How does the observed total amount of matter in the universe, including dark matter, compare with the amount of matter required to make its geometry flat?
A) The observed total amount of matter equals the amount needed, to within observational uncertainty.
B) The observed total amount of matter is about 1/3 the amount needed.
C) The observed total amount of matter is about twice the amount needed.
D) The observed total amount of matter is about 1/25 of the amount needed.

Question

Quizplus · Accepted Answer

The observed total amount of matter, including dark matter, is about 1/3 the amount needed to make the universe's geometry flat. This discrepancy is one of the reasons for the introduction of dark energy to account for the missing component that influences the universe's expansion and geometry.

How Does the Observed Total Amount of Matter in the Universe