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"Big Bang or the Big Bounce?" --New Science Points to a Continuum


                               SciAm_Big Bounce

The big bang may not have been the beginning of the universe, but merely the beginning of one of an infinite series of universes. Two fundamental concepts in physics, both of which explain the nature of the Universe in many ways, have been difficult to reconcile with each other. European researchers have developed a mathematical approach to do so that has the potential to explain what came before the Big Bang.

The big bang singularity --the single point from which the entire universe is supposed to have sprung-- is the major sticking point in the big bang theory; the calculations just can't account for such a singularity. Without evidence associated with the earliest instant of the expansion, the Big Bang theory does not provide any explanation for such an initial condition.

According to Einstein’s (classical) theory of general relativity, space is a continuum. Regions of space can be subdivided into smaller and smaller volumes without end.

The fundamental idea of quantum mechanics is that physical quantities exist in discrete packets (quanta) rather than in a continuum. Further, these quanta and the physical phenomena related to them exist on an extremely small scale (Planck scale).

So far, the theories of quantum mechanics have failed to ‘quantise’ gravity. Loop quantum gravity (LQG) is an attempt to do so. It represents space as a net of quantised intersecting loops of excited gravitational fields called spin networks. This network viewed over time is called spin foam.

Not only does LQG provide a precise mathematical picture of space and time, it enables mathematical solutions to long-standing problems related to black holes and the Big Bang. Amazingly, LQG predicts that the Big Bang was actually a ‘Big Bounce’, not a singularity but a continuum, where the collapse of a previous universe spawned the creation of ours.

European researchers initiated the ‘Effective field theory for loop quantum gravity’ (EFTFORLQG) project to further develop this exciting candidate theory reconciling classical and quantum descriptions of the Universe.

Scientists focused on the background-independent structure of LQG which requires that the mathematics defining the system of spacetime be independent of any coordinate system or reference frame (background).

They applied both semi-classical approximations (Wentzel-Kramers-Brillouin approximations, WKBs) and effective field theory (sort of approximate gravitational field theory) techniques to analyze a classical geometry of space, study the dynamics of semi-classical states of spin foam and apply the mathematical formulations to astrophysical phenomena such as black holes.

Results produced by the EFTFORLQG project team exceeded expectations. Scientists truly contributed to establishing LQG as a major contender for describing the quantum picture of space and time compatible with general relativity with exciting implications for unravelling some of the major mysteries of the Universe.

The Daily Galaxy via CORDIS

Image credit: With thanks to Pat Rawlings/SAIC


And where is the news now?
There is only a sentence "Results (...) exceeded expectations.", nothing else?! Is there at least a source, like a paper somewhere?

I think a good step forward

The headline use of "continuum" appears to be a common use of the word related to, for example, "continuing" rather than the technical meaning of of continuum than is used in the article- namely non-quantized.

This is about Loop Quantum Gravity? What exactly is the "New Science"?

Just wondering has there ever been any consideration that our Universe came from the "drain" side of a Black Hole? Maybe from different universe? If they suck everything in, it must "go" somewhere. Just a curious non-scientist person, has it been asked, or is it ridiculous? Editor's Comment: Einstein said that the human imagination is our most powerful tool.

i guess this is coming from one of the theories that the universe might end through a Big Crunch and close to singularity when it crunch too much will bang again ... but so far it's considered that the universe is expanding accelerated so I don't see what will make that acceleration stop and reverse to bring back the matter again ...

looks like we all get recycled in the end

This is soo exciting to read! I can't wait to read more info on these exciting ideas and the possible predictable outcomes that arise from these defining ideas. Thank you dailygalaxy for the awesome info.!

Spin foam never sleeps,
and gets very tired.

Loop quantum,
on the other hand...

My only question about this theory is it seems to contradict with new evidence that the universe is ever expanding. Not too long ago it was thought the universe would end in a Big Crunch because the force of gravity would eventually pull everything back together. Very recently there have been new discoveries related to dark matter, which as far as cosmologists can tell has a stronger force than gravity, and is pushing everything apart. If this is true, wouldn't that automatically debunk this theory? (I am by no means saying the Big Bounce theory doesn't have any bearing, I'm sure I'm just missing a key point in understanding it). Anybody have any ideas?

If the universe is expanding how could there be a continuum?

Dark energy is the energy responsible for expanding the universe. The best explanation they have for this that it is the vacuum energy and simply the cost of having space.

Hawking states that there was no singularity at the big bang, but the boundary conditions were something sort of like standing on the north pole and asking which way is north.

The multiverse theory is just outrageous and I can't see a way to solidly prove it.

Also Hawking states that whatever happened 'before' the big bang could not have influenced what happened after it.

I don't think it is a contraction that leads to a fresh Universe. I think it's a big snap. If we embrace the contraction idea than we've got a limited expansion of a limited universe in a boundless, marginless and infinite cosmos. If it's just expansion, which is accelerating, why would the one incarnation of the universe have happened now rather than an infinite time in the past. I'm saying in this case if it were to happen only once it would have already happened.

But, if the universe is continuous and eternal it's tempting to say that the expansion accelerates until matter itself decays. The final end of all matter happens at once throughout the continuous infinite cosmos. The reaction of empty space than would be to "snap-back" and produce a wealth of particles that coalaece into a new universe.

You may ask how all these galaxies in the infinite space could flee from eachother at an accelerating speed without bumping into one another. I say it is not so much that they are accelerating, but that SPACE ITSELF is pouring into the intergalactic gaps at a faster and faster pace until it will even pour into atoms themselves and they will decay. Where is this space coming from? I don't know the physics but as space is not a quantity with mass limitations it can follow energetic necessities like entropy freely, without regard to an idea of limited quantification. Not so lame.

Buddhism and quantum theory itself tells us that all things are connected at the level of the plank scale. the infinite cosmos is one unified structure and that is how it can all disappear in one final decay and reappear as simple particles throughout. I call this the ''snap-back" theory.

Boundless, marginless and infinite -the "open universe"

I can help but think about origins, or should I say, the lack thereof?...if this universe has no origination and simply is "bouncing" from a compressed singularity to the decompressed existence that we all live and breathe in, and has been doing that for all eternity, is the emptiness in which this is happening infinite, and therefore is there no telling how many universes are "bouncing" about doing the same as our own?

Should we be able to step back would we see multiple universes, and should we step back further see that these multiple universes are organized in some pattern, and stepping back even further see the pattern as only a smaller part of a much larger infinitum? Should we be able to step back far enough might we see even this much larger organization as nothing greater than how an atom might appear in our own universe?

And why is it that pondering such an ever enlarging macrocosm makes me also believe that there will be nothing in all of creation that can’t be split still further?

@bob - Black holes emit what is refered to as "hawking" radiation since stephen hawking discovered it. black holes do not dump what they suck in anywhere, instead they have super powerful gamma ray jets at their poles which release energy, over time if a black hole does not absorb any more mass it will eventually dissipate. black holes are also something of a misnomer as they are not holes and are not black exactly. a black hole is a collapsed star and as such is spherical and due to its immense gravity emits no light so it has no actual color. they are called black holes because when viewed against the background light from other stars/galaxies they appear to be "black holes" in space.

I see this infinite "open universe" as falling through time just like a net falls through the air. It gains speed and thins out and when it just really can't g accelerate any faster it breaks through the barrier that time//space has become and it is destroyed all it's momentum is lost. The force of this "break-through" becomes a dense cloud of particles. You may remember that particles are appearing and disappearing in intergalactic chilicosms like an effervescence, right now -from nothing. Then the descent through time continues. It's not really circular cause everything is made new and a completely different universe carries on, one after another.

@Keith & Bob -black hole dissapation gave me a clue to the imaginary structure I'm building concerning the cosmos. On the "drain" idea though , have your read that labs have gotten a photon to travel from one region to another without following any kind of line. Just reappearing from there to there. They've also done this with sequences of information in charged particles i think.

Time for the "answer man" to come to the rescue again!
We did not have a 'big bang' or ' big bounce' or anything like that.
What it was, was a "Big Tear" in another universe that allowed material to spill into what is now our universe!
(Remember light can't trvel faster than 300,000 KMS but a tear can go as fast as it wants, hence the initial 'expansion' of our universe.)

@Allan -where is this "another universe" -it must occupy space, but there is only one infinite space. Unless your speaking in sequential time. Then i understand, it is the same as i said, The old universe breaks through a limit and fresh particles are what passes through to the next. But all in the same space.

What the hell are you talking about?

A different Universe had a tear in the space-time continuum and this burped or farted our universe before it sealed up again.

We are the ultimate "dust in the wind!"

Of couorse this doesn't do much to explain where the other universe came from!

The evidence doesn't bear out the likeliness of a "Big Crunch," a "Big Bounce," or any other cyclic behavior on the part of the universe.

The evidence does bear out that the universe is expanding, and that the expansion is accelerating. Last I checked, someone won a Nobel Prize for discovering that little tidbit about the universe.

If the universe's expansion is accelerating, then how could it ever possibly "bounce" or "crunch" or anything else that people do on trampolines or with cereal? The best you could hope for would be a quantum event that resets the state of the universe to some previous configuration (or something like a previous configuration). But that would take a very long time to occur (you do the math).

So loop quantum gravity might predict a Big Crunch, but that doesn't square with evidence we've already collected that precludes a Big Crunch from ever occurring. So my sense is that loop quantum gravity is a nice little theory that doesn't have much to do with reality. Like Susskind and Guth, I'm going to stick with eternal inflation, 10^500 multiverses as predicted by string theory, and the holographic universe, since those theories are the ones that best fit the facts of the way things are in the universe today.

Multiverses and holographic universes fit in with the 'big tear' and a 2 dimoensional reality seems to fit in with the universe....... since everything happens in two's. Postitive negative, light dark, good bad, yes no, male female....., even in a two dimensional universe direction happens in 3 series of two's, up down, left right, forward backward!

I remember positing this theory about 20 years ago. a series of universes like a kind of sine wave.

If i recall it had something to do with the 'sum over histories' as being wrong...

in a similar way, backwards time travel is actually travelling forwards to a point in a 'copy' universe representing a point before any changes have taken place to make it different to this universe (i.e. the past, in effect) - this solves the 'kiling your own parents' conundrum.

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