Nuclear Mysteries: the Rope Trick Effect

August 9, 2017

Developing and testing the most destructive weapons in history was a process fraught with danger—and discovery. Here, an ultra-high-speed camera captured strange protrusions from the fast-growing fireball of a nuclear explosion.

The "Rope Trick"

Milliseconds after detonation, spikes of bright light emanate from the bottom of a nuclear fireball.

What's Happening Here?

Photographed milliseconds after a test bomb was detonated, the rapidly-expanding fireball of this nuclear explosion displays strange "legs" of bright plasma protruding toward the ground. These protrusions follow the ropes that stabilized a small tower supporting the warhead—much like the cables that you see supporting cell phone towers. As the unstable elements inside the bomb disintegrate in a chain reaction, extreme amounts of energy are released as radiation across the whole electromagnetic spectrum. A lot of this energy comes off as visible and infrared light, some of which strikes the ropes, heating them instantly to such a high temperature that they vaporize and take on the appearance seen here. Although scientists didn't understand what was happening at first, they developed this hypothesis and tested it by covering the ropes with a reflective substance—finding that this prevented the appearance of these "legs".