Millisecond Pulsars

Some pulsars spin at extraordinary rates. Millisecond pulsars rotate hundreds of times per second, faster than a kitchen blender. They reach these speeds through a process called spin-up, in which material transferred from a companion star deposits angular momentum onto the neutron star over millions of years.

Millisecond pulsars are so stable that they rival atomic clocks in timekeeping precision. A network of them across the galaxy forms a Pulsar Timing Array capable of detecting gravitational waves at frequencies too low for instruments like LIGO. In 2023, multiple pulsar timing arrays announced evidence for a gravitational wave background permeating the universe.