History UsefulNotes / DwarfPlanets

Makemake (pronounced "mackie mackie") is the last dwarf planet to be discovered. It was named after the creator deity in the myths of Papa Nui, the native people of Easter Island. Prior to that, it was called an "Easterbunny" due to the date of discovery falling shortly after Easter. Its mass is about 0.07% that of Earth, making it slightly more massive than Haumea. It has one natural satellite (officially designated "[=S/2015 (136472) 1=]" or nicknamed "[=MK2=]"), which sadly doesn't have a creative name as of yet and there isn't really that much interesting going on with the dwarf planet itself.

While the IAU currently lists Charon

Ceres has a complicated history of designations given to it since its discovery, even more so than Pluto. It was originally labeled as a planet when it was discovered on New Year's day 1801, and was quickly joined by the asteroids Pallas, Juno, and Vesta, all of which were also classed as planets. Ceres's discovery was taken as proof of the [[ScienceMarchesOn now-defunct]] Titus-Bode law[[note]]"Each planet in a star system should be roughly twice as far away from the star as the planet that comes before it." Ceres follows this law in relation to Mars, and, in fact, the law holds for every planet in the solar system except Neptune, whose discovery disproved it.[[/note]]. William Herschel argued as early as 1802 that Ceres and Pallas were not planets and at the time coined the term "asteroid" to distinguish them from the other planets and labeled Ceres as such, but his opinion was in the minority until the discovery of the fifth asteroid, Astraea, in 1845. By then, telescope technology had advanced enough that thousands of asteroids were promptly discovered over the next few years, and astronomers accepted that Ceres was merely the first. Ceres, Pallas, Juno, and Vesta were formally demoted from planet status in 1851, [[OlderThanTheyThink the first to do so]]. Their demotion also notably occurred after the discovery of Neptune in 1846; few people remember that Neptune spent its first five years post-discovery as the solar system's ''twelfth planet''. Ceres remained classified as an asteroid until 2006 with the reclassification of dwarf planets by the IAU; it was officially labeled as the sole dwarf planet in the inner solar system after being classified as the largest asteroid in the Asteroid Belt for over a century and a half.

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Pluto's most peculiar feature is its largest moon, Charon, which has one-eighth of Pluto's mass and one-half of its volume - an unusually big proportion for a planet and a moon. It lead to Pluto being occasionally labeled a dual planet, since calling Charon a satellite isn't fully accurate with how the objects revolve around one center of mass that lies in the empty space above Pluto's surface; this is in stark contrast to the Earth-Moon system, where the shared center of mass lies beneath Earth's surface. Pluto and Charon also have the distinction of being the only gravitationally round objects to have achieved a [[TidallyLockedPlanet two-way tidal lock]] within the lifespan of the solar system; no matter what, Pluto and Charon ''always'' show each other the same face, like two dancers holding hands while spinning in a circle. In addition, Pluto has four other irregular moons named Styx, Nix, Kerberos, and Hydra, which compared to Charon, are likely captured small Kuiper Belt objects similar to UsefulNotes/{{Mars}}' asteroid moons; Phobos and Deimos. An alternate hypothesis is that they are leftover debris from the giant impact that created Charon that somehow failed to coalesce. Like Charon, these moons do not orbit Pluto directly, instead revolving around the system's shared center of gravity in between Pluto and Charon.

The official IAU definition for fictional names of features on Charon is items and milestones of "fictional space".[[note]]Charon ''was'' discovered in 1978, which was arguably the heyday of science fiction on TV.[[/note]] With that one, the ''New Horizons'' team is really going to town. [[Franchise/StarTrek Vulcan Planum]] (with [[Creator/LeonardNimoy Spock Crater]]), [[Series/DoctorWho Gallifrey Macula]], [[Franchise/{{Alien}} Ripley Crater and Nostromo Chasma]], Anime/{{Macross}} and [[Series/{{Firefly}} Serenity Chasmae]], [[Franchise/StarWars Organa, Skywalker and Vader Craters]]...

!!Haumea
[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/haumea_hubble_0.png]]
[[caption-width-right:350:Haumea, Hi'iaka and Namaka as seen from the ''Hubble'' space telescope]]
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Dwarf Planets are those weird things that cannot be classified as planets due to their lower mass, but are too massive to be called planetoids or asteroids. The term is fairly new and was created in 2006 to classify Pluto and other objects whose gravity is large enough to compress them into a sphere (aka, being in so called hydrostatic equilibrium), but not large enough to achieve so-called "orbital dominance", where they are the only thing in their orbits.

Officially only two non-planetary objects (Pluto and Ceres) are confirmed to be in Hydrostatic equilibrium. But the IAU (whose opinions are probably the most universally accepted as things get in these matters) has also given the designation to three other objects (Eris, Haumea and Makemake) for various reasons and four others (Orcus, Quaoar, Gonggong and Sedna) tends to be generally accepted as dwarf planets even if the IAU has yet to officially give them that label. And based on our current knowledge of what's required for hydrostatic equilibrium, there could be as much as 50 more catalogued objects that also qualify.

Named after a Roman goddess of agriculture, Ceres is the largest asteroid and only dwarf planet in the Asteroid Belt, making up about a third of the belt's collective mass. It is the smallest of all the dwarf planets, but was the first to be discovered due to its proximity to Earth relative to the other ones. It has gravity of less than 3% that of Earth and possesses a tenuous atmosphere consisting largely of water vapor.

Ceres has a complicated history of designations given to it since its discovery, even more so than Pluto. It was originally labeled as a planet when it was discovered on New Year's day 1801, and was quickly joined by the asteroids Pallas, Juno, and Vesta, all of which were also classed as planets. Ceres' discovery was taken as proof of the [[ScienceMarchesOn now-defunct]] Titus-Bode law[[note]]"Each planet in a star system should be roughly twice as far away from the star as the planet that comes before it." Ceres follows this law in relation to Mars, and in fact the law holds for every planet in the solar system except Neptune, whose discovery disproved it.[[/note]]. William Herschel argued as early as 1802 that Ceres and Pallas were not planets and at the time coined the term "asteroid" to distinguish them from the other planets and labeled Ceres as such, but his opinion was in the minority until the discovery of the fifth asteroid, Astraea, in 1845. By then, telescope technology had advanced enough that thousands of asteroids were promptly discovered over the next few years, and astronomers accepted that Ceres was merely the first. Ceres, Pallas, Juno, and Vesta were formally demoted from planet status in 1851, [[OlderThanTheyThink the first to do so]]. Their demotion also notably occurred after the discovery of Neptune in 1846; few people remember that Neptune spent its first five years post-discovery as the solar system's ''twelfth planet''. Ceres remained classified as an asteroid until 2006 with the reclassification of dwarf planets by the IAU; it was officially labeled as the sole dwarf planet in the inner solar system after being classified as the largest asteroid in the Asteroid Belt for over a century and a half.

So far, Ceres has been visited by one spacecraft named ''Dawn'' in March of 2015 after exploring most of the Asteroid Belt and Vesta for eight years. It found that Ceres' surface is similar to that of UsefulNotes/{{Mercury}} and UsefulNotes/TheMoon, covered in countless impact craters, but due to being farther out from UsefulNotes/TheSun its composition is thought to be a combination of rock and water ices. Its most interesting features are bright white spots in the center of some craters, and for a short while, scientists were puzzled as to what they were. Later observations confirmed that these spots are patches of a type of salt brine coming from deep beneath Ceres' surface, revealing that Ceres has active cryovolcanoes, but for a brief moment, scientists were spooked over the possibility of alien civilizations based there.

** ''Literature/LuckyStarrAndThePiratesOfTheAsteroids'': Ceres is the local base for legitimate operations, but pirates occupy many of the smaller asteroids, and even attack the base itself.
* Ceres' first major appearance came in ''Literature/EdisonsConquestOfMars'', where the martians are engaged in a war with beings from Ceres.

* ''Literature/TheJenkinsverse'': Ceres is the main base of an asteroid mining company, named Hephaestus Consortium. They are Earth's premiere space-based mining operation, and develop some of the setting's future-tech.

* Designation: Plutino (Kuiper belt object in an 2:3 orbital resonance with Neptune)

Pluto's name was famously suggested by Venetia Burney, at the time an eleven-year-old student at Oxford. Burney was well-versed in Classical Mythology and felt that the god of the underworld was a fitting name for such a cold and dark planet. Her grandfather was a librarian at Oxford who saw that Burney's suggestion was relayed to Tombaugh; that same grandfather was the brother of the man who suggested the names currently used for Mars's moons. Burney lived to see Pluto's demotion, and stated in an interview that while her personal preference was for it to remain a planet, she understood why it was demoted. Burney was reportedly not happy when people mistakenly claimed that she took the name Pluto from [[WesternAnimation/PlutoThePup Mickey Mouse's Dog]].

Due to its small size and massive distance from the Sun, for two-thirds of a century, the best images of Pluto were just a blurry dot of reflected light. Even when the Hubble Space Telescope observed Pluto in 2002 and 2003, it could barely make out its blurry surface features despite being the most powerful space telescope launched by humans at that point (this [[https://www.youtube.com/watch?v=Tu327ZWGG1M video]] explains in further detail why Hubble could barely resolve Pluto's surface features despite seeing galaxies in fine detail millions of light years away). The mysteries surrounding Pluto were why UsefulNotes/{{NASA}} launched the ''New Horizons'' spacecraft in 2006. It arrived at Pluto in July of 2015, taking the first high resolution images of the dwarf planet in unprecedented detail.

Like Ceres before it, Pluto's demotion was largely a result of improvements in telescope technology. When first discovered, Pluto was thought to be [[{{Irony}} the solar system's largest planet]], surpassing even Jupiter. As telescope resolution improved, Pluto gradually "shrunk", going from similar in size to Uranus and Neptune, to similar to Earth and Venus, to similar to Mars. A running joke among astronomers at the time was that [[HilariousInHindsight Pluto was going to disappear entirely at the rate they were going]]. The beginning of the end came with the discovery of Charon in 1978. With a natural satellite in play, astronomers could finally apply [[https://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion#Third_law Kepler's Third Law]] to get a reasonably accurate measurement of Pluto's mass, discovering that Pluto was dwarfed even by our own Moon. Charon's discovery also occurred shortly after the introduction of the Giant Impact Hypothesis that explained the origin of Earth's moon. The similarities between the two systems was quickly noticed, and Charon was suggested to have formed the same way. This raised the obvious question of where the impactor that caused Charon's creation came from; probability alone indicated that Pluto wasn't alone in its region of space, and astronomers began actively searching for other members of the hypothetical Kuiper Belt.

* ''ComicBook/GuardiansOfTheGalaxy'': By the 30th century, mankind has settled Pluto, with the inhabitants being genetically engineered to survive there. On the plus side, they get superpowers. Downside, they're all wiped out by the Badoon, save for one guy, Martinex, who becomes a founding member of the Guardians. Since the Guardians first appeared in the 60s, descriptions and depictions of Pluto have had to move with the times.

* ''The Secret of the Ninth Planet'', by Donald Allen Wollheim. Presumably the secret is that Pluto isn't actually a planet (though it does hold a race of evil alien abductors in this case).

Haumea itself is a very unique and interesting to astronomers for many different reasons. For starters it has one of the fastest rotational periods of any body larger than 100km. Completing a rotation in less than 4 hours (in fact, were it to go any faster it would break in half) and giving it the shape of an elongated ellipsoid rather than a sphere. It's also one of the smallest bodies confirmed to have its own ring system which if scaled up would rival that of Saturn's and the center of a large cloud of smaller bodies known as the Haumeids (ranging from half its size to a few km) which are gravitationally interacting with it. It also has a big red spot on its surface which might be from the impact of a large meteorite.

All these things suggests that Haumea is actually the largest fragment of a once much larger object. And based on the dispersal pattern of the Haumeids the event must have happened at least one billion years ago somewhere in the Scattered disc (The Kuiper belt is too sparingly populated for such an event) with the debris from it having since migrated closer to the sun. But why it hasn't slowed down or how the ring system hasn't dispersed yet is unknown. Its possibly that rings are also a recent (astronomically speaking) development created by whatever impact also made the big red spot. And which might also have sped up its rotation speed.

Haumea is a good candidate for our next trans-Neptunian mission as it's much closer than Eris (a probe would "only" take around 14 years to reach it) and much more interesting than Makemake. And preliminary studies for an hypothetical mission are being done as of 2022.

Eris is the most notable member of the Scattered Disk, former members of the Kuiper Belt that were forced into heavily inclined and eccentric orbits after getting too close to Neptune's gravity well. Eris's orbit is tilted a whopping 44° and it has a difference of 59.455 AU between it's perihelion and aphelion. The fact that Eris was completely at the mercy of Neptune's gravity while Neptune itself was completely unaffected by Eris is considered one of the key distinctions between dwarf planets and true planets.

Eris is slightly smaller than Pluto, but its mass is higher, making it close to 23% the mass of the Moon. The resulting higher density indicates that Eris has proportionally more rock content than the other outer dwarf planets. It has one known moon named Dysnomia -- daughter of mythological Eris. Aside from being the ninth most massive object orbiting the Sun, it is also the next largest object in the Kuiper Belt that has not yet been visited by man-made objects. Given its massive distance from the Earth, this is unlikely to change any time soon.

Eris has been the target for many hypothetical missions. Including sending ''New Horizon'' after it when it was done with its Pluto study. The problem though is that Eris' elongated orbit and the fact that it recently (1977) hit its perihelion means that probes will essentially have to chase after it. And with our current technology the journey will take around 25 years.

In fact, there is debate over whether Ceres is technically still an asteroid. The 2006 IAU resolution defined planets, dwarf planets, and several other categories for the first time, but made no effort to do the same for asteroids. In fact, the only mention of asteroids is in a footnote stating that most should be placed into the category of "small solar system bodies" ([=SSSBs=]). Keyword 'most'.[=SSSBs=] and dwarf planets were placed into the same supercategory of "minor planets", but the two explicitly do not overlap. Thus, if the wording implies that Ceres is the sole exception to this rule about asteroids being [=SSSBs=], then it is the only object in the solar system that could potentially be both a dwarf planet and an asteroid at the same time. If Ceres is ''not'' exempted from the rule about asteroids, then it by definition cannot be one. No clarification has been forthcoming.

In fact, there is debate over whether Ceres is technically still an asteroid. The 2006 IAU resolution defined planets, dwarf planets, and several other categories for the first time, but made no effort to do the same for asteroids. In fact, the only mention of asteroids is in a footnote stating that most should be placed into the category of "small solar system bodies" (SSSBs). Keyword 'most'. SSSBs and dwarf planets were placed into the same supercategory of "minor planets", but the two explicitly do not overlap. Thus, if the wording implies that Ceres is the sole exception to this rule about asteroids being SSSBs, then it is the only object in the solar system that could potentially be both a dwarf planet and an asteroid at the same time. If Ceres is ''not'' exempted from the rule about asteroids, then it by definition cannot be one. No clarification has been forthcoming.

Named after a Roman goddess of agriculture, Ceres is the largest asteroid and only dwarf planet in the Asteroid Belt, making up about a third of the belt's mass. It is the smallest of all the dwarf planets, but was the first to be discovered due to its proximity to Earth relative to the other ones. It has gravity of less than 3% that of Earth and possesses a tenuous atmosphere consisting largely of water vapor.

It has been theorized that life might had once existed on Ceres due to its large quantities of ice (which could have once been a subterranean ocean) and the presence of organic compounds. Ceres is even one of the more plausible candidates for {{Panspermia}} in relation to Earth.

Due to its proximity within the Asteroid Belt, it's believed that Ceres is the original proto-planet that failed to form into a full-fledged planet because of UsefulNotes/{{Jupiter}}'s gravity robbing it of most of its surrounding material during the Solar System's formation. Had Ceres had enough material to form, it would've likely became the fifth terrestrial planet in the inner Solar System[[note]][[https://www.spaceflightinsider.com/missions/solar-system/ceres-may-have-formed-in-the-outer-solar-system/ Other proposals]] suggest Ceres came from the outer Solar System (the Kuiper Belt) to its current position, due to the gravitational effects of the migrations of the gas and icy giants during the formation of the Solar System, including the possibility of what is now Ceres' surface being in the distant past the bottom of a subsurface ocean in a larger "proto-Ceres"[[/note]]

Ceres has a complicated history of designations given to it since its discovery, even more so than Pluto. It was originally labeled as a planet when it was discovered on New Year's day 1801, and was quickly joined by the asteroids Pallas, Juno, and Vesta. Ceres' discovery was taken as proof of the [[ScienceMarchesOn now-defunct]] Titus-Bode law. William Herschel argued as early as 1802 that Ceres and Pallas were not planets and at the time coined the term "asteroid" to distinguish them from the other planets and labeled Ceres as such, but his opinion was in the minority until the discovery of the fifth asteroid, Astraea in 1845. By then, telescope technology had advanced enough that thousands of asteroids were discovered over the next few years, and astronomers accepted that Ceres was merely the first. Ceres, Pallas, Juno, and Vesta were formally demoted from planet status in 1851, [[OlderThanTheyThink the first to do so]]. Their demotion also notably occurred after the discovery of Neptune in 1846; few people remember that Neptune spent its first five years post-discovery as the solar system's twelfth planet. Ceres remained classified as an asteroid until 2006 with the reclassification of dwarf planets by the IAU; it was officially labeled as the sole dwarf planet in the inner solar system after being classified as the largest asteroid in the Asteroid Belt for over a century and a half.[[note]]And it kinda still is. There's still some debate over whether Ceres is at the lower boundary of what is considered a dwarf planet, leading to it being labeled as both a dwarf planet and an asteroid at the same time.[[/note]]

Named after the Roman god of underworld, Pluto is the most well-known of the dwarf planets, though it's mostly known for its career as the system's ninth planet. Discovered in 1930 by Clyde Tombaugh, for decades, it was classified as a full-fledged planet, but as more objects of similar size to Pluto were discovered in the outer Solar System, that method of classification became impractical and virtually impossible to be meaningfully utilized. Thus, in 2006 with a vote by the International Astronomical Union, the classification of dwarf planets was created.

Pluto's name was famously suggested by Venetia Burney, at the time an eleven year-old student at Oxford. Burney was well-versed in Classical Mythology and felt that the god of the underworld was a fitting name for such a cold and dark planet. Her grandfather was a librarian at Oxford who saw that Burney's suggestion was relayed to Tombaugh; that same grandfather was the brother of the man who suggested the names currently used for Mars's moons. Burney lived to see Pluto's demotion, and stated in an interview that while her personal preference was for it to remain a planet, she understood why it was demoted. Burney was reportedly not happy when people mistakenly claimed that she took the name Pluto from [[WesternAnimation/PlutoThePup Mickey Mouse's Dog]].

Pluto is the largest of the dwarf planets, though not quite the most massive. Its mass is less than a fifth of that of the Moon, its surface gravity is 6% of Earth's, and it has a surface area roughly similar to that of Russia. It consists of a silicone core covered by a thick layer of ice. Similar to [[UsefulNotes/TheMoonsOfJupiter Europa]], it likely has a liquid ocean beneath its crust. It has no magnetic field to speak of.

Pluto's most peculiar feature is its largest moon, Charon, which has one-eighth of Pluto's mass and one-half of its volume - an unusually big proportion for a planet and a moon. It lead to Pluto being occasionally labeled a dual planet, since calling Charon a satellite isn't fully accurate with how the objects revolve around one center of mass that lies in the empty space above Pluto's surface; this is in stark contrast to the Earth-Moon system, where the shared center of mass lies beneath Earth's surface. Pluto and Charon also have the distinction of being the only gravitationally round objects to have achieved a [[TidallyLockedPlanet two-way tidal lock]] within the lifespan of the solar system; no matter what, Pluto and Charon ''always'' show each other the same face, like two dancers holding hands while spinning in a circle. In addition, Pluto has four other irregular moons named Styx, Nix, Kerberos, and Hydra, which compared to Charon, are likely captured small Kuiper Belt objects similar to UsefulNotes/{{Mars}}' asteroid moons; Phobos and Deimos. An alternate hypothesis is that they are leftover debris from the giant impact that created Charon that somehow failed to coalesce. Like Charon, these moons do no orbit Pluto directly, instead revolving around the system's shared center of gravity in between Pluto and Charon.

Due to its small size and massive distance from the Sun, for two-thirds of a century, the best images of Pluto were just a blurry dot of reflected light. Even when the Hubble Space Telescope observed Pluto in 2002 and 2003, it could barely make out its blurry surface features despite being the most powerful space telescope launched by at that point (this [[https://www.youtube.com/watch?v=Tu327ZWGG1M video]] explains in further detail why Hubble could barely resolve Pluto's surface features despite seeing galaxies in fine detail millions of light years away). The mysteries surrounding Pluto were why UsefulNotes/{{NASA}} launched the ''New Horizons'' spacecraft in 2006. It arrived at Pluto in July of 2015, taking the first high resolution images of the dwarf planet in unprecedented detail.

The search bore fruit with the discovery of [[https://en.wikipedia.org/wiki/15760_Albion Albion]] in 1992. Initially declared the first member of the Kuiper Belt, it didn't take long to realize that the honor actually belonged to Pluto. The debate over Pluto's classification began in earnest, especially as hundreds more Kuiper Belt Objects and Scattered Disc Objects were discovered over the next decade. Public pressure however led to the issue being held off until it was finally forced with the discovery of Eris in 2005. Once a Trans-Neptunian Object more massive than Pluto was confirmed, the classification issue could no longer be pushed down the line, and Pluto was formally demoted in 2006.

The most massive of the dwarf planets and the reason Pluto isn't considered a planet anymore. It is named after the Greek goddess of discord, which is fitting considering it was the prime reason for the chaos which necessitated the creation of dwarf planet category -- the only alternative was making Eris the tenth planet, but with dozens of potential dwarf planets awaiting confirmation that would have opened a can of worms that astronomers did not want to deal with.

Eris is slightly smaller than Pluto, but its mass is higher, making it to 23% the mass of the Moon. The resulting higher density indicates that Eris has proportionally more rock content than the other outer dwarf planets. It has one known moon named Dysnomia -- daughter of mythological Eris. Aside from being the ninth most massive object orbiting the Sun, it is also the next largest object in the Kuiper Belt that has not yet been visited by man-made objects. Given its massive distance from the Earth, this is unlikely to change any time soon.

Eris has been the target for many hypothetical missions. Including sending ''New Horizon'' after it when it was done with its Pluto study. The problem though is that Eris elongated orbit and the fact that it recently (1977) hit its perihelion means that probes will essentially have to chase after it. And with our current technology the journey will take around 25 years.

Officially only two non-planetary objects (Pluto and Ceres) are confirmed to be in Hydrostatic equilibrium. But the IAU (whose opinions are probably the most universally accepted as things get in these matters) has also given the designation to three other objects (Eris, Haumea and Makemake) for various reasons. And four others (Orcus, Quaoar, Gonggong and Sedna) tends to be generally accepted as dwarf planets too even if the IAU has yet to officially give them that label. And based on our current knowledge of what's required for hydrostatic equilibrium there could be as much as 50 more catalogued objects that also qualify.

Haumea itself is a very unique and interesting to astronomers for many different reasons. For starters it has one of the fastest rotational periods of any body larger than 100km. Completing a rotation in less than 4 hours (in fact, were it to go any faster it would break in half) and giving it the shape of an elongated ellipsoid ratehr than a sphere. It's also one of the smallest bodies confirmed to have its own ring system which if scaled up would rival that of Saturn's, and it's the center of a large cloud of smaller bodies known as the Haumeids (ranging from half its size to a few km) which are gravitationally interacting with it. On and it has a big red spot on it which might be the impact from a large meteorite.

All these things suggests that Haumea is actually the largest fragment of a once much larger object. And based on the dispersal pattern of the Haumeids the event must have happened at least one Billion years ago somewhere in the Scattered disc (The Kuiper belt is too sparingly populated for such an impact) with the debris from it having since migrated closer to the sun. But why it hasn't slowed down or how the ring system hasn't dispersed yet is unknown. Its possibly that rings are also a recent (astronomically speaking) development created by whatever impact also made its big red spot. And which might also have sped up its rotation speed.

Eris has been the target for many hypothetical missions. Including sending New Horizon after it when it was done with its Pluto study. The problem though is that Eris elongated orbit and the fact that it recently (1977) hit its perihelion means that probes will essentially have to chase after it. And with our current technology the journey will take around 25 years.

Haumea itself is a very unique and interesting to astronomers for many different reasons. For starters it has one of the fastest rotational periods of any body larger than 100km. Completing a rotation in less than 4 hours (in fact, were it to go any faster it would break in half) and giving it the shape of an elongated ellipsoid ratehr than a sphere. It's also the smallest body confirmed to have its own ring system which if scaled up would rival that of Saturn's, and it's the center of a large cloud of smaller bodies known as the Haumeids (ranging from half its size to a few km) which are gravitationally interacting with it. On and it has a big red spot on it which might be the impact from a large meteorite.

Haumea itself is a very unique and interesting to astronomers for many different reasons. For starters it has one of the fastest rotational periods of any body larger than 100km. Completing a rotation in less than 4 hours (in fact, were it to go any faster it would break in half) and giving it the shape of an elongated ellipsoid ratehr than a sphere. It's also the smallest body confirmed to have its own ring system which if scaled up would rival that of Saturn's, and it's the center of a large cloud of smaller bodies known as the Haumeids (ranging from half its size to a few km) which are gravitationally interacting with it.

All these things suggests that Haumea is actually the largest fragment of a once much larger object. And based on the dispersal pattern of the Haumeids the event must have happened at least one Billion years ago somewhere in the Scattered disc (The Kuiper belt is too sparingly populated for such an impact) with the debris from it having since migrated closer to the sun. But why it hasn't slowed down or how the ring system hasn't dispersed yet is unknown.

Dwarf Planets are those weird things that cannot be classified as planets due to their lower mass, but are too massive to be called planetoids or asteroids. The term is fairly new and was created in 2006 to classify Pluto and other objects whose gravity is large enough to compress them into a sphere, but not large enough to achieve so-called "orbital dominance".

Currently, there are five objects in our solar system recognized as dwarf planets, with more than forty pending official confirmation:

Named after a patron deity of Hawai'i, Haumea (pronounced "how me uh") was the last of the dwarf planets to be officially recognized as such and its place in this category is still widely contested. The main problem with designating Haumea as a dwarf planet, and also its most distinctive feature, is its unusually high rotational speed which causes it to be significantly flattened at its equator, making it an ellipsoid rather than a spheroid like other dwarf planets.

Haumea's mass is about three times less than Pluto's and twenty times less than the Moon's. It has two natural satellites - Hi'iaka and Namaka, named after the daughters of its namesake - and a ring revolving around it.

Makemake (pronounced "mackie mackie") is the last dwarf planet to be discovered. It was named after the creator deity in the myths of Papa Nui, the native people of Easter Island. Prior to that, it was called an "Easterbunny" due to the date of discovery falling shortly after Easter. Its mass is about 0.07% that of Earth, making it slightly more massive than Haumea. It has one natural satellite (officially designated "[=S/2015 (136472) 1=]" or nicknamed "[=MK2=]"), which sadly doesn't have a creative name as of yet.

* ''Franchise/CthulhuMythos'': The "ninth planet" is a significant location, but that if that designation [[WatsonianVersusDoylist might not mean Pluto]].

Pluto's name was famously suggested by Venetia Burney, at the time an eleven year-old student at Oxford. Burney was well-versed in Classical Mythology and felt that the god of the underworld was a fitting name for such a cold and dark planet. Her grandfather was a librarian at Oxford who saw that Burney's suggestion was relayed to Tombaugh; that same grandfather was the brother of the man who suggested the names currently used for Mars's moons. Burney lived to see Pluto's demotion, and stated in an interview that while her personal preference was for it to remain a planet, she understood why it was demoted. Burney was reportedly [[BerserkButton not happy]] when people mistakenly claimed that she took the name Pluto from [[WesternAnimation/PlutoThePup Mickey Mouse's Dog]].

Due to its proximity within the Asteroid Belt, it's believed that Ceres is the original proto-planet that failed to form into a full-fledged planet because of UsefulNotes/{{Jupiter}}'s gravity robbing it of most of its surrounding material during the Solar System's formation. Had Ceres had enough material to form, it would've likely became the fifth terrestrial planet in the inner Solar System.

So far, Ceres has been visited by one spacecraft named ''Dawn'' in March of 2015 after exploring most of the Asteroid Belt and Vesta for eight years. It found that Ceres' surface is similar to that of UsefulNotes/{{Mercury}} and UsefulNotes/TheMoon, but due to being farther out from UsefulNotes/TheSun, its composition is thought to be a combination of rock and water ices. Its most interesting features are bright white spots in the center of some craters, and for a short while, scientists were puzzled as to what they were. Later observations confirmed that these spots are patches of a type of salt brine coming from deep beneath Ceres' surface, revealing that Ceres has active cryovolcanoes, but for a brief moment, scientists were spooked over the possibility of alien civilizations based there.

* ''Series/DoctorWho''.

%%* ''Series/DoctorWho''

Named after a Roman goddess of agriculture, Ceres is the largest and only dwarf planet in the Asteroid Belt, making up about a third of the belt's mass. It is the smallest of all the dwarf planets, but was the first to be discovered due to its proximity to Earth relative to the other ones. It has gravity of less than 3% that of Earth and possesses a tenuous atmosphere consisting largely of water vapor.

Ceres has a complicated history of designations given to it since its discovery, even more so than Pluto. It was originally labeled as a planet when it was discovered on New Year's day 1801, and was quickly joined by the asteroids Pallas, Juno, and Vesta. Cere's discovery was taken as proof of the [[ScienceMarchesOn now-defunct]] Titus-Bode law. William Herschel argued as early as 1802 that Ceres and Pallas were not planets and at the time coined the term "asteroid" to distinguish them from the other planets and labeled Ceres as such, but his opinion was in the minority until the discovery of the fifth asteroid, Astraea in 1845. By then, telescope technology had advanced enough that thousands of asteroids were discovered over the next few years, and astronomers accepted that Ceres was merely the first. Ceres, Pallas, Juno, and Vesta were formally demoted from planet status in 1851, [[OlderThanTheyThink the first to do so]]. Their demotion also notably occurred after the discovery of Neptune in 1846; few people remember that Neptune spent its first five years post-discovery as the solar system's twelfth planet. Ceres remained classified as an asteroid until 2006 with the reclassification of dwarf planets by the IAU; it was officially labeled as the sole dwarf planet in the inner solar system after being classified as the largest asteroid in the Asteroid Belt for over a century and a half.[[note]]And it kinda still is. There's still some debate over whether Ceres is at the lower boundary of what is considered a dwarf planet, leading to it being labeled as both a dwarf planet and an asteroid at the same time.[[/note]]

* A base in Ceres appears in the backstory of ''Videogame/StarControl'' as the place where the Chenjesu asked the Earthlings to join the Alliance of Free Stars to fight the Ur-Quan Hierarchy, and whose loss at the hands of the latter meant Earth's defeat.

Despite its size and importance to astronomy, Eris hasn't appeared in many works, largely because not much time has passed since its discovery.

Pluto's most peculiar feature is its largest moon, Charon, which has one-eighth of Pluto's mass and one-half of its volume - an unusually big proportion for a planet and a moon. It lead to Pluto being occasionally labeled a dual planet, since calling Charon a satellite isn't fully accurate with how the objects revolve around one center of mass that lies in the empty space above Pluto's surface; this is in stark contrast to the Earth-Moon system, where the shared center of mass lies beneath Earth's surface. Pluto and Charon also have the distinction of being the only gravitationally round objects to have achieved a [[TidallyLockedPlanet two-way tidal lock]] within the lifespan of the solar system; no matter what, Pluto and Charon ''always'' show each other the same face, like two dancers holding hands while spinning in a circle. In addition, Pluto has four other irregular moons named Styx, Nix, Kerberos, and Hydra, which compared to Charon, are likely captured small Kuiper Belt objects similar to UsefulNotes/{{Mars}}' asteroid moons; Phobos and Deimos. They are also hypothesized to be leftover debris from the giant impact that created Charon that somehow failed to coalesce.

Pluto's name was famously suggested by Venetia Burney, at the time an eleven year-old student at Oxford. Burney was well-versed in Classical Mythology and felt that the god of the underworld was a fitting name for such a cold and dark planet. Her grandfather was a librarian at Oxford who saw that Burney's suggestion was relayed to Tombaugh; that same grandfather was the brother of the man who suggested the names currently used for Mars's moons. Burney lived to see Pluto's demotion, and stated in an interview that while her personal preference was for it to remain a planet, she understood why it was demoted. Burney was reportedly [[BerserkButton not happy]] when people mistakenly claimed that she took the name Pluto from [[WesternAnimation/PlutoThePup Mickey Mouse's Dog]]