An atmosphere (from Greek ατμός - atmos, "vapor" σφαίρα - sphaira, "sphere") is a layer of gases that may surround a material body of sufficient mass. The gases are attracted by the gravity of the body, and are retained for a longer duration if gravity is high and the atmosphere's temperature is low. Some planets consist mainly of various gases, and therefore have very deep atmospheres (see gas giants).

Trivia about atmosphere

  • Tests show the planet Mercury has a thin one containing helium & sodium
  • Janice's project on the layers of this included the mesosphere & the thermosphere
  • From the Greek for "vapor", this plant protector contains the tropo-, strato-, meso-, & thermo- layers
  • This nearly transparent 3-syllable envelope of gases surrounding the Earth is about 78% nitrogen
  • "atm",you won't find it in a vacuum or in a restaurant on the moon
  • If it were not for the retarding influence of this, raindrops would attain bullet-like speeds
  • Due to its thick one of these, Saturn's Titan was once thought to be the solar system's biggest satellite
  • Changes in the tropospheric layer of this are what gives us weather