A Little Perspective on the New “9th Planet” (and the 10th, and the 11th)

By Corey S. Powell | January 22, 2016 7:15 pm
Planet 9 from Outer Space: The peculiar alignment and tilt of the 6 most distant objects in the solar system hint at the presence of an unseen massive planet orbiting far beyond Pluto. (Credit: Caltech/R. Hurt/IPAC)

Planet 9 from Outer Space: The peculiar alignment and tilt of the six most distant objects in the solar system hint at the presence of an unseen massive planet orbiting far beyond Pluto. (Credit: Caltech/R. Hurt/IPAC)

By now you’ve probably heard the announcement that astronomers Konstantin Batygin and Mike Brown think they’ve tracked down “Planet 9,” a long-rumored large world orbiting in the distant wilderness of the solar system. Even if you haven’t heard, the news may sound familiar, since a confusingly similar but completely separate report made the rounds just a month ago. (Students of history will recall that Planet X stories also circulated in 2014 and 2006, and have been a staple of the astronomy hype machine all the way back to the discovery of Ceres in 1801.)

The dreary truth is that the Batygin and Brown claim, while stronger than the ones that came before, is still soaked in uncertainty. But there’s another truth, far more exciting, that goes with it: The latest efforts to find Planet X are hugely revealing, even if these particular ones don’t hold up.

Reason #1: The competing claims starkly illustrate the difference between seeing and believing. The case for Planet 9 is much stronger than for the ones described in December, even though researchers have directly observed the earlier objects but have not seen Planet 9 at all. Better yet is reason #2: These stories keep popping up because overwhelming majority of the solar system is cloaked in darkness, and is just now coming into view. Even the latest maybe-planets turn out not to exist, it’s nearly certain that there are big, exotic things out beyond Pluto waiting to be found.

On the Trail of Planet 9

Since they haven’t been able to observe Planet 9 directly, Batygin and Brown have attempted to find it by following its gravitational shadow. There is a long and noble tradition of sleuthing out invisible objects by the way they pull at other, visible ones. In 1846, French mathematician Urbain Le Verrier deduced the existence of Neptune from deviations in the orbit of Uranus; Le Verrier concluded, correctly, that a then-unknown planet was responsible for the anomaly. Over the past two decades, astronomers have discovered hundreds of distant planets the same way, by noting how they pull on their parent stars. On the cosmic level, much of the evidence for dark matter in the universe comes from tracing its gravitational influence on bright galaxies.

Planet 9 appears to have left its gravitational mark by scrambling the orbits of other, smaller bodies in the Kuiper Belt–the loose swarm of frozen objects (including Pluto) that orbit in the vast, distant zone beyond Neptune. My colleague Ethan Siegel very ably explains Batygin and Brown’s gravitational deductive process here; the research paper is here.

Some breathless media reports notwithstanding, the evidence for Planet 9 is far from airtight, though it certainly is intriguing. If the planet real, it must be big, at least 10 times the mass of Earth, and would follow a huge looping orbit. Even at its closest point, it would lie perhaps five times as far from the sun as Pluto. It would be quite unlike anything else known in the solar system.

There is a contentious question hanging about what to call such an object. In their paper, Batygin and Brown pointedly refer to it as a planet, but the current definition of planet—the one that got Pluto kicked out of the club—requires that an object must have “has cleared the neighbourhood around its orbit” in the solar system. It is not clear that Planet 9 would meet that standard, despite Brown’s confident statements to the contrary. (Irony alert: Mike Brown is the same astronomer who discovered Eris, the large Kuiper Belt object that prompted the new planetary definition and the demotion of Pluto. His Twitter handle is @plutokiller.)

Now About Planets 10 and 11…

In short, the story of the maybe-planet-that-we-haven’t-seen is inconclusive. The story of the maybe-planet that we have seen is far, far more so.

ALMA--an array of 66 dishes in the Chilean Andes--is hugely sensitive to long-wave radiation from cool objects. One of those objects might (just maybe) be a new distant planet. (Credit: ESO/B. Tafreshi)

ALMA–an array of 66 dishes in the Chilean Andes–is hugely sensitive to long-wave radiation from cool objects. One of those objects might (just maybe) be a new distant planet. (Credit: ESO/B. Tafreshi)

The observational evidence for those other planets comes from ALMA, a powerful radio telescope array recently constructed in the Atacama desert of Chile. A large planet in the far outer reaches of the solar system would reflect exceedingly little light, but it would retain some heat from the time of its formation. Such heat would cause the planet to radiate, just a little, at millimeter-wave frequencies (between radio and microwave). That is the planetary emission Wouter Vlemmings of Sweden’s Chalmers University of Technology thinks he might have detected—not just once, but in two different directions. For simplicity I’ll call these sightings Planet 10 and Planet 11, though I should be clear that the researchers did not use those terms.

Actually, what Vlemmings and his colleagues have seen is an unexplained blip that showed up in one spot, then in another, over two pairs of observation. The simplest explanation, they say, is that they caught two solar-system objects passing through ALMA’s field of view. This interpretation comes with a boatload of caveats. The blips could be transient sources that switched on and off. The odds of making two amazing detections by pure chance are, er, astronomical. And ALMA is a new instrument; the blips might simply be imaging artifacts that the researchers do not yet understand. Even if they are real, the ALMA data cannot readily distinguish between a small, nearby body and a large, distant one.

What scientists need are multiple sightings, tracking the blips and proving that they move like real planets (or perhaps like something else entirely; that would be exciting, too). ALMA, with its small field of view and full observing schedule, is not well equipped to do that. For now, Planets 10 and 11 are stuck in limbo; they are intriguing anomalies and nothing more. You can explore the technical papers for yourself, here and here.

Fortunately, this is not where the story ends. If Planet 9 is real, it should be possible to observe it directly. It won’t be easy, since the planet’s inferred size and distance mean it would be extremely faint (10,000 times fainter than Pluto, give or take) and moving very slowly among a vast number of similarly dim stars. Nevertheless, giant telescopes like the Subaru in Hawaii could potentially find it.

Batygin and Brown are already looking, and others are about to join the search. In principle, ALMA could continue scanning for the more-improbable Planets 10 and 11. If another suspicious blip shows up, that too would merit related visible-light searches. In the meantime, ALMA is making all kinds of other stunning discoveries about stars and galaxies.

The Solar System’s Next Frontier

An especially exciting tool for exploring the outer reaches of the solar system is the upcoming Large Synoptic Survey Telescope, or LSST. Ignore the ominous-sounding name and think about it this way: It is an HD movie camera filming a reality show about the whole universe. Unlike other giant telescopes–Subaru included–that typically focus in on one small region at a time, the LSST will scan the whole sky every few days. If anything flashes, LSST will see it. If anything moves, LSST will see it.

Real-time observations of the ultra-faint sky will revolutionize astronomers’ ability to scan the dim outer reaches of the solar system. Nobody knows what we will find out there. But it is a 100% safe bet that we will find a lot, very likely including objects that don’t resemble any we’ve seen before, because we are entering uncharted territory. All of the major planets like within 30 Earth distances from the sun. (One sun-Earth distance is known as an astronomical unit, or AU; it’s a standard bit of astronomy jargon.) The Kuiper Belt extends out to about 50 AU. But the gravitational influence of the sun extends out to about 100,000 AU. That’s a hell of a lot of unexplored space!

Four zones of the solar system include a staggering amount of unexplored space--almost everything beyond Pluto is barely known. (Credit: M. Brown/Caltech/R.Hurt/C.Powell)

The four zones of the solar system include a staggering amount of unexplored space–almost everything beyond Pluto is barely known. (Credit: M. Brown/Caltech/R.Hurt/C.Powell)

Astronomers have only a vague sense of what lies out there. Some 4.5 billions of years ago, the gravitational chaos from the giant planets threw trillions of small icy bodies into that distant zone. Some ended up in a zone called the “scattered disk,” similar to the Kuiper Belt but bigger and less stable; some ended up in the Oort Cloud, a humongous reservoir of dormant comets believed to stretch nearly halfway to the next star.

Larger bodies probably got tossed out as well: planetary cores, ejected moons, all kinds of unstable flotsam from the solar system’s traumatic birth. Planet 9, if it’s real, might be a survivor from that chaotic era. (See my full account of the early chaos here.) Sizable objects, perhaps the size of the moon or Mars, might also have formed in situ beyond the Kuiper Belt.

Computer models show that the far outer solar system must be rich with scattered objects. We know for sure that a lot of stuff is floating around out there because we see traces of it on a regular basis: When objects from the scattered disk or Oort Cloud get disturbed, they plunge toward the sun and show up as comets. But comets are just a small (and perhaps very skewed) sampling of the whole mysterious population out there.

I hope astronomers find Planet 9, but I’m not terribly worried if they don’t. Planet 9 may not exist, but countless other exotic denizens of the outer-outer solar system undoubtedly do. They are real, and when we finally see them, they will be spectacular.

For astronomy news as it happens, follow me on Twitter: @coreyspowell

  • Tony Dunn

    I know they believe that it must have formed closer to the Sun, and got ejected out to its current orbit. But do they have any idea how its perihelion got lifted well past Neptune?

    Here’s a simulation I made showing just how slowly this planet would move against the background sky. Its motion would be due mostly to parallax, rather than its own orbital speed.

    • coreyspowell

      That’s a great question. Batygin & Brown discuss it just a little at the end of their paper, but really there is not good answer. If Planet 9 turns out to be real, you can bet the theorists will work overtime trying to figure out how it got there.


  • Mike Richardson

    Thanks for the post. I’ve heard a good bit about the so-called “Planet Nine,” but the other prospects spotted by ALMA were news to me. Following the amazing images from Pluto, news like this just continues to show that the outer solar system continues to be a fascinating and surprising frontier.

    • coreyspowell

      Yes–the most wonderful lesson from this story is that it shows us how much we still have to discover. There are untold numbers of objects out there, and what we find is almost always stranger than the things that we were able to imagine.

  • Christos Themistocles Fotinako

    Yes, it’s important to keep a proper perspective when big claims are made in science, but you just know that this thing is going to come and get us either by collision or the aliens that live on it migrating on mass to Earth. :)

    How long before Hollywood creates a disaster flick out Planet 9?

    • Tim Mueller

      They already did. It was called Melancholia.

  • Verp

    Not all the material that formed and made up this system was confined to the inner solar system, as the existence of the Kuiper belt and Oort cloud clearly shows. I’ve often wondered what new and perhaps massive objects we haven’t seen yet in the outer solar system.

    • jared

      The volumes are so large that it will take considerable time and effort to map the outer solar system. Yet, these are features that would be difficult to study in other solar systems, unlike the inner planets.

      • Verp

        I never suggested looking at our outer solar system would be quick, easy or complete.

    • coreyspowell

      In addition to the studies I mention in my post, infrared sky surveys are a powerful way to look for large, distant objects in the solar system. The best of these–the WISE survey–has not found anything, but a more sensitive version could pick up smaller objects that WISE could not see.

      I spoke with Kevin Luhman at Penn State and he confirmed that the proposed Planet 9 would be too faint to have shown up in the WISE survey. For objects this size and smaller, optical searches are best. For larger objects (giant planets and brown dwarfs), though, infrared is the way to go because it can pick up the lingering heat signature of such bodies.


  • nirmalgopa

    We may measure the distance of planets by New Process described in the book “Endless Theory of the Universe (Complete Unified Theory)” Published by LAP LAMBERT, August, 2014.

    The distance of unknown planets also written in this book out of Solar System.

    For other celestial body like stars, galaxies etc
    are listed in different forms of the equation 2 π^2 NA R.

    Lot of Things are there in this book. Any one may collect this book to read and research purpose.

    Nirmalendu Das
    Dated: 24-01-2016

  • Dr Scrubbington

    If this “9th planet” does turn out to exist, I say we name it “Bowie” in honor of one of the most influential artists of modern times. Just as David Bowie re-invented himself and changed the way we look at music forever, this new planet would re-invent the way we look at our home in the universe and completely change our perspective about what’s out there, forever.

    • Christos Themistocles Fotinako

      Well, Doctor, I feel the same way about Bruce Springsteen before he started to sing like Woodie Guthrie. I’d like it called “Springsteen”. He wrote so many great lines in his songs, I can’t help but think some of them could be made to fit Planet 9. For example:

      He was just blinded by the light
      Cut loose like a deuce, another runner in the night
      Blinded by the light
      Mama always told me not to look into the sights of the sun
      Oh, but Mama, that’s where the fun is
      I was blinded
      I was blinded
      I was blinded

  • Steve Crosson

    how many of earth’s years would it take for planet 9 to complete it’s
    orbit around the sun?

    • Mrihavenoname1

      around 15000

      • surgeen

        Until it is observed to have completed one orbit round the sun, the best name for it would be ‘Planet?’ – it could might not have been orbiting our sun after all, notwithstanding the approximation ridden calculation of its orbit round the sun

  • ex sea org member

    There are a lot of objects past Neptune and it is likely new planets will be discovered though the distances of them will mean finding anything meaningful will be difficult. The planets we observe represent a fairly “clean” solar system when in reality many star systems will be found to be like what ours really is – full of odd stuff.

  • nirmalgopa

    A small portion of distance of planets and stars given here by New Method for the Researchers and Readers. —– Nirmalendu Das

  • Brett Allen

    Again, the Sumerians were right!; just as they were with the present incarnation of Earth being formed from a cosmic collision. For not not familiar with the “pseudoscience” of Zecharia Sitchin’s translations of Sumerian tablets… here is his vindication. The 9th Planet, Nibiru, planet of the Crossing, was recorded by Sumerians to have an extreme elliptical orbit and stay out of view, and only come close to Earth every 3600 years when it causes chaos and catastrophe on our planet with its gravitational pull. Accounts in the tablets also tell of the Anunnaki (star visitors from this planet) watching its effects after they landed here on Earth; hence the Great Flood. In fact, around the world over 600 cultures have similar tales of Earth-ending events periodically overtaking the planet. In recent years the end of the Mayan Long Count, has left many expecting this announcement, and tie it directly to climate change! Nibiru (marduk) is the planet the Sumerians say caused the cosmic collision that created the present incarnation of Earth – once far larger.

    • OWilson

      Fascinating stuff, and, aside from the “star visitors” report, is a possible scenario.

      All ancient civilizations have their myths and lore, and because of the similarities of some accounts, it is at least possible that they are referring to the same major events.

      While the geological events we see today, mountain building and tektonics are relatively slow, there is a lot of evidence for catastrophic change.

      Vast volcanism, ocean basin flooding, the Siberian mammoth graveyard, where thousands of the animals met their end, dinosaur extinctions, could, and have, in the case of dinosaurs, be explained by celestial events.

      Even the Earth and it’s moon were shaped by celestial cataclysm.

      The timing 3,600 year periodicity seems to fit too.

      It would be interesting if future research could confirm a regular and close encounter of the cataclysmic kind :)

      • coreyspowell

        Yes, celestial impacts have caused catastrophic events on Earth. But no, a 3600-year cataclysm cycle due to Planet 9 is not in any way a possible scenario.

        • OWilson

          Darn it! :)

          • http://www.DomainOfMan.com/ domainofman

            The Mayans were tracking multiple cyclical events that were on the order of thousands of years. One repeated about every 3,149 years. A second one was on the order of 5,000 years. Another was approximately 666 years. However, these were probably comets rather than planets. I don’t think we will find any new objects of planetary size in the solar system, but there’s no harm in looking. It’s more likely we will find a small failed “twin” star beyond the Oort Cloud.

    • King Clovis

      The closest this “planet 9” would get to Earth would still be 7 times further out than Neptune, and it’s orbit is estimated at 15,000 years. This does not jive with Nibiru.

    • coreyspowell

      Well…this Planet 9 may very well not exist (I’d put the odds at less that 50-50). If it does, it is in an orbit that never comes within 2 billion miles of Earth, its orbital period is on the order of 20,000 years, and it would have been in its current orbit for 4.5 billion years, since the origin of the solar system.

      The evidence for Planet 9 comes from the arrangement of the orbits of objects at the far outer edge of the Kuiper Belt (or perhaps the inner Oort Cloud; the definitions are still up in the air). That arrangement represents a stable response to the gravity of Planet 9–that is exactly how Batygin and Brown have inferred its location. That means Planet 9 is NOT stirring up any chaos each time it moves through its orbit. It has had billions of years to achieve stability. In fact, the only reason we (think we) know Planet 9 is there is because it is in a stable arrangement, not an unstable one.

      I realize that this kind of information probably won’t convince the true believers in Nibiru. But from a scientific point of view, Planet 9–if it exists–presents no threat, and almost certainly has had no interaction with the inner solar system in the past 4 billion years.

    • Rita O’Gorman

      I too am a Sitchin fan. I have read several of his books. But Clovis is correct in saying that 3,600 year orbit of Nibiru dose not fit this new planet 9, if it exist. Then again this figure is Sitchin’s translation of a sar, I believe. These Sumerian tablets are translated and interpreted by Sitchin. It seems obvious to me that these tablets are foundation of the Jewish scripture. But the events Sitchin writes about are also in the Vedas. Tails of gods doing battle in their space ships. Could this be the foundation of the great war in heaven we find in the Bible replete with “those who where cast down to earth? Hmmm…fun stuff.

      • Rightofcenterleft

        Perhaps the 3600 years is the minimum apogee of an oblong orbit. In other words we see this planet as 2 timing orbits, the long and short orbit. Just a thought (on a post 2 years old)

    • Paul Manriquez

      I do believe the evidence for another “12th” planet (Sumerians counted Sun and Moon) to be convincing based on Sitchin’s Sumerian translations/interpretations. Now we see how likey it could be that a similar planet exists. Exoplanets are common in other solar systems, now we are starting to see them in ours. This was not known when Sitchin wrote The 12th Planet but he described Nibiru in that way. If this planet is found, look out nay sayers because your backs will be to the wall. Ancient astronaut theory is becoming more reasonable and realistic by the day.

  • Erik Bosma

    This just brings up more questions for me. Do the orbits of all these extra-Plutonic objects precess? And if they do, might this line-up of their orbits not just be coincidental? 70,000 years ago a small star passed within 0.1 light-years of the Sun. Could it not have had the gravity necessary to re-align these orbits to the way they are today? Which may also have been the reason for Pluto’s eccentric orbit. Perhaps someone could answer these for me in some future article.

  • Chetan Suri


  • KateGladstone

    I suggest we should name Planet Nine PROSERPINA:

    /1/ this restores planetary-name mnemonics that had P-for-Pluto,

    /2/ the name is appropriate for a world in the cold outer darkness that periodically comes closer to the Sun before receding again (as Proserpina in Roman myth periodically emerged from the cold, dark realm of Pluto),

    /3/ Proserpina’s mythological position as the queenly daughter of an Earth-goddess makes her name a good one for a world that’s being described as a “huge new Earth” ( = solid like the Earth, not gaseous like other outer planets),

    /4/ this gives our solar system another female-named major planet in addition to Venus: somewhat reducing the present gender inequity among major-planet names. Astronomy (and science in general) belongs to women as much as to men.

    • Taggart Romkey

      Another name that would fit that world would be Hecate, greek goddess of the crossroads and ghosts who was said to haunt the dark of night wherever roads met. That world if it exists would be at the crossroads between our solar system and the rest of the galaxy

  • Van Snyder

    John Couch Adams also calculated the position of Neptune. He started his work before Le Verrier, but sent his results to the Royal Greenwich Observatory two days after Le Verrier sent his results to the Berlin Observatory. Five days later, Le Verrier’s letter arrived and Galle (the astronomer at the Berlin Observatory) looked where he predicted and found Neptune. There is no report of Greenwich looking where Adams pointed. Adams acknowledged the priority of Le Verrier and Galle.

  • Van Snyder

    Astronomers use the same sorts of calculations that Le Verrier and Adams used to find Neptune, to infer the presence of dark matter in distant galaxies. The conjecture is that dark matter is ubiquitous. It appears to compose 75% of the universe. I’ve asked several times, if dark matter is ubiquitous and plentiful, why do we see no dynamical effects of it in the Solar System? Nobody has given me an answer that doesn’t involve vigorous hand waving. Maybe Planet 9 is actually the long-sought dynamical evidence of dark matter in the Solar System.

    • Marc Leif

      I think that’s a very good question. I’ve wondered too if no “local” interaction with dark matter wouldn’t be detectable. I always assumed dark matter interaction to be so weak as to be perceivable only at vast scales — but still since our solar system presumably swims in the “stuff” too, isn’t here some form of interaction?

  • jug

    The muslims have already colonized it!
    Like mushrooms, they grow well in the dark.

  • Alexandra

    We still know very little about the Universe.

  • http://www.royalcert.com Alphan Namli

    I hope astronomers find Planet 9 and more

  • DrunkanIdaho

    The line “There is a contentious question hanging about what to call such an object. In their paper, Batygin and Brown pointedly refer to it as a planet, but the current definition of planet—the one that got Pluto kicked out of the club—requires that an object must have “has cleared the neighbourhood around its orbit” in the solar system. It is not clear that Planet 9 would meet that standard…” is spurious, at best. If Earth were transplanted to the Kuiper belt, where this much larger planet is posited to exist, it wouldn’t fit this definition either (meaning it wouldn’t be able to clear out it’s neighborhood). So, that means Earth is a planet (by definition) in the Inner Solar system, but not in the Kuiper belt? To me that means the definition is flawed and begs for an update.

    • Marc Leif

      I quite agree the current “definition” is incomplete and only allows for a limited set of circumstances. The orbital mechanics of objects orbiting at such vast distances are going to involve very complicated interactions with other distant objects. “Clearing out” an orbit of such a volume of space won’t be possible.
      Then there are the varieties of myriad exoplanets. We’re still at a point if planetary astronomy where we’re calling everything that lives in the ocean a “fish”. There will be dozens or hundreds of classes of planets before it’s all over — if it ever is!

  • Anthony R. Lafemina

    Based on the evidence at hand now, can we approximate when we can see planet X or whatever we are calling it these days? I assume amateur astronomers will eventually be able to see it and record it, as they did with Jupiter getting hit. or not so much. Love your articles and tv interviews…thanks for keeping the world in the Loupe!

  • gsmonks

    I think . . . wait for it . . . I think that “Planet 9 From Outer Space” may be our first direct local evidence of Dark Matter, that there may in fact be no extra planetary body out there.

  • Justin McKeown

    Well Just because These two Scientists say an orbit of maybe 10,000 to 20,000 years does not mean that is exact truth. If you think about it I mean simp0ly without trying to analyze everything, Ok… Then lets assume they are on track of Nibiru. Then, I mean they havn’t seen it yet, but they are sure it is out there. And then how in the heck can they say how long it takes to do it’s orbit. I would lean more to the thinking of it actually is the long talked about Planet – X The winged Planet. Etc. I mean look at what people say is global Warming. Perhaps this is the slow way to let the truth out that we are in real danger. Of a great magnitude of destruction to come. This is a way to let people not panic. And yet a way to slowly let the truth out that things are going to get really bad. This World we know as home is going thru many natural changes so fast. And to think it is blamed on People causing global warming. You cannot believe just anything someone says. And especially an exact amount time of this planets orbit.. I know it is more than greenhouse gasses or fracking etc. This ball we know as home is under a lot of outside pressure and forces unseen to the eye. I think when we all find out, I bet ya they will eventually say what was thought as possibly a 10,000 year to 20,000 year orbit is actually closer to 3500 to 3600 year orbit. Simply because calculating at the distance farthest away compared to it speeding up as it get closer to the sun cuts off the years they suspected. I am not a know it all but I have been paying attention to this for years. We are on a course that something major will take place even in our lifetime. Just have to wait and see if this is what many people suspected many years ago. And if its a 3600 year orbit then in due time it will be visible and our world will change from the gravitational pull. Right in Line with the timing of events the bible in Revelation says will take place with the earth being destroyed and darkened …no light of day for month’s. I think this is all very interesting. It has my attention for sure. Take care everyone Just wanted to speak my own words is all.

    • Paul Manriquez

      Well said. I also believe that calculation of 10,000 to 20,000 yrs orbit is just a premature calculation. Even if it turns out to be true, Sitchin could be off as well. But the fact of the matter is there exists exoplanets that have the same elongated orbit as Sitchin, interpreted from Sumerian, said Nibiru had.

  • Jerry

    Well it’s now next winter. Have they found it?


Out There

Notes from the far edge of space, astronomy, and physics.

About Corey S. Powell

Corey S. Powell is DISCOVER's Editor at Large and former Editor in Chief. Previously he has sat on the board of editors of Scientific American, taught science journalism at NYU, and been fired from NASA. Corey is the author of "20 Ways the World Could End," one of the first doomsday manuals, and "God in the Equation," an examination of the spiritual impulse in modern cosmology. He lives in Brooklyn, under nearly starless skies.


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