Why do pulsars pulse?

Answer: Neutron stars rotate with beams

Neutron stars rotate with beams ✓ — Correct! Pulsars are rapidly rotating neutron stars (collapsed star cores, ~20km diameter). They have powerful magnetic fields with radiation beams emitted from magnetic poles (not aligned with rotation axis). As the star rotates (milliseconds to seconds per rotation), beams sweep across space like lighthouse. When beam points at Earth, we detect a pulse. Incredibly precise—used for testing relativity, detecting gravitational waves!

Magnetic fields oscillate naturally — Wrong. Magnetic fields are strong but don't oscillate to create pulses. Pulses come from rotation—beams sweep past Earth as neutron star spins.

Gravitational waves create pulses — Wrong. Gravitational waves don't cause pulses (though pulsars help detect them!). Pulses result from rotating neutron star's beamed radiation sweeping past Earth.