pulzár

A pulzar is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed as pulses of radiation at regular intervals when a beam sweeps across our line of sight, much like a lighthouse. Pulsars are a type of neutron star, the incredibly dense remnants of a massive star that has exploded as a supernova.

Neutron stars are incredibly dense, packing more mass than the Sun into a sphere only about 20 kilometers (12 miles) in diameter. Their rapid rotation and strong magnetic fields are key to their pulsed emission. As the neutron star spins, its magnetic field lines rotate with it. Charged particles are accelerated along these field lines, producing intense beams of radiation.

The term "pulsar" was coined by Jocelyn Bell Burnell and Antony Hewish in 1967. They initially detected regular radio pulses that were so precise they jokingly referred to them as "LGMs" (little green men). The period of the pulses can range from milliseconds to several seconds, depending on the pulsar. The shorter the pulse period, the faster the neutron star is rotating.

Pulsars are valuable tools for astronomers. By studying the precise timing of their pulses, scientists can test theories of gravity, probe the interstellar medium, and even search for gravitational waves. Some pulsars are found in binary systems, where their orbital motion can be extremely accurately measured, providing sensitive tests of Einstein's theory of general relativity.