Question

Accretion is the process by which

A) elements are transformed into heavier elements by nuclear reactions.
B) massive protoplanetary cores pull gas onto themselves to create giant planets.
C) clouds of interstellar gas and dust contract to form protostars.
D) dust grains and ice crystals coalesce to form planetesimals.

Answer 1

Accretion is the process by which massive protoplanetary cores pull gas onto themselves to create giant planets. It involves the gradual accumulation of mass through the attraction and collision of planetesimals. This process contributes to the formation of larger planets.

Step-by-step explanation:

Accretion is the process by which massive protoplanetary cores pull gas onto themselves to create giant planets. As protoplanets grow, they attract planetesimals (small chunks of solid matter) through gravity, which collide and stick together, gradually accumulating mass. This process leads to the formation of larger planets. For example, during the formation of the solar system, protoplanets grew in size by accreting planetesimals until they acquired a mass similar to that of Mercury or Mars.