View source for Bolide

{{Short description|Extremely bright meteor}}
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| image1            = Bolide.jpg
| image2            = SmallAsteroidImpacts-Frequency-Bolide-20141114.jpg
| caption1          = A bolide – a very [[fireball (meteor)|bright meteor]] of an apparent [[Magnitude (astronomy)|magnitude of &minus;4]] or brighter
| caption2          = World map of bolide events (1994–2013)<ref>{{cite news|title=We are not Alone: Government Sensors Shed New Light on Asteroid Hazards|url=http://www.universetoday.com/116355/we-are-not-alone-government-sensors-shed-new-light-on-asteroid-hazards/|access-date=12 April 2015|newspaper=[[Universe Today]]}}</ref>
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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 [[Impact crater|crater]]-forming body, or to one that explodes in the [[atmosphere]]. It can be a synonym for a [[Meteoroid#Fireball|fireball]], sometimes specific to those with an [[apparent magnitude]] of −4 or brighter.

==Definitions==
The word ''bolide'' ({{IPAc-en|'|b|oʊ|l|aɪ|d}}; from [[Italian language|Italian]] via [[Latin]],  {{etymology|grc|''{{wikt-lang|grc|βολίς}}'' ({{grc-transl|βολίς}})|[[missile]]}}<ref>{{cite Merriam-Webster|bolide}}</ref><ref>{{OED|bolide}}</ref>) 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.

One sense refers to an extremely bright [[meteor]], especially one that explodes in the atmosphere. In astronomy, it refers to a [[fireball (meteor)|fireball]] about as bright as the [[full moon]], and it is generally considered a synonym for a fireball. In geology, a bolide is a very large [[Impact event|impactor]].

One definition describes a bolide as a fireball reaching an [[apparent magnitude]] of −4 or brighter.<ref name="Belton">
{{Cite book
 |last= Belton
 |first= MJS
 |title= Mitigation of hazardous comets and asteroids
 |publisher= [[Cambridge University Press]]
 |date= 2004
 |url= https://books.google.com/books?id=Dw0A7T0fy6AC
 |isbn= 0521827647
}}{{rp|156}}</ref> Another definition describes a bolide as any generic large [[impact crater|crater-forming]] impacting body whose composition (for example, whether it is a rocky or metallic [[asteroid]], or an icy [[comet]]) is unknown.<ref name="WoodsHoleUSGS">
{{cite web
 |url= https://woodshole.er.usgs.gov/epubs/bolide/introduction.html
 |title= Introduction: What is a Bolide?
 |publisher= Woodshole.er.usgs.gov
 |date= 1 April 1998 |access-date= 16 September 2011
}}</ref>

A '''superbolide''' is a bolide that reaches an apparent magnitude of −17 or brighter,<ref name=Belton /><ref>
{{Cite book
 |last= Adushkin
 |first= Vitaly
 |author2= Ivan Nemchinov
 |title= Catastrophic events caused by cosmic objects
 |publisher= Springer
 |date= 2008
 |url= https://books.google.com/books?id=3Hd8Lw1hExUC
 |isbn= 978-1402064524
}}{{rp|133}}
</ref> 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 ==
{{see also|Meteoroid#Fireball}}
[[File:Meteoroid - Meteor (Bolide) - Meteorite.gif|thumb|Animation of a bolide's [[atmospheric entry]] and [[Meteor air burst|air burst]]]]

The [[International Astronomical Union|IAU]] has no official definition of "bolide", and generally considers the term synonymous with [[fireball (meteor)|fireball]], a brighter-than-usual [[meteor]]; however, the term generally applies to fireballs reaching an [[apparent magnitude]] &minus;4 or brighter.<ref name="Belton" /> Astronomers tend to use ''bolide'' to identify an exceptionally bright fireball, particularly one that explodes (sometimes called a detonating fireball).<ref name="oxforddicastro">{{cite book |url= https://www.oxfordreference.com/view/10.1093/acref/9780191851193.001.0001/acref-9780191851193-e-487 |title=A Dictionary of Astronomy |chapter=Bolide |edition=3 |year=2018 |at=bolide |editor1=Ian Ridpath |publisher=Oxford University Press |isbn=978-0191851193}}</ref> It may also be used to mean a [[Meteoroid#Acoustic manifestations|fireball that is audible]].

=== Superbolide ===
{{see also|Meteor air burst}}

Selected superbolide air bursts:
* [[Tunguska event]] (Russia, 1908)
* [[2009 Sulawesi superbolide]] (Indonesia, 2009)
* [[Chelyabinsk meteor]] (Russia, 2013)

== Geology ==
[[Geologist]]s use the term ''bolide'' differently from [[astronomer]]s. In [[geology]], it indicates a very large [[impact event|impactor]]. For example, the [[Woods Hole, Massachusetts|Woods Hole]] Coastal and Marine Science Center of the [[United States Geological Survey|USGS]] uses ''bolide'' for any large crater-forming impacting body whose origin and composition is unknown, as, for example, whether it was a [[S-type asteroid|stony]] or [[M-type asteroid|metallic]] asteroid, or a less dense, icy comet made of [[Volatile (astrogeology)|volatiles]], such as water, ammonia, and methane.<ref name="WoodsHoleUSGS" /> 

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 ==
{{multiple image
| direction         = horizontal
| align             = center
| height1           = 127
| height2           = 127
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| image1            = Взрыв метеорита над Челябинском 15 02 2013 avi-iCawTYPtehk.ogv
| image2            = Fireball geminids 2010-12-09 01-10ut.gif
| image3            = Bolide 9-22-24.webm
| caption1          = Footage of a superbolide [[Chelyabinsk meteor|exploding over Chelyabinsk]] Oblast, Russia in 2013.
| caption2          = A bolide from the [[Geminids]] meteor shower ([[Special Astrophysical Observatory of the Russian Academy of Science|SAO RAS]], [[Magnitude (astronomy)|vmag &thinsp;−3]]) in December 2010.
| caption3          = Dashcam footage of a bolide over Vermont, USA in September 2024. 
}}

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== See also ==
{{commonscat|Bolide}}
{{div col}}
* {{annotated link|Comet Shoemaker–Levy 9#Impacts|Comet Shoemaker–Levy 9 §&thinsp;Impacts}}
* {{annotated link|Earth-grazing fireball}}
* {{annotated link|Meteor procession}}
* {{annotated link|Tollmann's hypothetical bolide}}
* {{annotated link|Impact event#Airbursts}}
* {{annotated link|Bugatti Bolide}}
* {{annotated link|RBS 70}}
{{div col end}}

== References ==
{{reflist|30em}}

== External links ==
{{Wiktionary}}
* [https://archive.today/20130703201541/http://b612foundation.org/data-visualization-bolides/ historic record of bolides that have been witnessed entering the Earth’s atmosphere around the world from 861 through 2012] ([[B612 Foundation]])
* [https://cneos.jpl.nasa.gov/fireballs/ Bolide Events from 1988 to the present] neo.jpl.nasa.gov
*[https://impact.ese.ic.ac.uk/ImpactEarth/ImpactEffects/ Earth Impact Effects Program] Estimates crater size and other effects of a specified body colliding with Earth. 

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