What was the brightest fireball ever seen?
Some fireballs have been brighter than the Sun. The Chelyabinsk fireball in Russia in 2013 was, for a moment, about 30 times brighter than the Sun.
Most fireballs are bright, but a few are truly dazzling, brighter even than the Sun.
Chelyabinsk, 2013. On the morning of 15 February 2013, a space rock about 18 to 20 metres across entered the air over Chelyabinsk in Russia. It was moving at about 19 kilometres per second. As it broke apart, it flashed so brightly that, for a moment, it was about 30 times brighter than the Sun. People felt heat on their faces, and shadows swept across the ground. It was filmed by hundreds of cameras.
Tunguska, 1908. Witnesses of the Tunguska event in Siberia described a fireball as bright as the Sun streaking across the sky before a huge explosion. There were no cameras then, so we do not know exactly how bright it was.
Sikhote-Alin, 1947. People who saw this iron meteoroid fall in eastern Russia described a fireball brighter than the Sun, even in daylight.
Measuring brightness. Astronomers measure brightness on a scale called magnitude. The brighter something is, the lower, or more negative, its number. The full Moon is about magnitude minus 12.7, and the Sun about minus 26.7. The Chelyabinsk fireball was estimated at around minus 28 at its peak.
Such super-bright fireballs, called superbolides, are rare. Most of us will only ever see ordinary fireballs, which are still wonderful.