Carlo Revelli (2015) Seven Brief Lessons on Physics, translated by Simon Carnell and Erica Segree. First Lesson. The Most Beautiful of Theories.

First Lesson. The Most Beautiful of Theories.

I just nipped out at lunchtime to get a bigger brain, but they were all out, the only thing left –on special offer- was a Simon Cowell brain. I said to the lassie behind the counter, ‘Do I look that fuckin’ stupid?’

‘Or a two-for-one, David Cameron and… a black hole,’ she offered.

I didn’t hang about, I’ve got better things to do with my time. Of course I don’t need a bigger brain. After all, quite simply, The Most Beautiful of Theories is Einstein’s General Theory of Relativity. Kudos, a kind of mental judo, by owning this book, it makes me instantly brainer. It’s a general thing, some of you might not understand. Albert, like me, didn’t do that well at school. In second year of St Andrew’s school I sat my first exam in Physics. Question 2 had me going. Twenty-seven years later I was still sitting in the old gym hall, pondering.  Rovelli tells the reader Einstein ‘spent a year loafing aimlessly’ and he reminds us, ‘You don’t get anywhere by not wasting time’. I was off to a flier. Einstein didn’t sit any exams and neither did I – you can see where this is going?

I’m now going to explain gravity. And if it sounds like I’ve just made it up, it’s Einstein’s fault. Think back to Isaac Newton and the apple failing. That’s gravity at work, the force that draws all things together and keeps them apart, but on its day off it plays by different rules.  Newton imagined space to be ‘a great big empty container’. Farraday and Maxwell had filled the box with the pulses of an electromagnetic field and a gravitational field. Einstein’s genius was in seeing that the gravitational field is not diffused through space, something added, like a prosthetic nose. The gravitational field is space (and time and motion), the dancer and the dance, the singer and the notes of a song.

‘How can we describe the curvature of space?’ such as planets circling around the sun, asks Rovelli. I stuck my hand up here and shouted, ‘as a curve, sir?’ always a smart alec, although my name wasn’t alec. And, you know, I wasn’t far wrong. Bernhard Riemann had produced a doctoral thesis that was ‘completely useless’ and made no sense. Just the thing for the job. Riemann’s curvature (R) is equivalent to the energy of matter. I’ll not write out the full equation here because I’ve only got one lifetime to understand it, but I guess, you get the drift. Light stops moving in straight lines, space bends around a star and Mars bars become increasingly smaller the closer you come to buying one.

The whole of space can expand and contract, like the exhalation and inhalation of breath. Einstein’s equation predicted ‘The Big Bang’, or at least helped explain it in Homer Simpson bites as a young god slaving over an extremely small and extremely hot universe. Oops. Butter fingers.  Cosmic radiation flowing like waves from that small, fixed point in time and space were a glimpse of Einstein’s reality. I’m going to read a bit more of Riemann’s mathematics before I say more, but next up, Lesson 2, tomorrow, I’ll explain with the help of my old buddy Carlo Ravelli’s primer: Quanta.  Wow that should be big.