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Thread: Is Planet Nine almost certain, probable, possible or unlikely?

  1. #121
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    Quote Originally Posted by Roger E. Moore View Post
    Pluto might have an ocean? Could Planet Nine have an ocean, too?

    https://arxiv.org/abs/1903.05574

    Reorientation of Sputnik Planitia implies a Subsurface Ocean on Pluto

    F. Nimmo, et al. (Submitted on 13 Mar 2019)

    The deep nitrogen-covered Sputnik Planitia (SP; informal name) basin on Pluto is located very close to the longitude of Pluto's tidal axis[1] and may be an impact feature [2], by analogy with other large basins in the solar system[3,4]. Reorientation[5-7] due to tidal and rotational torques can explain SP's location, but requires it to be a positive gravity anomaly[7], despite its negative topography. Here we argue that if SP formed via impact and if Pluto possesses a subsurface ocean, a positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest N2 deposition. Without a subsurface ocean a positive gravity anomaly requires an implausibly thick N2 layer (greater than 40 km). A rigid, conductive ice shell is required to prolong such an ocean's lifetime to the present day[8] and maintain ocean uplift. Because N2 deposition is latitude-dependent[9], nitrogen loading and reorientation may have exhibited complex feedbacks[7].
    This does not address possibilities for Planet Nine.

  2. #122
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    Is Planet Nine an "Oort Planet"? Food for thought.

    https://arxiv.org/abs/1905.07044

    Stellar Flybys Interrupting Planet-Planet Scattering Generates Oort Planets

    Nora Bailey, Daniel Fabrycky (Submitted on 16 May 2019)

    Wide-orbit exoplanets are starting to be detected, and planetary formation models are under development to understand their properties. We propose a population of "Oort" planets around other stars, forming by a mechanism analogous to how the Solar System's Oort cloud of comets was populated. Gravitational scattering among planets is inferred from the eccentricity distribution of gas-giant exoplanets measured by the Doppler technique. This scattering is thought to commence while the protoplanetary disk is dissipating, 10 6 −10 7 yr after formation of the star, or perhaps soon thereafter, when the majority of stars are expected to be part of a natal cluster. Previous calculations of planet-planet scattering around isolated stars have one or more planets spending 10 4 −10 7 yr at distances >100 AU before ultimately being ejected. During that time, a close flyby of another star in the cluster may dynamically lift the periastron of the planet, ending further scattering with the inner planets. We present numerical simulations demonstrating this mechanism as well as an analysis of the efficiency. We estimate an occurrence of planets between 100 and 5000 AU by this mechanism to be <1% for gas giants and up to a few percent for Neptunes and super-Earths.

    LATE NOTE: Oh, uh, don't freak out when you see mention of Nirabu in the third sentence. It does get better.
    Last edited by Roger E. Moore; 2019-May-20 at 04:43 PM.

  3. #123
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    Quote Originally Posted by Roger E. Moore View Post
    LATE NOTE: Oh, uh, don't freak out when you see mention of Nirabu in the third sentence. It does get better.
    oops, they got the fake planet's name wrong, plus the source.

  4. #124
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    Until it is found then only speculation.

  5. #125
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    The jury is still out, it is argued, on whether Planet Ten exists, given this new analysis of TNO scattering.

    https://arxiv.org/abs/1905.09286

    OSSOS XVII: Probing the Distant Solar System with Observed Scattering TNOs

    Nathan A. Kaib, Rosemary Pike, Samantha Lawler, Maya Kovalik, Christopher Brown, Mike Alexandersen, Michele T. Bannister, Brett J. Gladman, Jean-Marc Petit (Submitted on 22 May 2019)

    Most known trans-Neptunian objects (TNOs) gravitationally scattering off the giant planets have orbital inclinations consistent with an origin from the classical Kuiper belt, but a small fraction of these "scattering TNOs" have inclinations that are far too large (i > 45 deg) for this origin. These scattering outliers have previously been proposed to be interlopers from the Oort cloud or evidence of an undiscovered planet. Here we test these hypotheses using N-body simulations and the 69 centaurs and scattering TNOs detected in the Outer Solar Systems Origins Survey and its predecessors. We confirm that observed scattering objects cannot solely originate from the classical Kuiper belt, and we show that both the Oort cloud and a distant planet generate observable highly inclined scatterers. Although the number of highly inclined scatterers from the Oort Cloud is ~3 times less than observed, Oort cloud enrichment from the Sun's galactic migration or birth cluster could resolve this. Meanwhile, a distant, low-eccentricity 5 Earth-mass planet replicates the observed fraction of highly inclined scatterers, but the overall inclination distribution is more excited than observed. Furthermore, the distant planet generates a longitudinal asymmetry among detached TNOs that is less extreme than often presumed, and its direction reverses across the perihelion range spanned by known TNOs. More complete models that explore the dynamical origins of the planet are necessary to further study these features. With observational biases well-characterized, our work shows that the orbital distribution of detected scattering bodies is a powerful constraint on the unobserved distant solar system.

  6. #126
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    Quote Originally Posted by Roger E. Moore View Post
    oops, they got the fake planet's name wrong, plus the source.
    Nirabu sounds cooler anyway.

  7. #127
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    Quote Originally Posted by Roger E. Moore View Post
    oops, they got the fake planet's name wrong, plus the source.
    Yeah, you'd think astronomers would be aware of the source: Nibiru (Babylonian astronomy).

    Nibiru is [Marduk's] star, which he made appear in the heavens... The stars of heaven, let him [Nibiru] set their course; let him shepherd all the gods like sheep.

    And from the Enuma Elish (Tablets 5 & 6):

    He (Marduk) made the stations for the great gods;
    The stars, their images, as the stars of the Zodiac, he fixed.
    He ordained the year and into sections he divided it;
    For the twelve months he fixed three stars.
    After he had ... the days of the year ... images,
    He founded the station of Nibir [the planet Jupiter] to determine their bounds;
    That none might err or go astray,

    ...

    Let his name be Nibiru, 'the Seizer of the Midst'!
    For the stars of heaven he upheld the paths,
    He shepherded all the gods like sheep!


    It all sounds very astronomical; of course, in antiquity, the "gods" were also planets.
    Where the telescope ends, the microscope begins. Which of the two has the greater view?

  8. #128
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    Could Planet Nine not be a planet but a black hole???

    https://www.sciencemag.org/news/2019...-be-black-hole

    For nearly 5 years, growing numbers of scientists have blamed the weird orbits of distant solar system objects on the gravitational effects of an as-yet-undiscovered “Planet Nine” that lies in the icy realm far beyond Neptune. But a pair of physicists is now floating an intriguing idea that could offer a new way to search for the object: What if that supposed planet is actually a small black hole?

    Previous studies have suggested Planet Nine, which some astronomers refer to as “Planet X,” has a mass between five and 15 times that of Earth and lies between 45 billion and 150 billion kilometers from the sun. At such a distance, an object would receive very little light from the sun, making it hard to see with telescopes.

    To detect objects of that mass, whether planets or black holes, astronomers can look for weird blobs of light formed when light “bends” around the object’s gravitational field on its journey through the galaxy (simulated image above). Those anomalies would come and go as objects move in front of a distant star and continue in their orbit.
    I am because we are
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  9. #129
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    Quote Originally Posted by selvaarchi View Post
    Could Planet Nine not be a planet but a black hole??? ...
    Of course it is much more likely that if planet nine exists, it is simply normal matter like everything else in the solar system, but just too far out to observe in visible light with our current instruments. But sure, if we haven't seen it yet, we can't rule out all sorts of things from the edge of physics. In this article, they propose a way to tell if it is a black hole by looking for cosmic rays from it in our existing data. If the search comes up empty, then there probably isn't a primordial (planet massed) black hole a few hundred AU from the Sun.
    Forming opinions as we speak

  10. #130
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    Quote Originally Posted by selvaarchi View Post
    Could Planet Nine not be a planet but a black hole???
    Here's their paper.

    It reports 6 microlensing events in the direction of the galactic bulge and they estimate the mass to be between 1/2 to 20 Earth masses, though they suggest ~ 5Me. [The direction is interesting.]
    We know time flies, we just can't see its wings.

  11. #131
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    Quote Originally Posted by George View Post
    Here's their paper.

    It reports 6 microlensing events in the direction of the galactic bulge and they estimate the mass to be between 1/2 to 20 Earth masses, though they suggest ~ 5Me. [The direction is interesting.]
    I wonder how many other astrophysics papers have a actual-size diagram of the object concerned.

  12. #132
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    I wonder if this new internstellar comet might be coming from its direction....

  13. #133
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    I wonder if we are due another round of Nibiru scare stories: "you can't see it coming because it is only the size of a tennis ball !!!1!"

  14. #134
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    Quote Originally Posted by Strange View Post
    I wonder how many other astrophysics papers have a actual-size diagram of the object concerned.
    That's probably the only one.

    Now, didn't the IBEX folk get fooled into thinking they saw evidence of a nearby black hole? I wonder.

    I want this to be a black hole.

    So many things you could do with it
    https://www.centauri-dreams.org/2019...civilizations/

  15. #135
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    Quote Originally Posted by Strange View Post
    I wonder if we are due another round of Nibiru scare stories: "you can't see it coming because it is only the size of a tennis ball !!!1!"
    It could be on a 3,600 year orbit and not get noticed. The small size reminds me of Borges "Aleph"

    Something I was thinking about--to tie this with the Fermi paradox.

    What if life began in its accretion disk?

    I've speculated about vorticity shedding off smokers--but how tight could vortices be in a small accretion disk? These would be like the mini-swirls Fujita thought could lie in the eyewalls of hurricanes.

    Then too--the paper talks about a torus of dark matter surrounding the solar system. Perhaps we could hear signals outside this torus.

    Or maybe--if a primordial black hole is also needed near an earth-like world to seed it with tholins heated and centrifuged out--it would make the Rare Earth Hypothesis even rarer.

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