Actually, there was SN1987A in the Large Magellanic Cloud (and, if Wikipedia is right, there was a supernova observed in 1604 that occurred in the Milky Way itself) but with the advances that have occurred in technologies used for astronomy as well as the science itself since that time, this is a significant event, no doubt.

A thought occurred in my head. If the said star was a Red Super-massive or a Blue Super-massive and it collapsed into a supernova. Is it possible that we might see the birth of a black hole? If we observe this enough we possibly might learn about the center of black holes and how they form? This brings up questions such as what happens in-between the periods of time at the end of the supernova and the beginning of a black hole? Am I correct in asking these questions or are these questions answered and nobody gave me the damn memo?

OK, so we manage to find out what happens between Death and Rebirth it just doesn't make sense to me. A star has a core with a bunch of atoms smashing each other with a fusion fuel system. Then suddenly Iron forms because all these atoms been smashing for T/B/Millions of years and then suddenly all that energy gets sucked in and the sudden explosion because of the immense gravity. All that energy converts to pure energy and it goes everywhere. Then a Black Hole forms. That just makes no sense. Do I have the wrong info and if I do please try and explain. Thank you again!

Emperor, think of it this way, a star for most of its life is in equilibrium. The energy output of the sun equals the force of gravity, that is, energy is trying to escape and gravity is trying to pull it back. As it ages the fusion reactions slowly changes from mostly hydrogen then to mostly helium then eventually iron. As the primary fusion materials grow in size and weight, the more energy is required to fuse the atoms. When the iron fusions are at a specific percentage, I'm not sure what the exact number is, the star will compress the core. During the core collapse, there is an outbound shockwave which creates the supernova blast. This shockwave travels through the rest of the gas and dust which then ignites in a secondary fusion reaction, this is the supernova blast. The minimum star size that can collapse into a black hole is 20 solar mass or 20 times the mass of the sun. The sun is a little less than a million miles wide, a 20 solar mass star is about 20 million miles wide. When the core collapses the black hole would be about 1.5 million miles wide. When gravity reaches the strength to prevent light escaping, then physics we know begins to fall apart. Atoms that we know are crunched to the point that protons, neutrons and electrons lose their meanings and become indistinguishable. A wonderful place.

So Khai, you have to think of it in terms of pressures. For example. When hydrogen is being fused together to helium it releases some energy. The actual process is somewhat more complicated but we'll stick with the basics to illustrate the point. After some time all of the hydrogen is fused in particular layers of the star. When the star runs out of hydrogen to fuse, the gravitational pressure from matter above those layers causes the layer in question to have a higher temperature and therefore higher pressure. That higher temperature causes the atoms to be moving at much higher speeds. These higher speeds allow the helium nuclear to collide together at a higher velocity. This energy level requirement generally goes up with heavier elements. So now your star is converting helium to heavier elements and releasing energy in the process. This energy release creates a pressure to counteract the energy/pressure of gravity thereby stabilizing the star. This process continues with heavier and heavier elements being fused together.

Now, you eventually get to a point where fusion into even heavier elements actually requires more energy than what goes into it. So now your fusion energy goes away. You're only left with the gravitational energy of the material. This creates intense pressure at the center of the star. Depending on the size of the star, this pressure may actually be large enough to overcome the degeneracy pressure of electrons. Basically, in quantum mechanics two electrons can't occupy the same orbital at the same time. I won't go into details of this but it basically means your electrons can't be compressed any further and still be electrons.

If your pressure is higher than the electron degeneracy pressure, it becomes energetically favorable for the electrons to merge with the protons to create neutrons. This process produces neutrons, some elementary particles and neutrinos. Now, neutrons take up far less space than electrons. The standard example is if you had a grain of sand, the electrons would be in a cloud the size of a room. So, your star which was originally held up through electron degeneracy pressure, now collapses even further and heats up even more.

Neutrinos don't react well with matter so they can escape the collapsing star rather easily. These neutrinos carry away energy from the star further accelerating the collapse.

Now, here's what we have. We have this massive collapse of several solar masses (alot of matter) into a much smaller point. When that matter hits this point, it hits solid neutrons. These neutrons can't be compacted any further so the falling matter hitting the neutron core causes a massive shockwave. Imagine a bank vault falling from a skyscrapper hitting the ground. A rather large shockwave is produced that travels outward. Same thing for your star, except now your matter is traveling at around 20% of the speed of light (about 60 Million meters per second). So this shockwave is very intense.

Now, as this shock-wave is occurring, the temperature of the star increases to about 10^5 times that of normal. This causes the further release of neutrinos carrying energy away from the star, about 10^46 joules of energy. A very very big energy release. Now, the interesting part is that the shock-wave reabsorbs about 10^44 joules of energy. This process isn't fully understood. It could be interactions of neutrinos with the collapsing matter. But, basically this re-absorption of energy is large enough to cause the explosion we observe.

What happens next really depends on the amount of matter left. If the amount of matter is below a certain point, this start because a very very dense neutron star. The neutron degeneracy pressure is strong enough to counter the gravitational pressure. If there is more matter left, the degeneracy pressure of nuetrons is overcome and the star further collapses into a black hole. As of yet, physicist don't know of any pressure capable of preventing the further collapse.

Now, this is one method a super nova occurs (type II). There are other version of supernovas know as Type 1a, b and c. Type Ia one occurs with a carbon and oxygen white dwarf. This star accumulates matter to become more massive and have a larger gravitational pressure than what electron degeracy pressure can counteract. Right before conversion to a nuetron star, the carbon and oxygen undergo fusion at a very very rapid pace. Within seconds a large amount of material in the star undergoes fusion releasing enough energy to unbind star. This most likely will not become a black hole afterwards due to the small amount of mass left.

Doggy - personal interest or do you work in the field? I've been thinking on the effect of the space curvature within the black hole and whether this would cause a collapse in the space from three dimensional down to two and possibly one dimension. After reading the article on the big bang starting out as one dimensional space, a whole new perspective opened up for me when it comes to thinking about space. I'm not to any point of believing or disbelieving that article yet. Any thoughts?

This happened when your Great X20 grandfather screwed my Great X20 grandmother ya bastard! :-]

Sorry Khai, my people were nowhere near your people. I think we were still trying to to figure out how to keep our hovels from sinking into the peat bogs in Ireland. :-0

I think my Great X20 Grandfather was more romantically inclined towards sheep. :-)

Thinking of Ewe, if you know what I mean, wink, wink, nudge, nudge.

No you guys had a great empire until your X18 invented beer and playboy. The rest went downhill from there. My uncle Kublai told us as children all about you guys. LOL thats a pretty large amount of guilt on your hands there!