Is it a scientific possibility that the big bang of this universe was actually just the result of a big crunch before it and that there have been multiple big bangs before the last one, each time collapsing the same type of universe that we have now?
Posts: 6464 | Location: Grayson, Georgia, USA | Registered: 06-03-02
Yes, this is the Big Bounce hypothesis, generally associated with a theory known as Loop Quantum Gravity. Here are additional articles: Link 1 and Link 2.
In this model the universe contracts to a hot, dense state that is nonetheless not a point singularity, allowing a new universe to re-emerge from a new big bang. Each cycle may produce a universe with different properties than the previous one.
This is in the realm of pure speculation.
Posts: 1957 | Location: U.S. | Registered: 06-03-02
In the Wikipedia article, it mentions "infinite density." What does that mean? ********************************************************* 05-23-06, 12:10 AM Professor Nobody knows. When calculations based on a physical model yield mathematical infinities, it signals some kind of problem or deficiency with the model. For instance, quantum mechanics orginally gave rise to infinities in certain calculations that were later resolved by Feynman and others by refining the theory (renormalization) to make the infinities go away.
The big bang model of cosmology is well established by several lines of physical evidence, and remarkable progress has been made in extrapolating the cosmological picture further and further back in time to higher and higher densities, but "infinite density" at time-zero means there is a missing piece of the puzzle because it cannot correspond to physical reality.
05-23-06, 08:27 AM methos Professor is correct that infinities are a problem to be solved. The solution in this case seems to be a theory combining relativity and quantum mechanics - a theory of quantum gravity.
Physically, though, what would be meant by infinity density is a point in space without any volume, but with mass.
Relativity also predicts these points of infinite density at the center of black holes. A theory of quantum gravity should help us there, as well.
05-23-06, 06:44 PM jusork Thanks guys. Good information.
Would it be incorrect to compare the big bang to an explosion of any kind? So that maybe beings from the previous universe, living in a universe that followed the steady state theory, somehow caused the expansion with some kind of special explosion using their technology. (I'm writing a story. Wink) Just how special would this explosion have to be to cause an expansion of space and time? Maybe I'm just unclear about what an 'expansion of space and time' really means.
05-23-06, 11:25 PM gerry That might make a good story, but it is very unlikely. However, one of the hottest topics in cosmology stems from the increasing popularity of M-Theory (an offshoot of String Theory), whereby two parallel universes, existing in the higher order dimensions of spacetime, catostrophically collide. The result of the collision is, through implosion, to condense all matter and density and time into a single point which then 'explodes' in a "Big Bang"to spawn another universe, which expands and accelerates (like ours) , only to eventually collide again with another parallel universe and start the "Big Bang" process all over again in a never ending cycle of birth and death. It is even postulated by some that the mysterious "Dark Matter" may be the result of gravity waves travelling between our universe and the parallel universe that exists beside us in the higher order dimensions perhaps only a proton's width apart from us. Gravity waves are the only postulated waves that can transverse the higher order dimensions between universes (light cannot, so don't try to find it)!
05-24-06, 12:18 PM babthrower Hey, I think we're the other side of a black hole, myself. Why not? Nobody knows what the other side of a black hole looks like, right? And let's say there was another universe, maybe one of many, and it had a black hole, and tons of stuff became reduced to particles by the pressure, and reconstituted on this side, then we would have and 'event' and a subsequent expansion, as the pressure was reduced on the 'stuff'.
Cool or what? Cool To bad would could never prove it.
05-24-06, 03:10 PM gerry Either we're on the other side of a black hole , OR,.....this is even cooler still...we're INSIDE a black hole! FrownThink about it. Light cannot escape a black hole. Neither can light escape our universe. We're trapped forever in our own mother of a black hole! Black holes within black holes, and so on, to infinity.
05-24-06, 03:32 PM babthrower By George, I think you've got it! It explains why we're so dense! Razz
05-24-06, 04:49 PM jusork Yeah, I've been reading a little about the M-Theory, too. I might be able to use the universe existing in a higher order dimension of spacetime concept. The former universe inhabitants escape the collapsing universe and, eons later, resettle in this universe. Their former planet is left behind. But maybe somehow it could lives on in a separate universe...anyway, the result will have devestating consequences! Ooooo!
quote: Originally posted by babthrower: Hey, I think we're the other side of a black hole, myself. Why not? Nobody knows what the other side of a black hole looks like, right? And let's say there was another universe, maybe one of many, and it had a black hole, and tons of stuff became reduced to particles by the pressure, and reconstituted on this side, then we would have and 'event' and a subsequent expansion, as the pressure was reduced on the 'stuff'.
So then the question is, what's on the real other side of a black hole. Eek Hmmm.
05-24-06, 05:29 PM methos "The other side of a black hole" is a frequent plot device in sci-fi, but has only slightly more grounding than faster than light travel.
05-26-06, 11:01 PM gerry
quote: Originally posted by methos: Professor is correct that infinities are a problem to be solved. The solution in this case seems to be a theory combining relativity and quantum mechanics - a theory of quantum gravity.
Physically, though, what would be meant by infinity density is a point in space without any volume, but with mass.
Relativity also predicts these points of infinite density at the center of black holes. A theory of quantum gravity should help us there, as well.
Do you think that a theory of quantum gravity will therfore unlock the secret of the 'zero' as well as the secret of the 'infinite'? I am talking zero and infinity in the physical sense within our universe, not the mathematical definition. I don't believe the physical zero or infinity can ever be proven to exist without such a theory. It may all boil down to what is going on within the tiny tiny tiny units of the Planck length and Planck time, which at present is a total unknown. For sample, as I advance my pointer finger slowly toward a wall, I can never actually touch it! if I did, then I could define a specific point of time when my finger is zero units from the wall. I can come within the Planck length of it only (more accurately, perhaps, I should call this the Minkowskian Planck spacetime interval). I only think I am touching the wall...but that's just the electromagnetic force acting in its finest split second. The absence of a physical zero also rules out the Singularity. As for infinity, who can imagine an infinite Universe...one that is unbounded (flat or open curved)and without end, which some cosmologists say is the fate of our universe....expanding to the infinite and ultimately void of all matter....hey, wait a Planck second...i think i've got it! Nothing at all occupying Infinite space...I can deal with that! Now everything occupying no space....zero and infinity are one and the same? Your comments are welcome.
05-27-06, 11:52 AM methos Prefaced by the admission that I'm speaking largely from ignorance, I'll answer yes and explain to the best of my knowledge. The infinities of black holes and the origin of the universe both result from a finite mass packed into zero space. Heisenberg's uncertainty principle, an integral part of quantum mechanics, doesn't seem to allow zero space to exist. A fusion of relativity and quantum mechanics would presumably solve the problem of infinities by packing the finite mass into some non-zero space. The densities, although enormous, would then be finite.
05-27-06, 09:52 PM gerry
quote: Originally posted by methos: .. The infinities of black holes and the origin of the universe both result from a finite mass packed into zero space...
That is an enormously profound statement. There's something mighty strange going on where 'near infinity' and 'near zero' meet. Is it not the Heisenberg Uncertainty Principle that allows matter to be created from nothing at all?
05-27-06, 11:50 PM Professor Given so many reciprocal relationships in physics, zero and infinity go hand in hand in many contexts (such as already described for volume and density). Remember that a quantity may be labeled "finite" only if it is neither infinite nor infinitesimal.
The term "singularity" is borrowed from mathematics to describe points where functions or their derivatives are undefined even though neighboring points are well behaved. In physics when it is used to describe the center of a black hole, the big-bang universe extrapolated back to time-zero, etc., it's nothing more than shorthand for a breakdown of theory. That's what I meant above when I said that "nobody knows" what infinite density means.
I quite agree that if we can develop a way to reconcile gravitation and quantum theory to yield a "theory of everything", then we may no longer need to speak of singularities in a physical context.
This message has been edited. Last edited by: DorianGreyed,
Posts: 6464 | Location: Grayson, Georgia, USA | Registered: 06-03-02
We have limited view, We see what is inside our Universe. And not all of that.
We know there are what is called Black holes, (poor wording) For it is just mass great enough to even prevent light from escaping it’s gravitational pull. And they continue to grow, Getting stronger with a greater reach around itself.
Sooner or later two of these will attract each other. And the Speed they come together, and the Solid hit as they are not able to fragment the other black hole will result in what could well be called a Big Bang II, Or maybe it was Big Bang XII that started this Universe as we see it.
As they collided, There would still be Matter being attracted by both coming in at high speeds, Resulting in effects on the Matter from the Collision or Altering a even scattering of the Matter of the Collision.
It would also result in a new part of expansion, with Matter older in it, then the time the collision happened, Like we have Suns dated older then our date for the Big Bang.
Big Bang just has Matter exploding and expanding, with no reason why it would, if it had just been there all along. Two Black hole masses would cause that, and reason for it.
Ken
Posts: 466 | Location: Ilion NY | Registered: 04-18-07
Theory predicts that as the [supermassive] black holes draw near, they kick out the surrounding stars in their neighborhood, which initially provided the braking power to bring them together. Merritt believes that when the distance between the black holes shrinks to about the size of the solar system, they start to radiate away energy as gravity waves. This then brings the black holes closer and closer, causing them to spin faster and faster, until they eventually collide in an enormous burst of gravitational radiation.
If two black holes collide, they will merge to form a bigger black hole. Two black holes may exist within each other's gravitational field without anything special happening. They have to come very close to each other for the black hole effects to become apparent, and then they'll merge!
Apparently there is no reason to expect a new Big Bang to occur every time black holes collide.
Posts: 1957 | Location: U.S. | Registered: 06-03-02
Ken, your comments seem to indicate that you believe black holes cannot lose mass. They actually are basically evaporating constantly through Hawking radiation.
Hawking showed that quantum effects allow black holes to emit exact black body radiation, which is the average thermal radiation emitted by an idealized thermal source known as a black body. The radiation is as if it is emitted by a black body of temperature which is related (inverse proportional) to the black hole mass.
so black holes are actually "dark brown"!
From the same article:
quote:
A...simplified view is that vacuum fluctuations cause a particle-antiparticle pair to appear close to the event horizon of a black hole. One of the pair falls into the black hole whilst the other escapes. In order to preserve total energy, the particle which fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process the black hole loses mass, and to an outside observer it would appear that the black hole has just emitted a particle.
As methos pointed out way earlier, we are lacking a good theory that unites quantum effects with gravity, so many details remain sketchy.
Posts: 1957 | Location: U.S. | Registered: 06-03-02
It's interesting that we turn to mathematics in order to model events in the world-of-the-inconceivably-small, and then we take it where the math leads.
It's as if the math has now assumed control, and determines the nature of our external reality.
So if there is an infinity symbol in the formula, and we can't lead from that statement to one that will allow us to cancel out the infinity symbol, then we must ask ourselves, "What would that infinity-symbol represent (in the real world)?"
This is very strange. It seems to imply we are somehow the creators of the reality we perceive.
So physics expands to include metaphysics. The metaphysics from which it descended four hundred years ago. Like Orobourus, sort of.
Posts: 6256 | Location: British Columbia, Canada | Registered: 06-11-02
Too deep for me, Babs -- I never heard of Orobourus.
There's nothing new about mathematics leading the way to a successful physical theory. That's the inductive part -- based on mathematical intuition and the search for symmetry and simplicity. "God's equations" must be elegant. Thereafter the theory lives or dies depending on its correspondence with observed reality.
One thing that makes the adventure of working in our field particularly rewarding, especially in attempting to improve the theory, is that... a chief criterion for the selection of a correct hypothesis... seems to be the criterion of beauty, simplicity, or elegance. --Murray Gell-Mann (1929- ) U. S. Physicist (Nobel Prize, 1969) "Particles and Principles" (source)
As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality. --Albert Einstein
Posts: 1957 | Location: U.S. | Registered: 06-03-02
No, it's not deep at all, Perf. It's sort of like the story told by the chemist Kekule. He said he had a dream about a snake biting its own tail (orobouros) after he had been trying long and hard to find out the structure of the benzene molecule. Benzene did take the form of a hexagon with a carbon and hydrogen atom at each of its six points.
But my point is that in mathematics, because it is a language that allows us to use symbols and make transformations according to a set of rules which we make up, then when these transformations lead to surprising or seemingly impossible statements, I wonder upon what basis we can safely conclude that these statements describe reality.
Posts: 6256 | Location: British Columbia, Canada | Registered: 06-11-02
I knew the Kekule story, but I didn't realize the self-eating snake has a name and carries an ancient pedigree!
You said, "...then when these transformations lead to surprising or seemingly impossible statements, I wonder upon what basis we can safely conclude that these statements describe reality."
Surprising -- OK. Seemingly impossible -- not OK.
In the latter case (infinite values, violations of causality, things not equal to themselves, etc.) you have to carefully re-examine all the assumptions in the mathematical or logical chain of reasoning to find the error -- if any (the twin paradox of special relativity was once regarded as a logical flaw -- until it turned out to be actually true!).
But no, physics does not devolve into metaphysics because theorists working with mathematical models realize that it's all in the speculative realm until experiments can be devised to test the predictions of the model. String theories, at the cutting edge of theoretical physics and cosmology, presently yield no results that are testable in laboratories or observatories -- the scales of distance (small) and energy (large) are out of reach by present-day technologies. A hypothesis alone is not science, and none of the theorists pretends that it is.
I am optimistic that, sooner or later, a breakthrough will occur to bring us closer to a "final theory."
Posts: 1957 | Location: U.S. | Registered: 06-03-02
But no, physics does not devolve into metaphysics because theorists working with mathematical models realize that it's all in the speculative realm until experiments can be devised to test the predictions of the model. String theories, at the cutting edge of theoretical physics and cosmology, presently yield no results that are testable in laboratories or observatories -- the scales of distance (small) and energy (large) are out of reach by present-day technologies. A hypothesis alone is not science, and none of the theorists pretends that it is.
Excellently stated.
Posts: 6256 | Location: British Columbia, Canada | Registered: 06-11-02
Negative Energy. I have no problem with there being what that Should be. But Energy with a reverse polarity isn’t it. Particle and anti-particle, or Matter and Anti-Matter have problems. They are both forms of Energy.
Negative Energy to be really that, Would have to be a Mass below Absolute Zero. So it would absorb energy which is above Absolute Zero in whatever form. Which would eliminate an equal amount of the below Zero mass and have Nothing remaining.
Where, when Matter and Anti-Matter interact, Energy is released showing they are just forms of energy.
If a Black hole is Mass, Below Absolute Zero, Then it will absorb all the energy it can till It has eliminated itself, or all the Energy and Matter around it. Which ever has the greater proportion.
As far as a Black Hole vaporizing? Not if it is a Mass of common Matter.
That is making Gravity self destructive. It draws till it becomes so strong it eliminates it’s own strength.
Hawking radiation? I do not believe anything written in Crayola. That is double talk going around in a circle. Heat goes to the point where if it is generated faster then the Surrounding can absorb the heat, Then it converts to Light, Light has to have the same limitations and have it convert to Matter, Light is fast, But generating it faster then the speed can carry it away has to result in it converting to another form.
Ken
Posts: 466 | Location: Ilion NY | Registered: 04-18-07
Thereafter the theory lives or dies depending on its correspondence with observed reality.
