History Main / BabyPlanet

* Baby Planets might be able to be constructed once we attain [[http://uncyclopedia.wikia.com/wiki/Magrathea Magrathean]] construction technology 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.[[hottip: *: I'm feeling too lazy to work the math right now, but it'd be super swell if someone wants to do it and see what it would take, and also to note the densest core material that wouldn't break down adjacent nuclear matter, and the smallest world that could be built on this design.]]
** As mentioned above, tidal forces are still a problem. If gravity is twice as strong by your feet than by your head, you're in serious trouble.

** And he [[WunzaPlot keeps encountering new stuff on it]], every day.

Not to be confused with ItsASmallWorldAfterAll or {{Planetville}}.

[[TheLittlePrince http://static.tvtropes.org/pmwiki/pub/images/the_little_prince1_7459.jpg]]

* ''SuperMarioGalaxy'' not only has baby planets, it has ''baby galaxies''. As in, galaxies that're not much bigger than a large paddock.

* King Kaio's planet in ''DragonballZ''. Despite being maybe fifty feet in diameter, it strangely has ten times earth's gravity. Based on Kaio's vague explanation, it apparently has the same mass as Earth, heavily compressed. This should technically make it a neutron star, but hey, nobody ever accused ''Dragonball Z'' of realism.

** Considering it's the afterlife, who says it's not a neutron star?
*** Would take a density of about [[http://www.google.com/search?q=(10*gravity+on+earth+*+(25+feet)**2+%2F+gravitational+constant)+%2F+(4%2F3+*+pi+*+(25+feet)**3) 50 million times that of water]], which is in the rough range of a neutron star. However, ''DragonBallAbridged'' teaches us it could just be a pirate.
**** Actually, 50 million times the density of water is in the white dwarf range, so it's made of electron degenerate matter.

** Let's be fair, that was just stylistic for the opening.
* MenInBlack has a whole galaxy that is so tiny it fits into something not bigger than a marble.

** There is also an [[AlternateCharacterInterpretation Alternate Interpretation]] that the stories about said planet are the fanciful tales of a sadly terminally ill child.
** Or the not-so-alternate explanation that since the Prince isn't even human to begin with, he may just be explaining things in a way a human would understand them.

** If it's that much neutronium, it should therefore have a tidal force too strong to allow a person to stand up. And what's holding that neutronium together against its [[EarthShatteringKaboom Earth-shattering]] internal pressure? There's a reason only stars with far more mass than the Sun become neutron stars...

* Aversion: In the original StarTrek episode ''That Which Survives'' the fact that a Luna-sized world has Earthlike atmosphere is one of the clues that something's amiss.

*** Not to mention just one realistically sized planet would kill your computer, let alone the untold thousands that Spore has!
**** Actually, you could do that. You simply don't render what you can't see. It would, however, require an insane amount of memory. One day, however, we might very well be able to simulate an entire planet on a consumer-grade computer. [[AGodIsYou And play Sims with it.]]

** Although each world appears locally spherical, moving around it reveals its topology to be toroidal. Which means the whole universe must be bent around it. So its ability to retain an atmosphere could be a result of the same NegativeSpaceWedgie.

* In YoshisIsland, you fight Raphael the Raven on one of these.
* Spacebuild maps for [[GarrysMod Garry's Mod]] have very small planets generally no bigger than about the size of a football field. This is of course because the maximum map sizes available are not particularly big.

*** Would take a density of about [[http://www.google.com/search?q=(10*gravity+on+earth+*+(25+feet)**2+%2F+gravitational+constant)+%2F+(4%2F3+*+ pi+*+(25+feet)**3) 50 million times that of water]], which is in the rough range of a neutron star. However, ''DragonBallAbridged'' teaches us it could just be a pirate.

*** Would take a density of about [[http://www.google.com/search?q=(10* gravity+ on+ earth+* + (25+ feet)** 2+ %2F+ gravitational+ constant)+ %2F+ (4%2F3+* + pi+* + (25+ feet)** 3) 50 million times that of water]], which is in the rough range of a neutron star. However, DragonBallAbridged teaches us it could just be a pirate.

* In "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''.

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* B-612 from Antoine de Saint-Exupery's ''TheLittlePrince'' may be the TropeCodifier, if not the TropeMaker. It is described as an asteroid, though.

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; 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 humor.

Often, this used for purely aesthetic reasons, particularly on cover art for games and [=CDs=]. Just as often it's ArtMajorPhysics.

* 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 literally 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 [[The Sims]] and [[Super Mario Galaxy]] in advert form. [[http://www.youtube.com/user/britishgas Some of them are gathered here.]]

* In "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 Earth gravity and air.

Not to be confused with ItsASmallWorldAfterAll.