The basic idea behind the planetesimal hypothesis is that
A)planets form as a direct result of the nuclear fusion of nebular gases and planetesimals.
B)small grains of cosmic dust and other solids gradual accrete to form planetesimals that may grow to become protoplanets and eventually planets.
C)planets form from the remains of super-giant planetesimals that undergo nuclear fission and blow apart,thereby creating smaller objects the planets.
D)early in the solar systemʹs history,a star passed near to the Sun and pulled off gases that eventually condensed to form planets.

Question

Quizplus · Accepted Answer

The planetesimal hypothesis proposes that small solid particles in the protoplanetary disk gradually accrete to form planetesimals, which then grow by further accretion into protoplanets and eventually planets. This process is supported by observations of debris disks around other stars, which show evidence of planetesimal formation and growth. The other answer choices are not supported by current scientific understanding of planetary formation.

The Basic Idea Behind the Planetesimal Hypothesis Is That