John Escobar and colleagues at UCLA have shown that the simple act of peeling an ordinary sticky tape in vacuum generates enough X-ray to take an image!
"At some point we were a little bit scared," says Juan Escobar, a member of the research team. But he and his co-workers soon realized that the X-rays were only emitted when the kit was used in a vacuum. "We don't want to scare people from using Scotch tape in everyday life," Escobar adds.
This kind of energy release — known as triboluminescence and seen in the form of light — occurs whenever a solid (often a crystal) is crushed, rubbed or scratched. It is a long-known, if somewhat mysterious, phenomenon, seen by Francis Bacon in 1605. He noticed that scratching a lump of sugar caused it to give off light.
The leading explanation posits that when a crystal is crushed or split, the process separates opposite charges. When these charges are neutralized, they release a burst of energy in the form of light.
As long ago as 1953, a team of scientists based in Russia suggested that peeling sticky tape produced X-rays. But "we were very sceptical about the old results," says Escobar. His team decided to look into the phenomenon anyway, and found that X-rays were indeed given off, in high-energy pulses.
Photo: Carlos G. Camara, Juan V. Escobar, Jonathan R. Hird and Seth J. Putterman