Sunday, December 8, 2013

Blackholes and the Big Bang

Several days ago, I had linked to an article on wormholes and quantum entanglement, which suggested that quantum entanglement was accomplished through wormholes between one particle and another; and that black holes are also entangled. A couple days later, I came across this 2012 article from Nikodem Poplawski at Inside Science that suggested that inside every black hole is a universe; and that our universe was formed by a black hole. He writes:

Successful as it is, there are notable unsolved questions with the standard big bang theory, which suggests that the universe began as a seemingly impossible "singularity," an infinitely small point containing an infinitely high concentration of matter, expanding in size to what we observe today. The theory of inflation, a super-fast expansion of space proposed in recent decades, fills in many important details, such as why slight lumps in the concentration of matter in the early universe coalesced into large celestial bodies such as galaxies and clusters of galaxies.

But these theories leave major questions unresolved. For example: What started the big bang? What caused inflation to end? What is the source of the mysterious dark energy that is apparently causing the universe to speed up its expansion?

The idea that our universe is entirely contained within a black hole provides answers to these problems and many more. It eliminates the notion of physically impossible singularities in our universe. And it draws upon two central theories in physics.

* * *

A 1960s adaptation of general relativity, called the Einstein-Cartan-Sciama-Kibble theory of gravity, takes into account effects from quantum mechanics. It not only provides a step towards quantum gravity but also leads to an alternative picture of the universe. This variation of general relativity incorporates an important quantum property known as spin. Particles such as atoms and electrons possess spin, or the internal angular momentum that is analogous to a skater spinning on ice.

In this picture, spins in particles interact with spacetime and endow it with a property called "torsion." To understand torsion, imagine spacetime not as a two-dimensional canvas, but as a flexible, one-dimensional rod. Bending the rod corresponds to curving spacetime, and twisting the rod corresponds to spacetime torsion. If a rod is thin, you can bend it, but it's hard to see if it's twisted or not.

Spacetime torsion would only be significant, let alone noticeable, in the early universe or in black holes. In these extreme environments, spacetime torsion would manifest itself as a repulsive force that counters the attractive gravitational force coming from spacetime curvature. ...

... the torsion mechanism suggests an astonishing scenario: every black hole would produce a new, baby universe inside. If that is true, then the first matter in our universe came from somewhere else. So our own universe could be the interior of a black hole existing in another universe. Just as we cannot see what is going on inside black holes in the cosmos, any observers in the parent universe could not see what is going on in ours.

The motion of matter through the black hole's boundary, called an "event horizon," would only happen in one direction, providing a direction of time that we perceive as moving forward. The arrow of time in our universe would therefore be inherited, through torsion, from the parent universe.

Torsion could also explain the observed imbalance between matter and antimatter in the universe. Because of torsion, matter would decay into familiar electrons and quarks, and antimatter would decay into "dark matter," a mysterious invisible form of matter that appears to account for a majority of matter in the universe.

Finally, torsion could be the source of "dark energy," a mysterious form of energy that permeates all of space and increases the rate of expansion of the universe. Geometry with torsion naturally produces a "cosmological constant," a sort of added-on outward force which is the simplest way to explain dark energy. Thus, the observed accelerating expansion of the universe may end up being the strongest evidence for torsion.
 There are other theories that also attempt to harmonize general relativity and quantum mechanics vis a vis black holes. This article from Gizmodo in October 2013 discusses the conflict between general relativity and quantum mechanics as to the destruction of information from particles that fall into a black hole:

Roughly speaking, what happens is that a vacuum fluctuation near the event horizon produces a virtual particle-antiparticle pair. One of the pair falls into the black hole, and the other becomes real and escapes from the black hole, as the first cannot reemerge through the black hole to recombine with the first particle.

Here's the problem. When matter and light fall into a black hole, it appears that whatever information that matter and light may have carried along with them vanishes in the process. Indeed, the sum of all Hawking radiation emitted during the life of a black hole informs you of the mass, spin, and electric charge of what fell into the hole, but nothing else.

Unfortunately, one of the fundamental tenets of quantum mechanics is that information is never destroyed. It appears that the first "successful" result combining general relativity and quantum effects leads to a fundamental conflict. This difficulty is known as the black hole information paradox.

... it might be reasonable to use a model, called loop quantum gravity, which treats spacetime as a fine structure woven of Planck-sized loops. In this description of physics, there is simply no concept of lengths smaller than the Planck length. While something of the sort is likely to be true in a full quantum theory of gravity, it is expected that this structure should emerge from the theory, rather than be made a basic assumption of the theory. Even though this model may not be a viable candidate for a full theory of quantum gravity, it might give some insight into what happens at the central singularity of a quantum black hole.

This brings us to the new work of Rodolfo Gambini and Jorge Pullin, recently published in Physical Review Letters. Gambini and Pullin have developed and solved the first well-behaved model of a quantum black hole, in which the central curvature singularity vanishes, and is replaced by a bridge that appears to lead into another universe. Other details of their treatment offer promise for reconciling other apparent paradoxes associated with blending general relativity and quantum mechanics. They are currently trying to extend their work to study of an evaporating quantum black hole.

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