Atmosphere of Mercury Atmosphere of Mercury Mercury 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 bar (1 nPa). The exospheric species originate either from the Solar wind or from the planetary crust. Solar light pushes the atmospheric gases away from the Sun, creating a comet-like tail behind the planet. The existence of a Mercurian atmosphere had been contentious before 1974, although by that time a consensus had formed that Mercury, like the Moon, lacked any substantial atmosphere. This conclusion was confirmed in 1974
Far-infrared astronomy Earth's atmosphere is opaque over most of the far-infrared, so that ground-based observations are limited to submillimetre wavelengths using high-altitude telescopes such as the James Clerk Maxwell Telescope, the Caltech Submillimeter Observatory, the High Elevation Antarctic Terahertz Telescope and the Submillimeter Array. Most far-infrared astronomy is performed by satellites such as the Herschel Space Observatory, Spitzer Space Telescope, IRAS, and Infrared Space Observatory. Upper-atmosphere observations are also possible, as conducted by the airborne SOFIA telescope. On 22 January 2014, European Space Agency scientists reported the detection, for the first definitive time, of water vapor on the dwarf planet, Ceres, largest