How Were Earth’s Atmosphere and Oceans Created

The creation of Earth’s atmosphere is related to the creation of the oceans. Both are direct result of density stratification.

 

Origin of Earth’s Atmosphere

Earth’s initial atmosphere consisted of leftover gases from the nebula. But those particles were blown out to space by the Sun’s solar wind. Then, a second atmosphere was most likely expelled from inside Earth by a process called outgassing. During the period of density stratification, the lowest-density material contained within Earth was composed of various gases. These gases rose to the surface and were expelled to form Earth’s early atmosphere. Gases are believed to have been similar to the gases emitted from volcanoes, geysers, and hot springs today: mostly water vapor (steam), with small amount of CO_2, Hydrogen, and other gases. The composition of the atmosphere changed over time because of the influence of life.

 

Origin of Earth’s Oceans

Origin of oceans directly linked to the origin of the atmosphere. As Earth cooled, the water vapor released to the atmosphere during outgassing condensed and fell to Earth. Evidence suggests that by at least 4 billion years ago, most of the water vapor from outgassing had accumulated to form the first permanent oceans on Earth.