Avatar (2009 film) habitable moon orbiting the gas giant Polyphemus in the Alpha Centauri star system. Pandora, whose atmosphere is poisonous to humans, is inhabited by the Na'vi, a species of , blue-skinned, sapient humanoids that live in harmony with nature and worship a mother goddess named Eywa. To explore Pandora's biosphere, scientists use Na'vi-human hybrids called "avatars", operated by genetically matched humans; Jake Sully, a paraplegic former Marine, replaces his deceased identical twin brother as an operator of one. Dr. Grace Augustine, head of the Avatar Program, considers Sully an inadequate replacement but accepts his assignment as a bodyguard. While protecting the
Exploration of the Moon astronomer Giovanni Battista Riccioli, who gave the large naked-eye spots the names of seas and the telescopic spots (now called craters) the name of philosophers and astronomers. In 1753 the Croatian Jesuit and astronomer Roger Joseph Boscovich discovered the absence of atmosphere on the Moon. In 1824 Franz von Gruithuisen explained the formation of craters as a result of meteorite strikes. The possibility that the Moon contains vegetation and is inhabited by selenites was seriously considered by major astronomers even into the first decades of the 19th century. In 1834–1836, Wilhelm Beer and Johann Heinrich Mädler published their four-volume and