planetesimaladj.n.

1904 T. C. Chamberlin in Carnegie Inst. Year Bk. II. 263 Among these [hypotheses] is the conception that the earth, instead of descending from a gaseous spheroid, may have been built up by the gradual ingathering of its material from a scattered meteoroidal or planetesimal condition.

1906 Athenæum 18 Aug. 191/1 For the last ten years Prof. Chamberlin, aided by Dr. Forest R. Moulton, of Chicago, has been developing what is called the Planetesimal Theory of the earth's origin.

1937 S. W. Wooldridge & R. S. Morgan Physical Basis Geogr. i. 5 The earth..grew from small beginnings by the addition of planetesimal matter.

1969 Nature 19 July 259/1 When planetologists meet to discuss the surface of the Moon they separate into those favouring the dominance of planetesimal (meteoric) impact and those who advocate volcanic activity.

1991 C. A. Ronan Nat. Hist. Universe 143/2 Asteroids are probably pockmarked with dents and even small craters caused by collisions with smaller planetesimal debris within the solar system.

1904 Amer. Geologist 33 95 The new hypothesis holds..that the globular planets were formed by the slow accretion or infalling of cold, discrete bodies or particles (‘planetesimals’).

1906 T. C. Chamberlin & R. D. Salisbury Geol. II. ii. 94 The planetesimals originated, by hypothesis, from gaseous matter shot forth from the ancestral sun.

1912 J. W. Gregory Making of Earth I. ii. i Still smaller than the minor planets are the bodies which are called planetesimals.

1952 H. C. Urey Planets vii. 219 Planetesimals probably formed simultaneously with the protoplanets and accumulated into larger objects.

1971 Sci. Amer. Oct. 52/3 Apollo 14 landed on the Fra Mauro formation, believed to be a blanket of ejecta thrown out by the giant meteorite or planetesimal that excavated the basin of Mare Imbrium.

2001 Science (Nexis) 10 Aug. 1127 As planetesimals orbit the central star, they are subject to gas drag from the protoplanetary disk.