Pulsar

space · neutron stars · cosmic lighthouses · astronomy

Spinning lighthouse. A pulsar is a neutron star, which is the leftover core of a star that exploded. It spins incredibly fast and shoots beams of radiation out from its magnetic poles, like a lighthouse beam sweeping across the ocean.

Super precise timing. Pulsars send out pulses of light at exact, regular intervals that can range from just a few milliseconds to a couple of seconds apart. These pulses are so regular that scientists can use them to measure time more accurately than almost any clock.

Extremely dense. A neutron star is packed so tightly that a chunk of it the size of a sugar cube would weigh as much as a mountain on Earth. All that density in such a small space makes pulsars one of the densest objects in the universe.

Only visible sometimes. We can only see a pulsar's light when one of its beams points directly at Earth. If the beam misses us, the pulsar is invisible, even though it's still there spinning and flashing away.

Cosmic mystery sources. Scientists think pulsars might be one source of ultra-high-energy cosmic rays, which are some of the most powerful and mysterious rays that zoom through space.