How does the addition of a nonzero cosmological constant affect the expansion of the universe?
A) It is possible for the mass density of the universe to be below the critical density and still collapse.
B) It is possible for the density of the universe to be below the critical density and still expand forever.
C) It is impossible to have a collapsing universe,regardless of its density.
D) It is impossible to have an expanding universe,regardless of its density.

Question

Quizplus · Accepted Answer

The addition of a nonzero cosmological constant has been found to be responsible for the current accelerating expansion of the universe. This means that even if the density of the universe is below the critical density, the universe will still expand forever due to the repulsive force of the cosmological constant. However, it is important to note that the value of the cosmological constant and its effect on the universe's expansion is still an area of active research and the subject of ongoing study.

How Does the Addition of a Nonzero Cosmological Constant Affect