Editing Asteroid (section)

=== Rotation ===
{{Further|List of fast rotators (minor planets)|List of slow rotators (minor planets)}}
Measurements of the rotation rates of large asteroids in the asteroid belt show that there is an upper limit. Very few asteroids with a diameter larger than 100 meters have a rotation period less than 2.2&nbsp;hours.<ref>{{cite web |title=About Lightcurves |series=Asteroid Lightcurve Photometry Database |website=ALCDEF |date=4 December 2018 |url=http://alcdef.org/ |access-date=27 December 2018}}</ref> For asteroids rotating faster than approximately this rate, the inertial force at the surface is greater than the gravitational force, so any loose surface material would be flung out. However, a solid object should be able to rotate much more rapidly. This suggests that most asteroids with a diameter over 100 meters are [[rubble pile]]s formed through the accumulation of debris after collisions between asteroids.<ref name=Rossi-2004/>