Unraveling the Big Bang Question: Escaping the Gravitational Pull of Black Holes

[Bill Minerick]

By definition, the gravitational force associated with a black hole precludes anything, even energy, from escaping once inside the event horizon, hence the name. If all of the matter and energy which exist in the Universe today were supposedly once contained within a space no bigger than a proton wouldn't that equate to a single enormous black hole? How did the Universe escape from it?

 

[Alex48674]

I think that has something to do with the theory that once matter is at a certain density (80% Plank) it has the ability to repel, which would then allow the universe to expand. I'm not sure though, and I'm very new to this stuff so I'd wait for someone else to reply, but there's my 2 cents. I'm not sure if those definitions and statements are exactly right that you said, but I'll wait for someone else to say so.

 

[marcus]

By definition, the gravitational force associated with a black hole precludes anything, even energy, from escaping once inside the event horizon, hence the name. If all of thewouldn't that equate to a single enormous black hole?

No, because the universe was expanding.

I don't accept that modern cosmology says "all matter and energy which exist in the Universe today were supposedly once contained within a space no bigger than a proton ".

Expansion may have started with a considerably larger, or even an infinite, volume. What you say sounds like a popularization or a misconception to me. But this doesn't matter. Density was in any case extremely high at start of expansion, according to pretty much any model.

How did the Universe escape from it?

A very high density region that is not expanding will collapse, and the formula for the Schwarzschild radius which you may know about does apply in that case.

But if the region is expanding it is a whole other ball game.

So there is no problem about the Universe "escaping" from its initial high density state.

Expansion was roaring along at an almost inconceivable rate at that point.
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what I am telling you is just what you get when you take a model based on our best law of gravity (Gen Rel) and fitting the observational data, and run it back in time.

The classical model only goes back to right after expansion began and doesn't explain how it started. Some recent quantum models go back to before expansion began and explain how it could have gotten started.

We don't know yet what the right model is of the very early universe and the start of expansion. Some do a pretty good job of explaining but they need to be tested. I'm in a kind of wait and see mode, myself.

But certainly what you are worried about is a non-problem. Any model we use says the Hubble parameter was huge enough at early times to completely overwhelm any tendency to make a black hole

 

[Golfer]

Thermodynamics, gravity, etc

By definition, the gravitational force associated with a black hole precludes anything, even energy, from escaping once inside the event horizon, hence the name. If all of the matter and energy which exist in the Universe today were supposedly once contained within a space no bigger than a proton wouldn't that equate to a single enormous black hole? How did the Universe escape from it?

The definition is correct BUT the situation for the Big Bang is different than the normal formation of a black hole. Consider the possibility that the universe could collapse. The black hole created in this collapse do not collapse to an infinitely small diameter. The second law of thermodynamics requires that as more matter is added to a black hole it gets BIGGER not smaller. Thus the situation at the Big Bang cannot be obtained.

However, the Big Bang expansion implies that the initial entropy was larger than that required for a black hole of the same diamter. Thus expansion would take place to reach this thermodynamic equilibrium. Also at Big Bang starting dimensions Einstein's theory of gravity has a replusive part related to the energy. This would force an expansion. Third, inflation theory would cause expansion due to the negative pressure involved.

The question is: Are these effects enough to drive the expanding universe past the corresponding black hole diameter. As far as I know, this is not known.

 

[marcus]

...

The question is: Are these effects enough to drive the expanding universe past the corresponding black hole diameter. As far as I know, this is not known.

I don't understand what you are asking, Golfer.
What do you think "the corresponding black hole diameter" is?

What universe distance do you think should be compared to that? Do you have an estimate of the diameter of the universe?

 

[Eric DMC]

By definition, the gravitational force associated with a black hole precludes anything, even energy, from escaping once inside the event horizon, hence the name. If all of the matter and energy which exist in the Universe today were supposedly once contained within a space no bigger than a proton wouldn't that equate to a single enormous black hole? How did the Universe escape from it?

That is a great question, it got me to ponder!
From what I understand that is the problem with the Big Bang Theory, its called the Singularity. Our universe laws did not exist; therefore we cannot explain why it happened.

Although I seam to remember reading about M theory having to do with the Singularity but I don’t remember much of the details.

 

[marcus]

If all of the matter and energy which exist in the Universe today were supposedly once contained within a space no bigger than a proton wouldn't that equate to a single enormous black hole? ...

Just to be clear I'll repeat. No.
It would not "equate to a single enormous black hole".

There are a bunch of different solutions to the equation of GR which involve very high density. The black hole solution is just one, and it can't accommodate rapid expansion.

You can think of it intuitively like this (Wallace correct me if I'm wrong here) expansion at the rate that must have prevailed initially would *tear apart* any black hole that tried to form, before it could even start collapsing.

According to standard expansion cosmology (the Big Bang, in pop-talk) it doesn't make sense to equate the initial conditions at the start of expansion with a black hole.
(However in quantum cosmology, the possibility does tentatively arise that the expansion of our spacetime was preceded by gravitational collapse in a prior region---quantum gravity allows for gravity to reverse at very high density and cause a "bounce". I am not talking about quantum cosmology here, just the standard picture.)

 

[MeJennifer]

A very high density region that is not expanding will collapse, and the formula for the Schwarzschild radius which you may know about does apply in that case.

One cannot simply stitch Schwarzschild-deSitter solutions for high density regions inside a FRW model.

 

[marcus]

One cannot simply stitch Schwarzschild-deSitter solutions for high density regions inside a FRW model.

Thanks Jennifer, that is certainly correct! And it supplies further justification for what I was trying to get across. We have been thru this several times already. simply because the "big bang" early universe contains very dense regions does not mean it contains black holes or is contained in a black hole.

However to be fair to the original poster, in the non-expanding case, a region with sufficiently high density WILL collapse. He's got that part right .
It is just that you can't insert that into the FRW picture of the early universe.

 

[wolram]

We lack the single most important fact to have any idea if any model of cosmology works, a physical measurement, in my opinion cosmology is just hand waving without one.

 

[Chronos]

Early universe models do not behave 'classically'. Inflation has no observational parallels in our current universe. The laws of physics may not have been fully emergent in the 'beginning' allowing events not currently permitted.

 

[wolram]

Early universe models do not behave 'classically'. Inflation has no observational parallels in our current universe. The laws of physics may not have been fully emergent in the 'beginning' allowing events not currently permitted.

And the lady with the bulging shopping trolley beats you to the single item isle, quantity is no substitute for quality.

 

[jal]

me no notin.
smart people rite paper … I find … I read … I put here for you …
https://www.physicsforums.com/blogs/jal-58039/can-the-universe-fit-into-the-cmb-1215/
you smart …read … think … find anser … go scool … rite paper …
I find your paper … put with oders

 

[Chronos]

Your point escaped me, wolram.

 

[Wallace]

And me. I'm not sure if you missed the last 80 years of physical measurements in cosmology!

 

[Golfer]

Not the early universe

It is obvious that the gist of my question was not clear. I am talking about the expansion of the universe reversing and compacting. This compaction should result in the 'mother of all black holes' which is probably much larger than original volume of the early universe. Once all matter is collected in this black hole, will there be a rebound?

 

[Eric DMC]

It is obvious that the gist of my question was not clear. I am talking about the expansion of the universe reversing and compacting. This compaction should result in the 'mother of all black holes' which is probably much larger than original volume of the early universe. Once all matter is collected in this black hole, will there be a rebound?

Sorry for the confusion, So far there is no evidence "I know of" for the Big Crunch. The universe is expanding at a increasing rate! If there is enough matter in the Universe eventually gravitaional forces will stop its expansion. When this happens gravity will cause the universe to reverse its direction and begin to collapse under its own weight. This phase of the Universe's life is known as the Big Crunch.
Eventually all of the matter in the Universe will collapse into a super dense state and possibly even collapse into an unimaginably massive black hole. Some theorize that the Universe could collapse into the same state that it began as and then blow up in another Big Bang. In this way the Universe would last forever but would continually go through these phases of expansion and contraction, Big Bang and Big Crunch and so on...

 

[Blueprint]

Yup, that's how I see the universe, on a continual cycle of Bangs and Crunches.

Maybe each time it happened more matter was converted from energy to get to what it is today, a lonnggg expansion that only just gets to contract?

 

[Golfer]

new physics

Both of the above comments imply that the black hole would [suddenly] expand and disappear. What is the physics for such an occurrence?

 

[Blueprint]

I read there's no point one can consider the centre of the universe. The Big Bang started from a singularity of infinite density, right?

Maybe once it reaches a critical mass, i.e. all the matter in the universe, gravity (or another force) becomes repulsive. Feel free to enlighten me :)

One thing I'd like to know, is how the maths cope with zero mass particles and infinite properties.

 

[Blueprint]

Golfer - apparently its the time-reversed argument of Penrose's theorum on gravitational collapse leading to a singularity... thing is.. the universe was so small at this point its very quantum physics related as opposed to general theory of relativity.

 

[Golfer]

Any paper on the subject

Blueprint

Do you know of any papers on this subject?

 

[Eric DMC]

No one knows or can explain in anyway how the Big Bang occurred. We can explain up to 1,000,000 of a second after the Big Bang "some crazy number like that" but what caused the Big Bang is completely unknown because the universes fundamental laws break down, this is called the Singularity. This is way I don’t believe that universe was a black hole, if our laws brake down, then gravity would not be a governing force, not saying its impossible, just not my personal opinion. If this kind of stuff interest you, then you should get the book Hyperspace by Michio Kaku. It is really a great read!

 

[MeJennifer]

the universes fundamental laws break down, this is called the Singularity

There is not such thing as the breaking down of the fundamental laws of the universe.

Scientists make theories and come up with what they call laws. Those man-made laws can indeed break down but that is due to the theory not due to nature.

By the way the term "law" is a misnomer IMHO, nature does not follow or break laws.

 

[Chronos]

Perhaps 'nature' has its own way of setting the plate, jennifer. I like the way you think, but not your conclusions.

 

[wolram]

And me. I'm not sure if you missed the last 80 years of physical measurements in cosmology!

There is no physical measurement, all you do measure is light travel with some other near distant calculations thrown in, AFAIK the only real measurement is to the moon.

 

[terminal_man]

By definition, the gravitational force associated with a black hole precludes anything, even energy, from escaping once inside the event horizon,

The problem you face is that this "definition' is correct only for things within this Universe.
We cannot measure what is possible outside the Universe because we cannot go there.

The Big Bang occurred, and is continuing to occur, 'out there' beyond the known Universe and may not, almost certainly is not, constrained by the same rules. If at some point the Universal expansion is reversed, the shrinking Universe will carry with it the rules that we know, and what happens next (illogical construct really, because 'next' refers to time and time only exists within the Universe) is beyond our ability to understand.

 

[terminal_man]

If all of the matter and energy which exist in the Universe today were supposedly once contained within a space no bigger than a proton

Actually, thinking more deeply on the problem it gets more weird.

For, as i understand the physics, Matter as we know it (like time) is also a product of this Universe and therefore did not exist prior to the Big Bang. indeed i understand it didn't start to exist until some time after the Big Bang, being built from Energy.

Also all the Energy we measure and refer to is based upon physical concepts of the Universe, and therefore can have no meaningful concept of existence without a Physical Universe against which to measure it.

So the idea that all the matter and energy were contained in anything is probably spurious. what existed, if that is the right word to use in regard to a non-space/non-time environment, was the potential for matter and energy.

Some event then triggered a change which resulted in the development of that potential into first energy and then matter.

From this let me postulate:

• The one Universal constant of time is change, for without change you cannot measure time;
• Conversely any change must include a measure of time, for without time there cannot be a 'before the change' or an 'after the change';
• So if prior to the Big Bang all was static and unchanging, because there was no time;
• Is the nature of the Big Bang Time Itself?

Of course, I'm probably the 10,000 person in the world to postulate this and the others probably did it better with lots of supporting formulas, but at least i know i didn't read it in a book.

 

[Blueprint]

... If at some point the Universal expansion is reversed, the shrinking Universe will carry with it the rules that we know...

Mankind can only exist in an expanding universe to ask the question, why is the universe expanding? In a shrinking universe, time runs backwards, i.e. you would die, live your life, then be born, so life cannot exist as I understand it. There is no life during the crunch phase of Friedmann's model.

Or maybe its just like matter and antimatter, opposites but essentially the same, time running the opposite way is just time, so life would still live its life in the right order.

I don't think time is born from energy Terminal, the way i saw it was the universe expanded into a canvas of pre-existing spacetime, a universe that is both finite but has no boundary.

 

[terminal_man]

...time is born from energy ...the universe expanded into a canvas of pre-existing spacetime, a universe that is both finite but has no boundary.

Actually (Dyni) i was arguing the Universe was created by time, and energy came into existence with the creation of the Universe, however minor point.

As for the pre-existence of spacetime, no that is quite contrary to the physics. Both time and space are the measure of the Universe, neither can exist outside of A Universe. It was the fact that time did not exist before the Big Bang that lead Hawking to call his ubiquitous book about Universal Physics "A Brief History of Time".

I'll look up the section in it where he explains that and send you the quote.

As for the concept of if we could exist in a Crunch, we really don't know that we aren't. Fundamentally, our perception of time is limited by our inability to get outside it and look in. So we 'think' the Universe is expanding because that's the way we see it, but another observer may have the opposite opinion.

(Strangely one of the Arthurian myths, had this concept in it, as at one point it was purported that Merlin 'lived his life backwards' having been born toward the end of time and growing older as the world got younger, hence his ability to predict the future.)

Marts.