A pulsar is a neutron star that spins very fast. These stars are incredibly dense, like a cosmic lighthouse. They shoot out strong beams of energy from their magnetic poles. We only see these beams when they sweep past Earth. This makes pulsars appear to blink on and off regularly. Every pulsar has a super precise and steady pulse interval. These pulses usually last from milliseconds to a few seconds.
Astronomers use pulsars as accurate natural clocks. Some pulsars found were even more precise than atomic clocks. The first planets outside our solar system were discovered orbiting a pulsar. Jocelyn Bell spotted the first pulsar signals in 1967. She was using a new radio telescope to analyze data. She first thought the signals might be from "little green men." But soon, other pulsars were found, showing they were natural. This discovery confirmed ideas about neutron stars, born from exploding stars.
