Noble gas periods of the periodic table, the noble gases are exactly the members of group 18. Noble gases are typically highly unreactive except when under particular extreme conditions. The inertness of noble gases makes them very suitable in applications where reactions are not wanted. For example, argon is used in incandescent lamps to prevent the hot tungsten filament from oxidizing; also, helium is used in breathing gas by deep-sea divers to prevent oxygen, nitrogen and carbon dioxide (hypercapnia) toxicity. The properties of the noble gases can be well explained by modern theories of atomic structure: their outer shell of valence electrons
Atmosphere of Pluto Solar Wind around Pluto (SWAP) instrument on the "New Horizons" spacecraft made the first measurements of this region of low-energy atmospheric ions shortly after its closest approach on 14 July 2015. Such measurements will enable the SWAP team to determine the rate at which Pluto loses its atmosphere and, in turn, will yield insight into the evolution of the Pluto’s atmosphere and surface. The reddish-brown cap of the north pole of Charon, the largest of Pluto's moons, may be composed of tholins, organic macromolecules produced from methane, nitrogen and other gases released from the atmosphere of Pluto and transferred over