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
[edit]The word bolide (/ˈboʊlaɪd/; from Italian via Latin, from Ancient Greek βολίς (bolís) 'missile'[2][3]) 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.[4] 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".[5] 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"[6]) has been interpreted by astronomers as a bolide in the modern sense.[7] 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.[8] 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.[9] 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.[10]
Astronomers use the word to describe any extremely bright meteor (or fireball), especially one that explodes in the atmosphere.[4] Geologists use the word to describe a very large impact event.[4]
One definition describes a bolide as a fireball reaching an apparent magnitude of −4 or brighter.[11] Another definition describes a bolide as any generic large crater-forming impacting body whose composition (for example, whether it is a rocky or metallic asteroid, or an icy comet) is unknown.[12]
A superbolide is a bolide that reaches an apparent magnitude of −17 or brighter,[11][13] which is roughly 100 times brighter than the full moon. Recent examples of superbolides include the Sutter's Mill meteorite in California and the Chelyabinsk meteor in Russia.
Astronomy
[edit]The IAU has no official definition of "bolide", and generally considers the term synonymous with fireball, a brighter-than-usual meteor; however, the term generally applies to fireballs reaching an apparent magnitude −4 or brighter.[11] Astronomers tend to use bolide to identify an exceptionally bright fireball, particularly one that explodes (sometimes called a detonating fireball).[14] It may also be used to mean a fireball that is audible.
Superbolide
[edit]Selected superbolide air bursts:
- Tunguska event (Russia, 1908)
- 2009 Sulawesi superbolide (Indonesia, 2009)
- Chelyabinsk meteor (Russia, 2013)
Geology
[edit]Geologists use the term bolide differently from astronomers. In geology, it indicates a very large impactor. For example, the Woods Hole Coastal and Marine Science Center of the USGS uses bolide for any large crater-forming impacting body whose origin and composition is unknown, as, for example, whether it was a stony or metallic asteroid, or a less dense, icy comet made of volatiles, such as water, ammonia, and methane.[12]
The most notable example is the bolide that caused the Chicxulub crater 66 million years ago. Scientific consensus agrees that this event directly led to the extinction of all non-avian dinosaurs, and it is evidenced by a thin layer of iridium found at that geological layer marking the K–Pg boundary.
Gallery
[edit]See also
[edit]- Comet Shoemaker–Levy 9 § Impacts – Comet that collided with Jupiter
- Earth-grazing fireball – Meteoroid that enters Earth's atmosphere and leaves again
- Meteor procession – Meteor that breaks apart into fragments travelling in the same direction
- Tollmann's hypothetical bolide – Hypothetical impact event
- Impact event#Airbursts – Collision of two astronomical objects
- Bugatti Bolide – track-focused hypercar
- RBS 70 – Swedish man-portable air-defense system
References
[edit]- ^ "We are not Alone: Government Sensors Shed New Light on Asteroid Hazards". Universe Today. Retrieved 12 April 2015.
- ^ "bolide". Merriam-Webster.com Dictionary. Merriam-Webster.
- ^ "bolide". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
- ^ a b c Sutter, Paul M. (16 January 2022). "Astronomy Jargon 101: Bolide". Universe Today.
- ^ "CHAP. 25.—EXAMPLES FROM HISTORY OF CELESTIAL PRODIGIES; FACES, LAMPADES, AND BOLIDES". Pliny the Elder, The Natural History, BOOK II. AN ACCOUNT OF THE WORLD AND THE ELEMENTS.
- ^ Pliny the Elder, The Natural History, BOOK II.
We have an account of a spark falling from a star, and increasing as it approached the earth, until it became of the size of the moon, shining as through a cloud; it afterwards returned into the heavens and was converted into a lampas; this occurred in the consulship of Cn. Octavius and C. Scri- bonius. It was seen by Silanus, the proconsul, and his attendants.
- ^ Kronk, Gary W. (28 September 1999). Cometography: Volume 1, Ancient-1799: A Catalog of Comets. Cambridge University Press. p. 515. ISBN 978-0-521-58504-0.
- ^ Stothers, Richard B. (1987). "The Roman fireball of 76 BC". The Observatory. 107: 211–213. Bibcode:1987Obs...107..211S. Archived from the original on 15 September 2022. Retrieved 4 June 2023.
- ^ Marvin, M. D. (1996). "Ernst Florens Friedrich Chladni (1756-1827) and the origins of modern meteorite research". Meteoritics & Planetary Science. 31 (5): 545-588.
- ^ Marvin, Ursula B. (1996). "Ernst Florens Friedrich Chladni (1756–1827) and the origins of modern meteorite research". Meteoritics & Planetary Science. 31 (5): 545–588. Bibcode:1996M&PS...31..545M. doi:10.1111/j.1945-5100.1996.tb02031.x. ISSN 1945-5100. S2CID 210038676.
- ^ a b c Belton, MJS (2004). Mitigation of hazardous comets and asteroids. Cambridge University Press. ISBN 0521827647.: 156
- ^ a b "Introduction: What is a Bolide?". Woodshole.er.usgs.gov. 1 April 1998. Retrieved 16 September 2011.
- ^ Adushkin, Vitaly; Ivan Nemchinov (2008). Catastrophic events caused by cosmic objects. Springer. ISBN 978-1402064524.: 133
- ^ Ian Ridpath, ed. (2018). "Bolide". A Dictionary of Astronomy (3 ed.). Oxford University Press. bolide. ISBN 978-0191851193.
External links
[edit]- historic record of bolides that have been witnessed entering the Earth’s atmosphere around the world from 861 through 2012 (B612 Foundation)
- Bolide Events from 1988 to the present neo.jpl.nasa.gov
- Earth Impact Effects Program Estimates crater size and other effects of a specified body colliding with Earth.