9310 A Scientific Mystery Story
As the title betrays, this is a mystery story. But, again as is promised in this title, it is not a detective mystery or an action story. No. It is an intellectual adventure, and a true one.
It started in 1961, in the bowels of the old buildings which made up the City and Guilds College in South Kensington. All around there was destruction, as the new Imperial College campus emerged. Down in the basement, however, there were still a few engineering labs left. This one, the setting for our story, was part of the new computer department; at a time when few had heard of such strange devices. This lab was the home of a number of analogue computers, machines which- in turn - few modern geeks will have heard of.
I should explain. Before simulations were the province of digital computers, in which the model is created by some form of program, we used to physically model the variables in terms of other materials. One of the most famous, at LSE, had used hydraulic circuits to model the British economy. Here, in the underbelly of C&G, we more modestly used electronic circuits to model physical variables.
That said, the desk-top computers we used were simplicity itself. The connections between the variables, the masses themselves or the springs which constrained their movement, were mapped out by valve-driven electronic circuits which were plugged into the top of this crude box of tricks. The fine tuning of the variables themselves was accomplished through the potentiometers mounted on the front of the box. The output was then shown by a conventional oscilloscope. HG Wells, who had of course been a student there in earlier years, would have loved the very Victorian feel of the resulting experimental layout.
The reason for this was, not least, that this was before the full impact of the transistor had made itself felt, and a full decade before the integrated circuits which made modern computers possible were ever dreamed of. Not long before I had worked at Farnborough, where a much larger analogue computer – filling a space the size of a small office building – had worked out the trajectories of the first ballistic missiles. That had run to just 5,000 electronic circuits, compared to the hundreds of millions inside a single modern chip, and had been limited to running for only a few minutes before one of those valves burnt out and the whole machine had to be shut down for this to be replaced.
Here I was, anyway, an undergraduate tasked with using my magic box to solve a simple three body problem. In the case of two masses connected by springs, you could work out their sinusoidal motions on the back of an envelope. Add just one more body, however, and the complexities multiplied many times over. That was why we were using the computers, crude as they were, to do the work. Even so, the expected output still was always some more complex variation on sinusoidal motion.
I sat there, varying the various controls, mesmerized by the pretty patterns on the oscilloscope and by the changes which occurred in these. After several hours, however, the repetition became monotonous in the extreme. But then monotony, often over months at a time, is the essence of most scientific experiments.
Suddenly, however, the machine went crazy. The pretty curves turned into ragged, almost chaotic, motion. As far as I could see, the motion was near random, which was something theory said was impossible.
The obvious explanation was that the machine had malfunctioned. Accordingly, having carefully noted down the readings of all the variables – after two full years at the college, I was by then well trained as an experimental scientist - I went to find the lecturer in charge. When I found him he gave me one of those withering looks reserved for students whose finger trouble makes their supervision more irksome than normal. “You must have broken it” was his distinctly unhelpful comment. To be fair, though, that was my own conclusion.
Indeed, his first action on reaching the machine was to roughly twiddle some of the knobs. The oscilloscope returned to its gentle sinusoidal motions, and he returned to his office to continue reading his newspaper. Scientists are as wont as the rest of us to resort to kicking their equipment, like some intransigent dog, when it does not obey them. Anyway, having been summarily dealt this punishment, the oscilloscope had returned to its gentle sinusoidal motions, and the lecturer returned to his office to continue reading his newspaper.
Feeling rather chastised myself, I returned the settings to where I had left off, ready to continue my set of readings. But, yet again, the scope showed random motion! Again I collected an increasingly irritated lecturer from his den. Once more a few twiddles, this time with more energy behind them, and calm returned. To prove my incompetence, however, he then carefully reset the variables to the ones that had caused the trouble. This time it was his turn to create chaos!
The chaos extended, as all the other experiments were disrupted; electronic parts being swapped backwards and forwards between the various machines - all of which were in theory identical. None of the bits failed on the other machines. More definitively, the same set-up on other machines, with identical settings, worked perfectly. The only conclusion we could reach was that the box itself was faulty. Accordingly it was removed from use and I was given another, in order to continue my run of measurements.
The disgraced box sat on a side table, as it was gradually pulled to pieces over the next weeks. Experts came and went, but nobody could discover exactly what the fault was. This was surprising, since the wiring inside the box was pretty basic and it had worked perfectly at other settings. Gradually, though, fewer and fewer visitors came to poke inside its covers, and one day it was quietly put back into use in the main lab. By then I was busy on my next set of experiments, and had forgotten all about it.
But the mystery, a real one, was that nobody had ever explained what had happened. The best science comes not from finding the right answers but from asking the right questions. This was a question begging to be answered and that should have set alarm bells ringing. But it all happened in an undergraduate laboratory, and undergraduates are notorious for getting the wrong results.
Indeed, it was not until the 1990s that I finally realized what had happened.
Thus, at about the same time as this problem occurred, in 1961, a meteorologist called Edward Lorenz had detected some similar results in a totally different field. He had, though, not been so easily deterred. Over the next couple of decades he had nagged away at the mathematics which he thought – rather than faulty equipment - was responsible, until he eventually persuaded others of the existence of his new ‘Chaos Theory’. In this way he, rather than I, found himself on the way to the Nobel Prize. But then he was a much better, and more persistent, scientist!
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