planetesimal A rocky and/or icy body, a few kilometers to several tens of kilometers in size, that was produced in the solar nebula. According to the planetesimal theory, the solar system formed from the collisional aggregation of a great many of these objects. Related category ASTEROIDS AND OTHER MINOR PLANETS: TYPES AND GROUPS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |