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Sorry Pluto, Eris is Bigger

Article written: 14 Jun , 2007
Updated: 26 Dec , 2015
by

For those of you hoping that Pluto the dwarf planet would get its full planethood status restored again, the news isn’t looking good. The most recent observations peg the newly discovered dwarf planet Eris as being 27% more massive. And if Pluto is a planet again, shouldn’t the even larger Eris get to be a planet too? Should we have 8 planets, or 10 or 20? Oh, it’s madness.

The latest observations were made by discoverer Mike Brown and his planet hunting team. They made detailed observations using the Hubble Space Telescope and Keck Observatory, and concluded that Eris has a density of about two grams per cubic centimetre; a mixture of ice and rock that matches the density of Pluto. Since its diameter is 2,400 km (1,500 miles), that pushes it above the mass of Pluto.

And Eris is much colder. Since it’s 97 astronomical units (the distance from the Earth to the Sun) away from the Sun, its average temperatures hover around -240 degrees Celsius (-400 degrees Fahrenheit). During its elliptical orbit, the dwarf planet can sweep in getting as close as 38 astronomical units.

Researchers think the planet is covered in a layer of methane that seeped out from inside the planet and then froze on the surface. This methane has then undergone a chemical transformation in the solar radiation, turning yellowish. The planet also has a moon, 150-km (93-mile) diameter Dysnomia. It orbits Eris every 16 days.

Original Source: Caltech News Release

Here are some interesting Pluto facts.


14 Responses

  1. Laurel Kornfeld says

    Both Pluto and Eris should be considered full fledged planets, as should any objects orbiting the sun (or any other star) that are not stars themselves and have achieved hydrostatic equilibrium. The fact that Eris is more massive than Pluto has absolutely no bearing on this. The IAU demotion was a sloppy and controversial decision by four percent of its membership, most of whom were not even planetary scientists. We should be broadening, not narrowing, our conception of what a planet is.

  2. Aqune says

    Pluto is never going to be a real planet. SAD

  3. Cameron says

    Yes it is. And maybe Eris, too.

  4. Cameron says

    I’m fine with Eris becoming a planet.

  5. Cameron says

    Just as long as Pluto is, too.

  6. Cameron says

    Nine planets! And I don’t mind a tenth at all!

  7. Cameron says

    I’d hate to post a fifth comment in a row, but just one more thing: Laurel, I totally agree with you. IAU made a couple mistakes with Pluto:
    Something could have knocked Pluto out of orbit. I think that something was Charon, and they got sperical shapes, as well as forming Hydra and Nix! The impact could have also caused Pluto to have an orbit that could allow it to pass Neptune! If it has a bad orbit, why isn’t it a planet? I’ll tell you this: just because Pluto has a bad orbit, doesn’t mean it’s not a planet!

    Also, New Horizons was on it’s way. By the time they erased Pluto, it was probably bareley an eighth there! I will never like IAU until they undo their stuff.

    THERE ARE NINE PLANETS IN OUR SOLAR SYSTEM! AND I DON’T MIND ERIS BECOMING ONE, EITHER!

  8. Bri :] says

    Awsomee ;]

    fer reall

  9. Yuvraj says

    I think Pluto should stay under the term dwarf planet. And if Pluto is one, then Eris should be one too! We have at least 10 planets in our Solar System and there is no denying it!!!

  10. Dmitri Yatsenko says

    Yes, Eris and Pluto are planemos. A dwarf planet is not a completely separate class of objects, it’s sort-of a planet. Who cares about how it orbits? In other planetary systems, planets several times (up to 8) more massive than Jupiter orbit in much, much more elliptical orbits. At first I did not even agree that a planet needs to be in orbit around the Sun or another star.

  11. Dmitri Yatsenko says

    Are there extrasolar dwarf planets?

  12. Jacqui says

    People say not to discriminate against small people, but out in space they are discriminating against small planets. Pluto is more than Micky Mouse’s pet dog. It is also the should-be ninth planet in our solar system. Our solar system includes four rocky planets and four gas giants. Pluto’s rock-ice composistion and unusual orbit sets it apart from both families, but it shares some of theses traits with the Kuiper Belt objects. Therefore, astronomers dive in a consistent heated battle to define whether or not Pluto is a planet or part of the Kuiper Belt.

    Pluto has recently been the subject of debate between those who say it should be counted among the Kuiper Belt objects, and those who don’t want to diminish Pluto’s status as the ninth planet. That debate boils down to what is a planet and what is not, a straightforward concept with no real definition. Yes, Pluto doesn’t fit one of the priorities to be a planet. This one difference is that Pluto doesn’t have a clear neighborhood around its orbit and is not a satellite. Because of that, Pluto is now a “dwarf planet,” one that orbits the Sun but that has insufficient mass to “gravitationally dominate” its region of the solar system—that is, enough mass to sweep away other stuff orbiting there. Originally classified as a planet, Pluto is now considered the largest member of a distinct population called the Kuiper Belt. Still trying to refine the definision, the task is growing more difficult as scientists discover the increasing number of weird worlds found circling other stars. And even worse, those little bodies that don’t qualify as planets will now be called plutoids or planetoids! Talk about respest.

    Both Pluto and Eris should be considered full fledged planets, as should any objects orbiting the sun, that are not stars themselves and have a nealy round shape. The fact that Eris is more massive than Pluto has absolutely no bearing on this. The IAU demotion was a sloppy and controversial decision by four percent of its membership, most of whom were not even planetary scientists. We should be broadening, not narrowing, our conception of what a planet is.

    Last year, the ninth planet was demoted because astronomers had a discovered a nearby object, planet-x, now officially named Eris, that was larger than Pluto. But instead of taking the route of accepting Eris into their family, which would have opened membership in the club of planets, astronomers decided to get more picky about what defines a planet. Two years after the controversial decision to take away Pluto’s status as a planet, astronomers are still unable to agree on how to define planet. When they finally came up with something, they quickly made it into a definition.

    On August 24th, 2006, scientists redefined a planet without Pluto, after the American Museum of Natural History created a solar system model without Pluto. When thinking about what the definition of an actual planet, and a dwarf-planet would be, astronomers discussed the current definition of a planet and decided that a “planet” is a body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity has a nearly round shape, and (c) has cleared the neighborhood around its orbit. A “dwarf planet” is a body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it has a nearly round shape, (c) has NOT cleared the neighborhood around its orbit, and (d) is NOT a satellite. After a week of debate, the IAU (International Astronomical Union) took Pluto out of planetary status because its orbit crosses Neptune’s and therefore fails one of three planetary requirements. Pluto DOES orbit the sun, is ball-shaped, but is not a satellite and it does not have an isolated orbit.

    I realize that Pluto is neither a dull, terrestrial planet or gas giant. It’s mostly ice. It’s smaller than our own Moon, and has an orbit so strange that it spends 20 years of its 248-year revolutionary period inside Neptune’s orbit. It’s tilted at a crazy 17-degree angle and its satellite, Charon, is so large that it’s been called a double planet. We have already kicked Pluto out of out planetary status before it has had one orbit! Why judge in such a hurry? 1930 was only like… five months ago in Pluto time! And instead of My Very Elegant Mother Just Served Us Nine Pizzas, I guess she’ll now have to serve us nachos, noodles or nectarines. I’d rather have nine pizzas.

  13. jacqui says

    u no wat, i don’t care wat scientists think, PLUTO SHOULD BE A PLANET!!!!!

  14. sparkle sista ;) says

    i agree with Cameron. Nine planets!
    or 10 or 20 or……………………

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