Atmosphere of Mars energy to escape the planet. In this process the light isotope of carbon (C) is most likely to leave the atmosphere. Hence, the carbon dioxide left in the atmosphere would be enriched with the heavy isotope (C). This higher level of the heavy isotope is what was recently found by the "Curiosity" rover that sits on the surface of Mars. The atmosphere of Mars is enriched considerably with the noble gas argon, in comparison to the atmosphere of the other planets within the Solar System. Unlike carbon dioxide, the argon content of the atmosphere does not condense, and hence the
Extraterrestrial atmosphere greenhouse effect, aerosol and cloud physics, and atmospheric chemistry and dynamics. Due to its small size (and thus its small gravity), Mercury has no substantial atmosphere. Its extremely thin atmosphere mostly consists of a small amount of helium and traces of sodium, potassium, and oxygen. These gases derive from the solar wind, radioactive decay, meteor impacts, and breakdown of Mercury's crust. 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. Venus' atmosphere is mostly composed of carbon dioxide. It contains minor amounts of nitrogen and