The Black Hole at the Birth of the Universe

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Our universe may have emerged from a black hole in a higher-dimensional universe, propose a trio of Perimeter Institute researchers in the cover story of the latest Scientific American.

The big bang poses a big question: if it was indeed the cataclysm that blasted our universe into existence 13.7 billion years ago, what sparked it?

Three Perimeter Institute researchers have a new idea about what might have come before the big bang. It’s a bit perplexing, but it is grounded in sound mathematics, testable, and enticing enough to earn the cover story in Scientific American, called “The Black Hole at the Beginning of Time.”

What we perceive as the big bang, they argue, could be the three-dimensional “mirage” of a collapsing star in a universe profoundly different than our own.

“Cosmology’s greatest challenge is understanding the big bang itself,” write Perimeter Institute Associate Faculty member Niayesh Afshordi, Affiliate Faculty member and University of Waterloo professor Robert Mann, and PhD student Razieh Pourhasan.

Conventional understanding holds that the big bang began with a singularity – an unfathomably hot and dense phenomenon of spacetime where the standard laws of physics break down. Singularities are bizarre, and our understanding of them is limited.

“For all physicists know, dragons could have come flying out of the singularity,” Afshordi says in an interview with Nature.

The problem, as the authors see it, is that the big bang hypothesis has our relatively comprehensible, uniform, and predictable universe arising from the physics-destroying insanity of a singularity. It seems unlikely.

So perhaps something else happened. Perhaps our universe was never singular in the first place.

Their suggestion: our known universe could be the three-dimensional “wrapping” around a four-dimensional black hole’s event horizon. In this scenario, our universe burst into being when a star in a four-dimensional universe collapsed into a black hole.

In our three-dimensional universe, black holes have two-dimensional event horizons – that is, they are surrounded by a two-dimensional boundary that marks the “point of no return.” In the case of a four-dimensional universe, a black hole would have a three-dimensional event horizon.

In their proposed scenario, our universe was never inside the singularity; rather, it came into being outside an event horizon, protected from the singularity. It originated as – and remains – just one feature in the imploded wreck of a four-dimensional star.

The researchers emphasize that this idea, though it may sound “absurd,” is grounded firmly in the best modern mathematics describing space and time. Specifically, they’ve used the tools of holography to “turn the big bang into a cosmic mirage.” Along the way, their model appears to address long-standing cosmological puzzles and – crucially – produce testable predictions.

Of course, our intuition tends to recoil at the idea that everything and everyone we know emerged from the event horizon of a single four-dimensional black hole. We have no concept of what a four-dimensional universe might look like. We don’t know how a four-dimensional “parent” universe itself came to be.

But our fallible human intuitions, the researchers argue, evolved in a three-dimensional world that may only reveal shadows of reality.

They draw a parallel to Plato’s allegory of the cave, in which prisoners spend their lives seeing only the flickering shadows cast by a fire on a cavern wall.

“Their shackles have prevented them from perceiving the true world, a realm with one additional dimension,” they write. “Plato’s prisoners didn’t understand the powers behind the sun, just as we don’t understand the four-dimensional bulk universe. But at least they knew where to look for answers.”

– Colin Hunter

00:04

if you turn that clock back and look at

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the first instance of the life of the

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universe you notice that as you go back

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in time temperatures get hotter

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densities go higher and at some point

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basically cannot use the standard theory

00:18

that Einstein gave us that's the Big

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Bang singularity classical cosmology

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could describe everything up to like

00:27

back to that time and because every

00:29

physics breaks down there this is the

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time that really really we want to know

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what happens but we don't have enough

00:35

tools we don't have a quick theory to

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describe that maybe the Big Bang as we

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think about it as a singularity in our

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past is not really there but rather a

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mirage of something more complicated

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something that actually happened in one

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higher dimension we found that okay we

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can interpret the singularity in a

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different way at some point a star dies

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a black hole forms in in four dimension

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these Galactus has an event horizon if

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the size of our universe is larger than

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the horizon and if we are living outside

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the horizon then we are protected from

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that singularity if you have a star that

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collapses and out of the remnants of

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that collapsing a star in a four

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dimensional universe a membrane emerges

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the properties of that membrane could

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very well describe the properties of the

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cosmology in which we live in and maybe

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that means that there was no Big Bang

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maybe there was a supernova explosion

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one higher dimension of course there

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would be differences obviously but the

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might be similarity is more than anybody

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might have imagined I think that is one

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possible case to consider lots of other

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brilliant people who had clever ideas

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but I love about cosmology is is asking

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big questions and you can try to answer

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them as ambitious it may sound

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I'm still not happy I want to know more

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I want to know what's beyond the Big

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Bang what happened before that

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so we just try to look back as far as we

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can and where we stopped we will try

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harder

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Perimeter Institute is a leading centre for scientific research, training and educational outreach in foundational theoretical physics. Founded in 1999 in Waterloo, Ontario, Canada, its mission is to advance our understanding of the universe at the most fundamental level, stimulating the breakthroughs that could transform our future. Perimeter also trains the next generation of physicists through innovative programs, and shares the excitement and wonder of science with students, teachers and the general public.

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