Astronomy Geeks: We have reached Pluto!

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  • Luke_I_am_your_spotter
    Luke_I_am_your_spotter Posts: 4,179 Member
    Joannah700 wrote: »
    pluto.jpg

    sincerly-pluto_o_94661.jpg
  • Joannah700
    Joannah700 Posts: 2,665 Member
    Oh, we know that Pluto was not un-designated as a planet because of size...it was something about orbits, right? Too many other objects in it's orbit...or something? I'd have to look it up.
  • Luke_I_am_your_spotter
    Luke_I_am_your_spotter Posts: 4,179 Member
    Joannah700 wrote: »
    Oh, we know that Pluto was not un-designated as a planet because of size...it was something about orbits, right? Too many other objects in it's orbit...or something? I'd have to look it up.

    actually, it was because of its size.
  • Joannah700
    Joannah700 Posts: 2,665 Member
    Jersey__Devil wrote: »
    Joannah700 wrote: »
    Oh, we know that Pluto was not un-designated as a planet because of size...it was something about orbits, right? Too many other objects in it's orbit...or something? I'd have to look it up.

    actually, it was because of its size.

    The IAU decided that a planet needs to meet 3 criteria - orbit the sun, have enough gravity to be mostly round and have cleared out it's orbit - Pluto fails on the last one.

    https://www.iau.org/public/themes/pluto/

    Though NASA says something about size on their website.

    Bogus. NASA is letting us down. Pictures will make up for it though. Hopefully we'll see some good ones tomorrow.
  • Meg5065
    Meg5065 Posts: 33 Member
    NASA didn't demote Pluto, the International Astronomical Union (IAU) did. It was after they found multiple small bodies that are in the same approximate size range in the far reaches of the Solar System. So it is officially a dwarf planet now -- one of many such in the Kuiper Belt. New Horizons is going to be sending the data from Pluto back over the next 9 months or so, and it's going to visit one or more Kuiper Belt Objects as it continues its flight to the edge of the Solar System and beyond. Totally cool.

    Meg
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  • Luke_I_am_your_spotter
    Luke_I_am_your_spotter Posts: 4,179 Member
    Meg5065 wrote: »
    NASA didn't demote Pluto, the International Astronomical Union (IAU) did. It was after they found multiple small bodies that are in the same approximate size range in the far reaches of the Solar System. So it is officially a dwarf planet now -- one of many such in the Kuiper Belt. New Horizons is going to be sending the data from Pluto back over the next 9 months or so, and it's going to visit one or more Kuiper Belt Objects as it continues its flight to the edge of the Solar System and beyond. Totally cool.

    Meg


    I always thought it was a combination of size and what you are saying with the Kuiper Belt. I was under the impression that, like you said, they found many objects similar in size to Pluto in the belt, but its when they finally discovered Eris that they decided to demote it to a dwarf planet since Eris is larger than Pluto. (Thus, its size was a big factor)
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