One sugar cube of neutron star matter would weigh about 1 billion tons on Earth, NASA says. The fastest known one spins 43,000 times a minute.
One sugar cube of neutron star material would weigh about 1 trillion kilograms, or 1 billion tons, on Earth. That is "about as much as a mountain," NASA says.
That is what happens when a star with up to twice the mass of the Sun is crushed into a ball about 20 km across, roughly the size of a city.
How a neutron star forms
When a star about eight times larger than the Sun runs out of fuel, its core collapses and it explodes as a supernova. What is left behind is a neutron star, the most dense object known, NASA's Imagine the Universe! page says.
Neutron stars are the densest material we can directly observe. Black holes are hidden behind their event horizons, so we cannot see what goes on inside them.
They spin like blender blades
Most neutron stars are seen as pulsars. Their beams of light sweep past Earth as they turn, so we see them flash on and off like a lighthouse.
- 43,000 times a minute: the spin of the fastest known pulsar, PSR J1748-2446ad. That is about 717 times a second (our math), twice as fast as a typical household blender, NASA says.
- Better than atomic clocks: over weeks, months or longer, pulsars pulse with more accuracy than an atomic clock.
The numbers
- 1 billion tons: one sugar cube of neutron star material, on Earth.
- 20 km: about how wide a neutron star is.
- 2 times: the most mass, compared with the Sun, a neutron star holds.
