When a star much bigger than the Sun runs out of fuel, it can collapse into a neutron star - a ball about the width of a small city but packed with more mass than the Sun. If that dead star is also spinning and shooting beams of radio waves from its magnetic poles, we see those beams flash past Earth like a lighthouse. We call it a pulsar.
Most pulsars blink slowly, maybe once a second. But some of them have a partner star nearby, and over millions of years they steal gas from the partner. That gas spins them up, like pushing a merry-go-round. The fastest one we’ve ever found, called PSR J1748-2446ad, completes 716 full rotations every single second. That’s faster than the blades of a kitchen blender, on an object the size of a city.
A spoonful of neutron star material would weigh about a billion tons on Earth. And the surface at the equator of the fastest pulsar is racing along at nearly a quarter of the speed of light. Somewhere in our galaxy right now, a tiny dead star is spinning hundreds of times faster than the second hand of your kitchen clock ticks once.
