Certain stages of stellar evolution,such as birth of a protostar and post-main-sequence red-giant evolution,come about because of an imbalance between gravity and
A) high-energy neutrino pressure.
B) radiation intensity.
C) the centrifugal force from rotation.
D) internal gas pressure.

Question

Quizplus · Accepted Answer

The imbalance between gravity and internal gas pressure is what drives the stages of stellar evolution mentioned in the question. In the case of a protostar, the gravitational collapse of gas and dust is halted by the emergence of strong internal gas pressure. In the case of a post-main-sequence red giant, gravity causes the star's core to contract and heat up, leading to increased gas pressure that balances out the force of gravity.

Certain Stages of Stellar Evolution,such as Birth of a Protostar