When a black hole is being created, why does a supernova explode instead of just imploding?

Question

I understand that a star uses up its energy and gravity takes over. But if the energy is used up, what is creating the massive energy of the explosion [which is apparently even more energy than the original hydrogen reaction] and also why would all of the star not simply bow to the will of gravity and implode all together instead of having particles explode outward contrary to the gravity pull?

Answer 1

well actually, a star both implodes AND explodes in a super nova. stars are in a constant battle. gravity trying to pull the gas in and nuclear energy trying to push it out. when a star collapses only some of the gas is pulled in by gravity, the rest is blasted out by the last remaining energy that was too great for gravity to hold back

Answer 2

The creation of a black hole has nothing in common with a supernova.

A supernova explosion is caused by the energy of the collapse rebounding from the iron core of the (collapsing) star which blows the star to smithereens in a matter of seconds. Not all the energy is used, but the lack of equilibrium between the outward nuclear pressure and the inward gravitation causes the collapse. Do not forget that e=mc^2 so there is a lot of energy still present even if the fuel for continued nuclear fusion is depleted sufficiently to trigger the collapse.

With a Black Hole, once something falls into a black hole beyond the event horizon nothing can escape. So, a BH simply cannot be compared to a star, from which energy, radiation and matter can all escape and does, with great violence.

Fusion is a slow nuclear process which can take millions if not billions of years to complete, but it ends in a second, which explains why the energy release is so powerful, as you noted.

Answer 3

The explosion occurs outside what eventually becomes the event horizon.  Therefore, it occurs outside the black hole:  if the matter has enough speed, it can still escape.

The definition of a black hole is simply linked to escape velocity (being greater than the speed of light).

Black holes do not "suck" everything around them (no more than any other object with the same mass).  

Even if our Sun were to be replaced by a black hole, as long as this black hole had the exact same mass as our sun, we would continue to orbit at the same distance, and at the same orbital speed.  It's just that things would get dark and cold for us, since even light could not escape from such an object.  No light = no heat.

The laws of gravity continue to work the same.  Our orbit would continue to work the same.

It is only when you get to the "event horizon" that gravity cannot be fought, not even by light.

Answer 4

first of all, when a star implodes, there is still a massive amount of energy left, just not enough to overcome gravity. Then as the star collapses, the rest of the energy is released in one big boom. Stars can burn for millions of years, so think how much energy would be released from the entire star exploding.

Answer 5

Well the star first implodes, then explodes.  When the fuel runs out, all that material falls back in at an incredible speed.  And with all that tonnage coming back like that, the pressure is so incredible, it generates the mother of thermonuclear explosions.  The nova.