Moulton, Forest Ray (1872–1952)
American astronomer who, at the University of Chicago, along with Thomas
Chamberlin, developed the Chamberlin-Moulton
planetesimal hypothesis about the origin of the planets (1904). According
to this hypothesis, material from the Sun was torn out by a passing star
and then condensed to form relatively small aggregates (planetesimals).
These planetesimals were then attracted to each other by gravity and gradually
accreted to form the planets. Moulton also suggested that the small moons
of Saturn are captured asteroids.