Black Holes continued...

Delving deeper into black holes after my last post, I think I'll need to add a few points here.

Black holes are formed not when the whole star has a mass of 1.44 solar masses. That is the mass of the collapsed core alone. The Chandrashekhar limit (1.44 Solar Masses) is just the limit beyond which the exclusion principle cannot support the core and it collapses.

Here's what actually happens.

If the mass of the star is 24 solar masses (henceforth, I'll refer to it as Msun) or less, about 7/8ths of it is blown away by the explosion. The core suffers the original gravity of the star made much worse by its existing radius. So it collapses. Now there are three possible endings for this sort of stellar death.

1) White dwarf:

This is a type of star that is extremely hot, and extremely dense. White dwarf stars have from 0.8 Msuns up to 1.44 Msuns. When its parents star is about to die, it expands into a Red Giant, blows off its outer layers, and collapses into this beauty. Like I said, extremely dense. A teaspoon of white dwarf material can weigh upto 5 tons on earth! Gravitational force on this star can crush you into a pancake in less than a second.
Unfortunately, they haven't got the pressure required to initiate nuclear fusion. So even though they may live for a long long time, they'll run out of heat eventually, and die.

2) Neutron star:

This is what results when a White Dwarf star has more than 1.44 Msuns, but less than 3 Msuns. These are born pretty much the same way. But because of the intense Gravitational force, even the atoms are squeezed together. The electrons combine with the protons in the nucleus to form neutrons. Now, the entire star is composed of just atomic nuclei composed almost entirely of neutrons. This is very dense, and by very, I mean very. A teaspoon of this stuff can weigh a million tons on earth. That's VERY VERY heavy.
Neutron stars live on almost forever. The curvature of space-time created by Neutron stars is second to only black holes.

3)Black Holes:

When a stellar core has a mass of more than 3 Msuns, it turns into the ultimate cosmic mystery; a black hole. Now I've explained about black holes already, so I won't go into much detail, but all in all, at the event horizon, the curvature is so strong that time actually stops. Even light cannot escape the gravity of this monster.
Needless to say, a teaspoon of this substance on Earth would literally swallow it up, along with half the Solar System. So don't try bringing a black hole to Earth.

Black holes don't live forever, but they come very very close. This is because of a type of radiation called 'Hawking Radiation'. More detail on this subject will be in the next post. But according to this theory, black holes constantly emit radiation. In the end, this radiation reduces that mass of the black hole to so low that it crossed the Chandrasekhar limit on the way down. Once it's less than 1.44 Msuns, it does not need to be contained in the centre, and explodes in a magnificent display. If Sagittarius A* (that's Milky Way's very own black hole) explodes, we won't need the Sun. It'll be so bright, it'll be 'day' even at night.