Floating island

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This article is about the natural phenomenon. For the dessert, see floating island (dessert). For Angel Island, the floating island in the Sonic the Hedgehog series, see Angel Island (Sonic).

Image:Uros island.jpg

Floating islands are a common natural phenomenon that are found in many parts of the world. They exist less commonly as a man-made phenomenon. Floating islands are generally found on marshlands, lakes, and similar wetland locations, and can be many hectares in size.

When they occur naturally they are sometimes referred to as tussocks, floatons, or sudds. Natural floating islands are composed of vegetation growing on a buoyant mat consisting of plant roots or other organic detritus.

They typically occur when growths of cattails, bulrush, sedge, and reeds extend outward from the shoreline of a wetland area. As the water gets deeper the roots no longer reach the bottom, so they use the oxygen in their root mass for buoyancy, and the surrounding vegetation for support to retain their top-side-up orientation. The area beneath these floating mats is exceptionally rich in aquatic lifeforms. Eventually, storm events tear whole sections free from the shore, and the islands thus formed migrate around a lake with changing winds, eventually either reattaching to a new area of the shore, or breaking up in heavy weather.

Natural floating islands may have been the source of many "disappearing island" legends, such as those of surrounding the Isle of Avalon.

Floating artificial islands are generally made of bundled reeds, and the best known examples are those of the Uros people of Lake Titikaka, Peru, who build their villages upon what are in effect huge rafts of bundled totora reeds. The Uros originally created their islands to prevent attacks by their more aggressive neighbours, the Incas and Collas. The Aztec capital, Tenochtitlan, was surrounded with chinampas, floating islands used for agriculture. Spiral Island was a more modern one-person effort of constructing an artificial floating island in Mexico.

The British Project Habbakuk proposed the construction of aircraft carriers made of ice-like Pykrete. Its size and speed made it more an artificial iceberg or island than a ship.

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In fiction

A "floating island" in fiction (sometimes called a "flying island"), is a fictitious landmass that flies above the surface of the earth (or in some cases through the depths of space), defying gravity. These islands are usually free-floating and can be directed by the whim of their inhabitants, although some may be permanently anchored. They are usually propelled and/or held aloft by one or more of the following means:

Helium, hydrogen or some other lighter than air gas.
A lodestone or magnet, as seen in Jonathan Swift's Gulliver's Travels' Laputa.
Magic of some kind.
Advanced science/technology — anti-gravity or some other form of non-paranormal levitation, as in Hayao Miyazaki's Castle in the Sky.

A well-known floating island in popular culture is the Angel Island of the Sonic the Hedgehog series. In Final Fantasy VI there is an entire floating continent, that ends up falling and creating an impact event. In many other fantasy settings flying islands or floating cities kept aloft by magic are prominent, such as the airborne cities of ancient High Netheril in the Forgotten Realms Dungeons & Dragons setting. Roger Dean is also planning a movie entitled Floating Islands. The movie is said to be based on the story of his album art for the band Yes and will feature several of their songs. Other references can be found in the science fiction TV series Star Trek (original; 1966) episode "The Cloud Minders", in Star Wars The Empire Strikes Back's Cloud City, and in "Chrono Trigger" as the Kingdom of Zeal.