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Mercury, being the closest to the Sun, with a weak magnetic field and the smallest mass of the recognized terrestrial planets, has a very tenuous and highly variable atmosphere (surface-bound exosphere) containing hydrogen, helium, oxygen, sodium, calcium, potassium and water vapor, with a combined pressure level of about 10 −14 bar (1 nPa). [2]
These gases derive from the solar wind, radioactive decay, meteor impacts, and breakdown of Mercury's crust. [ 4 ] [ 5 ] Mercury's atmosphere is not stable and is constantly being refreshed because of its atoms escaping into space as a result of the planet's heat.
Mercury is one of four terrestrial planets in the Solar System, which means it is a rocky body like Earth. It is the smallest planet in the Solar System, with an equatorial radius of 2,439.7 kilometres (1,516.0 mi). [4] Mercury is also smaller—albeit more massive—than the largest natural satellites in the Solar System, Ganymede and Titan.
These include the Moon (sodium gas), Mercury (sodium gas), Europa (oxygen), Io , and Enceladus (water vapor). The first exoplanet whose atmospheric composition was determined is HD 209458b, a gas giant with a close orbit around a star in the constellation Pegasus. Its atmosphere is heated to temperatures over 1,000 K, and is steadily escaping ...
The first atmosphere, during the Early Earth's Hadean eon, consisted of gases in the solar nebula, primarily hydrogen, and probably simple hydrides such as those now found in the gas giants (Jupiter and Saturn), notably water vapor, methane and ammonia.
Mercury is a chemical ... Mercury(I) hydride, a colorless gas, ... Preindustrial deposition rates of mercury from the atmosphere may be about 4 ng per 1 L of ice ...
The United States is currently facing the worst flu season in over 15 years, with cases surging in most states. Over 33 million Americans have gotten sick this season so far, and elevated flu ...
Atmospheric entry (sometimes listed as V impact or V entry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be uncontrolled entry, as in the entry of astronomical objects , space debris , or bolides .