Which of the following describes a role of gravity in the formation of our solar system?

Question

I. In the early stages of solar system formation, a fragment of an interstellar cloud of dust and gas collapsed and began rotating under the influence of gravity.
II. The eight planets were originally orbiting a nearby star, and the Sun's gravity pulled those planets into orbit around the Sun.
III. Gravity caused small particles in the rotating solar nebula to stick together and form larger particles. This process repeated itself, forming larger and larger particles that eventually became planets.
IV. The combined gravities of the planets pulled the Sun away from a nearby star cluster and into the center of the solar system.
A.
I and III only
B.
I, II, III, and IV
C.
I, II, and III only
D.
I, III, and IV only

Answer 1

The correct answer is A. I and III only.

Here's a brief explanation of each statement:

I. True. The formation of the solar system started with the collapse of a fragment of an interstellar cloud of dust and gas due to gravity, which caused it to begin rotating.

II. False. The planets were not originally orbiting a nearby star; they formed from the same protoplanetary disk around the Sun, not from another star.

III. True. Gravity did play a critical role in allowing small particles in the solar nebula to stick together, leading to the formation of larger bodies that eventually became planets.

IV. False. The Sun was formed in a solar nebula and did not get pulled away from a nearby star cluster; it formed from the collapse of the nebula itself.

Together, the valid options are I and III, thus A is the correct choice.