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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 .
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 partial pressure of helium in the Earth's atmosphere is about 0.52 pascals (7.5 × 10 −5 psi), and thus helium accounts for 5.2 parts per million of the total pressure (101325 Pa) in the Earth's atmosphere, and 3 He thus accounts for 7.2 parts per trillion of the atmosphere. Since the atmosphere of the Earth has a mass of about 5.14 × 10 ...
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.
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 NASA astronauts who became the first people to land on the moon's surface in the 1960s and 1970s also discovered a previously unknown lunar characteristic - it has an atmosphere, though quite ...
Although oxygen is the most abundant element in Earth's crust, due to its high reactivity it mostly exists in compound forms such as water, carbon dioxide, iron oxides and silicates. Before photosynthesis evolved, Earth's atmosphere had no free diatomic elemental oxygen (O 2). [2]
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 ...