Do we live in a 4D blackhole?

[DJ_KiDDvIcIOUs]

The standard Big Bang model tells us that the Universe exploded out of an infinitely dense point, or singularity. But nobody knows what would have triggered this outburst: the known laws of physics cannot tell us what happened at that moment. . . .

Afshordi and his colleagues [suggest that] our three-dimensional (3D) Universe is a membrane, or brane, that floats through a ‘bulk universe’ that has four spatial dimensions.

Ashfordi's team realized that if the bulk universe contained its own four-dimensional (4D) stars, some of them could collapse, forming 4D black holes in the same way that massive stars in our Universe do: they explode as supernovae, violently ejecting their outer layers, while their inner layers collapse into a black hole.

In our Universe, a black hole is bounded by a spherical surface called an event horizon. Whereas in ordinary three-dimensional space it takes a two-dimensional object (a surface) to create a boundary inside a black hole, in the bulk universe the event horizon of a 4D black hole would be a 3D object — a shape called a hypersphere. When Afshordi’s team modelled the death of a 4D star, they found that the ejected material would form a 3D brane surrounding that 3D event horizon, and slowly expand.

The authors postulate that the 3D Universe we live in might be just such a brane — and that we detect the brane’s growth as cosmic expansion. “Astronomers measured that expansion and extrapolated back that the Universe must have begun with a Big Bang — but that is just a mirage,” says Afshordi.

Pretty interesting theory

 

[NickNitro]

 

[Midnyte_Sun]

I think I understood that. But of the universe expands forever, how long before the big crunch? And do we go back to 4D and what happens if another membrane interacts with our expansion?

 

[zeroapoc]

Current theories say there will be no "big crunch". Dark energy is actually accelerating the expansion of the universe.

 

[Xeno]

Current theories say there will be no "big crunch". Dark energy is actually accelerating the expansion of the universe.

But if this universe unfolded from a black hole in a 4D universe, the expansion that scientists believe they've detected would simply be the brane on which this universe sits expanding out from the black hole. The expansion would be accounted for by the expansion of the brane itself, not necesarily by dark energy or dark matter.

When I was in school I attended a presentation by a group of Fermilab scientists who proposed exactly that scenario for the artificial creation of universes in a laboratory setting. Their theory involved slamming certain particles together at nearly light speed, but the results, the creation of a brane that would expand out of/adjacent to our 3D universe into an entirely new universe, was the same. An observer inside the brane would perceive all of space/time expanding away from whatever point they occupied, while observers outside of it would detect the entire surface of the brane expanding like the surface of an inflating balloon. In the case of a brane that was created from a black hole or other event in our 3D universe, one wonders whether the resulting child universe would have two dimensions? And if so, what would be the physical laws within that 2D brane?

It's a fascinating theory. I eagerly await Morgan Freeman's take on it.

(A link back to the source of the article would be appreciated.)

 

[Steyin]

Wouldn't this then help to explain, or rather, give reasonable proof for the existence of multiverses? After all, I'd assume there were more than 1 membrane aside from ours.

 

[childeroland]

Found it (io9's source): http://www.nature.com/news/did-a-hyper-black-hole-spawn-the-universe-1.13743#/b1

Where you can find Pourhasen et al's paper: http://arxiv.org/abs/1309.1487

 

[Alex_Spider]

This is fascinating stuff. There is so much going on out in the universe, our mind cannot even grasp or comprehend.

 

[Xeno]

I said I wanted to see Morgan Freeman's take on this. Well, wonder of wonders, an episode of Through The Wormhole that aired tonight addressed the possibility that this universe is a brane that branched off from one with more dimensions. The episode is called, "Is Reality Real?" Scientists and philosophers put forward a number of intriguing possible explanations for the birth and nature of our universe. It repeats at 2 AM on the Science Channel.

That's one reason why TTW is my favorite TV show and one of few that I never miss.

 

[Doctor Evo]

But if this universe unfolded from a black hole in a 4D universe, the expansion that scientists believe they've detected would simply be the brane on which this universe sits expanding out from the black hole. The expansion would be accounted for by the expansion of the brane itself, not necesarily by dark energy or dark matter.

Dark energy and dark matter have opposite effects with regard to the expansion of the universe.

 

[Kane52630]

But of the universe expands forever, how long before the big crunch?

It's already begun.