Colonization of Titan Zubrin has pointed out that Titan possesses an abundance of all the elements necessary to support life, saying "In certain ways, Titan is the most hospitable extraterrestrial world within our solar system for human colonization." The atmosphere contains plentiful nitrogen and methane, and strong evidence indicates that liquid methane exists on the surface. Evidence also indicates the presence of liquid water and ammonia under the surface, which are delivered to the surface by volcanic activity. Water can be used to generate breathable oxygen and nitrogen is ideal to add buffer gas partial pressure to breathable air (it forms about 78%
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