Stellar remnants · Collapsed stellar core
Neutron star
Nearest ~400 light-years · Light crosses it in 73 millionths of a second
- Across
- 22 km
- Vs Earth
- 0.17% of Earth
- Mass
- 1.4 Suns
Open Neutron star in Cosmic Scale
About
When a star far heavier than the Sun runs out of fuel, its core collapses in about a second and the rest of the star explodes as a supernova. What is left is a neutron star: roughly one and a half times the mass of the Sun squeezed into a ball the size of a city, held up only by the pressure of neutrons packed shoulder to shoulder.
A teaspoon of neutron-star matter would weigh about a billion tonnes on Earth.
At a glance
| Typical mass | 1.4 Suns |
|---|---|
| Density | ~10¹⁷ kg per m³ |
| Fastest spin | 716 turns a second |
| First found | 1967, as a pulsar |
Did you know
- A sugar cube of neutron-star material would weigh about as much as Mount Everest.
- Its surface gravity is around 200 billion times Earth's; falling one metre would take you to a tenth of the speed of light.
- Many sweep beams of radio waves around like lighthouses. We call those pulsars, and they keep time as well as atomic clocks.
Simulations
- Pulsar — How a dead star becomes a cosmic lighthouse
- A massive star explodes — How a star many times heavier than the Sun collapses and blows itself apart
- Two neutron stars collide — How two dead stars collide, forge gold, and were both heard and seen from Earth 130 million years later
- Magnetar — The strongest magnets known, and the day one flashed across the galaxy
- Dyson swarm — Catching a whole star's light: how a civilization could build it, and how it would look