• Question: i have heared from the internet that pluto was a star not planet

    Asked by Kabir on 11 Nov 2020.
    • Photo: Yannick Verbelen

      Yannick Verbelen answered on 11 Nov 2020:

      It was never classified as a star, it’s original classification was as planet but it has now been “demoted” you could say.

    • Photo: Declan Vogt

      Declan Vogt answered on 11 Nov 2020:

      Yeah, demoted to dwarf planet.

    • Photo: Steve Williams

      Steve Williams answered on 11 Nov 2020:

      Pluto was never a star. It was at one time recognised as a planet but I that has changed and it is now regarded as being too small to be considered an “official” planet. I think it just gives astronomers something to argue about.

    • Photo: Tris Warren

      Tris Warren answered on 11 Nov 2020: last edited 17 Nov 2020 12:38 am

      Pluto used to be a planet. But then scientists decided it should be called a dwarf planet, instead of a planet. They decided that because Pluto is very small compared to the other planets. Pluto also has a Moon called Charon and Charon is almost as big as Pluto. Pluto and Charon kind of orbit around each other which is another reason Pluto was no longer considered a planet.

    • Photo: John Davies

      John Davies answered on 12 Nov 2020:

      Pluto was never a star. A star is a large ball of gas which (usually anyway) generates heat and llght by nuclear reactions in its core. The Sun is a star. A planet is something which (usually) goes around a star. When Pluto was discovered it was described as a planet because it went around the Sun and because astronomers expected to find a planet about where PLuto was found. We now know that Pluto is much smaller than once thought, that it has a large moon and, most importantly that there are lots of other Pluto like objects in the outer solar system in what is called the Kuiper belt. Because of this astronomers had a big argument about what makes something a planet (I know because I was there) and at the 2005 IAU meeting defined a planet as Round, orbiting a star and dominating its local space by sweeping up all the little bits of stuff in nearby orbits. Pluto fits the first 2, but not the 3rd since there are lots of other mini-Plutos in the Kuiper belt. So it got demoted to ‘dwarf-planet’ . By the same rules asteroid Ceres got promoted to dwarf planet along with a few other things. The important thing is not what we call Pluto, but what it tells us about how the solar system formed. In that regard Pluto is REALLY interesting, whatever we call it.

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