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Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light. Different molecules absorb different wavelengths of radiation. For example, O 2 and O 3 absorb almost all radiation with wavelengths shorter than 300 nanometres. Water (H 2 O) absorbs at many wavelengths ...
The Earth's crust is one "reservoir" for measurements of abundance. A reservoir is any large body to be studied as unit, like the ocean, atmosphere, mantle or crust. Different reservoirs may have different relative amounts of each element due to different chemical or mechanical processes involved in the creation of the reservoir.
The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.
The Earth contains approximately 1.33 × 10 50 atoms. [135] Although small numbers of independent atoms of noble gases exist, such as argon , neon , and helium , 99% of the atmosphere is bound in the form of molecules, including carbon dioxide and diatomic oxygen and nitrogen .
Of the 94 naturally occurring chemical elements, 76 are listed in the table above. Of the remaining 18, it is not known how many occur in the human body. Most of the elements needed for life are relatively common in the Earth's crust.
The most known chemical elements whose covalent combinations make up most biological molecules on Earth. [2] All of these elements are nonmetals.. In animals in general, the four elements—C, H, N, and O—compose about 96% of the weight, and major minerals (macrominerals) and minor minerals (also called trace elements) compose the remainder.
[19] [70] [d] Earth is unusual among the planets of the Solar System in having such a high concentration of oxygen gas in its atmosphere: Mars (with 0.1% O 2 by volume) and Venus have much less. The O 2 surrounding those planets is produced solely by the action of ultraviolet radiation on oxygen-containing molecules such as carbon dioxide.
Earth–Moon system: mainly as ice sheets on Earth and in Lunar craters and volcanic rocks [194] NASA reported the detection of water molecules by NASA's Moon Mineralogy Mapper aboard the Indian Space Research Organization's Chandrayaan-1 spacecraft in September 2009. [195] Ceres [196] [197] [198]