Could a four-dimensional black hole have created our three-dimensional universe?
Okay, so that's not the same thing as a wormhole exactly. But the headline statement appears no better or worse when stacked against what astrophysicists don't know about the birth of the universe according to this story at NOVA.
“For all physicists know, dragons could have come flying out of the singularity,” says Niayesh Afshordi, an astrophysicist at the Perimeter Institute for Theoretical Physics. The "singularity" in this case is a point of infinite density and not the same as Ray Kurzweil's concept.
“In the current best theories that we have, we know that we don’t know,” says Sean Carroll, a theoretical physicist at Caltech.
At least they're honest. The problem is that when the equations of relativity are applied to the Big Bang, an infinite amount of answers results. In an effort to get around problems that a Big Bang singularity offers, Carroll and Afshordi tried something new and wrote a paper about their research. Here's what NOVA says:
"...the authors of the new paper turned to a model of the cosmos called the “braneworld.” In the braneworld, our observable, three-dimensional universe actually lives inside another universe which has extra spatial dimensions. To use a two-dimensional analogy, our universe is like the skimmable membrane (“brane”) of fat on top of the pea soup of the universe."
I have written about a distant variation on this "braneworld" theory before, however this is the first time that I've considered that our physical universe is the membrane itself above the far larger mass of existence. The new paper asks the question of what would happen if a black hole came into being within the "bulk" or "pea soup" of this model. Unlike black holes as we understand them in our current notions of cosmology, these black holes would be four-dimensional rather and have three-dimensional even horizons as opposed to two. The event horizon of this 4D black hole would be continuously expanding...not unlike our universe is. These monsters would bring forth the chattel and matter of what would be...well, us eventually.
So I guess it really has nothing to do with wormholes. Not exactly, anyway, no matter how much I like the imagery of a wormhole tear in the fabric of reality that an entire universe could plop through and into being. But why not? As the authors of the paper admirably, humbly, and accurately point out, we just don't know. There are still unanswered questions about gravity and why the expansion of the universe is accelerating and not slowing.
More than anything, I'm just thrilled that words and phrases such as "wormhole" and "4D black hole" have entered the scientific discourse. It was not so long ago that the paradigm would have in no way permitted it.
This really is progress.
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