Published online by Cambridge University Press: 12 April 2016
Theories on the origin and evolution of asteroids are confronted with three types of experimental tests. The first refers to the dynamic state of the asteroids and consists of orbital and in some cases spin data for bodies as small as about 1 km. (There are reasons to assume that the size spectrum extends to very small objects but nothing is known about them.)
The second type consists of observations of the chemical and structural properties of objects fallen to Earth from space. Here the relationship to asteroids is much more tenuous. Nevertheless, the study of meteorites has provided important insight into the chemical evolution of small bodies in space. As long as one realizes that such data refer only to bodies of special structure, composition, velocity, and other orbital characteristics, they can be useful also for conjectures about asteroids.