The combinations of it all would require many new unique words. So I think that the solution is to name those aspects which are of interest in the specific context. Even Earth has been generally accepted as a planet since only years. It is perceived as an anti-Pluto definition for good reasons. If your comment is meant for me, I do write articles myself on astronomy and planetary science.
Thank you Laurel. Astronomy is a science where anyone with a scope can contribute, and inspires a following of self taught experts with extremely accurate knowledge of this or that aspect of the field.
The idea that a bunch of tired delegates meeting once among themselves can say the last word on any topic, is risible. Another excellent article by Matt Williams. To clear one point it must be remembered that UT articles are always written very quickly, they need to be to keep up todate. Hence odd errors do occur, and must be expected, they are generally very quickly corrected. The reasons I advance for placing Pluto as a Outer Asteroid Belt object is that its orbit is inclined at 17 degrees to the rest of the Solar System and also that for a number of years it is actually closer to the Sun than Neptune.
When first Main Asteroid Belt objects were discovered, early 19th cent. If you put asteroids and Pluto in the same category, then it no longer forms a Belt. Pluto is NOT an asteroid. You are making the same mistake the four percent of the IAU did in , which is defining an object by its location rather than by its intrinsic properties. Asteroids are tiny rocks shaped only by their chemical bonds.
In contrast, objects in hydrostatic equilibrium squeezed by their own gravity into a spherical or nearly spherical shape are complex worlds, often with geology and weather, layered into core, mantle, and crust just like the terrestrial planets.
Calling objects like Pluto asteroids is bad science because it lumps together two completely different types of objects. So why should Mercury be considered a planet? While most planets in our solar system orbit almost on the same plane, this is not the case in other solar systems, where several giant exoplanets orbit one star all on different planes.
If we used the same logic on those systems, none of these objects could be considered planets. The comparison with the reclassification of asteroids in the 19th century, while often cited to support the IAU decision, is not really appropriate here.
When these objects were discovered, none could be resolved into a disk by the telescopes of the time. It turns out that the first object discovered, Ceres, is spherical after all, and is a complex world that is geologically active and may have a subsurface ocean. Two other objects in the asteroid belt, Vesta and Pallas, are not quite spherical but are much more larger and more complex than the rest of the asteroids. The Dawn mission showed Vesta to be layered into core, mantle, and crust, just like Earth.
Others rightfully argue that Vesta and Pallas deserve their own category in between asteroid and dwarf planet. In the 19th century, all these objects appeared simply as points of light. None could be distinguished from any other, and no one knew anything about the compositions of these worlds. Now that we do know these things, it is clear that the demotion of Ceres was an error, as was the demotion of Vesta and Pallas.
No scientist should decide what the public should say. At that distance, it takes roughly 13 hours for light to travel from the dwarf planet to reach us on Earth. The temperature on its surface changes depending on what point it is in its orbit. Eris has an albedo that is around 0. This high reflectivity of Eris can be because of the ices on its surface. These ices renew as its eccentric orbit takes it farther from the Sun. The Eridian surface indicates the presence of methane ice.
It is comparable to that of Pluto and Triton, the largest moon of Neptune. What makes Eris different though is that its surface appears white, unlike Pluto and Triton Triton, which have reddish features.
Eris was discovered on January 5, , at Palomar Observatory. The discovery of Sedna in made the team reanalyze their earlier data. Images of Eris were already taken on October 21, However, precovery images revealed data as early as It was only in that the slow-orbiting dwarf planet was finally identified.
The same team, led by Brown, also discovered the dwarf planet Makemake. They announced the discovery of both objects on July 29, Eris was initially given the alternative designation UB Later that year, a moon was discovered around it.
It was once thought that Eris was larger than Pluto and that it might be the missing 10th planet. That was the time when Pluto was not yet reclassified in After that, Eris did not make it as a planet because it does not have a clear orbit, just like Pluto. A diagram of the outer solar system. The Kuiper belt is shown as well as the orbits of the outer planets and dwarf planets.
The average distance of Eris is 68 AU from the Sun. That means 68 times the distance of the Earth from the Sun. Due to its oval orbit, this distance varies. Its closest approach or perihelion is about 38 AU. Eris is located in the far reaches of the Solar System called the Kuiper Belt. And in terms of the Sun-Earth distance, it is equivalent to approximately 95 AU.
The Kuiper belt is the cold and dark area beyond the orbit of Neptune. Icy and rocky objects of all sizes lie in this big disk. Methane, ammonia, and other frozen compounds are also believed to be in this region. The objects in the inner Kuiper belt are mostly held into place by orbital resonances with Neptune. In this relationship, the objects are in a repeating pattern or ratio with Neptune.
Pluto is in a resonance with Neptune. That means, whenever Neptune makes three orbits around the Sun, Pluto makes two. The Kuiper belt was named after Gerard Kuiper, after publishing a paper about the region beyond Pluto.
Sometimes, it is also called the Edgeworth-Kuiper Belt because astronomer Kenneth Edgeworth has also mentioned the objects there on a paper that he also published. The JWST website specifically mentions Eris as a target of interest and adds that the telescope will look at small objects in the solar system to better characterize what their landscapes are made of. Separately, a group of astronomers including Alan Stern, the principal investigator of the Pluto mission New Horizons has asked the community to reconsider the International Astronomical Union's definition of "planet.
This article was updated on July 10, by Space. Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community space. Nola Taylor Tillman is a contributing writer for Space.
She loves all things space and astronomy-related, and enjoys the opportunity to learn more. Eris's moon is named Dysnomia, the demon goddess of lawlessness and the daughter of Eris. This is fitting since the discovery of Eris led to the demotion of Pluto from planet to dwarf planet amidst continuing debate in the science community and the public.
Namesake Namesake Originally designated UB — and nicknamed for the television warrior Xena by its discovery team — Eris is named for the ancient Greek goddess of discord and strife. Potential for Life Potential for Life The surface of Eris is extremely cold, so it seems unlikely that life could exist there. A 3D model of Eris, a dwarf planet in the Kuiper Belt. DART team members have filled the spacecraft with fuel, and are running rehearsals as they approach launch on Nov.
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