“I just think too many nice things have happened in string theory for it to be all wrong. Humans do not understand it very well, but I just don’t believe there is a big cosmic conspiracy that created this incredible thing that has nothing to do with the real world.” -Edward Witten
You don’t have to be a fan of string theory to understand why it’s such a promising area of scientific research. One of the holy grails of physics is for a quantum theory of gravitation: that describes gravity on the same footing as the other three forces, in very strong fields and at very tiny distances. Surprisingly, by looking at analogies between gravity and field theories, replacing particles with strings might be the answer.
Feynman diagrams (top) are based off of point particles and their interactions. Converting them into their string theory analogues (bottom) gives rise to surfaces which can have non-trivial curvature. Image credit: Phys. Today 68, 11, 38 (2015).
It’s an incredibly difficult concept to understand why this would be the case without a slew of advanced mathematics, but last year, the world’s leading string theorist, Ed Witten, tried. That is to say, he wrote a piece for other physicists entitled, “What every physicist should know about string theory.” But what if you want to understand it and you’re not a physicist?
Gravity, governed by Einstein, and everything else (strong, weak and electromagnetic interactions), governed by quantum physics, are the two independent rules known to govern everything in our Universe. Image credit: SLAC National Accelerator Laboratory.