1. a burning cloud of gas at the centre of a nuclear explosion
2. a ball of fire
Origin and usage
Fireball dates back to the 1550s and is a combination of the words ‘fire’, from the Old English spelling ‘fyr’, and ‘ball’, from the Old English word ‘beal’ or ‘beall’ meaning ‘a round object’.
The word fireball is a noun that refers to a ball of fire. This can occur as the result of a nuclear explosion, but fireball is frequently used to describe a very bright meteor.
Several thousand fireball meteors travel through the Earth’s atmosphere every day. Many of these occur over oceans or uninhabited land, and because so many happen during the day when the sun is bright, it is fairly rare to actually witness a fireball.
Fireballs have two types of trails: smoke trails and trains. A smoke trail is commonly seen on fireballs observed during the day; they look a lot like the trails left by planes or other common aircraft. A train is a glowing tail of light that follows a meteor. Trains are most often seen on fireballs that appear in the dark night sky.
Most fireball meteors never reach the ground. Scientists estimate only 10 to 50 meteors fall to earth each day, but because most of these occur over vast bodies of water or in places where human life is scarce, most drops are never found by people. In fact, only about 2 to 12 dropped fireballs a day have the potential to be discovered by humans somewhere on the planet.
“My condition is good, but that was a real fireball, boy.”
(U.S. astronaut John Glenn, upon re-entering Earth’s atmosphere aboard the Friendship 7 orbiter)