A fireball is a brighter-than-usual meteor. The International Astronomical Union defines a fireball as "a meteor brighter than any of the planets" (magnitude -4 or greater). The International Meteor Organization (an amateur organization that studies meteors) has a more rigid definition. It defines a fireball as a meteor that would have a magnitude of -3 or brighter if seen at zenith.
This definition corrects for the greater distance between an observer and a meteor near the horizon. For example, a meteor of magnitude -1 at 5 degrees above the horizon would be classified as a fireball because if the observer had been directly below the meteor it would have appeared as magnitude -6.
There are probably more than 500,000 fireballs a year, but most will go unnoticed because most will occur over the ocean and half will occur during the daytime.
Fireballs reaching magnitude -14 or brighter are called bolides. The IAU has no official definition of "bolide", and generally considers the term synonymous with "fireball". Astronomers often use "bolide" to identify an exceptionally bright fireball, particularly one that explodes (sometimes called a detonating fireball). It may also be used to mean a fireball which creates audible sounds. In the late twentieth century, bolide has also come to mean any object that hits the Earth and explodes, with no regard to its composition (asteroid or comet). Continue reading
Eerie green fireball detected hours before smashing into Lake Ontario in the dead of night Live Science - November 22, 2022
A renegade meteor flared in Earth's atmosphere in the wee hours of Nov. 19, creating a bright green fireball in the sky over the eastern US and Canada. This fireball was a small meteor, detected by astronomers just three hours before it tumbled through Earth's atmosphere, caught fire and broke up into hundreds of pieces. Most of those pieces likely smacked straight into Lake Ontario, though some small chunks may have impacted land on the lake's southern shore, according to NASA.
Asteroid 2022 WJ1 impacts Earth over Niagara Falls, becoming the 6th asteroid to be detected before impact Watchers - November 20, 2022
A newly-discovered asteroid designated 2022 WJ1 impacted Earth's atmosphere over Niagara Falls at 08:27 UTC on November 19, 2022, becoming the 6th asteroid to be discovered before impacting Earth.
2022 WJ1 was a tiny asteroid on a collision course with Earth. But astronomers saw it coming, and NASA's Scout impact hazard assessment system calculated where it would hit Live Science - November 23, 2022
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