Since the first pulsar's discovery in 1967 by Jocelyn Bell and Anthony Hewish at Cambridge Observatory, astrophysicists have gained much more information on these unusual objects. Over seven hundred have since been found, many by our group here in Princeton, leading to substantially better understanding of the underlying physics.
Upon supernova, stars sometimes crush their cores into neutron stars which carry enormous magnetic fields and angular momenta. These fields exceed the earth's by a factor of around 1012, and they rotate about once per second despite having masses exceeding that of the sun! Such powerful electrodynamics produces beams of radio waves, which sweep across earth's observatories once per pulsar rotation. This produces a fascinating periodic signal which we observe and study--a pulsar.
A pulsar may have a binary companion. As this fellow star ages, it may swell over its Roche Lobe, causing it to slowly transfer revolving material to the pulsar. This causes the pulsar to rotate even faster, and some pulsars we study actually rotate hundreds of times per second!
This field is a rich one, with plenty of opportunity for better understanding of underlying pulse generation. Pulsar physics also provides insight into other branches of physics. For instance, because pulsars have so much mass and angular momentum, their pulses occur at extremely precise intervals; in fact, this stability provides several tests of subtle general relativistic effects.
If you want to learn more about pulsars, read the leaflet on pulsars from the Royal Greenwich Observatory. For a more in-depth look try the tutorial at Jodrell Bank Observatory. Or, if you have questions, feel feel free to mail us.
- Pulsar Physics
What's a Pulsar?
DM -- Distance