From a theoretical standpoint, a pulsar is a highly compact and dense celestial object that emits regular pulses of electromagnetic radiation. It is a type of neutron star, which is formed when a massive star undergoes a supernova explosion.
Pulsars are composed primarily of neutrons, densely packed together due to the extreme gravitational forces. They typically have a mass between 1.4 and 3 times that of the Sun but are compressed into a size of only about 10 to 20 kilometers in diameter. This extreme density gives rise to their unique properties.
The regular pulses emitted by pulsars are caused by their rapid rotation. As the pulsar spins, beams of radiation are emitted from its magnetic poles. These beams are not aligned with the rotational axis, so as the pulsar rotates, the beams sweep across space like a cosmic lighthouse, leading to periodic pulses of radiation that can be detected by telescopes on Earth.
The pulsar's rotation can be incredibly fast, ranging from milliseconds to a few seconds per revolution. This rapid rotation gives rise to highly precise pulse periods, making pulsars valuable tools for studying fundamental physics, testing theories of gravity, and exploring the properties of matter in extreme conditions.
Pulsars are observed across different parts of the electromagnetic spectrum, including radio waves, visible light, X-rays, and gamma rays. They have provided valuable insights into astrophysics, general relativity, and our understanding of stellar evolution and the behavior of matter under extreme conditions.