How Is a Pulsar Formed?

Creation

• A pulsar forms after a giant star runs out of fuel and explodes in a supernova. Leftover mass contracts and is compacted into a much denser form. It rotates faster than when it was a star because of conservation of angular momentum; this is similar to how a figure skater spins faster when she draws her arms closer to her body.

Discovery

• Pulsars were discovered in 1967 by University of Cambridge graduate student Jocelyn Bell Burnell. The pulsar's signals were initially thought to be evidence of extraterrestrial intelligence because of their regularity, and according to Bell Burnell, she called her discovery "LGM," or "Little Green Men," until the source of the signal was determined to be naturally occurring.

Features

• A pulsar's signals come from its intense magnetic field, which causes it to emit electromagnetic radiation from its north and south magnetic poles. If the pulsar rotates in such a way that the poles face Earth, then we see the rotation much as a ship at sea does a lighthouse: blinking on and off.

Fate

• Aside from their rotation, pulsars are exactly the same as neutron stars and, over time, that rotation will slow and eventually cease. When this happens, a pulsar then becomes a more common, non-rotating, neutron star.

Fun Fact

• Perhaps the most well-known pulsar is the one inside the Crab Nebula. According to NASA, it was formed during the famous supernova seen on Earth in 1054 A.D. and rotates roughly 30 times per second.