Atmosphere
![Mars's thin atmosphere](/Images/godic/202412/20/Mars_atmosphere_20044.jpg")
![The layers of Earth's atmosphere](/Images/godic/202412/20/Atmosphere_layers-en.svg0044.png")
![Earth's atmospheric gases scatter blue light more than other wavelengths, giving Earth a blue halo when seen from space](/Images/godic/202412/20/Top_of_Atmosphere0044.jpg")
![Graphs of escape velocity against surface temperature of some Solar System objects showing which gases are retained. The objects are drawn to scale, and their data points are at the black dots in the middle.](/Images/godic/202412/20/Solar_system_escape_velocity_vs_surface_temperature.svg0044.png")
An atmosphere (fromGreekἀτμός (atmos), meaning "vapour",andσφαῖρα (sphaira), meaning "sphere") is a layer of gases surrounding a planet or other material body, that is held in place by the gravity of that body. An atmosphere is more likely to be retained if its gravity is high and the atmosphere's temperature is low.