Inert gas asphyxiation lacks oxygen and consists of an asphyxiant gas (one or more of argon, nitrogen or carbon dioxide), causing the animals to lose consciousness. Argon and nitrogen are important components of a gassing process which seem to cause no pain, and for this reason many consider some types of controlled atmosphere killing more humane than other methods of killing. However, "stunning" is often done using carbon dioxide. If carbon dioxide is used, controlled atmosphere killing is not the same as inert gas asphyxia, because carbon dioxide at high concentrations (above 5%) is not biologically inert, but rather is toxic and also
Atmosphere of Uranus from the analysis of "Voyager 2" far infrared and radio occultation observations. The currently accepted value is in the upper troposphere, which corresponds to a mass fraction . This value is very close to the protosolar helium mass fraction of , indicating that helium has not settled towards the centre of the planet as it has in the gas giants. The third most abundant constituent of the Uranian atmosphere is methane , the presence of which has been known for some time as a result of the ground-based spectroscopic observations. Methane possesses prominent absorption bands in the visible and near-infrared,