A neutron star is so dense that if an object was dropped from one meter above the star’s surface, it would hit the surface at a speed of 7.2 million km per hour
Neutron stars are small but extremely dense stars that form when a star goes supernova, but doesn’t have enough mass to become a black hole.
Besides black holes, these are the densest things in the universe. They can have diameters anywhere from 6-20 miles and have masses comparable to the size of the sun and often many times more.
The density of a neutron star is 1 quadrillion the times that of water.
A neutron star is so dense that one teaspoon of its material would have a mass over about 900 times the mass of the Great Pyramid of Giza.
Since gravity is related to mass, this means the gravity is extremely powerful. If an object were to fall from a height of one meter, it would only take one microsecond to hit the surface of the neutron star, and would do so at around 2000 kilometers per second, or 7.2 million kilometers per hour.
The temperature inside a newly formed neutron star is from around 1011 to 1012 kelvin, but that falls fast as the massive amounts of neutrinos emitted bring a lot of that energy with them. Within a few years it’s a mere 10^6 kelvin. For reference, that’s around the temperature of the sun.