• Question: would you count pluto as a planet? if so, why?

    Asked by lexie2610 to Chris, Josh, Rebecca, Rob, Susan on 19 Jun 2015.
    • Photo: Susan Cartwright

      Susan Cartwright answered on 19 Jun 2015:

      No. I agree with the International Astronomical Union that it is a large member of the outer asteroid belt (the Kuiper belt, named after one of several astronomers who suggested that such a belt might exist). It is much smaller than any of the 8 major planets (it is smaller than the Earth’s moon), and it is in a region of space that has many smaller bodies, some of them not much smaller (at least one of them actually larger) in it. We don’t call the largest asteroid, Ceres, a planet anymore (though we did when it was first discovered, before we realised that it was part of an asteroid belt), and the same logic applies to Pluto. The only reason it’s at all controversial is that it took a lot longer to realise that Pluto was part of an asteroid belt than it did for Ceres.

    • Photo: Chris Armstrong

      Chris Armstrong answered on 19 Jun 2015:

      I do, but only from a sense of nostalgia, as all throughout the time I learnt about planets it was there. I agree with the new classification, and if I have to I will admit that its a dwarf planet.

      I’ll just say that dwarf really quietly.

    • Photo: Rebecca Dewey

      Rebecca Dewey answered on 19 Jun 2015:

      I understand that it has now been re-classified as a dwarf-planet, so no! It is not big enough to be a planet given all the other rocks that are floating around in it’s neighbourhood.

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