"At 8:03, My Brain Exploded"

September 17, 2008

When most people hear the phrase "string theory," they probably don't think, "comedy gold." But stand-up comedian Brian Regan dares to venture where many of his cohorts fear to tread in this bit describing his first viewing of a NOVA special on string theory (I assume it was The Elegant Universe): [UPDATE: The embedded video link seems to have broken overnight. You can find the routine here, and here (at 1:22 mark).]

For all his posturing as the big, dumb, chip-devouring couch potato, it's obvious that Regan has a bit more on the ball than that. First, he was watching NOVA; it's a popular show, but ratings-wise, it doesn't even begin to compete with network television staples like C.S.I. I'm not saying he's a techno-geek or anything, but I'll go out on a limb and say he's got a healthy curiosity about science and how the universe works.

Second, he grasps at least one of the essential concepts behind string theory: the fact that our current Standard Model of particle physics manages to merge three of the four fundamental forces -- at least at ultra-high temperatures, of the sort that only existed in the first fractions of a second after the big bang -- but physicists haven't yet figured out where gravity fits into the grander scheme of things. And Regan also remembered (and riffed upon) the fact that this was something that eluded one of the greatest minds of physics: Albert Einstein.

Einstein managed to unify space and time, energy and mass, and gravity and acceleration, but he got hung up on unifying gravity with all the other forces.  Physicists are still struggling to reconcile general relativity -- which applies to objects and physical systems on the macroscale, from missile trajectories to planetary motion -- and quantum mechanics, which governs the behavior of objects and systems at the subatomic level.

We have two different "rule books," and each works very well so long as they stick to their respective realms. All hell breaks loose when one tries to venture onto the other's turf: relativity breaks down at the atomic level, and quantum phenomena don't materialize at the macroscale. When was the last time you saw someone walk through a wall (Kitty Pryde from the X-Men movies doesn't count)? But at the quantum level, electrons "tunnel" their way through seemingly impenetrable energy barriers all the time. Getting these two to work together is a bit like mixing oil and water.

I won't even attempt to make sense of the more complex mind-boggling technical details -- we can't have people's brains exploding all over their computer monitors first thing Wednesday morning, can we? Employers take a very dim view of that. Basically, string theory attempts to solve the conundrum by re-envisioning point particles as tiny vibrating strings. (Nifty historical detail: the inspiration came from a long-forgotten equation by 18th century Swiss mathematician Leonhard Euler, dismissed by his contemporaries as a bizarre curiosity of no real significance. Boy, are their faces red!)

So, any particle, when sufficiently magnified, wouldn't look like a solid fixed point, but like a one-dimensional filament, or string, resembling a rubber band. The strings can stretch, contract, and wriggle like violin strings. And the different ways in which they vibrate determine why elementary particles have the masses and other properties that they do.

That's the more poetical aspect of string theory that has so captured the popular imagination; those of us who work with words and metaphors for a living are suckers for that sort of thing. If only it were really that simple! In reality, string theory is incredibly complicated and it's easy for a non-scientist to lose the narrative thread. It's also become increasingly controversial, with critics dismissing it as just pretty math that doesn't make testable predictions. And without something to test, the theory can't really be verified -- making it "not even wrong," in the words of one well-known critic, Peter Woit.

Maybe the Large Hadron Collider will discover something useful to give string theory some much-needed bolstering -- a supersymmetric particle or two would be nice, or even evidence for extra dimensions. Maybe the LHC won't find anything at all. Or maybe it will find something completely unexpected that will blow our minds and make string theory and everything else obsolete. In the meantime, that sure is some pretty math.