Science
What is a pulsar?
A pulsar is a rapidly spinning neutron star that beams radiation from its magnetic poles. As it spins, the beam sweeps past Earth like a lighthouse, so we detect regular pulses — sometimes hundreds per second — of incredibly precise timing.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains a pulsar.
Key things to understand
- 1It's a fast-spinning, highly magnetized neutron star.
- 2It emits beams of radiation from its magnetic poles.
- 3As it rotates, the beam sweeps past us, creating pulses.
- 4The pulses are astonishingly regular, like cosmic clocks.
- 5Some spin hundreds of times per second.
Frequently asked questions
- Why does a pulsar pulse?
- Its radiation beams sweep around as it spins; each time a beam points at Earth we detect a pulse, like a rotating lighthouse.
- How regular are pulsar pulses?
- Extremely — some rival atomic clocks in precision, which is why pulsars are used to test physics and even for navigation concepts.
- Is a pulsar the same as a neutron star?
- A pulsar is a neutron star that happens to beam radiation our way as it spins; not all neutron stars appear as pulsars to us.