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Helium-3 (3 He [1] [2] see also helion) is a light, stable isotope of helium with two protons and one neutron. (In contrast, the most common isotope, helium-4, has two protons and two neutrons.) Helium-3 and protium (ordinary hydrogen) are the only stable nuclides with more protons than neutrons. It was discovered in 1939.
Mars has a higher scale height of 11.1 km than Earth (8.5 km) because of its weaker gravity. [5] The theoretical dry adiabatic lapse rate of Mars is 4.3 °C km −1, [131] but the measured average lapse rate is about 2.5 °C km −1 because the suspended dust particles absorb solar radiation and heat the air. [2]
In the summer of 2008, the TEGA and WCL experiments on the 2007 Phoenix Mars lander found between 3–5wt% (percent by weight) calcite (CaCO 3) and an alkaline soil. [65] In 2010, analyses by the Mars Exploration Rover Spirit identified outcrops rich in magnesium-iron carbonate (16–34 wt%) in the Columbia Hills of Gusev crater. The magnesium ...
By one estimate, the solar wind has deposited more than 1 million tons of helium-3 (3 He) on the Moon's surface. [62] Materials on the Moon's surface contain helium-3 at concentrations estimated between 1.4 and 15 parts per billion (ppb) in sunlit areas, [ 1 ] [ 63 ] [ 64 ] and may contain concentrations as much as 50 ppb in permanently ...
Click on image to see more. Note how close the orbit of Mars is to the asteroid belt. Besides heat generated by molten rock, Mars has had much heat produced when asteroids impacted its surface making giant craters. The area around a large impact may take hundreds of thousands of years to cool. [4] 243 Ida and its moon Dactyl. Dactyl is the ...
Atmospheric escape of hydrogen on Earth is due to charge exchange escape (~60–90%), Jeans escape (~10–40%), and polar wind escape (~10–15%), currently losing about 3 kg/s of hydrogen. [1] The Earth additionally loses approximately 50 g/s of helium primarily through polar wind escape. Escape of other atmospheric constituents is much ...
Helium-3 propulsion would use the fusion of helium-3 atoms as a power source. Helium-3, an isotope of helium with two protons and one neutron, could be fused with deuterium in a reactor. The resulting energy release could expel propellant out the back of the spacecraft. Helium-3 is proposed as a power source for spacecraft mainly because of its ...
A cloud layer does "sink" with decreasing temperature. This way one exoplanet might have a cloud layer at a higher pressure (lower altitude) compared to a warmer exoplanet. [50] [51] High altitude clouds often block light coming from deeper layers of the atmosphere, including chemical absorption features.