Created By: zarpaulus on September 16, 2012 Last Edited By: zarpaulus on November 26, 2012
Troped

Centrifugal Gravity

The use of centrifugal force to simulate gravity

Name Space:
Main
Page Type:
Trope
Rename and expansion of Ring World Planet:

One of the most common shapes for a Space Station in fiction given that it allows one to simulate gravity by simply spinning it. The horizon curves up, not down, but only in one dimension. The sides of the cylinder will be walls, with or without a "ceiling." These can range in size from a true Dyson Sphere to a cylindrical space station. These variants of worlds usually at least pay some lip service to the known laws of physics, since a spinning ring generates a centrifugal force that could be used instead of gravity. However to exist for real, particularly large ones would have to be made of Unobtainium.

It's somewhat less practical for mobile spaceships due to the necessary design limitations.

Note that it would always be "day" in such a cylindrical world unless measures are taken to simulate day and night, either through sun shades, mirrors, or some combination of the above. An other alternative is choosing an orbit where the ring periodicaly gets shadowed by something, like putting it in a geostationary orbit.

Examples

[[foldercontrol]]

[[folder:Anime and Manga]]
  • The Gundam franchise helped popularize the O'Neill Cylinder space colony (see below in "Literature"), as well as other designs.
    • Actual ring shaped colonies (Known as the "Stanford Torus" or "Island 2" model) are only common in the Gundam Wing coninuity, though one also shows up in Gundam Unicorn, which was apparently the first ever built in the UC-verse and promptly got blown up.
  • In Cowboy Bebop most space stations are the ring type. The Bebop and many other ships have rotating sections and no gravity anywhere else on board.
  • The Amaterasu of Starship Operators has a rotating crew section, the showers have signs warning about coriolis forces.
[[/folder]]

[[folder:Comic Books]]

[[/folder]]

[[folder:Film]]
  • Possibly the most famous example, the space station from 2001: A Space Odyssey. In addition both the Discovery and the Alexei Leonov from 2010 have rotating sections.
  • Moonraker. Hugo Drax's secret space station spins on its axis, providing gravity to those inside. When James Bond stops the rotation, the station interior goes to zero gravity and everyone starts floating around.
  • Mission to Mars the main space ship seems to have this.
[[/folder]]

[[folder:Literature]]
  • Larry Niven's Ringworld is set on a world shaped like a vast ring with a sun at its centre. It's made of Unobtanium called scrith and is so massive that its geographical features include 1:1-scale maps of several planets (including Earth). These maps are significantly less than 1% of the ring's surface area.
  • The Culture of Iain M. Banks's novels builds Ringworld-style Orbitals (but smaller) as housing for many of its citizens. They have a few full size, fits-round-a-star Ringworlds too but they're much rarer, since you can get more useable area by using the same mass to build orbitals so most of the Culture regards them as tacky.
  • Arthur C. Clarke's Rama from the series started by Rendezvous with Rama, is a massive cylindrical spacecraft.
  • The protagonists of Gregory Benford's Beyond Infinity spend a brief time trapped in a Tunnelworld after an encounter with some 4-dimensional aliens. It was a closed loop, so traveling in any direction for a long enough time would return you to your point of origin.
  • Gerard O'Neill proposed a real world cylindrical space colony: Island Three.
    • The page illustration is a representation of the "Stanford Torus", another design inspired by both O'Neill's work and the classic "wheel-and-hub" space stations.
  • Earth in Illium and Olympos is surrounded by two huge ever moving rings. They are not fun places.
  • Thistledown, from Greg Bear's Way Series, is a hollowed out asteroid containing seven cylindrical chambers separated by bulkheads.
    • The seventh chamber connects to a cylindrical pocket universe with several million miles of terraformed interior.
  • The Anne McCaffrey novel The City Who Fought takes place entirely on a cylindrical space station.
  • In the Gor series the alien Kur race live on "steel worlds" hidden in the Asteroid Belt. The book Kur of Gor takes place on one, and we learn that it is like this. You can look up and see the opposite "land" side. Day & night and weather are controlled artificially. At one point they travel to one of the ends where the gravity is pracitally non-existent.
  • The Battle School of the Ender's Game series is built as a ring, though Bean deduces from emergency exit maps that it's larger than they're told, and there were plans to build more rings connected around it.
  • In Destruction of Phaena by Alexander Kazantsev, the eponymous planet's first (and last) space station was a ring that used centrifugal forces to emulate gravity. There was also a compartment in the middle of the ring, where they grew edible plants, which profited from the lack of "gravity".
  • The Whorl in Gene Wolfe's Books of the Long Sun is a rotating cylindrical spaceship. "Whorl" obviously refers to its rotation, but has become confused in the minds of its injhabitants with "world" to the extent that they also call planets whorls.
  • Robert A. Heinlein's The Cat Who Walks Through Walls opens on a space station of multiple levels and multiple rings.
  • One such space station is depicted in the 1959 children's book You Will Go to the Moon by Mae and Ira Freeman
[[/folder]]

[[folder: Live Action TV]]

  • The eponymous Babylon 5 is a spinning cylindrical space staion, as were Babylons 1 through 4.
[[/folder]]

[[folder:Tabletop Games]]
  • Sigil from Dungeons & Dragons Planescape setting is this. It's also a sort of hub that connects to all the other planes of existence.
  • In Eclipse Phase many people following the Fall live in space habitats, many of the bigger ones are toruses or O'neil cylinders. However there's also a number of habitats that don't bother with spinning since basic biomods counter the degeneration from microgravity.
[[/folder]]

[[folder:Video Games]]
  • Halo takes place on a world (Installation 04) resembling Banks' Orbitals at the midpoint between a gas giant and its moon. All of the other Halos appear to orbit gas giants as well.
    • The Pillar of Autumn starship is said to have cylindrical rotating sections within it to create gravity, but these are never seen in gameplay and the encountered layout does not seem to fit them.
  • Startopia has you turn one of these into a profitable space station.
    • Several, actually. Apparently, all known races use the same exact design for their space stations, right down to the color scheme.
  • EV Nova has several of these, mostly ring-around-a-planet style. Though one is (for all intents and purposes) THE Ringworld. (The Polaris use that one for effectively infinite farmland.)
    • For bonus Shout-Out points, that ringworld is named Tre'ar Helonis.
  • In Mass Effect, the Citadel is one of these. In particular, the Presidium is a huge ring with its own biosphere and simulated sky at one end of the space station.
    • The Alliance's Arcturus Station is described as a Stanford Torus.
  • You can make these in the Space Empires series. A Dyson Sphere is better, though.
  • Some of the planets in both Super Mario Galaxy and Super Mario Galaxy 2, such as the planet in which you fight Megahammer (a Humongous Mecha piloted by Bowser Jr.) on in the latter, actually look like these.
  • You can build these in Star Ruler, admittedly as a lategame option. They are Capital-H Huge, larger than some planetary orbits.
  • Shores of Hazeron has ancient ringworlds which can be colonized. The ringworlds are almost exactly like those from the Ring World novel, with mountains flanking the inner walls, and with shadow squares creating day/night cycles on the surface.
  • The Torus Aeternal in X3: Terran Confict is a massive space station ringing Earth's equator. It serves as a docking ring, shipyard, and orbital defense station. In X3: Albion Prelude, it gets blown up.
  • In the expansions of Galactic Civilizations 2 the limitations of centrifugal force are discussed in the description for the "Artificial Gravity" tech. Apparently during the stargate era a Drengin troop transport once had an arm motor jam and toss thousands of troops out into space. A number of the default human ship designs have rotating sections, in particular the colony ship.

[[/folder]]

[[folder:Web Original]]
  • The world of Pendor, from The Journal Entries of Kennet Shardik, is Niven's Ringworld with the Serial Numbers Filed Off, because Niven had threatened to sue Elf Sternberg over writing gay BDSM Known Space fanfic.
  • Darwin's Soldiers: Card of Ten takes place primarily on one of these.
  • So many space habitats in Orion's Arm. There are even Banks Orbitals, though system-encompassing rings are impossible to construct.
  • The space station Credomar in Schlock Mercenary is like this, but it's considered to be so inefficient that it's a mystery why anyone would build a space station like that. It's eventually revealed that Credomar wasn't really a space station, but a Wave Motion Gun disguised as a space station.
[[/folder]]


Community Feedback Replies: 34
  • September 16, 2012
    randomsurfer
    • The eponymous Babylon Five is a spinning cylindrical space staion, as were Babylons 1 through 4.
    • In the Gor series the alien Kur race live on "steel worlds" hidden in the Asteroid Belt. The book Kur of Gor takes place on one, and we learn that it is like this. You can look up and see the opposite "land" side. Day & night and weather are controlled artificially. At one point they travel to one of the ends where the gravity is pracitally non-existent.
  • September 17, 2012
    fulltimeD

    redacted----
  • September 17, 2012
    Tuckerscreator
    • The Battle School of the Enders Game series is built as a ring, though Bean deduces from emergency exit maps that it's larger than they're told, and there were plans to build more rings connected around it.

    You could add this also to the Halo example.
    • The Pillar of Autumn starship is said to have cylindrical rotating sections within it to create gravity, but these are never seen in gameplay and the encountered layout does not seem to fit them.
  • September 18, 2012
    nitrokitty
    I think we should extend this to just gravity through rotation, since it happens on more than just space stations. For example, the human starships in Babylon Five use rotating sections to simulate gravity, since they haven't figured out artificial gravity technology yet. The technology actually plays a critical role in space warfare since ships equipped with it can perform more stressful maneuvers without killing their crew.
  • September 18, 2012
    Koveras
    • In Destruction of Phaena by Alexander Kazantsev, the eponymous planet's first (and last) space station was a ring that used centrifugal forces to emulate gravity. There was also a compartment in the middle of the ring, where they grew edible plants, which profited from the lack of "gravity".
  • September 18, 2012
    fulltimeD
    Yeah expand this beyond just space stations- plenty of ships in harder sci-fi are also like this
  • September 18, 2012
    KevinKlawitter
    I hate to be "that guy", but strictly speaking, the ships and stations used by this trope would most likely be designed to generate gravity by application of Centripetal Force, not Centrifugal Force.
  • September 18, 2012
    zarpaulus
  • September 18, 2012
    zarpaulus
    What would you all suggest for a name if ships were to be included?
  • September 18, 2012
    TBTabby
    The space station Credomar in Schlock Mercenary is like this, but it's considered to be so inefficient that it's a mystery why anyone would build a space station like that. It's eventually revealed that Credomar wasn't really a space station, but a Wave Motion Gun disguised as a space station.
  • September 18, 2012
    fulltimeD
    Centripetal Gravity, maybe, for "Centripetal force"?
  • September 18, 2012
    fulltimeD
    Film
    • The Alexei Leonov, the Soviet ship from 2010: The Year We Make Contact, had a rotating section.
  • September 18, 2012
    KevinKlawitter
    ^^^I'm not saying Centrifugal Force doesn't exist. I'm saying it's not what people generally think it is. And that XKCD comic doesn't go that far in explaining the context and nuances.
  • September 18, 2012
    LeeM
    The Whorl in Gene Wolfe's Books of the Long Sun is a rotating cylindrical spaceship. "Whorl" obviously refers to its rotation, but has become confused in the minds of its injhabitants with "world" to the extent that they also call planets whorls.
  • September 20, 2012
    surgoshan
  • October 2, 2012
    Stratadrake
    Centrifugal Gravity works. ("Centripetal" does not, because it has the opposite meaning. Centripetal force is the inward-facing change in velocity needed to create a rotating motion in the first place; centrifugal is the reaction that an observer inside that motion feels. They're a cause/effect or action/reaction pair.)
  • October 2, 2012
    SharleeD
    • In Larry Niven's The Integral Trees, the trees it's named for rotate within the zero-gee environment of the gas torus, providing a substitute for gravity to humans living on the spinward face of their trunks. Unusual in that it's direct pressure of the rotating trunks, not centrifugal force, that does this.
  • October 2, 2012
    Stratadrake
    I had to look up that novel on Wikipedia to figure out how it differs from any other example. The trees themselves are centered in orbit (thus having zero local gravity near their center-of-mass), but their large size means that anyone on either end feels a "gravitational" pull away from the tree's center. The trees themselves do not spin, just orbit.
  • October 3, 2012
    captainsandwich
    I have seen lots of centrical space stations in fiction with no explanation on how they simulate gravity. Do these count?
  • October 3, 2012
    m8e
    I suggest that we make a trope about "Rotating Space Habitat" and one "Centifugal Gforce"

    I.e rename this one to "Rotating Space Habitat" rewrite it so it's clearly about the space Habitats. (That they are mostly self sustaining when it come to food/water/oxygen, often placed in Lagrangian points, animes with these often also have Humongous Mecha, they create Artificial Gravity with Centifugal Gforce etc).
  • October 3, 2012
    Arivne
    I would suggest deleting "cylinder or ring shaped" from the Laconic, because there's no reason to restrict it based on the station's shape.

    Film
    • Moonraker. Hugo Drax's secret space station spins on its axis, providing gravity to those inside. When James Bond stops the rotation, the station interior goes to zero gravity and everyone starts floating around.
  • October 3, 2012
    zarpaulus
    @m8e: You miss all the discussion on whether to include space ships? I don't think there's enough material for two tropes.

    @Arivne: It's by far the most efficient shape for Centrifugal gravity.
  • October 3, 2012
    m8e
    In that case we can move any ship examples to Artificial Gravity and make this "Rotating Space Habitat" (, "Rotating Space Colony", "Rotating Space Station" or something?)
  • October 3, 2012
    captainsandwich
    I think we should include spaceships. I also think we should include a space station in the shape even if the people in production only choose it because they think that is the typical shape of the space station (and thus in no way explicitly say or show its for gravity, I am ok with excluding examples that show the shape but it is not revealed to be the cause of the 'gravity' (if any).
  • October 3, 2012
    SharleeD
    ^^^^^^^ Whoever wrote that Wikipedia summary didn't understand how the integral trees work. They orbit the gas torus and spin around their midpoint, creating an impression of gravity when you stand on a part of the trunk that's spinning forwards. The reason this "gravity" is weaker at the center is that the ends are moving faster than the middle portion of the trunk does, as they move around the outer circumference of a wide circle. The trees, themselves, are nowhere near big enough to generate perceptible gravity from their mass, alone.
  • October 3, 2012
    norsicnumber2nd
    In Film, Victor Von Doom's Von Doom Spacecraft/lab thing in Fantastic Four is like this, a donut which is also cylindrical and supports a sphere in the middle with a bunch of access tubes, which are also cylindrical. Does the Death Star count, too?
  • October 3, 2012
    zarpaulus
    ^ No, the decks aren't oriented to use centrifugal force in either case.
  • October 4, 2012
    rodneyAnonymous
    There is no such thing as centrifugal force; that isn't a force. Centripetal force produces a centrifugal effect. Centrifugal Gravity is fine.
  • October 4, 2012
    Stratadrake
    @Sharlee: How "correct" the Wikipedia article is I can't judge, but their explanation does strike me as perfectly clear: Orbit is a careful balance between velocity and distance from planetary center-of-gravity; a lower altitude requires a faster velocity to maintain an orbit and vice versa. Now the trees' center is at perfect orbit altitude (someone at the center feels zero planetary gravity), but the bottom of the tree is slightly slower than orbit velocity at that lower altitude (as signified by the winds, which themselves travel at orbit velocity and are what gives the trees their eponymous shape) so someone standing at the bottom feels a small portion of planetary gravity (not gravity from the tree's own mass, which as you point out would not be much anyway). On the flipside, the tops of the trees are moving faster than orbit velocity at that altitude, so someone standing at the top feels a centrifugal 'gravity' away from the planet. The tree itself does not (in fact can not) "spin" because it is tidally locked - one end always points "in" toward planetary center, one end always points "out", much like how the same side of the Moon is always facing Earth.
  • October 7, 2012
    zarpaulus
    Ok, we've got two votes for Centrifugal Gravity and one for Rotating Space Habitat
  • October 15, 2012
    zarpaulus
    Going to launch tomorrow night.
  • October 15, 2012
    SquirrelGuy
    One such space station is depicted in the 1959 children's book You Will Go to the Moon by Mae and Ira Freeman

    A picture of the space station is on the Amazon page. http://www.amazon.com/dp/0394800079

    See also http://en.wikipedia.org/wiki/You_Will_Go_to_the_Moon_(book)
  • November 25, 2012
    FastEddie
    Do not use this as a rename. An article for ring habitats and one for O'Neil habitats is the better fix.
  • November 26, 2012
    zarpaulus
    How about a supertrope?
http://tvtropes.org/pmwiki/discussion.php?id=f1p2gugq6dmel8hrgfazfq4e&trope=CentrifugalGravity