How does the existence of dark energy 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 mass 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.
E) It is impossible for the mass density of the universe to be above the critical density and still expand forever.

Question

Quizplus · Accepted Answer

Dark energy is responsible for the accelerating expansion of the universe, which means that even if the mass density of the universe is below the critical density, the universe will continue to expand forever due to the influence of dark energy. Option A is incorrect as a collapsing universe would require the mass density to be above the critical density. Option C and D are incorrect as they are contradictory to observations and theories. Option E is incorrect as an expanding universe could have a mass density above the critical density if the influence of dark energy is stronger.

How Does the Existence of Dark Energy Affect the Expansion