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
A Planet Called Utopia same reason), and temporary personal relationships favored. Diseases are nonexistent, and cures have been found for all of them. Life involves pleasure and adventure (skiing, scuba diving, parachuting, automobile racing) all day long. The population nevertheless needs an occasional birth, so couples are allowed to have children according to a lottery system, such that the number of births is exactly equal to the number of accidental deaths in a year. The protagonist, Hardy Cronyn, is the first off-worlder to be allowed onto the planet in sixty years. A lot of diplomatic arm wrestling led to the planet's agreement to let