Friday, December 18, 2015

Physics of Reality - 4: Black Hole Complementarity by Charles Phelan

Physics of Reality – 4: Black Hole Complementarity 
by Charles Phelan

[Charles Phelan is a fellow Blogger at the popular Advaita Vision web site. He is a financial consultant by profession but has a wide range of interests with the rare quality of clarity and in-depth understanding in the fields of physics, consciousness research, philosophy, the Western esoteric tradition, and Advaita Vedanta. He is presenting here for our Readers a series of Posts highlighting the similarities in the thought process of the modern physicists at the cutting edge and what the ancient Advaita knowledge says.

I am grateful to him for readily agreeing to my request and sparing his time for contributing to our Blog. Charles can be reached at  -- ramesam.] 

The previous articles in this series explored the relevance to Advaita of some of the latest research in theoretical physics. Science is converging to a view that no description of reality can be complete without the observer, and that so-called “objective reality” is really more of a holographic illusion than anything truly solid or substantial. Today's scientists are busy trying to tease apart Maya's tricks to see how this illusion works. Leonard Susskind's theory of Black Hole Complementarity (BHC) -- the topic of this article -- provides a good example of this driving curiosity in action. 

Dr. L. Susskind
BHC is another breakthrough that forces us to dispense with any view of a single objectively real universe, and demonstrates yet again that “reality” is observer-dependent. Susskind developed BHC during his decades-long battle with Stephen Hawking. The disagreement was about a quantum loophole identified by Hawking, which became known as the paradox of information loss in black holes, and Susskind's theory was his proposed solution to the paradox.

Before we get further into the physics of black holes and information loss, let's briefly touch on a few points from Advaita. The Vedas speak of in terms of vast cosmological time scales, immense epochs (kalpas -- each but one day in the life of the creator Brahma), and the entire cycle of creation, preservation, and dissolution, sRiShTi-sthiti-laya.

If we are to take seriously the Advaita teachings on the accrual of puNya and pApa (i.e., karmic merit or demerit) to the jIva, then we can legitimately ask: What happens to the karmic "information" during the period of dissolution between kalpas? Does it somehow get "recorded" and carried over to the next cycle? Or does it get destroyed in the pralaya phase? Asking such questions is essentially no different from asking whether information is conserved or destroyed when it enters a black hole.

Just what is a black hole anyway? When a star collapses at the end of its life, completely spent of fuel and no longer able to produce fusion, it may shrink by orders of magnitude and become a white or brown dwarf or a neutron star, depending on its original size. Given sufficiently large mass, a star will collapse all the way to what is called a singularity, a point where the equations of physics break down and begin producing infinities. (Perhaps we can think of pralaya as a form of singularity?)

Black hole
Physicists call this singularity a black hole, simply because its gravitational force is so strong that even light cannot escape. No form of matter or energy that falls into the clutches of a black hole can ever get free again. To get out of Earth’s gravity well and into orbit, one must reach velocities exceeding 40,000 kilometers per hour, something we do routinely with chemical rocketry. With a black hole, even the speed of light is insufficient. For all practical purposes, the escape velocity of a black hole is infinite. There are no rockets, chemical, nuclear, or otherwise, that can possibly escape a black hole. (Sorry, Star Trek fans!) 

The point at which an object falling toward the singularity passes the point of no return is called the event horizon. Anything passing through the event horizon is doomed to eventually hit the singularity, where the force of gravity is so strong that a human being gets stretched into a piece of spaghetti thousands of miles long, most certainly not an enjoyable experience!

Dr. John Wheeler, a key 20th century figure in theoretical physics, and mentioned previously in this series, was also a pioneer in the study of black holes. In fact, he is the physicist who originally coined that term. One of Wheeler's early quips was, “Black holes have no hair.” By “no hair,” he meant they are completely smooth and featureless, without any apparent irregularities, essentially all the same as one another except for size. This, of course, was just Wheeler's poetic phrasing for what the equations of General Relativity were telling him about the structure of black holes. 

Along came Stephen Hawking, who proved that black holes are not entirely bald after all. Hawking discovered that there was more going on with black holes than had previously been assumed, and through a rigorous mathematical analysis he showed that they gradually evaporate and fade away to nothing. The reason for this evaporation has to do with the quantum entanglement of virtual particle pairs, with one part of the entangled pair falling inside the event horizon and the other outside, i.e., “hair." Theoretically, via this quantum mechanical process, photons are emitted as Hawking radiation, causing the black hole to eventually evaporate and then completely vanish. 

Hawking's analysis was rigorous and solid, and it left physicists like Leonard Susskind scratching their heads. If Hawking was correct, then objects falling into the black hole would carry information beyond the event horizon and into the singularity where it could never be recovered. That, of and by itself, does not represent a problem for physics. However, if the black hole were to fully evaporate later, then the information would be lost forever. This is a gross violation of the most fundamental understanding of physics, which firmly denies the possibility of any such information loss. It would be the equivalent of taking a safe and locking some valuables inside it, only to then watch the safe evaporate and vanish, along with the valuables. It seemed more a magic trick than science! 

Many physicists were intuitively convinced there was something wrong with Hawking's approach, but a solution remained elusive for decades. What it took to resolve the paradox of information loss was a series of advances in the physics of black hole entropy and String Theory. Combining several such breakthroughs, Leonard Susskind's proposed solution was Black Hole Complementarity.

What BHC states is that information falling into a black hole is reflected off a "stretched" hot horizon, and could theoretically be recovered from the Hawking radiation, AND that information also passes the event horizon and is eventually destroyed when it reaches the singularity. The catch is that both observations cannot be made at the same time, meaning that an observer outside the event horizon could confirm that information is reflected off the event horizon, and an observer inside could confirm information loss, but never both at the same time.

Stephen Hawking ultimately conceded the bets he had made about information loss in black holes. It had been proven to his satisfaction that the information going into a black hole could come back out via the evaporative Hawking radiation itself, rather than being lost permanently as he originally proposed. By 2008, Leonard Susskind published his book, “The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics.” The battle was over, but Hawking's brilliant challenge had stimulated an entire new wave of research leading to some truly astounding results.

(To Continue ….. Physics of Reality – 5:  will be posted on Dec 28, 2015)

Wishing All Our Readers

Season’s Greetings and
Best Wishes For a Happy And Prosperous
New Year

1 comment:

Peter Francis Dziuban said...

Fascinating. Thank you ramesam and Charles.