Bolide

A bolide is normally taken to mean an exceptionally bright meteor, but the term is subject to more than one definition, according to context. It may refer to any large crater-forming body, or to one that explodes in the atmosphere. It can be a synonym for a fireball, sometimes specific to those with an apparent magnitude of −4 or brighter.

Definitions

The word bolide (; from Italian via Latin, from Ancient Greek βολίς (bolís) 'missile') may refer to somewhat different phenomena depending on the context in which the word appears, and readers may need to make inferences to determine which meaning is intended in a particular publication. An early usage occurs in Natural History, where Pliny the Elder describes two types of prodigies, "those which are called lampades and those which are called bolides". At least one of the prodigies described by Pliny (a "spark" that fell, grew to the "size of the moon", and "returned into the heavens") has been interpreted by astronomers as a bolide in the modern sense. His description of an object coming near the earth and continuing back into the sky matches the expected trajectory of a fireball crossing above an observer. A 1771 fireball that burst above Melun, France, was widely discussed by contemporary astronomers as a "bolide" and was the subject of an official French Academy of Sciences investigation led by Jean-Baptiste Le Roy. In 1794, Ernst Chladni published a book proposing that meteors were small objects that fell to Earth from space and that small bodies existed in space beyond the moon. Though initially ridiculed, Chladni's book became the starting point for the modern field of meteoritics.