No Big Bang? Quantum equation predicts universe has no beginning

[TubbyTubby]

The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein’s theory of general relativity. The model may also account for dark matter and dark energy, resolving multiple problems at once.

The widely accepted age of the universe, as estimated by general relativity, is 13.8 billion years. In the beginning, everything in existence is thought to have occupied a single infinitely dense point, or singularity. Only after this point began to expand in a “Big Bang” did the universe officially begin.

Although the Big Bang singularity arises directly and unavoidably from the mathematics of general relativity, some scientists see it as problematic because the math can explain only what happened immediately after—not at or before—the singularity.

“The Big Bang singularity is the most serious problem of general relativity because the laws of physics appear to break down there,” Ahmed Farag Ali at Benha University and the Zewail City of Science and Technology, both in Egypt, told Phys.org.

Ali and coauthor Saurya Das at the University of Lethbridge in Alberta, Canada, have shown in a paper published in Physics Letters B that the Big Bang singularity can be resolved by their new model in which the universe has no beginning and no end.




https://richarddawkins.net/2016/03/no-bi...-beginning

The thought of the Universe either having a beginning or being eternal both equally blow my mind. I think the eternal model just shades it in the mind boggling stakes though.

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[Socratic Meth Head]

How do we explain Cosmic Background Radiation and the Universe's expansion?

[abaris]

I guess, this will be up for debate for a very long time.

[vorlon13]

Might be another way of saying the math breaks down at the instant of the BB. One Planck time later, math starts working.

Not sure I have a problem with that.

Like, did the BB make one universe, or a Googleplex number of universes or a Skewes Number of universes ? Not really surprised the numbers might get hinky right then and not work till all the universes de-correlate. And presumably, it all sorts out in 1X10^-43 seconds, and then here we are wondering about it.

[Alex K]

How do we explain Cosmic Background Radiation and the Universe's expansion?

Don't get them wrong, the usual "hot big bang" picture remains exactly the same in their model, we are really only talking about the first tiniest fraction of a second where general relativity breaks down and quantum gravity effects play a role. We knew already that the classical gravity cannot be extrapolated back to a singularity (If you've listened to me here in the past, I go on and on about that at every opportunity), but the question what happens *instead* is hard to answer reliably.

[vorlon13]

How many solar masses worth of gravitational radiation did the BB emit ??

(And I'm assuming that energy is irretrievable)

Was it enough grav energy that it 'raced' out ahead of the rest of the BB residue and extracted everything along behind it ??

[Minimalist]

How do we explain Cosmic Background Radiation and the Universe's expansion?

Cue some idiot with "goddidit" in  5....4....3....2....1....

[vorlon13]

. . . and God saw that the CBR was good . . .

[Alex K]

How many solar masses worth of gravitational radiation did the BB emit ??

(And I'm assuming that energy is irretrievable)

Was it enough grav energy that it 'raced' out ahead of the rest of the BB residue and extracted everything along behind it ??

Since the BB was not an explosion away from one specific point in space, it is not possible to give a number for the sum (we don't knowhow big the universe is). But apart from that, how much gravitational waves were emitted is still extremely model dependent. In inflation models, the closer the field energy during inflation is to the plamck scale, the more grav. waves result from the quantum fluctuations of spacetime. This value can so far be almost anything, just not too high. Remember the BICEP2 announcement in 2014? They claimed to have indirectly seen grav. waves from the big bang., but were wrong. If it had been right, we'd have known that something like inflation with field energy near the planck scale has taken place (10^16 GeV to be exact, so a factor 100-1000 below, but still!). Now we don't know and it can be much smaller.