The following is a concise list of information relating to the atmosphere of the earth and those of other know planets.

  1. Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass.
  2. The gases are attracted by the gravity of the body, and held fast if gravity is sufficient and the atmosphere's temperature is low.
  3. Some planets consist mainly of various gases, and thus have very deep atmospheres (see gas giant).
  4. Earth, Venus, Mars, and Pluto have atmospheres that envelop their surfaces, as do three of the satellites of the outer planets: Titan, Enceladus (moons of Saturn), and Triton (a moon of Neptune).
  5. The giant planets of the outer solar system - Jupiter, Saturn, Uranus, and Neptune - are composed predominantly of gases.
  6. Other bodies in the solar system possess extremely thin atmospheres. Such bodies are the Moon (sodium gas), Mercury (sodium gas), Europa (oxygen) and Io (sulfur).
  7. Surface gravity, the force that holds down an atmosphere, differs significantly among the planets. For example, the large gravitational force of the giant planet Jupiter is able to retain light gases such as hydrogen and helium that escape from lower gravity objects.
  8. It is thought that Venus and Mars may have both lost much of their water when, after being photodissociated into hydrogen and oxygen by solar ultraviolet, the hydrogen escaped.
  9. Earth's magnetic field helps to prevent this, as the solar wind greatly enhances the escape of hydrogen.
  10. Other mechanisms that can cause atmosphere depletion are solar wind-induced sputtering, impact erosion, weathering, and sequestration—sometimes referred to as "freezing out"—into the regolith and polar caps.
  11. On Earth, atmospheric composition is largely governed by the by-products of the very life that it sustains.
  12. Atmospheres are important in the ways they shape planetary surfaces.
  13. Wind can transport particles, both eroding the surface and leaving deposits (eolian processes).
  14. Frost and precipitation can leave direct and indirect marks on a planetary surface.
  15. Climate changes can influence a planet's geological history.
  16. Interstellar planets, theoretically, may also retain thick atmospheres.