Editing Asteroid (section)

=== Asteroid belt ===
{{Main|Asteroid belt}}
The majority of known asteroids orbit within the asteroid belt between the orbits of [[Mars]] and [[Jupiter]], generally in relatively low-[[orbital eccentricity|eccentricity]] (i.e. not very elongated) orbits. This belt is estimated to contain between 1.1 and 1.9&nbsp;million asteroids larger than {{cvt|1|km|1}} in diameter,<ref>{{cite press release
 | first1=Edward
 | last1=Tedesco
 | last2=Metcalfe
 | first2=Leo
 | date=4 April 2002
 | title=New study reveals twice as many asteroids as previously believed
 | publisher=European Space Agency
 | url=http://www.spaceref.com/news/viewpr.html?pid=7925
 | access-date=21 February 2008
 | archive-date=6 March 2023
 | archive-url=https://web.archive.org/web/20230306222828/https://spaceref.com/press-release/new-study-reveals-twice-as-many-asteroids-as-previously-believed/
 | url-status=dead
 }}</ref> and millions of smaller ones. These asteroids may be remnants of the [[protoplanetary disk]], and in this region the [[accretion (astrophysics)|accretion]] of [[planetesimal]]s into planets during the formative period of the Solar System was prevented by large gravitational perturbations by [[Jupiter]].

Contrary to popular imagery, the asteroid belt is mostly empty. The asteroids are spread over such a large volume that reaching an asteroid without aiming carefully would be improbable. Nonetheless, hundreds of thousands of asteroids are currently known, and the total number ranges in the millions or more, depending on the lower size cutoff. Over 200 asteroids are known to be larger than 100&nbsp;km,<ref>{{cite web
| last = Yeomans
| first = Donald K.
| date = 26 April 2007
| url = http://ssd.jpl.nasa.gov/sbdb_query.cgi
| title = JPL Small-Body Database Search Engine
| publisher = NASA JPL
| access-date = 2007-04-26
| at = Search for asteroids in the main belt regions with a diameter&nbsp;>100}}</ref> and a survey in the infrared wavelengths has shown that the asteroid belt has between 700,000 and 1.7&nbsp;million asteroids with a diameter of 1&nbsp;km or more.<ref>{{cite journal
|last1=Tedesco |first1= E. F.|last2=Desert |first2= F.-X.|name-list-style=amp| title=The Infrared Space Observatory Deep Asteroid Search
| journal=The Astronomical Journal
| date=2002
| volume=123
| issue=4
| pages=2070–2082
| bibcode=2002AJ....123.2070T| doi = 10.1086/339482
| doi-access=free
}}</ref> The [[absolute magnitude]]s of most of the known asteroids are between 11 and 19, with the median at about 16.<ref name="mpc">{{cite web
| last = Williams
| first = Gareth
|date=25 September 2010
| url = http://www.minorplanetcenter.org/iau/lists/MPDistribution.html
| title = Distribution of the Minor Planets
| publisher = Minor Planet Center
| access-date = 2010-10-27
}}</ref>

The total mass of the asteroid belt is estimated to be {{val|2.39e21}} kg, which is just 3% of the mass of the Moon; the mass of the Kuiper Belt and Scattered Disk is over 100 times as large.<ref name="Pitjeva2018">{{cite journal|last=Pitjeva|first=E. V.|author-link=Elena V. Pitjeva|title=Masses of the Main Asteroid Belt and the Kuiper Belt from the Motions of Planets and Spacecraft|journal=Solar System Research|volume=44|issue=8–9|pages=554–566|date=2018|arxiv=1811.05191|doi=10.1134/S1063773718090050|bibcode=2018AstL...44..554P|s2cid=119404378}}</ref> The four largest objects, Ceres, Vesta, Pallas, and Hygiea, account for maybe 62% of the belt's total mass, with 39% accounted for by Ceres alone.