The critical density for the Universe is about
A) equal to six hydrogen atoms per cubic meter.
B) the same as the density of Earth.
C) the same as the density of the Sun.
D) equal to 6,000 hydrogen atoms per cubic meter.
E) equal to 600,000 hydrogen atoms per cubic meter.

Question

Quizplus · Accepted Answer

The critical density of the Universe is approximately equal to six hydrogen atoms per cubic meter, which is the density required for the Universe to be flat.

The Critical Density for the Universe Is About