Black Holes - Big Bang?

[Iron4ever]

If Black holes exist at the centre of Galaxies, and Supermassive Blackholes or Quasars eventually envelop all the surrounding stars and planetary bodies around it, will the Black Holes over time devour each other creating a singular supermassive Black Hole?

If so , at the point were there is only 1 black hole in the universe and all the mass in the universe is swallowed up by this black hole, would you then get another Big Bang, Creating a whole new universe all over again?

[OpenMind5]

I find it hard to believe that a black hole could cover an infinite universe. But you never know.

 

Op5

[Iron4ever]

Maybe. If the universe is constantly expanding today there could reach a point where it starts to contract. If this is true i believe it is feasable for Back holes to colide and eventually become one.

[infamous]

would you then get another Big Bang, Creating a whole new universe all over again?

Welcome to Hypography Iron4ever, the physics related to these questions is unknown at this time and may remain that way for a very long time. Right now it is impossible for us to know the nature of existence within a black hole. Weather there exists a point where this material will ever again be ejected back into the universe is not known. The only theory relative to this event would be Hawkins radiation which defines this process as a very very slow evaporation of the black hole because of virtual particle formation at the event horizon. No known physical theory exists at present to explain the phenomenon your describing.

[Jay-qu]

It has been discussed under another topic that black holes can acctually evapourate due to Hawking radiation coming out of black holes the smaller a black hole the more radiation it emits... so over a long long time the process accelerates and the black hole can theoretically evapourate to nothing...

[damocles]

http://casa.colorado.edu/~ajsh/hawk.html

 

Hypermass singularities distributed across our space/time expand volumetrically away from each other at the same rate that other categories of mass concentration do

 

Gravitationally that means the hypermasses will distribute themselves across a space that will become "flatter" the older our universe becomes. The gravitation between the hypermasses will become weaker than the tractor force required to overcome the rate of inflation. No collapse of our universe into a big crunch as it appears now is likely, so there probably won't be a merging of all the small hypermasses into a single hypermass.

 

Instead, there will probably be Hawking evaporation into a vastly empty sea of virtual particles and a further flattening of space/time as the local hypermasses lose "density" to the moment when they release their remaining mass in a spectacular gamma ray burst.

 

On a sidebar;

 

The universe itself may to the external viewer appear to be a kind of hypermass.

[EWright]

The idea you discuss basically describes the theoretical (speculative?) idea behind a big crunch, which is essentially the big bang in reverse. In order for this to happen, the gravitational force of the universe has to overpower the current expansion. The idea behind this happening is diminishing, because for now it appears that "dark energy" (the unknown force causing the accellerated expansion of the universe) will prevail and everything will expand until the distances between any forms of matter/particles are so emmence that the universe 'appears' void.

 

However, if a big crunch were to occur, black holes would most certainly merge as all matter in the universe was squeezed into a smaller and smaller space. OK, actually space could still be considered infinite (all that there is and without a border), but all matter would be closer together and merging; black holes included.

 

The theory would stop short of what would happen to the eventual singularity that would result in such a collapse. Granted, it would most certainly be similar (possibly identicle) to the (theoretical) singularity that began this universe. But the question of whether it would ever give rise to another big bang, cannot be answered for certain.

 

But... if it never gives rise to space and time by which it can be conceived, would it even exist? ;)

[damocles]

EWright;

 

I am careful not to use the term singularity anymore, substituting hypermass instead, now that Hawking has nailed down the mathematics that proves that information is conserved inside a hypermass and can escape from it via quantum entanglement and/or Hawking radiation.

 

http://researchnews.osu.edu/archive/fuzzball.htm

 

From this thread:

 

http://www.dna88.com/forum/forum-article323.html

 

I give you Hawking's lecture;

 

Quote:

Can you hear me?

I want to report that I think I have solved a major problem in theoretical physics, that has been around since I discovered that black holes radiate thermally, thirty years ago. The question is, is information lost in black hole evaporation? If it is, the evolution is not unitary, and pure quantum states, decay into mixed states.

 

I'm grateful to my graduate student Christophe Galfard for help in preparing this talk.

 

The black hole information paradox started in 1967, when Werner Israel showed that the Schwarzschild metric, was the only static vacuum black hole solution. This was then generalized to the no hair theorem: the only stationary rotating black hole solutions of the Einstein-Maxwell equations are the Kerr-Newman metrics. The no hair theorem implied that all information about the collapsing body was lost from the outside region apart from three conserved quantities: the mass, the angular momentum, and the electric charge.

 

This loss of information wasn't a problem in the classical theory. A classical black hole would last for ever, and the information could be thought of as preserved inside it, but just not very accessible. However, the situation changed when I discovered that quantum effects would cause a black hole to radiate at a steady rate. At least in the approximation I was using, the radiation from the black hole would be completely thermal, and would carry no information. So what would happen to all that information locked inside a black hole, that evaporated away, and disappeared completely? It seemed the only way the information could come out would be if the radiation was not exactly thermal, but had subtle correlations. No one has found a mechanism to produce correlations, but most physicists believe one must exist. If information were lost in black holes, pure quantum states would decay into mixed states, and quantum gravity wouldn't be unitary.

 

I first raised the question of information loss in '75, and the argument continued for years, without any resolution either way. Finally, it was claimed that the issue was settled in favour of conservation of information, by AdS/CFT. AdS/CFT is a conjectured duality between supergravity in anti-deSitter space and a conformal field theory on the boundary of anti-deSitter space at infinity. Since the conformal field theory is manifestly unitary, the argument is that supergravity must be information preserving. Any information that falls in a black hole in anti-deSitter space, must come out again. But it still wasn't clear how information could get out of a black hole. It is this question I will address.

 

Black hole formation and evaporation can be thought of as a scattering process. One sends in particles and radiation from infinity, and measures what comes back out to infinity. All measurements are made at infinity, where fields are weak, and one never probes the strong field region in the middle. So one can't be sure a black hole forms, no matter how certain it might be in classical theory. I shall show that this possibility allows information to be preserved and to be returned to infinity.

 

I adopt the Euclidean approach, the only sane way to do quantum gravity non-perturbatively. [He grinned at this point.] In this, the time evolution of an initial state is given by a path integral over all positive definite metrics that go between two surfaces that are a distance T apart at infinity. One then Wick rotates the time interval, T, to the Lorentzian.

 

The path integral is taken over metrics of all possible topologies that fit in between the surfaces. There is the trivial topology: the initial surface cross the time interval. Then there are the nontrivial topologies: all the other possible topologies. The trivial topology can be foliated by a family of surfaces of constant time. The path integral over all metrics with trivial topology, can be treated canonically by time slicing. In other words, the time evolution (including gravity) will be generated by a Hamiltonian. This will give a unitary mapping from the initial surface to the final.

 

The nontrivial topologies cannot be foliated by a family of surfaces of constant time. There will be a fixed point in any time evolution vector field on a nontrivial topology. A fixed point in the Euclidean regime corresponds to a horizon in the Lorentzian. A small change in the state on the initial surface would propagate as a linear wave on the background of each metric in the path integral. If the background contained a horizon, the wave would fall through it, and would decay exponentially at late time outside the horizon. For example, correlation functions decay exponentially in black hole metrics. This means the path integral over all topologically nontrivial metrics will be independent of the state on the initial surface. It will not add to the amplitude to go from initial state to final that comes from the path integral over all topologically trivial metrics. So the mapping from initial to final states, given by the path integral over all metrics, will be unitary.

 

One might question the use in this argument, of the concept of a quantum state for the gravitational field on an initial or final spacelike surface. This would be a functional of the geometries of spacelike surfaces, which is not something that can be measured in weak fields near infinity. One can measure the weak gravitational fields on a timelike tube around the system, but the caps at top and bottom, go through the interior of the system, where the fields may be strong.

 

One way of getting rid of the difficulties of caps would be to join the final surface back to the initial surface, and integrate over all spatial geometries of the join. If this was an identification under a Lorentzian time interval, T, at infinity, it would introduce closed timelike curves. But if the interval at infinity is the Euclidean distance, beta, the path integral gives the partition function for gravity at temperature 1/beta.

 

The partition function of a system is the trace over all states, weighted with e-beta H. One can then integrate beta along a contour parallel to the imaginary axis with the factor e-beta E. This projects out the states with energy E0. In a gravitational collapse and evaporation, one is interested in states of definite energy, rather than states of definite temperature.

 

There is an infrared problem with this idea for asymptotically flat space. The Euclidean path integral with period beta is the partition function for space at temperature 1/beta. The partition function is infinite because the volume of space is infinite. This infrared problem can be solved by a small negative cosmological constant. It will not affect the evaporation of a small black hole, but it will change infinity to anti-deSitter space, and make the thermal partition function finite.

 

The boundary at infinity is then a torus, S1 cross S2. The trivial topology, periodically identified anti-deSitter space, fills in the torus, but so also do nontrivial topologies, the best known of which is Schwarzschild anti-deSitter. Providing that the temperature is small compared to the Hawking-Page temperature, the path integral over all topologically trivial metrics represents self-gravitating radiation in asymptotically anti-deSitter space. The path integral over all metrics of Schwarzschild AdS topology represents a black hole and thermal radiation in asymptotically anti-deSitter.

 

The boundary at infinity has topology S1 cross S2. The simplest topology that fits inside that boundary is the trivial topology, S1 cross D3, the three-disk. The next simplest topology, and the first nontrivial topology, is S2 cross D2. This is the topology of the Schwarzschild anti-deSitter metric. There are other possible topologies that fit inside the boundary, but these two are the important cases: topologically trivial metrics and the black hole. The black hole is eternal. It cannot become topologically trivial at late times.

 

In view of this, one can understand why information is preserved in topologically trivial metrics, but exponentially decays in topologically non trivial metrics. A final state of empty space without a black hole would be topologically trivial, and be foliated by surfaces of constant time. These would form a 3-cycle modulo the boundary at infinity. Any global symmetry would lead to conserved global charges on that 3-cycle. These would prevent correlation functions from decaying exponentially in topologically trivial metrics. Indeed, one can regard the unitary Hamiltonian evolution of a topologically trivial metric as the conservation of information through a 3-cycle.

 

On the other hand, a nontrivial topology, like a black hole, will not have a final 3-cycle. It will not therefore have any conserved quantity that will prevent correlation functions from exponentially decaying. One is thus led to the remarkable result that late time amplitudes of the path integral over a topologically non trivial metric, are independent of the initial state. This was noticed by Maldacena in the case of asymptotically anti-deSitter in 3d, and interpreted as implying that information is lost in the BTZ black hole metric. Maldacena was able to show that topologically trivial metrics have correlation functions that do not decay, and have amplitudes of the right order to be compatible with a unitary evolution. Maldacena did not realize, however that it follows from a canonical treatment that the evolution of a topologically trivial metric, will be unitary.

 

So in the end, everyone was right, in a way. Information is lost in topologically nontrivial metrics, like the eternal black hole. On the other hand, information is preserved in topologically trivial metrics. The confusion and paradox arose because people thought classically, in terms of a single topology for spacetime. It was either R4, or a black hole. But the Feynman sum over histories allows it to be both at once. One can not tell which topology contributed the observation, any more than one can tell which slit the electron went through, in the two slits experiment. All that observation at infinity can determine is that there is a unitary mapping from initial states to final, and that information is not lost.

 

My work with Hartle showed the radiation could be thought of as tunnelling out from inside the black hole. It was therefore not unreasonable to suppose that it could carry information out of the black hole. This explains how a black hole can form, and then give out the information about what is inside it, while remaining topologically trivial. There is no baby universe branching off, as I once thought. The information remains firmly in our universe. I'm sorry to disappoint science fiction fans, but if information is preserved, there is no possibility of using black holes to travel to other universes. If you jump into a black hole, your mass-energy will be returned to our universe, but in a mangled form, which contains the information about what you were like, but in an unrecognisable state.

 

There is a problem describing what happens, because strictly speaking the only observables in quantum gravity are the values of the field at infinity. One cannot define the field at some point in the middle, because there is quantum uncertainty in where the measurement is done. However, in cases in which there are a large number, N, of light matter fields, coupled to gravity, one can neglect the gravitational fluctuations, because they are only one among N quantum loops. One can then do the path integral over all matter fields, in a given metric, to obtain the effective action, which will be a functional of the metric.

 

One can add the classical Einstein-Hilbert action of the metric to this quantum effective action of the matter fields. If one integrated this combined action over all metrics, one would obtain the full quantum theory. However, the semiclassical approximation is to represent the integral over metrics by its saddle point. This will obey the Einstein equations, where the source is the expectation value of the energy momentum tensor, of the matter fields in their vacuum state.

 

The only way to calculate the effective action of the matter fields, used to be perturbation theory. This is not likely to work in the case of gravitational collapse. However, fortunately we now have a non-perturbative method in AdS/CFT. The Maldacena conjecture says that the effective action of a CFT on a background metric is equal to the supergravity effective action of anti-deSitter space with that background metric at infinity. In the large N limit, the supergravity effective action is just the classical action. Thus the calculation of the quantum effective action of the matter fields, is equivalent to solving the classical Einstein equations.

 

The action of an anti-deSitter-like space with a boundary at infinity would be infinite, so one has to regularize. One introduces subtractions that depend only on the metric of the boundary. The first counter-term is proportional to the volume of the boundary. The second counter-term is proportional to the Einstein-Hilbert action of the boundary. There is a third counter-term, but it is not covariantly defined. One now adds the Einstein-Hilbert action of the boundary and looks for a saddle point of the total action. This will involve solving the coupled four- and five-dimensional Einstein equations. It will probably have to be done numerically.

 

In this talk, I have argued that quantum gravity is unitary, and information is preserved in black hole formation and evaporation. I assume the evolution is given by a Euclidean path integral over metrics of all topologies. The integral over topologically trivial metrics can be done by dividing the time interval into thin slices and using a linear interpolation to the metric in each slice. The integral over each slice will be unitary, and so the whole path integral will be unitary.

 

On the other hand, the path integral over topologically nontrivial metrics, will lose information, and will be asymptotically independent of its initial conditions. Thus the total path integral will be unitary, and quantum mechanics is safe.

 

It is great to solve a problem that has been troubling me for nearly thirty years, even though the answer is less exciting than the alternative I suggested. This result is not all negative however, because it indicates that a black hole evaporates, while remaining topologically trivial. However, the large N solution is likely to be a black hole that shrinks to zero. This is what I suggested in 1975.

 

In 1997, Kip Thorne and I bet John Preskill that information was lost in black holes. The loser or losers of the bet are to provide the winner or winners with an encyclopaedia of their own choice, from which information can be recovered with ease. I'm now ready to concede the bet, but Kip Thorne isn't convinced just yet. I will give John Preskill the encyclopaedia he has requested. John is all-American, so naturally he wants an encyclopaedia of baseball. I had great difficulty in finding one over here, so I offered him an encyclopaedia of cricket, as an alternative, but John wouldn't be persuaded of the superiority of cricket. Fortunately, my assistant, Andrew Dunn, persuaded the publishers Sportclassic Books to fly a copy of "Total Baseball: The Ultimate Baseball Encyclopedia" to Dublin. I will give John the encyclopaedia now. If Kip agrees to concede the bet later, he can pay me back.

 

In plain English the smallest hypermass possible is "fuzzy" and has a spatial VOLUME radius equal to indeterminantly bounded space 1/2 the plank distance from the center of the sphere.

 

Such a hypermass evaporates and gives up information in the particles it releases that give the hypermass its own unique fingerprint. That means, it has to have some ultimate compression limit that is far short of unity, which further means that the hypermass will always have a minimum volume depending on the amount of mass accreted. Now what this volume per hypermass is I am not quite ready to describe as being directly proportional to such properties as measured mass quantity, gravitational acceleration, and inertia(represented by rotational angular momentum imparted on a drag mass by the spinning hypermass).

 

What it does present is a further problem in the old big bang model.(Can you see this coming?) That inflation event from flat space had to start with the property of space itself. There has to be "volume" in a universe before you can inflate it, thus giving it a property called "time".

[alxian]

if all the known and theorized universe was energy it would be very very small.

 

now..

 

even if the entire universe is expanding couldn't small areas condense and then explode?

 

something like our visible part of it? all condensed into one even that then exploded leaving a uniform expansion in its wake we attribute to the "universe" as a whole?

 

 

is there a limit to how much energy can be bound by the known laws of relativity before it explodes (by lets say all the matter-energy in the becoming one polarity) [ionizing itself somehow]? what is the matter-energy boundary?

 

like at the core of a dark star matter begins to convert into energy the more its compressed the more energy is produced at the core, like a contained atomic explosion bound by the insane gravity of the event, the matter of the star and its energy core polarize and you get a massive explosion?

[Jay-qu]

I went to a lecture the other night and it was about The Australian Synchrotron thats been built not to far from my house, anyway one part of it was about natural synchrotrons, 2 examples been quasars and super massive galactic blackholes formed at the centre of galaxies because they have sucked in lots of mass. And by some strange phenomena jets of electrons and other particals are spat out (like in this pic.) while all the mass is getting sucked in... anyway it was really interesting