Sunday, October 27, 2013

Confused about Black Hole Paradox

SciAm reports:
Physicists Euphoric but Confused about Black Hole Paradox

“The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘eureka!’ but ‘that's funny,’” Isaac Asimov once said. Well, something seriously funny is going on in theoretical physics these days. A recent conundrum about black holes is threatening to overturn some of the most basic tenets of physics, and many scientists are nothing but thrilled.

“To me it’s the best thing that’s happened in awhile,” says University of California, Berkeley, physicist Raphael Bousso of the so-called “black hole firewall paradox,” which concerns what happens at the boundary of a black hole. “This is a 9 on the Richter earthquake scale—it’s by far the most shocking and surprising thing that has happened in my career.” The quandary prompting such jubilation is an idea first put forward in July 2012, which was extended in a paper published October 21 in Physical Review Letters. Physicists have long assumed that space is smooth at a black hole’s event horizon—the point of no return where nothing that passes through can escape. A person crossing over that line shouldn’t immediately notice anything amiss, however, and neither should a distant observer watching that person. But physicists have also assumed that information can never be destroyed. The new work says those two ideas are mutually incompatible. “It’s a paradox because several things we believed were true can’t all be true,” says Joseph Polchinski of the Kavli Institute for Theoretical Physics and U.C. Santa Barbara, one of the main architects of the firewall idea.

Polchinski and his colleagues conclude that not only is space not smooth at a black hole horizon—at that point the laws of physics completely break down. Instead of an unobtrusive boundary, the scientists argue that there must actually be a sharp division they call a firewall. “The firewall is kind of a wall of energy—it could be the end of spacetime itself,” Polchinski says. “Anything hitting it would break up into its fundamental bits and effectively dissolve.” ...

“The last year has witnessed the kind of development we live for,” Columbia University physicist Brian Greene says. “It’s where the rubber hits the road.” ...

How to move forward now is less than clear, however. “I think it’s fair to say quantum gravity is stuck,” says Matt Strassler, a visiting physicist at Harvard University. “It’s not obvious that any big progress is being made at the moment.”
Is there any better proof that physics has lost its way?

First, the interior of a black hole is not observable. You can say whatever you want about it, and no one can ever prove you right or wrong.

Second, quantum mechanics has almost nothing to do with cosmology. Quantum mechanics might help explain fusion reactions in stars, and a few things like that of cosmological relevance, but no good has come from trying to look at the wave function of a galaxy or black hole or anything like that.

Third, the firewall paradox is based on the supposed conservation of information, but no one has ever been able to show that information is conserved in any experiment, and there is no good theoretical reason for believing that it should be conserved.

Fourth, there seem to be some other quantum assumptions that no one has verified.

Fifth, you have to subscribe to a particular wave function ontology. The wave function may represent our knowledge of reality, instead of reality.

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