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Caltech Researchers Find Evidence of a Planet Beyond Pluto

883 points by cyanbane 11y ago

beamatronic 11y ago
Why wouldn't their calculations be able to suggest possible locations for the planet?
- antognini 11y ago
  They do, and at the end of the press release it says that Brown has begun an observing campaign to find the planet. Unfortunately detecting these very distant objects is very difficult. The light we see from them is reflected light from the Sun, so their apparent brightness goes as 1/r^4, not 1/r^2 like most objects. And because they are so close, there is a strong parallax from the motion of the Earth. THe consequence from this is that the object will actually drift across the image as you are taking it, smearing it out. In order to detect it you either have to take very short images so that it doesn't move too much (in which case you don't get very much light), or have some idea as to the direction of the smear so that you can correct for it. Either way it's a very hard observation to make! Fortunately if this planet is as big as they claim it to be it should be relatively easy to detect compared to Sedna and the other Kuiper Belt objects.
  - hmahncke 11y ago
    Also, we don't know where in its orbit the planet happens to be right now. If we're lucky, it's relatively close to the sun, and it will be detectable. If we're unlucky, it's relatively far away from the sun, and it could easily be undetectable by current observatories because the orbit is so eccentric. [Source: I saw Mike Brown give a talk on this topic at the Cal Academy of Sciences, where he hoped he was lucky...]
    - abecedarius 11y ago
      Note that an eccentric orbit spends most of its time out in the far reaches, since it moves much slower out there. The odds are against the happy case.
  - daveguy 11y ago
    I would expect a smear with characteristics of the planet would be as effective to identify it as a single snapshot. Wouldn't the direction be well identified from indirect detection? Is the blur also less effective because of increased background exposure?
    - jschwartzi 11y ago
      Well, if the smear takes the light level below the noise floor of the sensor then you can't even say that there's a smear.
      - mkrfox 11y ago
        That's why you don't see any cars in long exposures of highways.
  - qb45 11y ago
    Are you sure it's r^4, not 4r^2?
    - antognini 11y ago
      Yes. The solid angle subtended by the planet (and hence the amount of reflected light) goes as 1/r^2, and then the apparent brightness of the reflected light to us goes as an additional 1/r^2. The total dependence is then 1/r^2 * 1/r^2 = 1/r^4.
      - gohrt 11y ago
        This is a really good physics puzzler. The key point is that Pluto does not reflect light like a mirror, it scatters light relatively uniformly, causing more light loss to an observer than, say, a mirror that points the reflection directly at an Earth observer.
    - jcrites 11y ago
      The light reaching the object from the sun drops off by 1/r^2, and then the light reaching Earth from the object drops again by 1/r^2. Since the latter light is a portion of the former, you multiply them for 1/r^4.
    - bzbarsky 11y ago
      Yes, it's definitely r^4. If we assume that the planet is far from the sun compared to the earth, such that the earth-planet distance and the sun-planet distance are both approximately r, then the amount of light the planet gets from the sun is proportional to 1/r^2. Then the planet reflects that light in all directions, and the fraction of it that comes back to us on earth is also proportional to 1/r^2. 1/r^2 * 1/r^2 = 1/r^4.
  - gene-h 11y ago
    Perhaps one of the "stubby hubble" telescopes the NRO donated to NASA would be useful for this task[0]. They are essentially the hubble telescope with a much shorter focal length(hence the nickname), so one of the uses suggested for them is observing faint objects in the solar system like asteroids. [0]https://en.wikipedia.org/wiki/2012_National_Reconnaissance_Office_space_telescope_donation_to_NASA https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O...
  - martinpw 11y ago
    In a previous life, back in the pre-CCD days I worked at an observatory searching for new asteroids. Used to be the way it was done you would point a telescope at the part of the sky directly opposite the sun (min r^4 so best chance of detection), expose a photographic plate, and repeat a few hours later. Develop the plates, mount them in a blink comparator [1] and scan manually, flipping back and forth between the plates for ~3 hours to look for anything that moved. Exclude false positives like plate blemishes (aka Eastman-Kodak Objects) or dust grains. If you see something, and it is smeared indicating motion during the exposure, mark it as a possible candidate. Revisit the same patch of sky the next night, search again. Use the datapoints to extrapolate forward, check again a couple of weeks later. If you haven't lost it (which frequently happened if it was at the limit of visibility), extrapolate back to the previous opposition (~4 years for a main belt asteroid) and search the archives for a match. If you get one, then extrapolate further back and check all previous oppositions. If you get a match on three separate oppositions, congratulations, you have a discovery. Vastly different now - a single observation can net large numbers of asteroids and sensitivity is so much better. Still the search for this potential new planet is definitely going to be daunting given the distance. [1] https://en.wikipedia.org/wiki/Blink_comparator https://en.wikipedia.org/wiki/Blink_comparator
  - angst_ridden 11y ago
    That's why you use Goldstone and Arecibo, and bounce your signal!
- umeshunni 11y ago
  They have a possible location - about 20 times farther from the sun than Pluto.
- SolarNet 11y ago
  Because they have only been able to find the orbit. Not the current location in the orbit.
- InclinedPlane 11y ago
  They do, but there are two problems. One is that that still leaves a pretty big range for possibilities for where the planet could be. The other is that we don't know where along the orbit the planet is now. Even if we knew the exact orbit of the planet simply not knowing where it was along that orbit means we'd have to scan a lot of the sky to spot it. Having a bit more ambiguity about the orbital parameters means we will have to scan much, much more of the sky to spot it.
japaget 11y ago
Link to paper by Batygin and Brown: http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22/pdf http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22...
dexwiz 11y ago
We have been looking for a "missing" objects for a while. The nemesis star theory says the sun has a brown dwarf companion. This object would interact with the Oort Cloud instead of the Kuiper belt. But this theory has been pretty much refuted. This theory definitely looks more promising. Finding eccentric Kuiper belt objects, and aligning them with a missing object seems to be a good bet. Giving the object an orbit should make the search easier, and we will probably have a conclusion one way or another within a few years. https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star) https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star)
pavel_lishin 11y ago
> * the putative ninth planet—at 5,000 times the mass of Pluto—is sufficiently large that there should be no debate about whether it is a true planet* That's 10x the mass of the Earth, right, or about 3x the size of Neptune?
- vidarh 11y ago
  > That's 10x the mass of the Earth It even says so in the first paragraph of the article.
- zeroonetwothree 11y ago
  This is the second sentence of the article: "The object, which the researchers have nicknamed Planet Nine, has a mass about 10 times that of Earth"
- lotharbot 11y ago
  10x the mass of earth is about 60% of the mass of Neptune or 80% of the mass of Uranus. So it's smaller than all of the gas giants in the system, but considerably larger than the rocky planets. http://nssdc.gsfc.nasa.gov/planetary/factsheet/ http://nssdc.gsfc.nasa.gov/planetary/factsheet/
gregwtmtno 11y ago
Skepticism is warranted, but keep in mind that Mike "pluto killer" Brown, one of the authors, has an impressive track record. He discovered Eris and Sedna.
mturmon 11y ago
Provocative title for this Caltech press release. Mike Brown, the co-author of the paper reported here, discovered Eris, a KBO like Pluto, in 2005. This discovery prompted the IAU in 2006 to demote Pluto out of the realm of "planet" into a "dwarf planet". At the time, Alan Stern's New Horizons mission to Pluto had just been launched, it finally arrived last year. Stern was incensed that NH started out as a visitor to the 9th planet and was going to end up as a visitor to one of many KBOs, and not even the largest one (Eris is more massive). The quotes given at the time (http://www.space.com/2791-pluto-demoted-longer-planet-highly-controversial-definition.html http://www.space.com/2791-pluto-demoted-longer-planet-highly...) are revealing: "Pluto is dead." -- Mike Brown "This definition stinks, for technical reasons...It's a farce." -- Alan Stern For more: http://www.space.com/12709-pluto-dwarf-planet-decision-5-years-anniversary-iau.html http://www.space.com/12709-pluto-dwarf-planet-decision-5-yea... Stern is visiting Pasadena on a New Horizons victory lap next week. Should be interesting.
- lhorie 11y ago
  Small nitpick: "largest" refers to mean radius, "massive" refers to mass (aka weight). Pluto is the second most massive, but it is the largest. (To be fair, it is a very close call: its diameter is only ~25km larger than Eris) I'm excited to see this story unfold, if nothing else because it's fun looking up the mythological[1][2][3] origins of the names given to new celestial bodies :) [1](https://en.wikipedia.org/wiki/Makemake https://en.wikipedia.org/wiki/Makemake) [2](https://en.wikipedia.org/wiki/90377_Sedna https://en.wikipedia.org/wiki/90377_Sedna) [3](https://en.wikipedia.org/wiki/Haumea https://en.wikipedia.org/wiki/Haumea)
  - overcast 11y ago
    Mass isn't weight, it's the amount of matter. Weight is the measure of the pull of gravity on mass.
    - lhorie 11y ago
      Sorry, you're right. I should've qualified that I meant the colloquial usage of the word "weight".
nkoren 11y ago
If it holds up, this is fantastic. Given how interesting the Pluto system has turned out to be, I can only fantasise about a potential super-earth system relatively nearby. However, to be completely pedantic: would this actually be a planet? Or still a dwarf planet, despite its massive size? Keep in mind that the definition of planethood is not only that it's large enough to be rounded by its own gravity, but that it has also "cleared its orbit". I get the impression that this would cut through broad swathes of the still-cluttered Kuiper belt, and thus would only qualify as a "dwarf" despite its massive size. I checked the original papers for references to whether it had cleared its orbit, and couldn't find any. Correct me if I'm wrong?
- Symmetry 11y ago
  The criteria for clearing an orbit are apparently somewhat involved[1]. It can't just be a matter of no other bodies having the same distance from the sun or Pluto would disqualify Neptune and Jupiter would be disqualified by its trojans. Because the planets in these cases mass so much more than other other nearby bodies those other bodies dance to the planet's tune and aren't counted against the planet in terms of clearing it's neighborhood. But if you look at the large bodies in the asteroid belt or the TNOs then their influence is very much mutual. It's not entirely obvious if the new body would be a planet under the listed criteria since I don't think we have a good handle on the total trans-Neptunian population. In fact by Soter's µ criteria we might just need a single Pluto-sized object to cross this planet's path to disqualify it. [1]https://en.wikipedia.org/wiki/Clearing_the_neighbourhood https://en.wikipedia.org/wiki/Clearing_the_neighbourhood
  - Symmetry 11y ago
    I was misremembering Pluto's mass as being 1/10 of Earth's when it's really 1/500th. It would take a large number of TNOs to push this hypothetical object from being a planet to being a dwarf planet.
- clord 11y ago
  From what I understand, it has cleared the space but there are still harmonic crossings that can't be cleared. Interesting challenge to the new definition - must the orbit be clear, or only clear sailing through the orbit.
FreedomToCreate 11y ago
If Planet Nine exists I wonder how the astrologers will tweak there models.
- nkrisc 11y ago
  This is the most important question here.
logingone 11y ago
I don't seem to have a grasp of our visibility of our solar system. We can see a number of the planets with the naked eye, a number of the moons with binoculars and a few hundred $/£/€/.. telescope. Yet even with these great big radio telescopes, antenna arrays, Hubble, etc, we seem to be quite unaware of what's in our neighbourhood. Anyone have figures of how much we've surveyed?
- tomr_stargazer 11y ago
  When it comes to small (-er than, say, Jupiter) bodies in the distant outer Solar system, here's one relevant piece of information: Because these bodies' light is purely reflected solar light, whose brightness drops as the sun-object distance squared (d^2), their brightness as seen from Earth drops as the sun-object distance to the fourth power (d^4), making them incredibly faint.
- bzbarsky 11y ago
  It's all about distances. The planets we can see with the naked eye are at most 11AU from us (Saturn is at 10AU at aphelion). For comparison, Neptune is never closer than about 29AU to us. Brightness goes down as the square of the distance. But it gets worse, because that's brightness at given source brightness. Planets don't radiate intrinsically; they reflect sunlight. And sunlight brightness drops off as the square of distance from the sun. Which is to say that even if they were the same size and albedo (they're not), Neptune would appear about 81 times dimmer than Saturn to us. Oh, also (linear) angular size goes down linearly with distance. So if you want to see the two planets as disks of the same size, you need to have a field of view three times narrower, which means you need 9 times as many of them to cover the sky. And if you want the same amount of light gathered, you have to spend 81 times longer gathering it, per the above brightness calculation. All of which is to say that the time needed to do an "equivalent" sky survey N times further away (within the solar system, where all the illumination is coming from the sun) scales as N^6. And planets do move, so you might still miss one if you survey a place where it's not yet, then take a while to get to where it used to be, such that it has moved. This is why Neptune was found via its gravitational interactions followed by a survey of a small part of the sky, not brute-force observation. Anyway, back to the topic at hand, the proposed Planet Nine orbits 20 times farther out than Neptune. 20^6 is 64 million. So if we assume we've pretty much surveyed everything out to the radius of Neptune's orbit at some resolution, and then spent about 64000 times as much time surveying stuff out to the distance Planet Nine is proposed to be at, at the same resolution (I doubt we have), then we've probably surveyed about 0.1% of the stuff out there. I can't tell you what the actual number is, unfortunately, but I suspect the answer is we haven't really done very good systematic surveys out at that distance.
ChuckMcM 11y ago
Ah Planet X which is now planet IX with Pluto's demotion :-). I am guessing that you can confirm it by looking for star occulusions. Presumably the planet would blank out stars as it passed between earth and those stars. So would it be possible to find it using existing plates?
- dzdt 11y ago
  It is pretty well impossible to discover a planet by occultations. For one thing, in most parts of the sky the density of stars is pretty low. People do study occultations by known distant objects -- that provides some of the best available info on physical size and presence of atmosphere for KBO's. But in most parts of the sky, it is years in between occultations, which last just minutes. You have to be looking in the right place at the right time. And the sky is full of variable stars, so just looking for changes is hard.
danieldrehmer 11y ago
I'm puzzled by how a planet this big could form in an orbit so distant. The fact that the material in that region is so spread out and the orbital period of such object is so long matters. I would love to read some thoughts on that.
- pavel_lishin 11y ago
  It could have formed closer to the sun in the early stages of our solar system, and been flung out into a more irregular orbit after that.
- losteric 11y ago
  As mentioned in the article, this planet could have formed closer to the sun before getting thrown out by Jupiter/Saturn.
sandworm101 11y ago
Giant, weird orbit, debate ... there can be only one name. This is Planet X. Also because X would be 10th discovered planet, a reference that pluto, while not a planet today, was indeed the ninth _discovered_ planet.
- slg 11y ago
  If you are going by that logic, Pluto was at least the 10th planet discovered and this is at least the 11th. Ceres was discovered before either Neptune or Pluto and spent 50 years as a "planet". It eventually went through a similar reclassification process as Pluto as other similar objects were discovered. The only reason you don't see the same controversy around its classification is because it was recategorized a century before any of us were born.
  - sandworm101 11y ago
    If naming was all about logic then 1/2 the places on earth would need to be renamed. Naming is about emotion, style, history, and personal preference. Even total mistakes (the Giant Squid) are grandfathered through. Galileo named the moons of Jupiter after his sponsors. I just hope this thing doesn't become "X, brought to you by iPhone8".
    - asavadatti 11y ago
      I think you are confusing naming and classification.
      - sandworm101 11y ago
        Something can be called "Planet X" without being classified as a planet. Take "Planet Hollywood". Incorporating planet into the name should at least protect against future reclassification.
- gus_massa 11y ago
  From https://en.wikipedia.org/wiki/Ceres_(dwarf_planet) https://en.wikipedia.org/wiki/Ceres_(dwarf_planet) > Ceres was the first asteroid discovered, by Giuseppe Piazzi at Palermo on 1 January 1801. It was originally considered a planet, but was reclassified as an asteroid in the 1850s when many other objects in similar orbits were discovered. > [...] > Ceres was assigned a planetary symbol, and remained listed as a planet in astronomy books and tables (along with 2 Pallas, 3 Juno, and 4 Vesta) for half a century.
dluan 11y ago
More from the folks behind the paper: http://www.findplanetnine.com/ http://www.findplanetnine.com/
- Faint 11y ago
  Have to recommend this, especially Konstantin Batygins piece has great narrative.
tdaltonc 11y ago
> Batygin and Brown inferred its presence from the peculiar clustering of six previously known objects that orbit beyond Neptune. This raised a big red flag in my mind. This must produce a literally astronomical multiple comparisons problem. Yes they reported sigma = 3.8, but if they didn't do their multiple comparisons correction right (which I am in no position to determine), they're basically reading tea leaves. If you're not familiar with multiple comparisons, it's kind of like [this](https://www.goodreads.com/quotes/649893-you-know-the-most-amazing-thing-happened-to-me-tonight https://www.goodreads.com/quotes/649893-you-know-the-most-am...) or [this](https://xkcd.com/882/ https://xkcd.com/882/). If you look at enough extra-neptunian bodies, some of them are going to be in an odd looking cluster.
- jessriedel 11y ago
  I think you're right that that's one of the chief concerns, but I think you paint it incorrectly as a technical problem. ("Multiple comparisons" as you call it. Particle physicists call it the "look-elsewhere effect": https://en.wikipedia.org/wiki/Look-elsewhere_effect https://en.wikipedia.org/wiki/Look-elsewhere_effect ) The easy, though tedious, part of the look-elsewhere effect is to calculate a probabilisitic correction for all the various combinatorics of X objects in Y orbits over a time period of length Z that one might have seen. The hard, and borderline philosophical, part is to identify the proper reference class, i.e., what qualitatively different sorts of observations might have also considered evidence for planet nine, and how many other astrophysical searches are we running that might have given us weird results? This is really where frequentist approaches strain to be useful, and it's hard to avoid resorting to a Bayesian prior. Analogously for particle physics, it's easy to compute the chance of getting a 4-sigma deviation for two different experiments in any gamma-gamma energy bins, so the after-the-fact corrections to the significant of a fluctuation in a particular bin are easy to compute. Much more difficult is to consider all the hundreds of parallel searches going on, of greatly varying levels of motivation, and correcting based on that.
  - jerf 11y ago
    I'd also observe that in terms of prior probability, "There is a ninth planet in the solar system that we have not yet detected" is probably hovering at least in the low-integer percentages, and I imagine some scientists would place it higher than that. The general idea is not a wild, far-out one by any stretch of the imagination.
theptip 11y ago
Did anyone else notice that the rendering of the orbits in the article looks strikingly similar to Kerbal Space Program's orbit UI?
- onetwotree 11y ago
  I did :-) Maybe they use Kerbal to render the results of "real" simulation software?
  - rspeer 11y ago
    Not that improbable. I recall that the discoverers of exoplanet Wolf 1061c, when journalists asked for a picture of the planet, gave them a screenshot from a simulation called Universe Sandbox 2.
- SolarNet 11y ago
  Or is it perhaps the other way around. Did Kerbel use the same UI as a popular rendering program used by astronomers.
  - ceejayoz 11y ago
    Or, third option, "there's only a few decent ways to represent orbits on a graphic".
    - theptip 11y ago
      The colour schemes are very similar though. There are many colour schemes one could choose.
  - speeder 11y ago
    I know that the main author of KSP was a big fan of Orbiter before making KSP, and I think he was aware of other astronomy software.
  - noselasd 11y ago
    I always reconed Kerbal was inspired by http://www.agi.com/products/stk/ http://www.agi.com/products/stk/ , heavily used in the space industry
bpg_92 11y ago
For a moment there, I thought of Nibiru :D
givan 11y ago
https://en.wikipedia.org/wiki/Zecharia_Sitchin https://en.wikipedia.org/wiki/Zecharia_Sitchin He believed this hypothetical planet of Nibiru to be in an elongated, elliptical orbit in the Earth's own Solar System, asserting that Sumerian mythology reflects this.
- ceejayoz 11y ago
  A broken clock is right twice a day.
onetwotree 11y ago
This is pretty solid science, even if, as others have pointed out, there's a bit of academic drama-rama and green jellybean stuff going on. In particular, their model made a prediction that they didn't set out looking for, which corresponded to existing observations. And of course, the whole hypothesis is easily testable. While they don't know where the hypothetical planet might be on it's orbit, it sounds like there's a good shot that small telescopes should be able to spot it. Exciting stuff.
rbanffy 11y ago
The scales involved are astonishing. If the orbit is correct, less than one year has passed on it since the invention of writing here on Earth.
- blue1 11y ago
  What do you mean? 700 AU it's about 4 light days.
  - rbanffy 11y ago
    "Planet 9" takes about 11 thousand years to go around one orbit.
hackuser 11y ago
The NY Times covers the story well: http://www.nytimes.com/2016/01/21/science/space/ninth-planet-solar-system-beyond-pluto.html http://www.nytimes.com/2016/01/21/science/space/ninth-planet... EDIT: After reading the comments in this discussion, many of which are addressed in the NYT article, I'd say the NYT article is almost certainly worth reading.
- SadismoNoise 11y ago
  https://www.youtube.com/watch?v=TkBMAHUkibY https://www.youtube.com/watch?v=TkBMAHUkibY
  - elbigbad 11y ago
    I really like the people and format of HN. Unfortunately these kinds of posts (random gifs, memes, video links) really detract from it. Luckily they only come up sporadically and when they do they're quickly gone.
  - davesque 11y ago
    It was just a joke, people. Lighten up.
- purpled_haze 11y ago
  I just wished they hadn't indicated this new planet is the "ninth planet". Dwarf planets are no less planets than little people are people.
  - roborodent 11y ago
    The video I saw from Caltech suggested a mass of 1-10 times Earth's.
    - purpled_haze 11y ago
      You misunderstood. I was saying that this new planet is not the 9th planet if you include dwarf planets as "planets".
luckystarr 11y ago
If this turns out true, that planet needs to be called "Tartarus". :D
- david-given 11y ago
  Yuggoth, surely?
JamesUtah07 11y ago
At first I thought this was another one of those planet x articles that talks about some hypothetical planet way out but then I saw that Mike Brown was involved and immediately got really excited. I hope they find something out there and we can send a probe to it in my lifetime.
mast 11y ago
Very cool. It reminds me about a book I read called "In Search of Planet Vulcan" (http://www.amazon.com/In-Search-Planet-Vulcan-Clockwork/dp/0738208892 http://www.amazon.com/In-Search-Planet-Vulcan-Clockwork/dp/0...). Before Einstein, astronomers tried to explain the motion of Mercury by suggesting there might be another planet inside Mercury's orbit.
ilyagr 11y ago
There is an awesome summary by Emili Lakdawala at the Planetary Society (as is often the case with such news). http://www.planetary.org/blogs/emily-lakdawalla/2016/01200955-theoretical-evidence-for-planet-9.html http://www.planetary.org/blogs/emily-lakdawalla/2016/0120095...
mud_dauber 11y ago
LV-426. Just sayin'.
photonwins 11y ago
Does it mean Voyager hasn't really escaped Sun's influence yet?
- skykooler 11y ago
  Voyager won't escape the Sun's influence for hundreds of years. The "boundary of the solar system" is not the same as the Sun's influence (and, indeed, is somewhat poorly defined, given how many times Voyager has crossed it.)
pavpanchekha 11y ago
They should call it Pluto.
based2 11y ago
https://news.ycombinator.com/item?id=9872387 https://news.ycombinator.com/item?id=9872387
johngossman 11y ago
This is very cool. Along with a visible supernova and a super bright comet, this is one of those things I dreamed about as an astronomy nerd kid. Though part of me wants to say "Pictures or it didn't happen!"
c3534l 11y ago
I've been seeing news stories about Planet X for far too long to take any of this seriously, no matter how seemingly trustworthy the news source is.
runewell 11y ago
The biggest casualty of Science this decade has been elementary school dioramas.
- wnoise 11y ago
  *dioramas
atorralb 11y ago
they can photograph distant galaxies, but they can't be sure how many planets there actually are on our solar system. weird.
ck2 11y ago
If true, voyager hasn't left the solar system yet.
xenophonf 11y ago
No one's mentioned Tyche yet? https://en.wikipedia.org/wiki/Tyche_%28hypothetical_planet%29 https://en.wikipedia.org/wiki/Tyche_%28hypothetical_planet%2... In searching for Tyche, the WISE missions ruled out the possibility of anything larger than Saturn (95x the mass of Earth) out to about 10000 AU and anything larger than Jupiter (317x the mass of Earth) out to about 26000 AU. WISE was able to detect objects the size of Neptune (17x the mass of Earth) out to about 700 AU, so it should be possible to find the object proposed by the Caltech astronomers here (10x the mass of Earth at around 600 AU). I don't know if WISE's current condition would allow it to perform such a search, as it's completely out of coolant.
- avz 11y ago
  For comparison: * the aphelion of Sedna, the most distant dwarf planet of our Solar system is at 937 AU from the Sun [1], * distance between Proxima Centauri and the binary Alpha Centauri is 15,000 ± 700 AU [2], * one light year is 63,241.1 AU, * distance to the nearest star (Proxima Centauri [2]) is 4.2421 ly = 268,274.973 AU, [1] https://en.wikipedia.org/wiki/90377_Sedna https://en.wikipedia.org/wiki/90377_Sedna [2] https://en.wikipedia.org/wiki/Proxima_Centauri https://en.wikipedia.org/wiki/Proxima_Centauri EDIT: formatting and added Proxima-Alpha Centauri distance.
- mutagen 11y ago
  Their site at http://www.findplanetnine.com/p/blog-page.html http://www.findplanetnine.com/p/blog-page.html addresses the areas the Tyche survey and other surveys cover. My TLDR: * The WISE survey might only find Planet X at it's nearest approach. Kevin Luhman has redone the survey using the most sensitive WISE bands that only cover a narrow area of the sky and hasn't found Planet X. * They reviewed the Catalina Sky Survey and eliminated most of the areas they'd expect Planet X. * The Pan STARRS site survey didn't find Planet X. Conclusion: Planet X is at aphelion, difficult to find with the Milky Way as a (stunning) backdrop. I just found their paper: http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22 http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22 I wonder how their conclusions match with David Nesvorny's paper predicting a 5th planet having been ejected from the Solar System: http://arxiv.org/pdf/1109.2949v1.pdf http://arxiv.org/pdf/1109.2949v1.pdf
mgav 11y ago
Maybe it's a Death Star?
axxl 11y ago
At WWDC last year one of the lunchtime presentations was by Michael Brown, one of the researchers involved here. He was one of the people who proved that Pluto should not be considered a planet and went over the history of the discovery/classification of planet bodies. He also mentioned that they had some evidence of a planet body beyond Pluto due to its gravitational affect of some of the smaller bodies out there even then. Interesting to see this is finally coming to something! He has the appropriate/amusing twitter handle of http://twitter.com/plutokiller http://twitter.com/plutokiller
richmarr 11y ago
Reading the article I didn't see a mention of a previously hypothesised fifth gas giant... so here's a link in case anyone's interested or knows something more. https://en.wikipedia.org/wiki/Hypothetical_fifth_giant_planet https://en.wikipedia.org/wiki/Hypothetical_fifth_giant_plane...
neur0tek 11y ago
Niburu!
empressplay 11y ago
I just want to know if Planet X is covered by human-enslaving robots.
peter303 11y ago
This how Qigong found the Clone Planet in Star Wars 2. Although the planet had be erased from the galactic database, it left a gravitational signature on nearby systems.
osoti 11y ago
The stars who sizzled the Golden Globes 2015 http://goo.gl/Iz6899 http://goo.gl/Iz6899
dmichulke 11y ago
May it receive a name starting with P so that My Very Educated Mother Just Showed Us Nine Planets works again
jharohit 11y ago
Now only if they name the ninth planet starting with a 'P', my childhood mnemonic "My Very Educated Mother Just Served Us Nine Pizzas" would finally be complete again! :D My suggestion is 'Prometheus' - sounds tragic and bad ass at the same time!
- dr_zoidberg 11y ago
  Well that would be consistent with the roman/greek names for planets and large moons. Now we have to find a stronger tie between the theory and the myth. In some article regarding this news I've read that Planet 9 might have ended in its orbit due to encounters with Jupiter/Saturn. Not exactly an eagle eating its liver, but it can be paralled to "the punishment from Zeus(Jupiter)".
  - jharohit 11y ago
    :) well nicely connected with the punishment story! I would further go and say that we can draw parallels with the Kuiper Belt objects to the eagles "tormenting" Prometheus while he is chained to a "cold, lonely mountain rock" like our new mysterious planet stuck in a dark lonely corner of the solar system!
    - dr_zoidberg 11y ago
      Alright, time to write to IAU with a name proposal!
carlosgg 11y ago
Thanks for the link. There's a course taught on Coursera by one of the CalTech researchers, Mike Brown, if anyone is interested. It's archived but they have kept it open. https://www.coursera.org/course/solarsystem https://www.coursera.org/course/solarsystem

883 points by cyanbane 11y ago

beamatronic 11y ago

Why wouldn't their calculations be able to suggest possible locations for the planet?

antognini 11y ago
They do, and at the end of the press release it says that Brown has begun an observing campaign to find the planet. Unfortunately detecting these very distant objects is very difficult. The light we see from them is reflected light from the Sun, so their apparent brightness goes as 1/r^4, not 1/r^2 like most objects. And because they are so close, there is a strong parallax from the motion of the Earth. THe consequence from this is that the object will actually drift across the image as you are taking it, smearing it out. In order to detect it you either have to take very short images so that it doesn't move too much (in which case you don't get very much light), or have some idea as to the direction of the smear so that you can correct for it. Either way it's a very hard observation to make! Fortunately if this planet is as big as they claim it to be it should be relatively easy to detect compared to Sedna and the other Kuiper Belt objects.
- hmahncke 11y ago
  Also, we don't know where in its orbit the planet happens to be right now. If we're lucky, it's relatively close to the sun, and it will be detectable. If we're unlucky, it's relatively far away from the sun, and it could easily be undetectable by current observatories because the orbit is so eccentric. [Source: I saw Mike Brown give a talk on this topic at the Cal Academy of Sciences, where he hoped he was lucky...]
  - abecedarius 11y ago
    Note that an eccentric orbit spends most of its time out in the far reaches, since it moves much slower out there. The odds are against the happy case.
- daveguy 11y ago
  I would expect a smear with characteristics of the planet would be as effective to identify it as a single snapshot. Wouldn't the direction be well identified from indirect detection? Is the blur also less effective because of increased background exposure?
  - jschwartzi 11y ago
    Well, if the smear takes the light level below the noise floor of the sensor then you can't even say that there's a smear.
    - mkrfox 11y ago
      That's why you don't see any cars in long exposures of highways.
- qb45 11y ago
  Are you sure it's r^4, not 4r^2?
  - antognini 11y ago
    Yes. The solid angle subtended by the planet (and hence the amount of reflected light) goes as 1/r^2, and then the apparent brightness of the reflected light to us goes as an additional 1/r^2. The total dependence is then 1/r^2 * 1/r^2 = 1/r^4.
    - gohrt 11y ago
      This is a really good physics puzzler. The key point is that Pluto does not reflect light like a mirror, it scatters light relatively uniformly, causing more light loss to an observer than, say, a mirror that points the reflection directly at an Earth observer.
  - jcrites 11y ago
    The light reaching the object from the sun drops off by 1/r^2, and then the light reaching Earth from the object drops again by 1/r^2. Since the latter light is a portion of the former, you multiply them for 1/r^4.
  - bzbarsky 11y ago
    Yes, it's definitely r^4. If we assume that the planet is far from the sun compared to the earth, such that the earth-planet distance and the sun-planet distance are both approximately r, then the amount of light the planet gets from the sun is proportional to 1/r^2. Then the planet reflects that light in all directions, and the fraction of it that comes back to us on earth is also proportional to 1/r^2. 1/r^2 * 1/r^2 = 1/r^4.
- gene-h 11y ago
  Perhaps one of the "stubby hubble" telescopes the NRO donated to NASA would be useful for this task[0]. They are essentially the hubble telescope with a much shorter focal length(hence the nickname), so one of the uses suggested for them is observing faint objects in the solar system like asteroids. [0]https://en.wikipedia.org/wiki/2012_National_Reconnaissance_Office_space_telescope_donation_to_NASA https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O...
- martinpw 11y ago
  In a previous life, back in the pre-CCD days I worked at an observatory searching for new asteroids. Used to be the way it was done you would point a telescope at the part of the sky directly opposite the sun (min r^4 so best chance of detection), expose a photographic plate, and repeat a few hours later. Develop the plates, mount them in a blink comparator [1] and scan manually, flipping back and forth between the plates for ~3 hours to look for anything that moved. Exclude false positives like plate blemishes (aka Eastman-Kodak Objects) or dust grains. If you see something, and it is smeared indicating motion during the exposure, mark it as a possible candidate. Revisit the same patch of sky the next night, search again. Use the datapoints to extrapolate forward, check again a couple of weeks later. If you haven't lost it (which frequently happened if it was at the limit of visibility), extrapolate back to the previous opposition (~4 years for a main belt asteroid) and search the archives for a match. If you get one, then extrapolate further back and check all previous oppositions. If you get a match on three separate oppositions, congratulations, you have a discovery. Vastly different now - a single observation can net large numbers of asteroids and sensitivity is so much better. Still the search for this potential new planet is definitely going to be daunting given the distance. [1] https://en.wikipedia.org/wiki/Blink_comparator https://en.wikipedia.org/wiki/Blink_comparator
- angst_ridden 11y ago
  That's why you use Goldstone and Arecibo, and bounce your signal!
umeshunni 11y ago
They have a possible location - about 20 times farther from the sun than Pluto.
SolarNet 11y ago
Because they have only been able to find the orbit. Not the current location in the orbit.
InclinedPlane 11y ago
They do, but there are two problems. One is that that still leaves a pretty big range for possibilities for where the planet could be. The other is that we don't know where along the orbit the planet is now. Even if we knew the exact orbit of the planet simply not knowing where it was along that orbit means we'd have to scan a lot of the sky to spot it. Having a bit more ambiguity about the orbital parameters means we will have to scan much, much more of the sky to spot it.

japaget 11y ago

Link to paper by Batygin and Brown: http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22/pdf http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22...

dexwiz 11y ago

We have been looking for a "missing" objects for a while. The nemesis star theory says the sun has a brown dwarf companion. This object would interact with the Oort Cloud instead of the Kuiper belt. But this theory has been pretty much refuted. This theory definitely looks more promising. Finding eccentric Kuiper belt objects, and aligning them with a missing object seems to be a good bet. Giving the object an orbit should make the search easier, and we will probably have a conclusion one way or another within a few years. https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star) https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star)

pavel_lishin 11y ago

> * the putative ninth planet—at 5,000 times the mass of Pluto—is sufficiently large that there should be no debate about whether it is a true planet* That's 10x the mass of the Earth, right, or about 3x the size of Neptune?

vidarh 11y ago
> That's 10x the mass of the Earth It even says so in the first paragraph of the article.
zeroonetwothree 11y ago
This is the second sentence of the article: "The object, which the researchers have nicknamed Planet Nine, has a mass about 10 times that of Earth"
lotharbot 11y ago
10x the mass of earth is about 60% of the mass of Neptune or 80% of the mass of Uranus. So it's smaller than all of the gas giants in the system, but considerably larger than the rocky planets. http://nssdc.gsfc.nasa.gov/planetary/factsheet/ http://nssdc.gsfc.nasa.gov/planetary/factsheet/

gregwtmtno 11y ago

Skepticism is warranted, but keep in mind that Mike "pluto killer" Brown, one of the authors, has an impressive track record. He discovered Eris and Sedna.

mturmon 11y ago

Provocative title for this Caltech press release. Mike Brown, the co-author of the paper reported here, discovered Eris, a KBO like Pluto, in 2005. This discovery prompted the IAU in 2006 to demote Pluto out of the realm of "planet" into a "dwarf planet". At the time, Alan Stern's New Horizons mission to Pluto had just been launched, it finally arrived last year. Stern was incensed that NH started out as a visitor to the 9th planet and was going to end up as a visitor to one of many KBOs, and not even the largest one (Eris is more massive). The quotes given at the time (http://www.space.com/2791-pluto-demoted-longer-planet-highly-controversial-definition.html http://www.space.com/2791-pluto-demoted-longer-planet-highly...) are revealing: "Pluto is dead." -- Mike Brown "This definition stinks, for technical reasons...It's a farce." -- Alan Stern For more: http://www.space.com/12709-pluto-dwarf-planet-decision-5-years-anniversary-iau.html http://www.space.com/12709-pluto-dwarf-planet-decision-5-yea... Stern is visiting Pasadena on a New Horizons victory lap next week. Should be interesting.

lhorie 11y ago
Small nitpick: "largest" refers to mean radius, "massive" refers to mass (aka weight). Pluto is the second most massive, but it is the largest. (To be fair, it is a very close call: its diameter is only ~25km larger than Eris) I'm excited to see this story unfold, if nothing else because it's fun looking up the mythological[1][2][3] origins of the names given to new celestial bodies :) [1](https://en.wikipedia.org/wiki/Makemake https://en.wikipedia.org/wiki/Makemake) [2](https://en.wikipedia.org/wiki/90377_Sedna https://en.wikipedia.org/wiki/90377_Sedna) [3](https://en.wikipedia.org/wiki/Haumea https://en.wikipedia.org/wiki/Haumea)
- overcast 11y ago
  Mass isn't weight, it's the amount of matter. Weight is the measure of the pull of gravity on mass.
  - lhorie 11y ago
    Sorry, you're right. I should've qualified that I meant the colloquial usage of the word "weight".

nkoren 11y ago

If it holds up, this is fantastic. Given how interesting the Pluto system has turned out to be, I can only fantasise about a potential super-earth system relatively nearby. However, to be completely pedantic: would this actually be a planet? Or still a dwarf planet, despite its massive size? Keep in mind that the definition of planethood is not only that it's large enough to be rounded by its own gravity, but that it has also "cleared its orbit". I get the impression that this would cut through broad swathes of the still-cluttered Kuiper belt, and thus would only qualify as a "dwarf" despite its massive size. I checked the original papers for references to whether it had cleared its orbit, and couldn't find any. Correct me if I'm wrong?

Symmetry 11y ago
The criteria for clearing an orbit are apparently somewhat involved[1]. It can't just be a matter of no other bodies having the same distance from the sun or Pluto would disqualify Neptune and Jupiter would be disqualified by its trojans. Because the planets in these cases mass so much more than other other nearby bodies those other bodies dance to the planet's tune and aren't counted against the planet in terms of clearing it's neighborhood. But if you look at the large bodies in the asteroid belt or the TNOs then their influence is very much mutual. It's not entirely obvious if the new body would be a planet under the listed criteria since I don't think we have a good handle on the total trans-Neptunian population. In fact by Soter's µ criteria we might just need a single Pluto-sized object to cross this planet's path to disqualify it. [1]https://en.wikipedia.org/wiki/Clearing_the_neighbourhood https://en.wikipedia.org/wiki/Clearing_the_neighbourhood
- Symmetry 11y ago
  I was misremembering Pluto's mass as being 1/10 of Earth's when it's really 1/500th. It would take a large number of TNOs to push this hypothetical object from being a planet to being a dwarf planet.
clord 11y ago
From what I understand, it has cleared the space but there are still harmonic crossings that can't be cleared. Interesting challenge to the new definition - must the orbit be clear, or only clear sailing through the orbit.

FreedomToCreate 11y ago

If Planet Nine exists I wonder how the astrologers will tweak there models.

nkrisc 11y ago
This is the most important question here.

logingone 11y ago

I don't seem to have a grasp of our visibility of our solar system. We can see a number of the planets with the naked eye, a number of the moons with binoculars and a few hundred $/£/€/.. telescope. Yet even with these great big radio telescopes, antenna arrays, Hubble, etc, we seem to be quite unaware of what's in our neighbourhood. Anyone have figures of how much we've surveyed?

tomr_stargazer 11y ago
When it comes to small (-er than, say, Jupiter) bodies in the distant outer Solar system, here's one relevant piece of information: Because these bodies' light is purely reflected solar light, whose brightness drops as the sun-object distance squared (d^2), their brightness as seen from Earth drops as the sun-object distance to the fourth power (d^4), making them incredibly faint.
bzbarsky 11y ago
It's all about distances. The planets we can see with the naked eye are at most 11AU from us (Saturn is at 10AU at aphelion). For comparison, Neptune is never closer than about 29AU to us. Brightness goes down as the square of the distance. But it gets worse, because that's brightness at given source brightness. Planets don't radiate intrinsically; they reflect sunlight. And sunlight brightness drops off as the square of distance from the sun. Which is to say that even if they were the same size and albedo (they're not), Neptune would appear about 81 times dimmer than Saturn to us. Oh, also (linear) angular size goes down linearly with distance. So if you want to see the two planets as disks of the same size, you need to have a field of view three times narrower, which means you need 9 times as many of them to cover the sky. And if you want the same amount of light gathered, you have to spend 81 times longer gathering it, per the above brightness calculation. All of which is to say that the time needed to do an "equivalent" sky survey N times further away (within the solar system, where all the illumination is coming from the sun) scales as N^6. And planets do move, so you might still miss one if you survey a place where it's not yet, then take a while to get to where it used to be, such that it has moved. This is why Neptune was found via its gravitational interactions followed by a survey of a small part of the sky, not brute-force observation. Anyway, back to the topic at hand, the proposed Planet Nine orbits 20 times farther out than Neptune. 20^6 is 64 million. So if we assume we've pretty much surveyed everything out to the radius of Neptune's orbit at some resolution, and then spent about 64000 times as much time surveying stuff out to the distance Planet Nine is proposed to be at, at the same resolution (I doubt we have), then we've probably surveyed about 0.1% of the stuff out there. I can't tell you what the actual number is, unfortunately, but I suspect the answer is we haven't really done very good systematic surveys out at that distance.

ChuckMcM 11y ago

Ah Planet X which is now planet IX with Pluto's demotion :-). I am guessing that you can confirm it by looking for star occulusions. Presumably the planet would blank out stars as it passed between earth and those stars. So would it be possible to find it using existing plates?

dzdt 11y ago
It is pretty well impossible to discover a planet by occultations. For one thing, in most parts of the sky the density of stars is pretty low. People do study occultations by known distant objects -- that provides some of the best available info on physical size and presence of atmosphere for KBO's. But in most parts of the sky, it is years in between occultations, which last just minutes. You have to be looking in the right place at the right time. And the sky is full of variable stars, so just looking for changes is hard.

danieldrehmer 11y ago

I'm puzzled by how a planet this big could form in an orbit so distant. The fact that the material in that region is so spread out and the orbital period of such object is so long matters. I would love to read some thoughts on that.

pavel_lishin 11y ago
It could have formed closer to the sun in the early stages of our solar system, and been flung out into a more irregular orbit after that.
losteric 11y ago
As mentioned in the article, this planet could have formed closer to the sun before getting thrown out by Jupiter/Saturn.

sandworm101 11y ago

Giant, weird orbit, debate ... there can be only one name. This is Planet X. Also because X would be 10th discovered planet, a reference that pluto, while not a planet today, was indeed the ninth _discovered_ planet.

slg 11y ago
If you are going by that logic, Pluto was at least the 10th planet discovered and this is at least the 11th. Ceres was discovered before either Neptune or Pluto and spent 50 years as a "planet". It eventually went through a similar reclassification process as Pluto as other similar objects were discovered. The only reason you don't see the same controversy around its classification is because it was recategorized a century before any of us were born.
- sandworm101 11y ago
  If naming was all about logic then 1/2 the places on earth would need to be renamed. Naming is about emotion, style, history, and personal preference. Even total mistakes (the Giant Squid) are grandfathered through. Galileo named the moons of Jupiter after his sponsors. I just hope this thing doesn't become "X, brought to you by iPhone8".
  - asavadatti 11y ago
    I think you are confusing naming and classification.
    - sandworm101 11y ago
      Something can be called "Planet X" without being classified as a planet. Take "Planet Hollywood". Incorporating planet into the name should at least protect against future reclassification.
gus_massa 11y ago
From https://en.wikipedia.org/wiki/Ceres_(dwarf_planet) https://en.wikipedia.org/wiki/Ceres_(dwarf_planet) > Ceres was the first asteroid discovered, by Giuseppe Piazzi at Palermo on 1 January 1801. It was originally considered a planet, but was reclassified as an asteroid in the 1850s when many other objects in similar orbits were discovered. > [...] > Ceres was assigned a planetary symbol, and remained listed as a planet in astronomy books and tables (along with 2 Pallas, 3 Juno, and 4 Vesta) for half a century.

dluan 11y ago

More from the folks behind the paper: http://www.findplanetnine.com/ http://www.findplanetnine.com/

Faint 11y ago
Have to recommend this, especially Konstantin Batygins piece has great narrative.

tdaltonc 11y ago

> Batygin and Brown inferred its presence from the peculiar clustering of six previously known objects that orbit beyond Neptune. This raised a big red flag in my mind. This must produce a literally astronomical multiple comparisons problem. Yes they reported sigma = 3.8, but if they didn't do their multiple comparisons correction right (which I am in no position to determine), they're basically reading tea leaves. If you're not familiar with multiple comparisons, it's kind of like [this](https://www.goodreads.com/quotes/649893-you-know-the-most-amazing-thing-happened-to-me-tonight https://www.goodreads.com/quotes/649893-you-know-the-most-am...) or [this](https://xkcd.com/882/ https://xkcd.com/882/). If you look at enough extra-neptunian bodies, some of them are going to be in an odd looking cluster.

jessriedel 11y ago
I think you're right that that's one of the chief concerns, but I think you paint it incorrectly as a technical problem. ("Multiple comparisons" as you call it. Particle physicists call it the "look-elsewhere effect": https://en.wikipedia.org/wiki/Look-elsewhere_effect https://en.wikipedia.org/wiki/Look-elsewhere_effect ) The easy, though tedious, part of the look-elsewhere effect is to calculate a probabilisitic correction for all the various combinatorics of X objects in Y orbits over a time period of length Z that one might have seen. The hard, and borderline philosophical, part is to identify the proper reference class, i.e., what qualitatively different sorts of observations might have also considered evidence for planet nine, and how many other astrophysical searches are we running that might have given us weird results? This is really where frequentist approaches strain to be useful, and it's hard to avoid resorting to a Bayesian prior. Analogously for particle physics, it's easy to compute the chance of getting a 4-sigma deviation for two different experiments in any gamma-gamma energy bins, so the after-the-fact corrections to the significant of a fluctuation in a particular bin are easy to compute. Much more difficult is to consider all the hundreds of parallel searches going on, of greatly varying levels of motivation, and correcting based on that.
- jerf 11y ago
  I'd also observe that in terms of prior probability, "There is a ninth planet in the solar system that we have not yet detected" is probably hovering at least in the low-integer percentages, and I imagine some scientists would place it higher than that. The general idea is not a wild, far-out one by any stretch of the imagination.

theptip 11y ago

Did anyone else notice that the rendering of the orbits in the article looks strikingly similar to Kerbal Space Program's orbit UI?

onetwotree 11y ago
I did :-) Maybe they use Kerbal to render the results of "real" simulation software?
- rspeer 11y ago
  Not that improbable. I recall that the discoverers of exoplanet Wolf 1061c, when journalists asked for a picture of the planet, gave them a screenshot from a simulation called Universe Sandbox 2.
SolarNet 11y ago
Or is it perhaps the other way around. Did Kerbel use the same UI as a popular rendering program used by astronomers.
- ceejayoz 11y ago
  Or, third option, "there's only a few decent ways to represent orbits on a graphic".
  - theptip 11y ago
    The colour schemes are very similar though. There are many colour schemes one could choose.
- speeder 11y ago
  I know that the main author of KSP was a big fan of Orbiter before making KSP, and I think he was aware of other astronomy software.
- noselasd 11y ago
  I always reconed Kerbal was inspired by http://www.agi.com/products/stk/ http://www.agi.com/products/stk/ , heavily used in the space industry

bpg_92 11y ago

For a moment there, I thought of Nibiru :D

givan 11y ago

https://en.wikipedia.org/wiki/Zecharia_Sitchin https://en.wikipedia.org/wiki/Zecharia_Sitchin He believed this hypothetical planet of Nibiru to be in an elongated, elliptical orbit in the Earth's own Solar System, asserting that Sumerian mythology reflects this.

ceejayoz 11y ago
A broken clock is right twice a day.

onetwotree 11y ago

This is pretty solid science, even if, as others have pointed out, there's a bit of academic drama-rama and green jellybean stuff going on. In particular, their model made a prediction that they didn't set out looking for, which corresponded to existing observations. And of course, the whole hypothesis is easily testable. While they don't know where the hypothetical planet might be on it's orbit, it sounds like there's a good shot that small telescopes should be able to spot it. Exciting stuff.

rbanffy 11y ago

The scales involved are astonishing. If the orbit is correct, less than one year has passed on it since the invention of writing here on Earth.

blue1 11y ago
What do you mean? 700 AU it's about 4 light days.
- rbanffy 11y ago
  "Planet 9" takes about 11 thousand years to go around one orbit.

hackuser 11y ago

The NY Times covers the story well: http://www.nytimes.com/2016/01/21/science/space/ninth-planet-solar-system-beyond-pluto.html http://www.nytimes.com/2016/01/21/science/space/ninth-planet... EDIT: After reading the comments in this discussion, many of which are addressed in the NYT article, I'd say the NYT article is almost certainly worth reading.

SadismoNoise 11y ago
https://www.youtube.com/watch?v=TkBMAHUkibY https://www.youtube.com/watch?v=TkBMAHUkibY
- elbigbad 11y ago
  I really like the people and format of HN. Unfortunately these kinds of posts (random gifs, memes, video links) really detract from it. Luckily they only come up sporadically and when they do they're quickly gone.
- davesque 11y ago
  It was just a joke, people. Lighten up.
purpled_haze 11y ago
I just wished they hadn't indicated this new planet is the "ninth planet". Dwarf planets are no less planets than little people are people.
- roborodent 11y ago
  The video I saw from Caltech suggested a mass of 1-10 times Earth's.
  - purpled_haze 11y ago
    You misunderstood. I was saying that this new planet is not the 9th planet if you include dwarf planets as "planets".

luckystarr 11y ago

If this turns out true, that planet needs to be called "Tartarus". :D

david-given 11y ago
Yuggoth, surely?

JamesUtah07 11y ago

At first I thought this was another one of those planet x articles that talks about some hypothetical planet way out but then I saw that Mike Brown was involved and immediately got really excited. I hope they find something out there and we can send a probe to it in my lifetime.

mast 11y ago

Very cool. It reminds me about a book I read called "In Search of Planet Vulcan" (http://www.amazon.com/In-Search-Planet-Vulcan-Clockwork/dp/0738208892 http://www.amazon.com/In-Search-Planet-Vulcan-Clockwork/dp/0...). Before Einstein, astronomers tried to explain the motion of Mercury by suggesting there might be another planet inside Mercury's orbit.

ilyagr 11y ago

There is an awesome summary by Emili Lakdawala at the Planetary Society (as is often the case with such news). http://www.planetary.org/blogs/emily-lakdawalla/2016/01200955-theoretical-evidence-for-planet-9.html http://www.planetary.org/blogs/emily-lakdawalla/2016/0120095...

mud_dauber 11y ago

LV-426. Just sayin'.

photonwins 11y ago

Does it mean Voyager hasn't really escaped Sun's influence yet?

skykooler 11y ago
Voyager won't escape the Sun's influence for hundreds of years. The "boundary of the solar system" is not the same as the Sun's influence (and, indeed, is somewhat poorly defined, given how many times Voyager has crossed it.)

pavpanchekha 11y ago

They should call it Pluto.

based2 11y ago

https://news.ycombinator.com/item?id=9872387 https://news.ycombinator.com/item?id=9872387

johngossman 11y ago

This is very cool. Along with a visible supernova and a super bright comet, this is one of those things I dreamed about as an astronomy nerd kid. Though part of me wants to say "Pictures or it didn't happen!"

c3534l 11y ago

I've been seeing news stories about Planet X for far too long to take any of this seriously, no matter how seemingly trustworthy the news source is.

runewell 11y ago

The biggest casualty of Science this decade has been elementary school dioramas.

wnoise 11y ago
*dioramas

atorralb 11y ago

they can photograph distant galaxies, but they can't be sure how many planets there actually are on our solar system. weird.

ck2 11y ago

If true, voyager hasn't left the solar system yet.

xenophonf 11y ago

No one's mentioned Tyche yet? https://en.wikipedia.org/wiki/Tyche_%28hypothetical_planet%29 https://en.wikipedia.org/wiki/Tyche_%28hypothetical_planet%2... In searching for Tyche, the WISE missions ruled out the possibility of anything larger than Saturn (95x the mass of Earth) out to about 10000 AU and anything larger than Jupiter (317x the mass of Earth) out to about 26000 AU. WISE was able to detect objects the size of Neptune (17x the mass of Earth) out to about 700 AU, so it should be possible to find the object proposed by the Caltech astronomers here (10x the mass of Earth at around 600 AU). I don't know if WISE's current condition would allow it to perform such a search, as it's completely out of coolant.

avz 11y ago
For comparison: * the aphelion of Sedna, the most distant dwarf planet of our Solar system is at 937 AU from the Sun [1], * distance between Proxima Centauri and the binary Alpha Centauri is 15,000 ± 700 AU [2], * one light year is 63,241.1 AU, * distance to the nearest star (Proxima Centauri [2]) is 4.2421 ly = 268,274.973 AU, [1] https://en.wikipedia.org/wiki/90377_Sedna https://en.wikipedia.org/wiki/90377_Sedna [2] https://en.wikipedia.org/wiki/Proxima_Centauri https://en.wikipedia.org/wiki/Proxima_Centauri EDIT: formatting and added Proxima-Alpha Centauri distance.
mutagen 11y ago
Their site at http://www.findplanetnine.com/p/blog-page.html http://www.findplanetnine.com/p/blog-page.html addresses the areas the Tyche survey and other surveys cover. My TLDR: * The WISE survey might only find Planet X at it's nearest approach. Kevin Luhman has redone the survey using the most sensitive WISE bands that only cover a narrow area of the sky and hasn't found Planet X. * They reviewed the Catalina Sky Survey and eliminated most of the areas they'd expect Planet X. * The Pan STARRS site survey didn't find Planet X. Conclusion: Planet X is at aphelion, difficult to find with the Milky Way as a (stunning) backdrop. I just found their paper: http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22 http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22 I wonder how their conclusions match with David Nesvorny's paper predicting a 5th planet having been ejected from the Solar System: http://arxiv.org/pdf/1109.2949v1.pdf http://arxiv.org/pdf/1109.2949v1.pdf

mgav 11y ago

Maybe it's a Death Star?

axxl 11y ago

At WWDC last year one of the lunchtime presentations was by Michael Brown, one of the researchers involved here. He was one of the people who proved that Pluto should not be considered a planet and went over the history of the discovery/classification of planet bodies. He also mentioned that they had some evidence of a planet body beyond Pluto due to its gravitational affect of some of the smaller bodies out there even then. Interesting to see this is finally coming to something! He has the appropriate/amusing twitter handle of http://twitter.com/plutokiller http://twitter.com/plutokiller

richmarr 11y ago

Reading the article I didn't see a mention of a previously hypothesised fifth gas giant... so here's a link in case anyone's interested or knows something more. https://en.wikipedia.org/wiki/Hypothetical_fifth_giant_planet https://en.wikipedia.org/wiki/Hypothetical_fifth_giant_plane...

neur0tek 11y ago

Niburu!

empressplay 11y ago

I just want to know if Planet X is covered by human-enslaving robots.

peter303 11y ago

This how Qigong found the Clone Planet in Star Wars 2. Although the planet had be erased from the galactic database, it left a gravitational signature on nearby systems.

osoti 11y ago

The stars who sizzled the Golden Globes 2015 http://goo.gl/Iz6899 http://goo.gl/Iz6899

dmichulke 11y ago

May it receive a name starting with P so that My Very Educated Mother Just Showed Us Nine Planets works again

jharohit 11y ago

Now only if they name the ninth planet starting with a 'P', my childhood mnemonic "My Very Educated Mother Just Served Us Nine Pizzas" would finally be complete again! :D My suggestion is 'Prometheus' - sounds tragic and bad ass at the same time!

dr_zoidberg 11y ago
Well that would be consistent with the roman/greek names for planets and large moons. Now we have to find a stronger tie between the theory and the myth. In some article regarding this news I've read that Planet 9 might have ended in its orbit due to encounters with Jupiter/Saturn. Not exactly an eagle eating its liver, but it can be paralled to "the punishment from Zeus(Jupiter)".
- jharohit 11y ago
  :) well nicely connected with the punishment story! I would further go and say that we can draw parallels with the Kuiper Belt objects to the eagles "tormenting" Prometheus while he is chained to a "cold, lonely mountain rock" like our new mysterious planet stuck in a dark lonely corner of the solar system!
  - dr_zoidberg 11y ago
    Alright, time to write to IAU with a name proposal!

carlosgg 11y ago

Thanks for the link. There's a course taught on Coursera by one of the CalTech researchers, Mike Brown, if anyone is interested. It's archived but they have kept it open. https://www.coursera.org/course/solarsystem https://www.coursera.org/course/solarsystem