Most supernova take a fraction of a second up to a couple seconds to explode. What we observe as the actual supernova is the light and energy that come out of that explosion. Typical supernova get brighter during the first 3 weeks or so after that very fast explosion.

A neutron star has a mass of about 1.4 times the mass of the sun, but is not much bigger than a small city, about 15 km in radius. A teaspoon of neutron star material would weigh about 10 million tons. The gravitational field is intense; the escape velocity is about 0.4 times the speed of light.

After puffing off its outer layers, the star collapses to form a very dense white dwarf. One teaspoon of material from a white dwarf would weigh up to 100 tonnes. Over billions of years, the white dwarf cools and becomes invisible. Stars heavier than eight times the mass of the Sun end their lives very suddenly.

Of course, no matter what type of black hole you fall into, you’re ultimately going to get torn apart by the extreme gravity. No material, especially fleshy human bodies, could survive intact. So once you pass beyond the edge of the event horizon, you’re done. There’s no getting out.

The closest that a black hole has to a surface is the event horizon, the location at which light can no longer escape, but this is not a solid surface that you can stand on.

seventy miles

The reason nothing can escape a black hole is because within the event horizon, space is curved to the point where all directions are actually pointing inside. The escape velocity from within a black hole’s event horizon is faster than the speed of light, hence light cannot go at that speed and thus cannot escape.