Allegedly, this is a photograph of the beginning of a nuclear detonation. It was taken in 1952 during the Tumbler-Snapper tests in Nevada. At this point, the fireball is about sixty-six feet across. How was the photographer able to get a shutter speed fast enough to do it? He used a Kerr cell, which is a device that uses polarizing filters to block the passage of light.
Link -via The Presurfer