Neutron Stars by the Numbers

Neutron stars push the limits of physics in every way:

• They pack 1.4 to 2 solar masses into a sphere just 20 kilometers across
• A sugar cube of the material would weigh 1 billion tons
• The fastest pulsars rotate 716 times per second
• Magnetars have magnetic fields a quadrillion times stronger than Earth's

These objects sit right at the boundary between matter as we know it and the total gravitational collapse of a black hole. Add slightly more mass to a neutron star and it crosses that threshold forever.