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Could the Big Bang have been more of a Big Bounce?

Could the Big Bang have been m...
Researchers have developed a mathematical model that suggests that the Big Bang may not have been the beginning of everything, but merely the result of a previous universe collapsing in on itself
Researchers have developed a mathematical model that suggests that the Big Bang may not have been the beginning of everything, but merely the result of a previous universe collapsing in on itself
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Researchers have developed a mathematical model that suggests that the Big Bang may not have been the beginning of everything, but merely the result of a previous universe collapsing in on itself
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Researchers have developed a mathematical model that suggests that the Big Bang may not have been the beginning of everything, but merely the result of a previous universe collapsing in on itself
Dr Gielen (left) and Dr Turok (right) discussing the Big Bounce model
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Dr Gielen (left) and Dr Turok (right) discussing the Big Bounce model

How the universe began is one of the most brain-breaking questions you could possibly ask, and the Big Bang is probably the answer most people accept. But what if the infinitely dense point from which the entire universe burst forth wasn't the beginning of everything, but merely the middle of an ongoing cycle? That's the theory of the Big Bounce, which suggests that the universe regularly cycles through periods of expansion and contraction, meaning the Big Bang may have been preceded by an earlier universe collapsing in on itself. A new study details how this might be possible.

The idea of the Big Bounce has been bouncing around since 1922, but explaining just how the universe transitions between expanding and contracting has always been an issue. What's to stop a universe just contracting into a point and collapsing completely? According to researchers from Imperial College London and the Perimeter Institute for Theoretical Physics in Canada, it may be the same quantum mechanics that prevent atoms from deteriorating into nothing.

In our universe as it currently is, there's an asymmetry between the laws of the subatomic world and those that govern larger matter. Large-scale physics and quantum mechanics exist side-by-side now, but that doesn't mean it's always been the case: back when the universe was young and everything in it was tiny, quantum mechanics may have been the only set of laws in effect, an idea known as conformal symmetry. So the same processes that keep electrons from losing energy as they orbit the nucleus and destroying the atom may have prevented the universe from collapsing into oblivion.

Dr Gielen (left) and Dr Turok (right) discussing the Big Bounce model
Dr Gielen (left) and Dr Turok (right) discussing the Big Bounce model

"Quantum mechanics saves us when things break down," says Steffen Gielen, of Imperial College London. "It saves electrons from falling in and destroying atoms, so maybe it could also save the early universe from such violent beginnings and endings as the Big Bang and Big Crunch."

With this idea in mind, the researchers built a mathematical model for how the universe might evolve, based on conformal symmetry and other early-universe theories, such as the prevalence of radiation over ordinary matter. The result? It all fit.

"The big surprise in our work is that we could describe the earliest moments of the hot Big Bang quantum mechanically, under very reasonable and minimal assumptions about the matter present in the universe," says Neil Turok of the Perimeter Institute for Theoretical Physics. "Under these assumptions, the Big Bang was a 'bounce,' in which contraction reversed to expansion."

Further study is being conducted into how things like galaxies, which disrupt the model, can be incorporated into it. The research is published in the journal, Physical Review Letters.

"Our model's ability to give a possible solution to the problem of the Big Bang opens the way to new explanations for the formation of the universe," said Dr Gielen.

We've reached out to the researchers to get the nitty gritty quantum mechanics details on how this all would have happened and will let you know when we hear back.

Source: Imperial College London

18 comments
gizmowiz
That sounds logical a cyclic Universe with energy to matter and back again.
MainframeGeek
Evidence shows that expansion of our universe has been accelerating, not decelerating. Doesn't look like it fits a "Big Crunch" model.
Ichabod Ebenezer
SoundED logical until we discovered the rate of expansion was increasing. Dark energy will prevent the universe from ever being close enough to collapse for one of these bounces. There is no reason to expect there was a previous inflationary period where dark energy didn't exist. I thought I had heard the last of this theory 15 years ago...
SomersetSmile
There is a third possibility, the Big Rip with the expansion rate faster than the speed of light. The zero point vacuum could propagate a Big Bang. Another possibility could be based on the recent discovery that they have been able to create an atomic state which measurement propagates back into the past for that atom. If there were multiple past parallel universes that were only dependent on the differences in that atom. Then all of these alternate parallel universes might be pinched out of being, creating a void next to the remaining universes. This might explain the acceleration being blamed on Dark Energy.
ljs
No credit or refernce given to Roger Penrose?
TimLong01
But if the red shift is caused by photon energy loss due to numerous mechanisms, rather than by the Doppler shift, then dark matter/dark energy isn't necessary nor is the expansion-contraction theories. (Less energy increases wavelength)
BGriffin
If the universe is curved such that traveling in one direction long enough brings you back to your starting point, then increasing expansion away from the point of origin could actually be collapse back to the point of origin.
BGriffin
This theory doesn't require that the same thing is bound to occur in the future, merely because it might have occurred previously. There might have only been one bounce after which we never really get things back together again.
toddzrx
This is just another attempt to prove that the universe has always and will always exist; i.e., the Steady State Theory, but in a different form where the universe goes through cycles of expansion and contraction. Sorry, but a simple thought experiment debunks the possibility: this model of the universe still requires infinite time into the past, but then how could we arrive at today? Additionally, this doesn't get around the requirement of the universe needing a cause.
katgod
Ichabod, While increasing rate of expansion would seem to argue against the bounce theory, this is only true if you think you understand the topology of the universe and I suspect that the topology is also up for grabs.