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Discovery of 'Goblin' Solar System Object Bolsters the Case For Planet Nine (gizmodo.com) 102

Astronomers have discovered a dwarf planet, dubbed "the Goblin," in the outer reaches of the Solar System that never gets any closer to the Sun than 6 billion miles. Some experts say its orbital configuration points to the existence of Planet Nine, a hypothetical planet in our Solar System that is estimated to be about 10 times the mass of Earth. Gizmodo reports: The Goblin, or 2015 TG38 as it's more formally called, is what's known as an extreme trans-Neptunian object, or ETNO. As the moniker implies, these objects, of which there are potentially thousands, are located well beyond the orbit of Neptune. The researchers who discovered the object, a team led by Scott Sheppard from the Carnegie Institution for Science and Chadwick Trujillo from Northern Arizona University, estimate that the Goblin is around 185 miles (300 kilometers) in diameter. At this size, it could very well be sphere-like in shape. Its mean distance from the Sun is about 80 astronomical units (AU), where 1 AU is the average distance from the Earth to the Sun. That's 7.45 billion miles, or 12 billion kilometers.

The Goblin's extreme orbital path means it never comes close enough to impose gravitational influence on the Solar System's giant planets, like Neptune or Jupiter. And at the astounding distance of 2,300 AU, it gets slotted into an emerging astronomical category known as Inner Oort Cloud objects (IOCs), of which 2012 VP113 and Sedna are the only other two known members. [...] The discovery of 2015 TG38 is bolstering the case for Planet Nine -- a hypothetical planet, sometimes referred to as Planet X, that's allegedly several times larger than Earth and located hundreds of AU away. As noted in the new study, published today in The Astronomical Journal, the location of Goblin's perihelion is similar to what's observed with Sedna and 2012 VP113, along with other ETNOs. This is a clue to astronomers that something potentially big, i.e. a super-Earth, is pushing these objects into similar types of orbits.

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Discovery of 'Goblin' Solar System Object Bolsters the Case For Planet Nine

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  • by Anonymous Coward

    My very erratic mother just served us goatse?

    Works for me.

  • Its mean distance from the Sun is about 80 astronomical units (AU)

    and

    at the astounding distance of 2,300 AU

    ?

    • by Anonymous Coward

      Both. Gets as close as 80 and as far as 2300. The orbit isn't exactly a circle.

      • When they stated 80 AU they also stated 300 km diameter of the body. When they stated 2300 AU they also stated "several times larger than Earth". Earth diameter is about 12740 km.

        • Re:Don't think so (Score:4, Informative)

          by Anonymous Coward on Wednesday October 03, 2018 @04:33AM (#57416358)

          You've misread. Goblin's not the one that's several times larger than Earth -- Goblin is the 300km one. The fact that Goblin's orbit is where it is, is more evidence pointing to an as-yet unobserved hypothetical planet further out, Planet Nine, that is several times larger than Earth.

          • by evanh ( 627108 )

            Oops, thanks. That all makes sense now ... Heh, and reading the full article, I see the opening paragraph makes the two body point very clear at the outset. :D

      • Re: 80 or 2300? (Score:4, Interesting)

        by CrimsonAvenger ( 580665 ) on Wednesday October 03, 2018 @05:34AM (#57416528)

        Both. Gets as close as 80 and as far as 2300. The orbit isn't exactly a circle

        80 AU's is mentioned as the mean distance. NOT the minimum distance. If 80 AU's is the mean distance, and 2300 AU were aphelion (which is NOT what they said), the Goblin would have to have an orbit that pretty much brushed the Sun, took a few tens of thousands of loops around the Sun down near Mercury, followed by a close pass of Mercury that tossed it out toward Jupiter, then a close pass of Jupiter tossed it into the outer system to reach that 2300 AU level, then fall back to the Sun, close pass by Jupiter, another close pass by Mercury to keep it low for a few thousand years, lather, rinse, repeat.

        Now, it's quite possible that they meant to write (and didn't, because they were idiots who didn't know what the words meant) that perihelion was 80 AU, and aphelion was 2300 AU.

        Or someone cut & pasted from two articles to make this article. And one of the articles referred to one object, but the other referred to another....

        • by MrKaos ( 858439 )

          Now, it's quite possible that they meant to write (and didn't, because they were idiots who didn't know what the words meant) that perihelion was 80 AU, and aphelion was 2300 AU

          I wonder if this object is big enough to be the object that influences the variations in the earth precession?

        • 80 to 2300? Are we sure we can call this a Dwarf Planet and not just a Huge Comet? I'm sure there is a typo in there somewhere. Or this planet got knocked out of orbit. I can't imagine it lasting from the creation of the solar system with such an eccentric orbit.

        • Gizmodo: "... the Goblin is around 185 miles (300 kilometers) in diameter. ... Its mean distance from the Sun is about 80 astronomical units .... But it actually gets even farther away than that .... it never gets any closer than about 65 AU—its perihelion point. ... but its aphelion, the point at which it’s the farthest from the Sun, is a whopping 2,300 AU."

          Obviously it isn't possible for all three of those numbers to be correct. Gizmodo got it wrong. From the Carnegie press release [carnegiescience.edu]: "... 201

  • by ytene ( 4376651 ) on Wednesday October 03, 2018 @04:04AM (#57416310)
    Fascinating bit of research; kudos to the authors.

    Just one bit of pedantry (sorry!). When the OP writes, "This is a clue to astronomers that something potentially big, i.e. a super-Earth, is pushing these objects into similar types of orbits.", the use of the term "super-Earth" prompted a non-technical friend of mine [who was reading the article over my shoulder] to ask, "So there's, like, an amazing Earth, way out in space, right on the edge of our solar system?"

    Obviously I explained that in this context the phrase simply meant, "physically bigger than the Earth in size and/or mass" and that in reality, any planet orbiting beyond Pluto would be a barren world of rock and/or ice, to which the response was, "Well, why doesn't the article say that, then?"

    Given the way that lots of content covered by slashdot gets picked up by the mainstream media, maybe we should try and avoid terms liable to confuse or be misunderstood by less technical readership?
    • Re: (Score:1, Troll)

      by Type44Q ( 1233630 )

      Well, why doesn't the article say that, then?

      These days "journalism" is more akin to marketing - complete with all the lying.

      • These days? Only these days?

        • Only these days?

          Technically, ever since the TLA's took over the media under COINTELPRO's Operation Mockingbird... but it's gotten a lot worse, and a lot more obvious.

    • Are you really expecting BeauHD to EDIT?!?!!

      Gotta wonder what planet you're on. ;-)

      Just be glad TFS wasn't turned into some "Russia! Russia! Russia!" crap.

    • by Anonymous Coward

      Super earth means rocky planet, not gas giant.

    • by Gavagai80 ( 1275204 ) on Wednesday October 03, 2018 @04:53AM (#57416416) Homepage

      There is actually a possibility of life in a planet X (or even in Pluto), if it has an internal ocean heated by radioactive decay. So it might be a bit of a paradise after all, on the inside, for all we know.

    • Super Earth wears a red cape. It's faster than a speeding bullet and able to leap buildings in a single bound!

      It also shows up around super phone booths.

    • I dare you to tell Kal-El that to his face!

    • by MrKaos ( 858439 )

      he use of the term "super-Earth" prompted a non-technical friend of mine [who was reading the article over my shoulder] to ask, "So there's, like, an amazing Earth, way out in space, right on the edge of our solar system?"

      Should have told him it is the home of all the Super people, like Super Man and really fantastically dressed.

    • Part of the problem is the science of astronomy itself, and their inability to come up with precise definitions that keep up with their scientific revelations.

      For example, a quick googling for 'scientific definition of a star' gives me:
      Star: A huge ball of gas held together by gravity. The central core of a star is extremely hot and produces energy. Some of this energy is released as visible light, which makes the star glow.

      By that definition, Jupiter, Saturn, and Neptune are all technically stars - they ar

      • Jupiter, Saturn, and Neptune don't have a hot core, they don't produce energy and they don't emit visible light.
        So they contradict your definition. And are obviously not stars. To be a star Jupiter would need to be 10 times as heavy.

    • Yeah yeah, mass and ice and stuff... What I want to know is, if we have a Super Earth just sitting out there, then why the heck is Elon screwing around with Mars instead of getting us to the nice big Super Earth? Think of the beaches that place must have!
    • You want to avoid technical terms on a technical website? That's what Google Search for.
    • Super Earth includes all rocky planets that should have become gas giants but aren't. (About 1.2 Earth masses.) I'm not completely sure how much smaller than that it goes, but Earth doesn't become a Super Earth every time a meteor storm adds mass, so there is a range of masses that constitute Earth mass.

  • While I'm aware research is still in its early phase --- are they suggesting that, should Planet X exist, that Goblin is actually a Moon?

    I heard Goblin described as "at the very small end of a dwarf-planet." Are they suggesting it is a planet that was knocked out of orbit by X? Or is it technically orbiting X making it a moon?

    Or do we need a different definition --- rocks that float in space?!

    OOhhh -- I see the movie now. Super Earth X. Magical planet of mysterious inhabitants.
    The sequel will be called

    • No, Goblin would not orbit the new planet, it orbits the sun, therefore it is not a moon. That it is gravitationally affected is irrelevant.

  • by rossdee ( 243626 ) on Wednesday October 03, 2018 @08:11AM (#57417078)

    With a perihelion of 80, and an aphelion of 2300, Goblin is not a planet, its a comet.

    • Depends. If you go by structure and intrinsics, it might well be a planet. If you go by extrinsics, it's a dwarf planet. The definition of a comet has nothing to do with the shape of the orbit.

  • So you could say this is "Planet 9 from Outer Space"?

    *rimshot* Thank you! I'll be here all week -- don't forget to tip your waitress!!

  • Is it 80 AU away or 2,300 AU away?

  • by GuB-42 ( 2483988 ) on Wednesday October 03, 2018 @09:21AM (#57417456)

    I suggest that we call planet 9 "Pluto". There is another object called "Pluto" but since it isn't a planet, it should be no problem, right?

    • I suggest that we call planet 9 "Pluto". There is another object called "Pluto" but since it isn't a planet, it should be no problem, right?

      Well, we'll have Pluto, and Planet Pluto, then. Or something.

      Much like we have Washington State and Washington, D.C. Depending on where you're at (and sometimes the context of the conversation overrides this), Washington refers to either the State or D.C.

      Since we've already got duplicate naming conventions totally figured out, and with all ambiguity removed, calling it Pluto shouldn't be a problem for anybody. You've got my vote!

    • It's a planet. Some fools designate it a dwarf planet, but a dwarf planet is still a planet.

  • If they made Pluto a planet again (planet #9), then Planet X would be Planet Ten. Or should that be iPlanet X?

  • Lord John Whorfin: Where are we going? The Red Lectroids: Planet Ten! Lord John Whorfin: When? The Red Lectroids: Real soon!
  • it never comes close enough to impose gravitational influence on the Solar System's giant planets,

    I would think the massive diameter of 300 km is enough to make sure of that. What kind of gravitational influence would an object like that have, even if it were to come close?

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