The release of juvenile gases and water to the surface from a magma source.
The release of gas from cooling molten rock or the interior of the Earth. Much of the atmosphere's gaseous constituents, like water vapor, nitrogen, and argon, came from outgassing.
Outgassing is a problem encountered in high-vacuum environments and applications. For example, NASA maintains a list of low-outgassing materials to be used for spacecraft, as outgassing can cause deposits on optical elements, thermal radiators, or solar cells. Materials not normally considered absorbent can release enough light molecules to interfere with industrial or scientific processes.