Which of the following factors is the most important in determining whether universal expansion continues forever or collapses back onto itself?
A) The average density of the universe
B) The total mass of the universe
C) The average temperature of the universe
D) The total size of the universe

Question

Quizplus · Accepted Answer

The average density of the universe determines whether the gravitational attraction between matter will result in the universe slowing down and ultimately collapsing back onto itself, or if the expansion will continue forever. If the average density is above a certain value known as the critical density, then the universe will collapse. If it is below the critical density, then the expansion will continue forever. The other factors listed (total mass, average temperature, total size) can be important in understanding the nature and evolution of the universe, but do not have as direct an impact on its ultimate fate as density does.

Which of the Following Factors Is the Most Important in Determining