Atmosphere of Triton asymmetry was actually observed during star occultations by Triton in 1990s. Before Voyager 2 arrived, a nitrogen and methane atmosphere with a density as much as 30% that of Earth had been suggested. This proved to be a great overestimate, similar to the predictions of the atmospheric density of Mars, but like on Mars, a denser early atmosphere is postulated. Voyager 2 flew past Triton five hours after closest approach to Neptune in mid-late August 1989. During the flyby, Voyager 2 took measurements of the atmosphere, finding methane and nitrogen in the atmosphere. In the 1990s, observations from Earth were
Hollow Earth the Earth. Ancestors of the Inca supposedly came from underground caves which are located east of Cuzco, Peru. Edmond Halley in 1692 put forth the idea of Earth consisting of a hollow shell about thick, two inner concentric shells and an innermost core. Atmospheres separate these shells, and each shell has its own magnetic poles. The spheres rotate at different speeds. Halley proposed this scheme in order to explain anomalous compass readings. He envisaged the atmosphere inside as luminous (and possibly inhabited) and speculated that escaping gas caused the Aurora Borealis. De Camp and Ley have claimed (in their "Lands