Rapatronics. Sounds like science fiction, doesn’t it – or maybe a berserk new music style. Except it isn’t.
In fact, rapatronics – ‘Rapid Action Electronics’ – was a technology for taking ultra-high speed photographs, invented by Harold Edgerton in the 1940s. That’s right – around 70 years ago. The system used oscillating magnetic fields to polarise and then depolarise a Faraday cell made typically of flint glass, turning it briefly transparent and acting as a shutter with exposure times down to 4 millionths of a second.
Pretty cool tech even by today’s standards, and what’s even cooler is that the principle of using magnetic fields to polarise material was discovered by Michael Faraday in 1845.
Thing is, with a shutter speed of 1/4,000,000 of a second you need a pretty bright flash to properly expose the film. An atomic flash, in fact. In 1947, Edgerton and two friends set up a company, EG&G, to make rapatronic cameras capable of photographing the first microseconds of nuclear test blasts. Each camera was good for one shot – there was no way of transporting roll film fast enough, so Edgerton typically ganged up a rack of them to take a series of shots at millisecond intervals. They were in operation by 1950 and used, for the last time, in 1962. By then the US, Britain and Soviet Union were already talking about a nuclear test ban treaty; and it was signed the following year – ending all nuclear tests except those held underground.
Edgington was also able to use his shutters to photograph hummingbirds in flight for the first time, at much slower shutter speeds, photographed bullets passing through playing cards, and was still working on camera systems in the 1980s – notably a strobe system that could take motion pictures of creatures that normally moved too slowly to be detected.
But his ghostly monochrome images of those atomic weapons tests remain perhaps the iconic demonstration of his inventiveness – and a sobering reminder of the wider mind-set of that age. The mid-twentieth century was still the age when humanity believed nature could be conquered. The atomic weapons and cameras used to photograph them ran to the edges of the laws of physics. It was an age when all things ‘atomic’ symbolised high-tech, superiority and power. When bigger was better – including, for a while, atomic bombs.
I still wonder how we got away with the twentieth century – why the world didn’t dissolve into armageddon, probably by accident. But we did get away with it. The dangerous stand-off was defused. Sanity prevailed.
Next time, of course, we may not be so lucky.
Copyright © Matthew Wright