Pulsar
A pulsar is a type of neutron star that emits beams of radiation from its magnetic poles. As the star rotates rapidly, these beams sweep across space like a lighthouse beam, creating regular pulses of radiation that can be detected from Earth.
Discovery and Characteristics
The first pulsars were discovered in 1967 by radio astronomers Jocelyn Bell and Antony Hewish. Initially thought to be signals from extraterrestrial civilizations, they were soon identified as rapidly rotating neutron stars.
Pulsars rotate extremely quickly, from once every few seconds to hundreds of times per second. The fastest known pulsar rotates 716 times per second.
How Pulsars Work
Pulsars have intense magnetic fields that accelerate charged particles near the star’s surface. These particles emit radiation, particularly in radio wavelengths, along the magnetic field lines. The radiation is beamed out in narrow cones from the magnetic poles.
As the neutron star rotates, these beams sweep across Earth periodically, creating the characteristic pulsing effect.
Types and Importance
- Rotation-powered Pulsars: The most common type, powered by the star’s rotation
- Millisecond Pulsars: Very old pulsars that have been spun up by accreting matter
- X-ray Pulsars: Emit primarily X-rays, often in binary systems
Pulsars are used as precise cosmic clocks for testing theories of gravity and detecting gravitational waves. They also help astronomers measure distances and study the interstellar medium.