Digitization Unearths New Data From Cold War-Era Nuclear Test Films
The film is silent, but it starts with a bang. The screen blows out white, then a tropical beach comes into view, before an explosion tears across the horizon. A two-tiered mushroom cloud flows skyward, revealing a dark, intense plume of smoke that smolders in the distance.
Another film, showing the charmingly titled "Operation Teapot", is a black-and-white nightmare: A ball of fire comes into the frame over a mound in the distance, engulfing the sky and setting off a wave of soil or smoke or both, so powerful that the camera starts to shake.
These are films of the nuclear age, and there are thousands of them. They document the 210 atmospheric nuclear tests the United States conducted between 1945 and 1962.
Until recently, these government-commissioned films had been scattered around different archives, though the bulk of them sat in boxes at Los Alamos National Laboratory in New Mexico. Fortunately, a team of physicists and film archivists at Lawrence Livermore National Laboratory in California decided to digitize the films before it was too late.
Greg Spriggs, a weapon physicist and the project lead, notes that the film canisters were already starting to smell of vinegar — one of the byproducts of film decomposition.
Spriggs and his team started digitizing the films using special scanners that move the film without gripping it by the holes in the edges. But as they watched the old films, they noticed something: the nuclear yield data based on the images was wrong.
These aren’t just any old government movies: They are scientific documents that are key to understanding nuclear power. And even though the films are very old, scientists don’t get access to these sort of nuclear tests anymore: atmospheric nuclear tests have been banned since 1963.
Today, nuclear physicists run virtual nuclear tests on supercomputers. But those tests are based in part in research on the old films. And, unsurprisingly, there are better methods of measurement today.
So Spriggs and his team set about reanalyzing all of the old films, using new techniques. The indicators remain the same, in some ways: the double flash of light, the fireball, and the shock wave captured on film all offer significant information for researchers on the energy generated by the nuclear blast. But today’s new tools offer greater precision.
For instance, the size, speed and duration of the fireball created can be used to estimate the weapon’s yield. The old methods involved analysts studying the film, advancing it frame by frame to see where the edge of the fireball seemed to be, and measuring its radius. This created plenty of room for human error, and, indeed, the yield numbers generated by this method produced inconsistent results.
But the newly digitized films allow researchers to more clearly see the fireball’s edge, allowing for much more accurate yield estimates. "We were finding that some of these answers were off by 20, maybe 30, percent," says Spriggs. "One of the payoffs of this project is that we’re now getting very consistent answers. We’ve also discovered new things about these detonations that have never been seen before. New correlations are now being used by the nuclear forensics community, for example."
The lab has posted a number of the films on YouTube, and the ability to watch these films from the cold remove of one’s desk chair is an arresting experience.
These brief portals to the Cold War are oddly devoid of context. Each film on Lawrence Livermore’s Atmospheric Nuclear Test playlist is accompanied by nothing more than its code name — no date, no location, no mention of lingering radiation. The films are silent, the explosions otherworldly. But they were in our world: enormous nuclear weapons, unleashed over Nevada and the Marshall Islands.
For his part, Spriggs hopes that the films are a deterrent to using such weapons in the future.
"It’s just unbelievable how much energy’s released," he said. "We hope that we would never have to use a nuclear weapon ever again. I think that if we capture the history of this and show what the force of these weapons are and how much devastation they can wreak, then maybe people will be reluctant to use them."
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