It's 1916. Albert Einstein has just published the general theory of relativity, which describes the curvature of light influenced by mass. “Which means,” says theoretic physicist Gideon Koekoek, “that the light from a star is curved by the sun, and looking from earth is in a different place than you would think.”
Even during the publication, there was a rumour that only three people could possibly understand the theory. At that same time, Eddington, a British astrophysicist who had collaborated on Einstein's experiments, had a physicist friend visiting. When he confronted Eddington with the ‘three’ people, the Brit became silent. The physicist asked him what he was thinking.
Eddington: ‘I was wondering who the third person is.’
The anecdote gave the theory a daunting reputation. There is another one, again with Eddington in the leading role: in 1919, the New York Times sent a journalist to the astrophysicist in order to bring the general theory of relativity into the limelight. In his article, the reporter stated that it was so difficult that no more than twelve people in the world would understand it. “What had happened: The New York Times had sent a sports reporter, who probably had nothing to do at the time. You have to realise that science at the time was not news. Newspapers didn't have science pages back then. It was too distant from their readers.”
The stories fed and maintained the myth of incomprehensibility, says Koekoek, who is setting up a Maastricht physics group centred on gravitational waves and who teaches at the Science Programme. “You see it with students, they are scared of the theory. Many sound out beforehand whether the subject is too difficult. I ask them two things: if they have had the special theory of relativity (for those who can't remember: time and distance depend on the speed with which you pass through space). And I want to know if they are afraid of mathematics. You actually have to wrestle through a new kind of mathematics for the general theory of relativity: tensor algebra.”
Every second-year physics student who is prepared to do that, says Koekoek, can understand this theory. Although this doesn't take away from the fact that the general theory of relativity is for diehards who have taken on the idea of studying theoretical physics or cosmology. The special variant, which has a more limited scope, is what you often need as a physics student and is a lot easier, says Koekoek.
Quantum mechanics is another story. “The relativity theories can be grasped, in the sense that you can form an idea, of that curved space. This is not possible with quantum mechanics, which is counterintuitive and like nothing we know. We know that this theory is correct; it is the most tested of all theories and appears to be correct to ten decimals. It also works, because what most people don't know is that every transistor has run on it since the fifties. But what exactly the physics of it is, remains veiled in mystery.”