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The troposphere is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about 12 km (7.5 mi; 39,000 ft), although this altitude varies from about 9 km (5.6 mi; 30,000 ft) at the geographic poles to 17 km (11 mi; 56,000 ft) at the Equator, [17] with some variation due
The Moon's surface contains helium-3 at concentrations on the order of 10 ppb, much higher than the approximately 5 ppt found in the Earth's atmosphere. [ 117 ] [ 118 ] A number of people, starting with Gerald Kulcinski in 1986, [ 119 ] have proposed to explore the Moon, mine lunar regolith, and use the helium-3 for fusion .
What little atmosphere the Moon has consists of some unusual gases, including sodium and potassium, which are not found in the atmospheres of Earth, Mars, or Venus. At sea level on Earth, each cubic centimeter of the atmosphere contains approximately 10 19 molecules; by comparison the lunar atmosphere contains fewer than 10 6 molecules in the ...
Hematite, a mineral composed of ferric oxide (Fe 2 O 3), has been found on the Moon. This mineral is a product of a reaction between iron, oxygen, and liquid water. Oxygen from the Earth's atmosphere may cause this reaction as indicated by there being more hematite on the side of the Moon facing the Earth. [46]
The composition of Earth's atmosphere is determined by the by-products of the life that it sustains. Dry air (mixture of gases) from Earth's atmosphere contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and traces of hydrogen, helium, and other "noble" gases (by volume), but generally a variable amount of water vapor is ...
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.
Hydrogen is the most abundant element to the universe—it's actually element number one—and the atomic weight is 1.008, so 10/08 is designated National Hydrogen and Fuel Cell day, because many ...
The abundance of elements in Earth's crust is shown in tabulated form with the estimated crustal abundance for each chemical element shown as mg/kg, or parts per million (ppm) by mass (10,000 ppm = 1%).