Editing Meteoroid (section)

{{Short description|Sand- to boulder-sized particle of debris in the Solar System}}
{{distinguish|Metroid|Matroid}}
[[File:Meteoroid meteor meteorite.gif|thumb|upright=1.5|A ''meteoroid'' shown entering the atmosphere, causing a visible ''[[meteor]]'' and hitting the Earth's surface, becoming a ''[[meteorite]]'']]

A '''meteoroid''' ({{IPAc-en|ˈ|m|iː|t|i|ə|r|ɔɪ|d}} {{respell|MEE|tee|ə|royd}})<ref>{{cite encyclopedia |url=https://dictionary.cambridge.org/dictionary/english/meteoroid |title=meteoroid |encyclopedia=[[Cambridge English Dictionary]]}}</ref> is a small rocky or metallic body in [[outer space]].
Meteoroids are distinguished as objects significantly smaller than ''[[asteroid]]s'', ranging in size from grains to objects up to {{convert|1|m|abbr=on}} wide.<ref name="Rubin2010"/> Objects smaller than meteoroids are classified as ''[[micrometeoroids]]'' or ''[[space dust]]''.<ref name="Rubin2010"/><ref>{{cite news |url=http://www.universetoday.com/36398/what-is-the-difference-between-asteroids-and-meteorites/ |title=What is the difference between asteroids and meteorites |first=Nancy |last=Atkinson |date=2 June 2015 |work=Universe Today}}</ref><ref>{{cite web |url=http://www.thefreedictionary.com/meteoroid |publisher=The Free Dictionary |title=meteoroids |access-date=1 August 2015}}</ref> Many are fragments from [[comet]]s or asteroids, whereas others are [[impact event|collision impact]] [[space debris|debris]] ejected from bodies such as the [[Moon]] or [[Mars]].<ref>{{cite web |url=http://education.nationalgeographic.co.uk/encyclopedia/meteoroid/ |title=Meteoroid |work=National Geographic |access-date=24 August 2015 |archive-url=https://web.archive.org/web/20151007141358/https://education.nationalgeographic.co.uk/encyclopedia/meteoroid/ |archive-date=7 October 2015}}</ref><ref>{{cite web |url=http://solarsystem.nasa.gov/planets/profile.cfm?Object=Meteors&Display=OverviewLong |title=Meteors & Meteorites |work=NASA |access-date=1 August 2015 |archive-date=26 December 2003 |archive-url=https://web.archive.org/web/20031226135836/http://www.solarsystem.nasa.gov/planets/profile.cfm?Object=Meteors&Display=OverviewLong}}</ref><ref>{{cite web |url=http://www.nasa.gov/mission_pages/asteroids/overview/fastfacts.html |title=Asteroid Fast Facts |publisher=NASA |date=31 March 2014 |access-date=1 August 2015}}</ref>

The visible passage of a meteoroid, comet, or asteroid [[atmospheric entry|entering Earth's atmosphere]] is called a [[meteor]], and a series of many meteors appearing seconds or minutes apart and appearing to originate from the same fixed point in the sky is called a [[meteor shower]].

An estimated 25 million meteoroids, micrometeoroids and other [[space debris]] enter Earth's atmosphere each day,<ref>{{cite news |last=Lidz |first=Franz |url=https://www.smithsonianmag.com/smithsonian-institution/oldest-material-smithsonian-institution-came-outer-space-180971017/ |title=The Oldest Material in the Smithsonian Institution Came From Outer Space |work=[[Smithsonian (magazine)|Smithsonian]] |date=2019-01-09 |access-date=2019-01-09}}</ref> which results in an estimated 15,000 tonnes of that material entering the atmosphere each year.<ref>{{cite episode |first=Stuart |last=Gary |title=Survey finds not all meteors the same |series=ABC Science |network=ABC |air-date=2011-12-22 |url=http://www.abc.net.au/science/articles/2011/12/22/3396756.htm}}</ref>
A ''[[meteorite]]'' is the remains of a meteoroid that has survived the [[ablation]] of its surface material during its passage through the atmosphere as a meteor and has impacted the ground.