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The Earth's atmosphere, hydrosphere, and biosphere together hold less than 0.05% of the Earth's total mass of oxygen. Besides O 2 , additional oxygen atoms are present in various forms spread throughout the surface reservoirs in the molecules of biomass , H 2 O , CO 2 , HNO 3 , NO , NO 2 , CO , H 2 O 2 , O 3 , SO 2 , H 2 SO 4 , MgO , CaO ...
After the Huronian glaciation came to an end, the Earth entered a long period of geological and climatic stability known as the Boring Billion. However, this long period was noticeably euxinic , meaning oxygen was scarce and the ocean and atmosphere were significantly sulfidic , and that evolution then was likely comparatively slow and quite ...
The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust, [2] was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen. [3]
Near the Earth's surface, it is a pollutant formed as a by-product of automobile exhaust. [43] At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft. [44] The metastable molecule tetraoxygen (O 4) was discovered in 2001, [45] [46] and was assumed to exist in one of the six phases of solid oxygen.
With ozone concentrations in the order of 10-6-10-5 relative to molecular oxygen, ozone photodissociation becomes the dominant photodissociation reaction, and most of the stratosphere heat is generated through this procsees, with highest heat generation rate per molecule at the upper limit of the stratosphere (stratopause), where ozone ...
The stratosphere is the second-lowest layer of Earth's atmosphere. It lies above the troposphere and is separated from it by the tropopause. This layer extends from the top of the troposphere at roughly 12 km (7.5 mi; 39,000 ft) above Earth's surface to the stratopause at an altitude of about 50 to 55 km (31 to 34 mi; 164,000 to 180,000 ft).
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The most familiar is molecular oxygen (O 2), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (O 3). Others are: Atomic oxygen (O 1), a free radical. Singlet oxygen (O * 2), one of two metastable states of molecular oxygen. Tetraoxygen (O 4), another ...