What is a Pulsar?

It is predicted that supernovae triggered by stars that do not have enough mass for their cores to form black holes will result in neutron stars.

Neutron stars are small (about 20km across), rotate rapidly and are incredibly dense. They are mostly made of neutrons that formed as electrons combined with protons in the atomic nuclei of the dying stars’ collapsing cores. Their powerful magnetic fields lead to radio pulses that can be detected on the Earth each time they rotate. These objects are known as pulsars when the pulses can be detected on the Earth.1

History

The British astronomer Jocelyn Bell Burnell discovered pulsars while completing her PhD at Cambridge University in the late 1960s. Using a radio telescope designed by her adviser Anthony Hewish and Martin Ryle (both men later shared a Nobel prize for their work), Bell Burnell found strange radio pulses coming from a single point in the sky.

After a period of confusion about what was causing the pulses, Bell Burnell and her colleagues confirmed that pulsars, as the sources of pulses came to be known, are emitted by rapidly spinning neutron stars.2

Known Pulsars

The Vela Pulsar (watch here)

The Crab Pulsar

47 Tucanae

Bonus: Pulsar Sounds (Listen Here)

1 http://www.bbc.co.uk/science/space/universe/sights/pulsars

2 http://www.bbc.co.uk/science/space/universe/scientists/jocelyn_bell_burnell