Sky Islands

Contesto e storia

Seaborne floating islands have been found in literature since Homer's Odyssey, written near the end of the 8th century BCE, described the island of Aeolia. They reappear in Pliny the Elder's Natural History of the 1st century CE. Richard Head's 1673 novel The Floating Island describes a fictional island named Scotia Moria. In The Voyages of Doctor Dolittle, the characters sail to a floating island, which later becomes fixed in place. In the DC Comics universe, Themyscira is sometimes depicted as a group of floating islands. In Jules Verne's Propeller Island, the characters are on an artificial floating island that is actually a ship. In Yann Martel's novel Life of Pi, there is a floating island. In Michael Ende's children's novel "Jim Button and Luke the Engine Driver" the main characters resolve the presumed problem of overpopulation of the original island by attaching a floating extension to it.

Guida alla lettura

A design similar to Fuller's Cloud Nine may permit habitation in the upper atmosphere of Venus, with temperature and atmospheric pressure being incredibly high on the surface. As scientifically and fictionally described by Geoffrey A. Landis, the easiest planet (other than Earth) to place floating cities at this point would appear to be Venus. Because the thick carbon dioxide atmosphere is 50% denser than Earth's atmosphere, breathable air with a composition similar to the latter is a lifting gas in the dense Venerean atmosphere, with over 60% of the lifting power that helium has on Earth. At an altitude of 50 km above the Venerean surface, the environment is the "most Earthlike in the solar system", according to Landis, with a pressure of approximately 1 bar and temperatures ranging between 0–50 °C (32–122 °F). In addition to Venus, floating cities have been proposed in science fiction on several other planets. For example, floating cities might also permit settlement of the outer three gas giants, as the gas giants lack solid surfaces. Jupiter is not promising for habitation due to its high gravity, escape velocity and radiation, but the Solar System's other gas giants (Saturn, Uranus, and Neptune) may be more practical. In 1978, the British Interplanetary Society's Project Daedalus envisioned floating factories in the atmospheres of Jupiter refining helium-3 to produce fuel for an interstellar probe. Michael McCollum notes that the "surface" gravity of Saturn (that is, at the visible cloud layer, where the atmospheric pressure is about the same as Earth's) is very close to that of Earth, and in his novel The Clouds of Saturn, he envisioned cities floating in the Saturnian atmosphere, where the buoyancy is provided by envelopes of hydrogen heated by fusion reactors. Uranus and Neptune also have upper atmosphere gravities comparable to Earth's, and even lower escape velocities than Saturn. Cecelia Holland populated Jupiter, Saturn and Uranus with mutant humans, the Styth, in floating cities in her only SF novel, Floating Worlds (1975). Donald Moffitt's novel Jovian (2003) features floating cities forever floating in the Jovian atmosphere, a worthwhile enterprise due to their ability to extract useful gases. The book concentrates on the cultural differences (and political tensions) developing between "Jovian" humans and Earthbound ones.

Lo sapevi?

• In the treatise De Grandine et Tonitruis (815), Carolingian bishop Agobard of Lyon describes Magonia, a cloud realm populated by felonious aerial sailors.
• In 1960, the architects Buckminster Fuller and Shoji Sadao proposed the construction of a 1-mile-diameter (1.6 km) thermal airship, which they called Cloud Nine.