Pulsars: Cosmic Lighthouses Spinning in Space

Learn how rapidly rotating neutron stars create extremely regular pulses that can act like cosmic clocks.

What is a pulsar?

A pulsar is a rotating neutron star that emits beams of radiation from regions near its magnetic poles. If one of those beams sweeps across Earth, we detect a pulse each time the star rotates.

How neutron stars form

When a massive star exhausts its nuclear fuel, its core can collapse during a supernova. The remaining core may become a neutron star: a compact object containing roughly stellar-scale mass in a city-sized volume.

Why the pulses are regular

Neutron stars can rotate very quickly and maintain stable spin rates. Some pulsars rotate many times per second. Their regular signals make them among the most precise natural clocks known.

What pulsars are used for

Astronomers use pulsars to test gravity, study interstellar matter and investigate extreme physics. Networks of very stable pulsars are also used to search for long-wavelength gravitational waves.

Why they are fascinating

Pulsars combine intense gravity, strong magnetic fields and rapid rotation. They show how matter behaves under conditions that cannot be reproduced on Earth.