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The atmosphere returns to a CO 2 and N 2 dominated atmosphere after H 2 escapes from Earth to space. From: Nicholas F. Wogan et al 2023 Planet. Sci. J. 4 169. Licensed under CC-BY 4.0. A large factor controlling the redox budget of early Earth's atmosphere is the rate of atmospheric escape of H 2 after Earth's formation.
A paleoatmosphere (or palaeoatmosphere) is an atmosphere, particularly that of Earth, at some unspecified time in the geological past.. When regarding geological history of Earth, the paleoatmosphere can be chronologically divided into the Hadean first atmosphere, which resembled the compositions of the solar nebula; the Archean second atmosphere (also known as the prebiotic atmosphere), which ...
The atmospheric chemistry is believed to have been "weakly reducing", where reduced gases like CH 4, NH 3, and H 2 were present in small quantities. [9] The composition of the prebiotic atmosphere was likely periodically altered by impactors, which may have temporarily caused the atmosphere to have been "strongly reduced". [11]
Atmospheric chemistry is a branch of atmospheric science that studies the chemistry of the Earth's atmosphere and that of other planets. This multidisciplinary approach of research draws on environmental chemistry, physics, meteorology, computer modeling, oceanography, geology and volcanology, climatology and other disciplines to understand both natural and human-induced changes in atmospheric ...
[64] [65] The Hadean atmosphere has been characterized as a "gigantic, productive outdoor chemical laboratory," similar to volcanic gases today which still support some abiotic chemistry. Despite the likely increased volcanism from early plate tectonics, the Earth may have been a predominantly water world between 4.4 and 4.3 Gya.
A warm little pond is a hypothetical terrestrial shallow water environment on early Earth under which the origin of life could have occurred. The term was originally coined by Charles Darwin in an 1871 letter to his friend Joseph Dalton Hooker.
4, which is a powerful greenhouse gas and was produced by early forms of life known as methanogens. Scientists continue to research how the Earth was warmed before life arose. [15] An atmosphere of N 2 and CO 2 with trace amounts of H 2 O, CH 4, carbon monoxide (CO), and hydrogen (H 2) is described as a weakly reducing atmosphere. [16]
However, when porphyrin-based photoautotrophs evolved and started to photosynthesize, which included both the primitive purple bacteria using bacteriochlorophyll and cyanobacteria using chlorophyll, highly reactive dioxygen was released as a byproduct of water splitting and started to accumulate, first in the ocean and then in the atmosphere.