Life in the Fast Train: a Scientific Journey

As a junior faculty member at Nordita, it goes without saying that I would like to spend all my days at the office thinking about physics — my scientific journey so to say. Despite working at a physics institute that, paradoxically, doesn’t necessarily always happen. Often for me, this stems from periods of focusing on grant writing or the concatenation of time set aside for administrative purposes. Though also important, during such periods it can feel like my scientific journey is on hold.

Once during one of those periods, I was stuck on the financial paragraph of a grant proposal. Something with personnel and overhead costs that is really beyond the scope of what a theoretical physicist can comprehend.

So, after some hours of struggling, I went to the administrative part of Nordita for guidance. However, halfway through the hallway I heard my name: “Watse, you like general relativity, don’t you?”. And although the answer to that question is a firm affirmative one, I was directly cautioned by the way this question was phrased.

When I turned to the direction from which the voice came, I saw a senior faculty member staring at me, then at a hallway-whiteboard, and then back at me. The whiteboard bore equations that were familiar. “I got the following question from a high-school teacher” says the senior faculty member. “Say you put an entire train track on a weight scales. Then you put a train, say of 100.000 kg, on the tracks and make it travel at 99% of the speed of light. What’s the force acting on the scales when the train passes by?”

I start to mutter something about relativistic mass. Before potentially making a fool out of myself by trying to argue (or remember) if one should divide or multiply by the infamous Lorentz factor, I am stopped in my tracks (pun intended) by the senior faculty member. “Yes Watse, that was my first response as well. Some special relativity equations that have been seared into our brains due to our bachelor studies. But what I am playing with, is how to derive the actual force by starting from general relativity. Curved spacetime and all that. It is nothing new, but I just want to derive it from first principle”. We stood there puzzling for half an hour or so, excitedly writing equations, until we were satisfied.

And even after the friendly Nordita administrators helped me discover that the most appropriate place for my financial paragraph was in the rubbish bin, I felt satisfied with my day. Yes, we had merely reproduced a textbook result, but that was not the point. It made me feel like that day was all about the scientific journey again!