Attempts to unite general relativity with quantum mechanics have so far failed. The latest ideas using string theory — based on a concept of elementary particles being tiny strings whizzing through space-time — have not produced verifiable predictions, so some authors have condemned them as "not even wrong". Yet now, suddenly, a strange anomaly has been measured, with neutrinos appearing to travel faster than light. To avoid an obvious conflict with Einstein's relativity, some physicists have conjectured that the photons of light might be following a longer path involving the hidden quantum dimensions of string theory.

These hidden dimensions, all tightly curled up, extend four-dimensional space-time to ten or eleven dimensions. To get the idea, imagine adding just one further dimension, tightly curled up into a small circle. Doing this at each point of a one-dimensional line yields the two-dimensional surface of a cylinder. Doing it at each point of any space yields something one dimension higher, and doing it to four-dimensional space-time yields something five dimensional. This idea was propounded by Theodor Kaluza and Oskar Klein back in the 1920s in order to merge electromagnetism with gravity, but it came up with the wrong numbers and was abandoned. The point is that electromagnetic waves — of which light is one example — can be regarded as spinning round a tiny circle, and hence be thought of as barrelling down tiny cylinders, corkscrewing as they go. Neutrinos on the other hand are entirely unaffected by electromagnetism, so depending on how space-time is merged with the extra dimensions they may follow more direct paths, hence the apparent time difference.

Comparing the present confusion with the past, the astonishing experimental evidence of the late 19th century led to a new way of combining time with space, and hence to special relativity, but that was not the end of it. Einstein's persistent willingness to ask questions led to the curvature of space-time in general relativity, helping us understand the strange phenomenon of black holes and much more.

What is now needed is not just a mathematical way of combining space-time with the extra dimensions of string theory — which may explain the anomaly — but the ability and willingness to ask some really probing questions.

Will it happen? Perhaps some clever young person, going to and from work on the Clapham omnibus, is looking out of the window and thinking...deeply. I do hope so.