ESS55
Prof. Jin-Yi Yu
Origins of the
Atmosphere
qWhen the Earth was formed 4.6
billion years ago, Earth’s atmosphere was probably mostly hydrogen
(H) and helium (He) plus hydrogen compounds, such as methane
(CH4) and ammonia (NH3).
èThose gases eventually
escaped to the space.
qThe release of
gases from rock through volcanic eruption (so-called outgassing) was the
principal source of atmospheric gases.
èThe primeval
atmosphere produced by the outgassing was mostly water vapor (H2O), with some Nitrogen (N2) and Carbon
dioxide (CO2), and trace amounts of other gases.