Earth's secondary atmosphere was a hundred times as dense as its present atmosphere, yet the temperature was only sufficient to keep liquid water from freezing and not high enough to vaporize liquid water. Why wasn't the temperature higher?
A) Earth formed beyond the snow line and migrated inward, and at this time it was too far from the Sun to be warm enough to vaporize water.
B) The developing Sun was not as hot as it is now.
C) The secondary atmosphere contained very little carbon dioxide, so there was not enough of a greenhouse effect to enhance the temperature.
D) The dense secondary atmosphere enhanced Earth's albedo. With less radiation striking Earth, the temperature did not rise substantially.

Question

Quizplus · Accepted Answer

The developing Sun was not as hot as it is now, which means it emitted less energy, resulting in a cooler Earth despite the dense atmosphere.

Earth's Secondary Atmosphere Was a Hundred Times as Dense as Its