As everyone knows, nothing can come out of a black hole and at it's centre there is a SINGULARITY.
Also, well known is that the Universe started as a SINGULARITY and just after breakfast, there was a Big Bang.
Now a four year old child could spot a problem at this point, but just in case you haven't got one to hand, I will spell it out.
Obviously, if all of the Universe was infinitely small, then it must have been the most massive black hole possible.
Therefore nothing could possibly come out of it,
Yet, here we are, for better or (more likely) worse.

Scientists who study these things have known about a snag with the two great theories, Quantum Mechanics and General Relativity for some time.
For very massive things, the theory Gravity in General Relativity is applicable (it's about 100 years old this year).
For very small things, Quantum Mechanics is applicable, probably the most accurate theory ever devised.
Gravity is so weak, it is not noticeable for tiny things such as protons, so is ignored in Quantum Mechanics.
Quantum Mechanics actually applies to all things, but it's effects are only noticeable at the sub-atomic scale.
However, a Singularity is by definition very small and very massive, so both theories are applicable.
It is very likely that there are billions of black holes in the Universe and therefore lots of Singularities to bother us.
Unfortunately, the two great theories have not been combined. They are so different, they just don't get on.
People have tried, but the calculations lead to infinitely silly answers with lots of infinities, which can't exist in reality.
What we need is new data and a new Einstein to think of a brand new theory that works at all scales.
Remember, it was new data that made people question Newton's theories and Einstein picked up the ball and scored.
One idea to consider is the ballerina and roundabout theory (this is just a brain storming diversion).
When a ballerina pulls in her arms, she spins faster (it's a simple mechanical principle).
In theory, her rotational velocity could reach infinity if she were able to become a singularity, but other effects stop it happening.
In particular, particles will tend to fly off , like children on a playground roundabout.
When matter enters a black hole, it's nearly always at an angle, so rotates around the centre.
As it approaches the centre, the ballerina effect increases the velocity, but perhaps it never reaches the centre for the other reason.
So the very centre may be empty, or to be more specific, has no mass, therefore no gravitational pull and no Singularity.
Imagine drilling a hole to the centre of the earth. As you go deeper, the gravity increases until you get near the centre.
At the centre, you'd be pulled in all directions, so would feel no net gravity, just like in a black hole (perhaps).

Discuss.

Ted, a wonderful topic.

But who said we were living in reality

The Big Bang but even more so what existed before this event is a truly interesting discussion.

Some think that our universe came into being from a mass (a wave of energy say) that became so dense and heavy that at one point it simply dropped off from it (like a raindrop from a cloud)

Were this to be the case then clearly time existed before us and it maybe that there are many many Universes out there dating back to who knows when?

Time maybe the most curious thing of all!

As for Black Holes, again, truly amazing things!
It is said that there's one at the centre of every Galaxy & they obviously have a purpose, the energy giving the power to spiral them around it?
As we advance might we one day figure them out? might we one day set foot inside them and if so what will we discover? is it as you say completely empty? does it lead somewhere?

Now i know "Interstellar" is a piece of Science Fiction but i actually found the ending with the black hole a fun gimmick (it may well be impossible) but it was interesting if nothing else.
Maybe there is a Libray of Time in there for each Galaxy

We know very little but it won't stop us trying to learn...I think we're going to find things are far stranger than we ever invisaged.

Great start to this thread Ted, Thanks.

Hi Ted, a great topic In fact according to current theory, Hawking radiation can escape from a black hole and accordingly it is possible for a black hole to evaporate.
In terms of the size of the black hole, it becomes infinitely dense and infinitely small at the point of singularity and this is where the current theories of physics no longer apply, physics can not deal with infinities it seems.

I would like to believe that the singularity is in fact a big bang, creating another Universe, a black hole is like the Big bang in reverse, so why not go all the way and have it create a new one

Gravity and it's marriage to the other 3 forces is indeed a real problem and there is for sure a Noble prize waiting for the brain or brains that manage this union or "Grand unified Theory" Who knows it could be one of the LM founder backers

For me one of the big challenges we ( Mankind) face is one of Energy and it seems amazing that such large amounts of energy can be found stored in something like a black hole, just waiting to be tapped. I wonder what a black hole energy collector would look like and how it might work? time will tell ---- excuse the pun.

chris perkins wrote: Hi Ted, a great topic In fact according to current theory, Hawking radiation can escape from a black hole and accordingly it is possible for a black hole to evaporate.

Good point Chris. But to be picky - isn't Hawking Radiation accelerated particles from just outside the event horizon? Hence, has it really escaped?

Discuss

I think you are right Stefan, it is the energy from the Black hole that is depleted by the process of the photon creation as the virtual particle falls into the black hole and hence the evaporation, for sure I don't really understand the process, but there again I don't suppose many do
So is a Black hole really black?

Discuss

I thought that the Universe was creating space as it expanded, so nothing is leaving the initial singularity?