**Correction: A previous black hole firewall story by Jennifer Ouelette was published in Simons Science News and reprinted in Scientific American. I had originally said it was published in Scientific American.
Some readers may have loved Dennis Overbye’s cover story on black holes in yesterday’s Science Times. If you get a buzz off cool terminology and superficial brushes with awesomely geeky science, well, great. But the story was less rewarding for those who expected their reading efforts to pay off with some genuine comprehension of the subject matter.
The subject of the story is, roughly, what happens to someone falling into a black hole. On the positive side, the question is not just a curiosity. It’s a huge deal in the theoretical physics community, since the outcome of this thought experiment creates a paradox revealing the limitations of current physics. Delving into the paradox may lead to some new, deeper, more all-encompassing theory. (The importance of this problem is something I picked up last winter while on fellowship at the Kavli Institute for Theoretical Physics. I heard a version of the story first hand from a very patient physicist named Joe Polchinski.)
There’s no real news peg now – this issue over the fate of black hole divers emerged last summer and has already been written about several places last year:
George Musser covered it here for his Scientific American blog
Jennifer Ouelette covered it here at some length for Simons Science News, reprinted in Scientific American.
There’s nothing wrong with coming late to the party, as long as the Times advances the story beyond what these other writers have done. And there’s definitely room for another story on the same topic as long as it makes the science more comprehensible and suitable for a newspaper readership. Taking it on was a perfectly reasonable, even brave decision on the part of the Times.
In the end, however, there wasn’t much in the Times story that hadn’t been covered in Scientific American/Simons Science News in 2012. Overbye takes readers through much of the same territory, and quotes most of the same sources, and oddly, the Times lede is the only one that presents the debate as news:
A high-octane debate has broken out among the world’s physicists about what would happen if you jumped into a black hole, a fearsome gravitational monster that can swallow matter, energy and even light.
As for comprehensibility, I’d give the Times third place out of the three. And all these pieces lacked something in explaining the nature of the question. At issue (I think) are calculations showing that for quantum mechanics to be preserved, someone falling into a black hole would be incinerated by a “firewall” of particles right at the boundary known as the event horizon.
We’re told it’s a paradox, in part because there’s a violation of Einstein’s equivalency principle, which, as Overbye describes it, says this: “A freely falling person would not feel his weight. It is known simply as the equivalence principle; it says that empty space looks the same everywhere and to everyone.”
Okay, but why does this firewall present a paradox? If you fell into a burning building you’d get incinerated, and that’s not a violation of general relativity. If conditions around a black hole create some sort of nasty hot wall of particles, how is that more of a violation of equivalence than someone falling into an actual wall of fire?
Is it because it’s not an actual firewall of particles and energy but some weird kink or discontinuity in space and time? Or is the problem that the firewall is some kind of consequence of extreme gravity? As a reader, I don’t think I should have to be guessing and inferring at this point. This is the kind of thing that really needs to be spelled out. Offering a deeper or more complete explanation is not a form of dumbing down.
The Times piece brushes by a possible explanation here:
Their calculations showed that having information flowing out of a black hole was incompatible with having an otherwise smooth Einsteinian space-time at its boundary, the event horizon. In its place would be a discontinuity in the vacuum that would manifest itself as energetic particles — a “firewall” — lurking just inside the black hole.
But instead of developing this idea of a “discontinuity in the vacuum” and explaining more thoroughly why this firewall would violate the tenets of relativity, we’re yanked through a quickie lesson in quantum entanglement and then holographic universe. The purpose is to explain how the scientists got to the firewall idea, I think, but these sections ask a lot of readers.
Consider two particles (let’s call them Bob and Alice) that have been radiated by a black hole. Bob left it eons ago, as it began leaking radiation; quantum entanglement theory dictates that in order for the black hole to keep track of what information it has been transmitting, Bob out there has to be entangled with Alice, who just left.
But that scenario competes with another kind of entanglement, between particles on either side of the event horizon, the black hole’s boundary. If space is indeed smooth, as Einstein postulated, and if quantum field theory is correct, Alice must be entangled with another particle, Ted, who is just inside the black hole.
But quantum theory forbids promiscuous entanglements. In the language of quantum information, Alice can marry either Bob or Ted, but not both, even if the second marriage happens inside the black hole where most of us can’t see it.
Got that? It's a lot of effort trying to keep Bob and Alice and Ted straight and comprehend why Alice isn’t supposed to have a relationship with two guys and what this has to do with the question. Wait, what was the question again?
By this point, I’m feeling as if nobody is tending to the quality of my reading experience. It’s not really clear how all this difficult material fits with the initial problem – and again that may come back to a flaw in the foundation of the piece. It’s not clear enough from the start why this “firewall” violates relativity, and later it’s not clear how all the quantum entanglement business explains why the firewall comes into play, if that is indeed why we’re supposed to read it.
This subject is explainable and it’s fascinating. Curious lay readers can get it. But the scientists should be working harder so the readers don’t have to. These physicists say they’re “surprised” or they think an idea is “odious” and yet the authors don’t push them to fully explain why they feel the way they do. The physicists in these stories aren’t being pushed hard enough to explain and develop the concepts they introduce.
If the scientists aren’t making sense, it may be because they’ve skipped something that’s second nature or old hat to them but not to the rest of us. Some ideas in physics are not intuitive, but there’s logic and coherence to it.
There’s another level of interpretation that would allow more readers to get this with a lot less strain.
The black hole paradox is a big deal to the scientists for a reason. Who knows – this could end up as part of the textbook material used to torture mid 21st century college students. So everyone who has taken it on and the editors who enabled them all deserves some credit for vision.
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