Lightning Captured by X-Ray Camera

The first x-ray images of a lightning strike have been captured by a, well, lightning-fast camera, scientists say. The pictures suggest a lightning bolt carries all its x-ray radiation in its tip. (Get lightning facts.)

During recent thunderstorms in Camp Blanding, Florida, the camera's electronic shutter "froze" a lightning bolt—artificially triggered by rockets and wires—as it sped toward the ground at one-sixth the speed of light.

"Something moving this fast would go from the Earth to the moon in less than ten seconds," said Joseph Dwyer, a lightning researcher at the Florida Institute of Technology in Melbourne.

Scientists have known for several years that lightning emits radiation, said Dwyer, who revealed the photos at an annual meeting of the American Geophysical Union in San Francisco earlier this month.

But until now scientists didn't have the technology to take x-ray images quickly enough to see where the radiation comes from, he said.

(Read "New Lightning Type Found Over Volcano?")

Lightning Imaged by 1,500-Pound Camera

Making a camera capable of taking such quick images was an achievement in and of itself, Dwyer emphasized.

"You can't just go buy a camera and point it at lightning," he said. "We had to make it."

The resulting 1,500-pound (680-kilogram) camera—created by Dwyer's graduate student Meagan Schaal—consists of an x-ray detector housed in a box about the size and shape of a refrigerator. The box is lined with lead to shield the x-ray detector from stray radiation.

X-rays enter the box through a small hole that in turn focuses them, like an old-fashioned pinhole camera.