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[[quoteright:350:[[Anime/DragonBallZ http://static.tvtropes.org/pmwiki/pub/images/king_kai_planet_4934.jpg]]]]

An inhabitable planet that is far smaller than astronomically possible, often less than a few functional miles in diameter. As a general rule, a BabyPlanet is small enough that you can see its curvature even on the surface. In RealLife, a body this small would be called an asteroid, and would be incapable of supporting an atmosphere (of useful density at a life-supporting temperature), and would probably not even be spherical, but in fiction, these often sport [[AllPlanetsAreEarthLike an entire ecosystem]] awkwardly compressed into the minute available space.

Although SciFiWritersHaveNoSenseOfScale, they usually aren't this far off the mark on accident; this trope usually comes about either because of limitations in technology's ability to represent planets in a realistic scale, or just for the sake of aesthetic.

Often, this is used for purely aesthetic reasons, particularly on cover art for games and [=CDs=]. Just as often it's ArtMajorPhysics. In photography, this effect is often created with very-wide angle (or ''fisheye'') lenses.

Bonus points if it's [[WorldShapes unusually shaped]] too.

Related to FloatingContinent. Not to be confused with ''VideoGame/LittleBigPlanet'', ItsASmallWorldAfterAll or {{Planetville}}.

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!!Examples:

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[[folder: Advertising ]]

* In the UK, British Gas have been running a series of rather fun adverts based on the idea that "your home is your world"; the person whose boiler is up the plonk lives on a tiny planet that is their house, drive and garden!! And their cars and vans take them to other planets and some planets have theme parks... sounds like a cross between ''VideoGame/TheSims'' and ''VideoGame/SuperMarioGalaxy'' in advert form. [[http://www.youtube.com/user/britishgas Some of them are gathered here.]]

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[[folder: Anime and Manga ]]

* King Kai's planet in ''Anime/DragonBallZ''. Despite being maybe fifty feet in diameter, it strangely has ten times earth's gravity. Based on King Kai's vague explanation, it apparently has the same mass as Earth, heavily compressed. This should technically make it a neutron star, but then, nobody ever accused ''Dragonball Z'' of realism. Even if they did, it's ''still'' the self-built home of a PhysicalGod, and ''still'' set up in a corner of the afterlife, so it might as well be decorated with "AWizardDidIt" in 50-foot-high neon any way the audience looks at it.
* An episode of ''KeroroGunsou'' had one of Keroro's last-ditch invasion schemes involve stealing garbage and water from Earth to create a mini-planet. We learn it was a "last-ditch" scheme because unauthorized planet creation is against the law, and when the planet creation goes out of control it nearly becomes big enough to qualify as a full planet, leading to the Keronians nearly getting arrested by SpacePolice officer Poyon.
* In ''Manga/OyasumiPunpun'', Punpun dreams up a small meteor that fits the bill, which he names Punpunia. It's really only big enough for his house, family, and a few stray animals.

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[[folder: Comic Books ]]

* A SilverAge ''[[Franchise/{{Superman}} Superboy]]'' story had Clark Kent travel to a small asteroid/planet, where he found someone with powers similar to his own. At the time, the preferred explanation for Superman's powers was that Krypton was larger than Earth, so the native race [[HeavyWorlder evolved to counteract the more powerful gravity]]. The boy on the asteroid, it turned out, was from Earth, so on his little world he got to have some of the same benefits Superboy did. The native races of all 3 ecosystems evolved to be [[HumanAliens identical in size and shape]]. . .

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[[folder: Film ]]

* The CGI shots of the Earth in ''Film/{{Zombieland}}'' (which are apparently the mental images of the narrator).
* The movie ''Timelock'' is set on a prison asteroid. It is at least established to be ''very cold'' outside (and the worst offenders are hung outside in a state of suspended animation). Then the movie goes and violates its own logic at the end, when [[spoiler:Riley sticks three small nuclear devices on Villum and knocks him into an abyss. Villum is shown ''alive and well'' in the very last minute of the movie]].

[[/folder]]

[[folder: Literature ]]

* "Asteroid B-612" from Antoine de Saint-Exupery's ''Literature/TheLittlePrince'' may be the TropeCodifier, if not the TropeMaker. It's house-sized, which makes it ''bigger'' than most neighboring planets. And he [[WunzaPlot keeps encountering new stuff on it]] every day, including baobab trees.
* Justified in Creator/LarryNiven's ''[[Literature/KnownSpace Protector]]'' due to use of gravity generators, etc.
* Played straight and justified in the novel ''[[http://www.wilmccarthy.com/tc.htm The Collapsium]]'' by {{Wil McCarthy}}: one of the main characters lives on an artificially constructed planet which is only a few hundred kilometers wide. It has a core made out of [[http://en.wikipedia.org/wiki/Degenerate_matter degenerate matter in the form of neutronium]] which gives it Earth-normal gravity, holds it in a spherical shape and allows it to retain an atmosphere.
* The Literature/MushroomPlanet in the eponymous novels.
* The Creator/FredericBrown story ''Placet is a Crazy Place'' features a tiny planet with a breathable atmosphere with a core made of extra-dense 'heavy' matter to give it its shape and gravity. It even has life forms made of heavy matter that "fly" through the crust (which is like air to them since they are so dense), causing earthquakes. It obviously suffers from the "what keeps the heavy matter from expanding" problem, but might be excused since it is a story from the 40s and ScienceMarchesOn. Also, the heavy matter "birds" that cause earthquakes are completely 100% excused by the RuleOfFunny; the buildings on Placet are small and light, and never last more then three weeks. The birds fly right through the foundations.
* Gary Gibson's ''Stealing Light'' has at least one asteroid fitted with a Shoal 'world engine', and their Coreships.

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[[folder: Live Action TV ]]

* Several episodes of ''Series/TheTwilightZone'' TOS had asteroids with normal Earth gravity and a breathable atmosphere.
** Played straight in "The Lonely"
** {{Lampshaded}} in "Elegy". The astronauts specifically mention that an asteroid shouldn't have Earth gravity and atmosphere.
** {{Subverted}} in "I Shot An Arrow Into The Air". Some shipwrecked astronauts think they're on such an asteroid: they're actually on Earth!
* ''Series/{{Lexx}}'':
** Season 2 had something like this, a small planetoid with an artificial atmosphere that was a TV studio center. Our 'heroes' wind up there and find that if their ratings slide they'll be in trouble.
** In one episode, a planetoid was so small you could see grazing sheep on its surface from orbit. For unexplained reasons, it had Earthlike gravity.
* Aversion: In the original ''Series/{{Star Trek|The Original Series}}'' episode "That Which Survives" the fact that a Luna-sized world has Earthlike atmosphere is one of the clues that something's amiss.
* The official atlas for the ''Series/{{Firefly}}'' verse says even the small moons, barely large enough to be balls (think Mimas or Enceladus), are terraformed using gravitic technology.
* Justified with a Baby Universe in The New World of Mr. Tompkins. The gravitational constant is enormous.
** Inverted in Relativity Land- Relativity Land should be a black hole if gravity still works the same despite the speed of light being 30 mph or less.

[[/folder]]

[[folder: Music ]]

* Album cover art: The miniature planet on [[http://picasaweb.google.com/lh/photo/Q9r15QRrpK3jTkp4GdXp9Q the cover]] of ''Fragile'' by Music/{{Yes}}. (On the back cover, the planet breaks up and the population escape in a wooden space glider. This later inspired Jon Anderson's solo album ''Olias of Sunhillow''.)

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[[folder: Video Games ]]

* ''VideoGame/{{Spore}}''. The planets look regular-sized from close, but appear increasingly tiny as you advance towards the Space Stage. To give you an idea of scale: You can find Earth. The UK is about the size of an average spaceship.
* ''VideoGame/KingdomHearts''. One of the unique artistic features in the first game was condensing of most of the disney worlds into miniature planets, most of which could be seen from 'space'. the worlds themselves, while modeled after the various Disney worlds, tend to be as small as possible, no more than a few miles each. the residents don't seem to notice.
* ''VideoGame/SuperMarioGalaxy'' not only has baby planets; it has ''baby galaxies''. As in, galaxies that're not much bigger than a large [[http://dictionary.reference.com/browse/paddock paddock]].
* ''RatchetAndClank''
* The Special Stages of ''VideoGame/{{Sonic 3 and Knuckles}}''.
* The cover of ''VideoGame/SimCity Societies''.
* ''PopulousTheBeginning''
* The Prince Planet in ''VideoGame/KatamariDamacy'' (very obviously based on Literature/TheLittlePrince's,) as well as Earth itself if you get big enough to notice the curvature.
* The cover of ''VideoGame/AnimalCrossing: Wild World'', and in addition, in-game the ground curves downward into the distance.
* The freeware game ''Frozzd'' features dozens of such planets.
* The American cover art for ''Bullfrog's Theme Park'' game.
* ''VideoGame/CosmicOsmo''
* In ''VideoGame/YoshisIsland'', you fight Raphael the Raven on one of these. To be clear, it ''is'' the world's moon.
* Spacebuild maps for ''[[GarrysMod Garry's Mod]]'' have very small planets generally no bigger than about the size of a football field. This is because the maximum map sizes available are not particularly big.
* ''[[http://www.colibrigames.com/ The Tiny Bang Story]]''.
* ''{{Albion}}''. The titular planet is considerably smaller than Earth, but is mostly made up of exceptionally heavy metal, making the planet's mass just slightly smaller than Earth's.
* ''''VideoGame/AngryBirds Space'' features many levels with small planetoids that have gravity bubbles that affect the birds' trajectories.
* Planets in ''VideoGame/PlanetaryAnnihilation'' range between this and more reasonable sizes, depending on the settings used. Nevertheless, they're much closer than would really be possible, in order that interplanetary travel doesn't take ages.
* ''VideoGame/IncobotoMini'' has the main character running across several small planets as part of the gameplay.
* One of your party members in ''VideoGame/{{Anachronox}}'' is an entire miniaturized planet, Democratus.

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[[folder: Web Animation ]]

* ''WebAnimation/{{Brackenwood}}'' itself is not as small as many examples, but still far smaller than should be able to support [[SingleBiomePlanet a vast, pole-to-pole forest]].
* [[http://www.weebls-stuff.com/onthemoon/ Anything Can Happen On the Moon]].

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[[folder: Webcomics ]]

* In ''Webcomic/TheInexplicableAdventuresOfBob,'' the [[http://bobadventures.comicgenesis.com/d/20070626.html planetoid of Fleen]] follows this trope, even to the point of depicting Literature/TheLittlePrince's asteroid floating nearby.
* Prospit and Derse from ''Webcomic/{{Homestuck}}'': If the size of the towers on their respective moons is any indication, they are smaller than a [[Franchise/StarWars Death Star]], though still quite big. This ultimately applies to almost every planet in the Incipisphere; the [[InsistentTerminology Lands]] are likely less than a hundred kilometers in diameter, small enough that at a fairly distant view the players' homes are still visible, [[{{Bizarrchitecture}} giant tower status]] notwithstanding. Skaia and The Battlefield within it are large, but still fairly small for a planet.

[[/folder]]

[[folder: Web Original ]]

* Discussed on [[http://what-if.xkcd.com/68/ this issue]] of the ''Blog/WhatIf'' Blog, mostly with regard to what the gravitational effects of such a world would be, if it could exist.

[[/folder]]

[[folder: Western Animation ]]

* ''WesternAnimation/{{Futurama}}'':
** Briefly alluded to in an episode where a planet implodes, leaving behind something the size of a large boulder with a few of its native animals pathetically hanging on. As far as the cast is concerned, this is an acceptable level of survival for them.
** "The Mutants Are Revolting" with Mrs. Astor's asteroid. Has both an atmosphere and normal gravity.
** Inverted when [[WeirdSun the Sun]] seems to have Earth gravity...and is a [[LethalLavaLand lava]] [[SingleBiomePlanet planet.]]
** One episode has Fry remarking on how small entire planets can appear when you're flying through space, at which point a Saturn-like planet that appeared to be off in the distance is revealed to actually be about the size of a large bug when it hits the ship's windshield like one.
* ''WesternAnimation/TheClangers''' The Clanger Planet. It has vaguely moonlike craters, and in one episode a Lunar Module lands and an astronaut plants a flag (which the Clangers adopt as a tablecloth,) but it's referred to by the narrator as a "star" and exists among other similar worldlets. But since the Clangers occasionally leave it for the space above without any breathing problems, it runs strictly on Cartoon Physics.
* The ''Franchise/TransformersGeneration1'' portrayal of Cybertron. Curvature could often be seen, and buildings could be seen from space. When Cybertron was moved into Earth's orbit, it was shown to be smaller than the moon - close enough for a plane-bot to fly to in under a minute, and yet the entire planet could be easily seen whenever it was in frame. Asteroid-sized is generous, and yet it's shown to have gravity comparable to Earth.
** And then in the comics it's the size of Saturn. [[SciFiWritersHaveNoSenseOfScale Way too far the other way, guys.]]
*** Arguably, that issue is {{justified|Trope}} by the fact that [[ThatsNoMoon Cybertron itself is the body of]] [[PhysicalGod Primus]]. [[DoingInTheScientist Surely as a]] PhysicalGod, [[DoingInTheScientist he could whatever size he pleases, regardless of what the laws of physics say.]]
* In ''WesternAnimation/DuckDodgersInTheTwentyFourthAndAHalfCentury'', Planet X gets reduced down to a rock that's barely large enough for Dodgers and Marvin Martian to both stand on. Nonetheless, it still has air, and some weird kind of gravity that allows someone to ''fall off''.
--> '''Duck Dodgers''': As I was saying, this planet ain't big enough for the both of us! ''(pushes Marvin off)'' I claim this planet in the name of the Earth!
--> '''Cadet''': A-a-a-a-big deal.
* [[ExactlyWhatItSaysOnTheTin All the planets]] in ''[[http://www.tinyplanets.com/ Tiny Planets]]''.
* All the planets in WanderOverYonder are small enough for buildings, mountains, and other features around that size area to be visible from space.

[[/folder]]

[[folder: Real Life ]]

* Theoretically, you could have things like this. They just would have to be on the larger end of this scale (or be very deep), and have constant support (artifical atmosphere, seeding life, etc). There's no real idea how this would work in practice, but there's decent ideas that it could work.
** One way that probably wouldn't work would be compacting a large planet to a smaller size. The escape velocity of an object depends on how compact it is; that is, the ratio of its mass to radius. So the more you compact a planet, the higher the surface gravity would be - the Earth itself compacted to 3 miles across wouldn't be a black hole, but we certainly wouldn't suggest walking around on it.
** Baby Planets might be able to be constructed once [[Franchise/TheHitchhikersGuideToTheGalaxy Magrathean]] construction technology is attained, by creating a world around a superdense core. Considerably less mass than the Earth would be required given the distance from the surface to the gravitational center would be significantly less, so long as the gravitational pull of the core was not enough to decompose the shell of nuclear matter around it, and as long as the diameter is large enough that tidal forces (difference in gravity between feet and head) don't cause serious trouble. Except neutronium is unstable in piles less than 1/10 of a solar mass due to the fact that neutrons are more massive than protons. Anything lighter than 1/10 of a solar mass and made of nuclear matter will decay, then explode as the electrical repulsion overcomes gravity.
** A black hole inside a hollow shell could work (this is used in ''The World is Round'', a novel by physicist Tony Rothmann, though in this case the planet in question is much ''larger'' than Earth, and the scheme is used to keep the surface gravity ''down''). Black holes less than about the mass of the Moon are theoretically thermodynamically unstable, though this is ''much'' less of a problem than with neutronium (they would eventually evaporate, but it turns out the lifetime for a black hole of mass 10^11 kg ... roughly the mass of a hill of dry sand 250 m high ... is in the billions of years, with larger holes having even longer lifetimes).
* Icy moons, such as Europa and Enceladus, are theorized to be capable of housing aquatic life and ecosystems. Europa is a bit smaller than earths moon, and Enceladus is about the size of the British Isles. However, as small on the scale of celestial bodies they are, they are still much larger than a true Baby Planet.
* [[http://www.hongkiat.com/blog/30-examples-tutorials-of-stunning-polar-panorama-photos/ Polar panorama photos]] look very much like tiny planets and can be made from any panorama photo, such as a cityscape.

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