Newton: not new?

Last week, I promised someone to explain what my research is all about, over a grey-Saturday-morning coffee. Since most people are not familiar with the mathematical lingo I tend to speak in my own little bubble, I had to go way back in order to explain how 'spin invariant differential operators' relate to secondary school knowledge in physics and mathematics. I therefore started from the idea of mathematical equations coming from physics, like Newton's laws of motion, and their connection with the notions of 'symmetry' and 'invariance' - which, in a sense, underlie basically everything in physics. Or, as the Nobel laureate Philip Anderson wrote in his widely read 1972 article 'More is Different': "it is only slightly overstating the case to say that physics is the study of symmetry."

Newton's laws, for example, are invariant under translations in time and space. This is a formal statement, which must be expressed in terms of sound mathematical concepts (group theory, to be more precise), but it can easily be reformulated in layman speak. On the one hand, it basically says that the aforementioned laws are the same here - on earth - as elsewhere in our universe (spatial invariance). On the other hand, dinosaurs experienced the same laws - but didn't bother writing them down - and your grand-grand-grandchildren will still have to learn the very same laws, provided we don't screw their natural resources and future in the meantime (temporal invariance). To put it simple: Newton could have been an alien from the planet Zork, living in the 12th century. The same basic principle then also applies to different sets of equations, still inspired by physics, with different underlying notions of invariance. So, there you have it: my research interest in a nutshell (a hard one to crack, unfortunately).

Later that day however, on the train from Antwerp to Ghent, I suddenly realized that Newton could not just have been anyone. I mean, we all know that he allegedly came up with the idea of gravitation after an apple hit his British head. Imagine, however, what would have happened if Newton was an African scientist, taking his lunch break in the comfy shadow zone underneath a palm tree. I am pretty sure that falling coconuts do obey the laws of gravity, but I am afraid that Newton would not have been able to pass this particular piece of crucial information, since coconuts on the head sound more like 'cranial skull fracture' than 'life-altering insight'.

Even if he only got mildly injured - from a small concussion maybe - things could have gone horribly wrong. Newton could have been dyslexic, right? We have all learned at school that F = ma (force equals mass times acceleration: the subtle buzz you might hear at this very moment is most likely a distant bell ringing), but what if he had written that m = Fa? I will leave the details as an exercise for the interested reader, but this would have lead to bizarre science classes. And I am pretty sure that 'becoming an astronaut' wouldn't be as high on the young toddler's 'what do you want to be when you grow up'-list as it is now...

In the end, I once again realized that people are precisely who they are when they are. And also, that it can be fruitful to go all the way back every once in a while...