Sunday, March 13, 2011

Breakdancers and Pulsars

Puslars: All pulsars are neutron stars. A pulsar can be distinguished because the Earth is in its beam of radiation that sweeps across as the neutron star (its a pulsar now) rotates.

Why does this happen?
When the star was formed (we are talking about right at the beginning of the star's life), there was rotation in the dust cloud as it compressed together. This rotation is conserved due to the conservation of momentum.

As a star collapses, it spins faster and faster - in the same way a breakdancer does a faster headspin by pushing his legs up higher and bringing his arms together.


But neutron stars are way cooler because their magnetic field increases as they spin faster. Squish the Earth into a pea and the magnetic field lines would be very close. This accelerates charged particles which emit EM radiation (Radio to X ray) in a fine beam along the lines of the poles.

If these "beams" are not in line with the axis of rotation of the neutron star, the radation pulsates (aha! Puls-ar) like a lighhouse! If the light house sweeps across the Earth we can detect these radio waves or X rays!


What will you get you the marks in the Exam:
1.) Neutron star rotates rapidly and has a large magnetic field
2.) Charged particles accelerated due to large magnetic field
3.) Produces directed beams of EM radiation 


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