Floating city (science fiction)

In science fiction, floating cities are settlements that strictly use buoyancy to remain in the atmosphere of a planet. However the term generally refers to any city that is flying, hovering, or otherwise suspended in the air via any means technological or even magical.

Earth

In Jonathan Swift's satirical novel "Gulliver's Travels", Swift envisioned Laputa, an island city floated in the sky. The island was suggested to levitate above the Earth by use of the force of magnetism. In the 1920s, Hugo Gernsback speculated about floating cities of the future, suggesting that 10,000 years hence "the city the size of New York will float several miles above the surface of the earth, where the air is cleaner and purer and free from disease carrying bacteria." To stay in the air, "four gigantic generators will shoot earthward electric rays which by reaction with the earth produce the force to keep the city aloft." [see [http://davidszondy.com/future/city/floatingcity.htm illustration from the magazine "Science and Invention", February 1922] , on Urban Utopias web page (accessed September 23, 2008)]

Although Swift's proposal was intended as satire, Buckminster Fuller proposed the concept more seriously in the form of the Cloud nine (Tensegrity sphere) megastructure [cite book | last = Fuller | first = Buckminster| coauthors = Kiyoshi Kuromiya | title = [http://buckminster.info/Biblio/By/By-BkTOC-CriticalPath.htm Critical Path] | publisher = St. Martin's Griffin | date = 1981 | isbn = 0312174918] , in which he envisioned a dome over an entire city, allowing it to float freely in the sky and move wherever it was blown by wind across the surface of the Earth. He proposed a one-mile diameter geodesic sphere that would be heated by sunlight, functioning as a thermal airship.

Venus

see also: Colonization of Venus

A design similar to Fuller's "Cloud Nine" might permit habitation in the upper atmosphere of Venus, where at ground level the temperature is too hot and the atmospheric pressure too great. As proposed by Geoffrey A. Landis, the easiest planet (other than Earth) to place floating cities at this point would appear to be Venus [cite journal|last=Landis |first=Geoffrey A.| year=2003| title=Colonization of Venus| url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=APCPCS000654000001001193000001| journal=Conference on Human Space Exploration, Space Technology & Applications International Forum, Albuquerque NM| month=Feb. 2-6] . Because the thick carbon dioxide atmosphere is 50% denser than air, breathable air (21:79 Oxygen-Nitrogen mixture) is a lifting gas in the dense Venusian atmosphere, with over 60% of the lifting power that helium has on Earth. In effect, a balloon full of human-breathable air would sustain itself and extra weight (such as a colony) in midair. This means that any large structure filled with air would float on the carbon dioxide, with the air's natural buoyancy counteracting the weight of the structure itself. [cite web| last = Atkinson| first = Nancy| title = Colonizing Venus With Floating Cities| publisher = Universe Today| date = July 16th, 2008| url = http://www.universetoday.com/2008/07/16/colonizing-venus-with-floating-cities/ | format =| accessdate = 2008-09-23 ]

At an altitude of 50 km above the Venusian surface, the environment is the "most Earthlike in the solar system" [Landis, quoted in Atkinson "op. cit."] , with a pressure of approximately 1 bar and temperatures in the 0°C-50°C range [Citation| last = Seif| first = A.| editor-last = Hunten "et al".,| editor-first = D. M. | contribution = Thermal Structure of the Atmosphere of Venus| title = Venus| pages = 215-279| publisher = University of Arizona Press| place = Tucson, AZ| year = 1985] . Because there is not a significant pressure difference between the inside and the outside of the breathable-air balloon, any rips or tears would cause gases to diffuse at normal atmospheric mixing rates, giving time to repair any such damages. In addition, humans would not require pressurized suits when outside, merely air to breathe and a protection from the acidic rain.

Since such colonies would be viable in current Venusian conditions, this allows a dynamic approach to colonization instead of requiring extensive terraforming measures in advance. The main challenge would be using a substance resistant to sulfuric acid to serve as the structure's outer layer; ceramics or metal sulfates could possibly serve in this role. (The sulfuric acid itself may prove to be the main motivation for creating the structure in the first place, as the acid has proven to be extremely useful for many different purposes.)

Other Planets

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 unacceptable 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 "surface" gravities comparable to Earth's, and even lower escape velocities than Saturn.

"Cloud cities" have also been proposed, floating by means of antigravity or other science-fictional means, on a number of fictional planets, most notably at Bespin in the Star Wars film The Empire Strikes Back.

Examples

*Cloud City is a floating city on Bespin, a fictional planet in the Star Wars universe managed by Lando Calrissian.

*In the episode, "The Cloud Minders," Stratos is a fictional floating city on the planet Ardana and ruled by High Advisor Plasus.

*In the Firefly episode Trash, the planet of Bellerophon is shown to be host to dozens of floating estates with "gracious living, ocean views and state-of-the-art security."

*The novel "Orion Shall Rise" by Poul Anderson features an aerostat city called "Skyholm," located above present-day France.

*In the novel "The Ringworld Engineers", Louis Wu seeks a way to save the Ringworld by bartering for information in the library of a floating city.

*SkyTown is a floating city on planet Elysia in "" from the "Metroid" video game series.

*Airhaven is a floating city in the Mortal Engines Quartet, that, through attaching gas bags, lifted itself into the air to avoid cities trying to eat it according to Municipal Darwinism.

*There are numerous floating habitats on the Venus-like planet Chilo in Tobias S. Buckell's novel Sly Mongoose. Buckell credits Geoffrey A. Landis with providing the background information on the floating cities. [Buckell, Tobias, "The Big Idea: Tobias Buckell" interview in [http://scalzi.com/whatever/?p=1374 Whatever] , Aug. 19, 2008 (Retrieved on 2008-09-23).]

*There are several floating cities in the games Skies of Arcadia for the Sega Dreamcast and Skies of Arcadia Legends for the Nintendo Gamecube.

*Atlantis from the "Stargate" universe is a probable example of a floating city. Although the city ship weights several million tons, it is buoyant enough to float on water and, given that it's energy shield can hold the atmosphere inside nearly indefinitely, it should be able to float in a particularly dense atmoshpere.

ee also

*Colonization of Venus
*Walking city

References