second, emitting a double
pulse in each rotation in the radio through gamma-ray spectrum.
The top right image catches the Crab Pulsar (in the yellow region in the center)
pulsing in X-rays.
