Planet Nine could turn out to be our missing super Earth

Posted: October 5, 2017 by oldbrew in Astrophysics, predictions, solar system dynamics
Tags: ,

Where is Planet 9? [credit: NASA]

Planetary theorists say super-Earths are commonly found in other planetary systems, but missing – so far – in our solar system. The evidence seems to be mounting, so is it just a case of tracking one down?

It might be lingering bashfully on the icy outer edges of our solar system, hiding in the dark, but subtly pulling strings behind the scenes: stretching out the orbits of distant bodies, perhaps even tilting the entire solar system to one side, says NASA’s Jet Propulsion Laboratory.

If a planet is there, it’s extremely distant and will stay that way (with no chance — in case you’re wondering — of ever colliding with Earth, or bringing “days of darkness”). It is a possible “Planet Nine” — a world perhaps 10 times the mass of Earth and 20 times farther from the sun than Neptune.

The signs so far are indirect, mainly its gravitational footprints, but that adds up to a compelling case nonetheless.

One of its most dedicated trackers, in fact, says it is now harder to imagine our solar system without a Planet Nine than with one. “There are now five different lines of observational evidence pointing to the existence of Planet Nine,” said Konstantin Batygin, a planetary astrophysicist at Caltech in Pasadena, California, whose team may be closing in.

“If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them.”

Batygin and his co-author, Caltech astronomer Mike Brown, described the first three breadcrumbs on Planet Nine’s trail in a January 2016 paper, published in the Astronomical Journal. Six known objects in the distant Kuiper Belt, a region of icy bodies stretching from Neptune outward toward interstellar space, all have elliptical orbits pointing in the same direction.

That would be unlikely — and suspicious — enough. But these orbits also are tilted the same way, about 30 degrees “downward” compared to the pancake-like plane within which the planets orbit the sun.

Continued here.

  1. oldbrew says:

    Pluto has a 17.6 degree orbital tilt 😎


  2. ivan says:

    They can find planets orbiting distant stars yet they can’t find a large one in our own backyard – strange.

    If we accept that they are seeing gravitational anomalies maybe, just maybe, those observations are saying that they don’t know everything about gravity like they thought they did and that should be their area of concern but that requires original thought.

    The problem is that we are in the age of ‘consensus’ science where individual original non group-think ideas are banned so anyone that steps out of line becomes de-funded – not the way to advance science.

  3. p.g.sharrow says:

    I wonder how long it will take astronomers to “Discover” the Brown Dwarf that periodically passes through our Solar System. There are a lot of clues as to where to look…pg

  4. Curious George says:

    Mr. Urbain Le Verrier used paper and pencil to predict a position of planet Neptune in 1840. NASA has supercomputers, but that’s the only visible sign of progress in this field.

  5. oldbrew says:

    The further out from the Sun you look, the bigger the area you have to search and ’20 times further out than Neptune’ is a vast amount of search area. Also the orbit period of such a body is thousands of years, meaning its orbit speed is extremely slow compared to the background stars. Not impossible but no pushover either.

    With exoplanets there is no specific target so anything found at random can be zoomed in on so to speak.

    This is how Eris (558 year orbit) was discovered. The three frames were taken over a period of three hours.
    Any candidate Planet 9 would be much slower-moving, but obviously a great deal bigger (Eris like Pluto is smaller than the Moon).

  6. E.M.Smith says:

    My usual complaint about calling this “Planet 9”:

    It is out in the land of KBOs and Oort. It has not “cleared the neighborhood”. So, by the definition that killed Pluto, it isn’t a planet. Then, by the old definition if we resorted to it, Pluto is planet 9, then there are a couple of other planet sized KBOs to count, so this thing would be about Planet 15…

    But in no case can it be “Planet 9″…

  7. oldbrew says:

    EMS – a few points…

    Re Oort: ‘no confirmed direct observations of the Oort cloud have been made’ but it should be ‘somewhere between 50,000 and 200,000 AU’.

    The Kuiper belt has a cliff edge at 50 AU.

    ‘In 2003, Bernstein, Trilling, et al. found evidence that the rapid decline in objects of 100 km or more in radius beyond 50 AU is real, and not due to observational bias.’

    ’20 times farther from the sun than Neptune’ is ~600 AU i.e. a very long way from both Kuiper and theoretical Oort.
    1 AU is Earth-Sun distance.

    Pluto is a lot smaller than the Moon 🙂

  8. richard verney says:

    Planet Nine, if it exists, is very unlikely to be a planet, based upon the current definition of the planet.

    Planet Nine, if it exists, is hiding in all the debris of the outer reaches of the solar system, so it would appear that it has not cleared these other objects from its orbit; hence the reason for the difficulty in discovering it!

    Perhaps if Planet Nine is discovered, the definition of planets will be reviewed.

  9. richard verney says:

    Sorry, I had not read the comments before posting my comment. I see that E M Smith has raised the same point.

  10. oldbrew says:

    Since nobody knows much about what is beyond about 50-100 AU, and even less so at 600 AU, most options should still be on the table.

    There’s the ‘scattered disk’ but it ‘is still poorly understood: no model of the formation of the Kuiper belt and the scattered disc has yet been proposed that explains all their observed properties.’

    Constraints on additional planets
    – – –
    How many dwarf planets are there in the outer solar system? (updates daily)

    (As of 1 Nov 2013 also includes latest thermal and occultation results)

    As of Fri Oct 6 2017
    there are:
    10 objects which are nearly certainly dwarf planets,
    30 objects which are highly likely to be dwarf planets,
    70 objects which are likely to be dwarf planets,
    149 objects which are probably dwarf planets, and
    703 objects which are possibly dwarf planets.

  11. oldbrew says:

    Michael E. Brown & Konstantin Batygin
    June 2016

    INTRODUCTION [extract]
    With the discovery of 2010 GB174 (Chen et al. 2013)
    and 2012 VP113 (Trujillo & Sheppard 2014) – the second
    and third high perihelion Sedna-like objects –
    additional patterns began to emerge. Most importantly,
    Batygin & Brown (2016) point out that all welldetermined
    orbits of Kuiper belt objects (KBOs) beyond
    Neptune with semimajor axis, a, larger than 227 AU approach
    perihelion within 94 degrees of longitude of each
    other. Moreover, these objects also share very nearly the
    same orbital plane, which is tilted an average of 22 degrees
    to the ecliptic. The combined probability of these
    two occurrences happening simply due to chance is less
    than 0.01%.
    Importantly, of all KBOs with a > 100 AU,
    the five with the largest perihelion distances are likewise
    confined to the same perihelion region and orbital plane.

    Batygin & Brown (2016) show that a distant massive
    eccentric planet will cause clustering of the perihelion
    and orbital planes of distant Kuiper belt objects in the
    manner observed, and, additionally, will naturally lead
    to the creation of objects with high perihelion orbits like
    [bold added]
    – – –
    Sedna: The coldest most distant place known in the solar system; possibly the first object in the long-hypothesized Oort cloud
    – by Mike Brown

  12. stpaulchuck says:

    Jupiter isn’t where it’s supposed to be and Planet 9 isn’t either (if it’s rocky). They could explain each other. But first it has to be validated. A visual spotting with something like the Hubble would be super cool!

  13. Geoff Sharp says:

    My usual complaint is that Planet 9 with it’s suggested mass CANNOT be orbiting the Sun. Basic physics would significantly change the path of the Sun around the SSB if Planet nine existed, so the only possibly would be a rogue planet passing through our neighbourhood or perhaps a stationary object being dragged along…which is probably unlikely.

  14. oldbrew says:

    They frame it as ‘Planet 9 or else…’

    “If you were to remove this explanation and imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five different puzzles, and you must come up with five different theories to explain them.”

    But facts at 600 AU are hard to come by.

  15. richard verney says:

    Personally, I do not consider that we know or understand enough, to add credibility to what is ,in my opinion, simply speculation regarding the existence of Planet 9.

    If it does exist, it will take us a long time before we know accurate details as to its orbit, so even after its discovery (assuming it exists and is found), it will be a long time before it adds to our understanding of the formation of the solar system.

  16. oldbrew says:

    A planet at ~600 AU would in theory at least be in a zone with not many other bodies.

    Dwarf planet Sedna’s semi-major axis is 506.8 AU

    ‘The scale bar is in astronomical units, with each set distance beyond 1 AU representing 10 times the previous distance.’ The Oort cloud is still theoretical.

  17. oldbrew says:

    Sedna orbit in white with hypothetical Planet nine.

  18. E.M.Smith says:


    Note that at closest approach, your map of proposed supposed “planetv9” orbit is well inside many other orbits of non-planets. I.e. none of them have “cleared their area”…

    Per Oort cloud: since nobody knows the edges of it, nobody can say P9 hasn’t got overlap and failed to clear it. As there are far more non-planets out far with highly inclined and stretched orbits, to assert P9 is different with no evidence is folly. It ought to be called a distant “object” until some evidence of what it is, exists. Otherwise, I’m just as valid to call it our Dark Star Companion, or Nemesis, or Oort Megalumpkin, or anything else.

    BTW, comparing Pluto size to the Moon is irrelevant. Pluto self rounds. Besides, IMHO, the Moon ought to be classed as a planet and Earth / Moon as a binary planet system. The Moon is never retrograde in orbit around the sun and is always solar concave.

  19. E.M.Smith says:

    Includes some critique of the planet deffinition that dumped Pluto…

  20. oldbrew says:

    EMS: re ‘your map of proposed supposed “planetv9” orbit is well inside many other orbits of non-planets. I.e. none of them have “cleared their area” ‘
    – – –
    The map is 2D, so it can’t be relied on in that way. For example the perihelion of Pluto is ‘inside’ that of Neptune but they are never close and Neptune has cleared its area. Also Planet 9 would only be at its closest to the Sun every ~12,000 years in theory.
    (re Pluto – look at all the other red blobs i.e. Plutinos nearby 🙂 )

    Agree the Moon is a tricky one. Its rotation period is almost the same as a Carrington rotation.

  21. E.M.Smith says:

    And look at all the yellow blobs by Saturn, Uranus, and Neptune. Then there is the special pleading for Jupiter’s trojans, then… the simple fact is the “cleared the area” standard is stupid and broken. Even Earth has not cleared the area. Things keep whacking into us.

    The terrestrial planets (Mercury, Venus, Earth and Mars) are shown on the diagram by Cyan or White squares, and their orbits are represented by the blue ellipses around the Sun (the yellow dot at the centre). The Earth is highlighted because of its special importance to us. Small green points mark the location of asteroids which do not approach close to the Earth right now. This does not exclude the possibility that they will do so in the future but generally we can consider the Earth to be safe from these for the near future. Yellow objects (with the exception of the one in the middle which we astronomers call the Sun 😉 are Earth approaching asteroids which are called Amors after the first one discovered. Amors have orbits which come close to the Earth but they don’t cross the Earth’s orbit. However, their orbits are close enough to the Earth that they could potentially be perturbed by the influence of the planets and begin to cross the Earth’s orbit in a short time. There are over 300 known objects on such orbits.

    Finally the red boxes mark the location of the Apollo and Aten asteroids. These cross the Earth’s orbit and are the most directly identifiable astronomical threat for the near future. Included in this selection is the infamous asteroid, 1997XF11, which made a major impact on the world’s headlines in March 1997 when observations indicated that it had a good chance of colliding with the Earth in 2028. Thankfully, new observations were made and the newly calculated orbit predicts a close approach of about 600,000 kilometres. Other asteroids which have orbits which may hit the Earth are 1999 AN 10 and 1998 OX 4. Further observation is required to determine their orbits in sufficient detail to predict an impact or a near miss.

    It is estimated that there are perhaps 100,000 to 1,000,000 undiscovered asteroids on similar Earth crossing orbits.

    Have a Nice Day.

  22. oldbrew says:

    Clearing the neighbourhood – Wikipedia

    In the end stages of planet formation, a planet (as so defined) will have “cleared the neighbourhood” of its own orbital zone, meaning it has become gravitationally dominant, and there are no other bodies of comparable size other than its satellites or those otherwise under its gravitational influence. A large body that meets the other criteria for a planet but has not cleared its neighbourhood is classified as a dwarf planet. This includes Pluto, which is constrained in its orbit by the gravity of Neptune and shares its orbital neighbourhood with Kuiper belt objects. [bold added]

    Obviously asteroids, comets and the like are not ‘of comparable size’.
    – – –

    Small Asteroid Gives Earth a Close Shave in Highly Anticipated Flyby
    By Mike Wall, Senior Writer | October 12, 2017 07:00am ET

    A small asteroid buzzed Earth early Thursday (Oct. 12) in a close flyby that scientists had been looking forward to for months.

    The space rock, known as 2012 TC4, zoomed about 26,000 miles (42,000 kilometers) above Antarctica at 1:42 a.m. EDT (0542 GMT) Thursday. That’s about 11 percent the distance between Earth and the moon, and just beyond the orbit of geostationary satellites.

  23. oldbrew says:

    Is there another world on the edge of our solar system? Nasa says it is likely mysterious Planet Nine DOES exist

    Nasa highlights five different lines of evidence of the existence of Planet 9
    Imagining Planet 9 doesn’t exist generates more problems than it solves
    The team is now using the Subaru Telescope in Hawaii to find Planet 9
    It hopes the detection of the mysterious world will also shed light on its origin
    PUBLISHED: 13 October 2017

    Read more:

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