The scientists at CalTech have some bad news for those of you still holding vigil for Pluto’s reintroduction into your favorite solar system mnemonic. (My Very Energetic Mother Jumps Skateboards Under Nana’s, um…TBD.) A new paper in The Astronomical Journal produces new evidence which uncovers the existence of an icy gas giant planet, sized somewhere between Earth and Neptune, chilling far past the orbit of Pluto.
They are calling it: Planet Nine.
Ed Wood would be so proud.
Although no one has spotted and captured this mysterious celestial body through telescopic means, scientists Michael Brown and Konstantin Batygin believe that their Planet Nine has serious planet game due to the telltale orbits of dwarf planets and other objects in its vicinity. They believe this “massive perturber” found its way far out of our view due to the massive gravitational forces of Jupiter and Saturn.
Check out this neat animation of the planet’s projected orbit in comparison to the larger bodies in our solar system.
As astronomical fame and fortune goes, the credit of discovering Planet Nine (should it actually exist in that official form) goes to the individual who successfully photographically captures it as evidence to present to the scientific community at large.
Planet paparazzi, you have your assignment. FOR SCIENCE!
This should really say “There is Evidence for a Ninth Planet” etc. There have been many times in the past that we’ve believed there might be a planet somewhere only to find there wasn’t, like the planet Vulcan that was once believed to be between the Sun and Mercury until Mercury’s orbital anomalies were explained by General Relativity, or the hypothetical red or brown dwarf Nemesis that was postulated in 1984 as a trigger for cometary-impact extinction events but that hasn’t been borne out by observations. This is a prediction that needs to be tested, not a discovery per se. I really hope it’s true, because it’d be exciting to discover a whole new Solar planet (and maybe even more further out?), but let’s not count our chickens just yet.
I wonder how much sky we’re talking about searching. The articles show this nice straight line of an orbit but I imagine there’s a lot of uncertain about the exact path through space. If there isn’t a planet (in which case what on not on earth is screwing with those orbits? {Science! Where right or wrong, it’s still cool}), then the amount of sky it might be in dictates how long it’ll take to prove the negative.
What intrigues me is that if there’s one undiscovered planet out there, then perhaps there could be more. Looking back over the history of planetary science, all the changing assumptions over the past couple of centuries about how many planets there were in the system and which bodies were planets vs. asteroids or whatever, it demonstrates how arrogant we were to assume we’d fully charted the Solar System after 1930. What we think of today as the Solar System may be recognized a century or two from now as simply the Inner Solar System.
Some years ago when I looked through old books that had gathered on the bookshelves I found two guides of the solar system with different publication dates. The newer one had about 60 more moons than the older one. If there are so many new moons, why not some planets, too?
It’s actually the Tenth Planet, beyond Pluto, and it’s full of Cybermen. Beware! :
@5, Either that, or it’s Yuggoth, which isn’t much better.
“Where are we going?”
“Planet Ten!”
“When are we going?”
“Real soon!”
They’d better name it Planet 9 from Outer Space.
It’s estimated that we’ve only identified about 1% of all the significant Kupier Belt Objects, and this Planet 9 would be the most significant by far. New telescopes should enable us to identify many, many more over the next decade (some say close to 100%) so it’s very likely we’ll soon have more direct evidence of Planet 9 (we really need a better name here; I nominate Goofy). One more interesting note, there is debate over whether Goofy is technically a planet. It could be that it’s 10 times as massive as Earth but still considered a “dwarf planet” because it hasn’t cleared it’s orbital neighborhood (something made almost impossible by it’s highly elliptical orbit). Since this makes no sense at all, it might provoke another reconsideration of what the definition of a planet should be. Pluto might be back in the game thanks to Goofy.
Mark’s Very Extravagant Mother Just Sent Us Nine Parrots. Nine!
@9/Nick31: While I’m not crazy about the whole orbit-clearing definition (arguably even Jupiter hasn’t cleared its orbit, since it has the Trojans), I do think it makes far more sense to classify Pluto as part of the same category as other large KBOs, because it’s clearly more physically similar to them than it is to rocky planets like the inner four. We need to stop being so hung up on the useless binary standard of “planet/not planet” and develop a more detailed and useful classification system. First off, expunge the nonsensical idea that a dwarf planet is somehow not a planet. A dwarf star is a star; a dwarf galaxy is a galaxy; a dwarf tree is a tree; so a dwarf planet should be a planet. No sense putting “planet” in its name if it’s not supposed to be a planet. What we need is a whole range of categories — minor body, dwarf planet, terrestrial planet, superterrestrial planet, Neptune-type/ice giant, Jupiter-type/gas giant, brown dwarf, star. It’s a whole continuum, and our old definitions don’t come close to doing it justice. We need to reject nostalgia for the limited assumptions of the past and embrace a new way of defining and classifying planetary bodies.
And let’s expunge this silly notion that Pluto’s redefinition is somehow a “demotion” or taking it “out of the game.” Being a planet is not “better” than being a dwarf planet. This isn’t a beauty pageant, it’s science. Definitions change as our knowledge improves. We used to think Ceres and the other Main Belt asteroids were planets, until we realized it made more sense to create a new category of object that fit their characteristics better. That was not a demotion, it was an improvement of our understanding. Pluto hasn’t been kicked out of some elite club, it’s just been given a more accurate designation, one that serves its nature far better — and, incidentally, improves its status enormously by making it the archetype of a whole new class of objects, rather than the also-ran, afterthought planet it used to be seen as.
@ChristopherLBennett – I agree with you. I don’t think Pluto got demoted, but I think the new classifications are flawed. Right now, unlike everything else such as stars, galaxies and so on, putting the word “dwarf” in front of planet means it’s technically not considered to be a planet according to the IAU. It’s confusing. I think that a simpler definition would make sense. So something that orbits a star, has reached hydrostatic equilibrium, and isn’t undergoing nuclear fusion at its core (and hasn’t in the past) is a planet. If you want to classify them more than that then call them gas giant planets (Jupiter, Saturn), ice giant planets (Uranus, Neptune), terrestrial planets (Earth, etc.), terrestrial giant planets (super-Earths, Planet Nine Goofy), and so on. So yes, we will end up with way more than 10 planets. Maybe even 50 or more. Whether you call Ceres and Pluto and the other large KBOs minor planets or dwarf planets or something else, they still get to be planets.
My Very Easy Mother Just Sat Up ‘N Puked.
I invented that one on the spot in an astronomy course.
I was surprised when I first discovered that there were mnemonics for remembering the order of the planets. I learned about astronomy so early in life that the planets were practically as familiar to me as the alphabet, so I never needed a reminder.
@14/Christopher: Same here! A classmate first told me about the mnemonics when I was in primary school, and what she said was: “I know a sentence that enumerates all nine planets.” I had no idea what she was talking about and answered: “So do I – ‘The nine planets are Mercury, Venus,…’ “.
I wonder how many (non-dwarf) planets our system really has. If this superterrestrial world is out there, it’s quite possible there are others between it and the Oort Cloud. There’s a lot of space out there that we haven’t come close to investigating fully. I suspect people in the future will look back with amazement at our generation’s stubborn attachment to the assumption that there ought to be exactly nine planets, no more and no fewer.
After all, our estimate of the number of planets has changed many times in the past. For ages it was seven — Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn. Then we figured out Earth was a planet and the Sun and Moon weren’t, and it was six planets. Then we found Uranus and it was seven. Soon thereafter we found Ceres and other small bodies between Mars and Jupiter, and there was no consensus about whether to call them planets or asteroids, so that when Neptune was discovered, many considered it the twelfth or thirteenth planet rather than the eighth — and the number kept swelling as more asteroids were found in quick succession. At least the first four asteroids found were often listed among the planets until the 1860s, though the US Naval Observatory jumped between calling them “small planets,” “asteroids,” and “minor planets” until finally settling on “asteroid” for good in 1929, just a year before Pluto’s discovery.
So it’s really rather anomalous that the estimate held at nine planets for a whole 76 years — long enough for the public to start thinking of that quantity as a fixed certainty of the universe rather than just a current best estimate. (Although many astronomers were unhappy with calling Pluto a planet all along, just as many in the previous century had disagreed with calling Ceres and Vesta planets.) I expect the next few decades to be more like the 19th century, a time in which our estimate of the number of planets and our ideas of how to classify Solar System objects will be in flux. (Which is really going to date a lot of science fiction.)
If they don’t wind up naming it Persephone, I’m going to be very upset.
@17/NomadUK: Well, Persephone is already the name of asteroid #399. Then again, there’s both an asteroid and a Jovian moon called Europa.
I know that Arthur Clarke and Larry Niven (and Douglas Adams) favored Persephone as the name of the “tenth planet,” but I think it would be the wrong choice given what we know now. After all, Persephone was the wife of Pluto. We now know that Pluto is an archetypal large Kuiper Belt object, an icy dwarf planet, while this planet, if it exists, would be a totally different physical type of body, a superterrestrial or borderline-Jovian planet. It’s also more closely associated with bodies like Sedna than it is with Pluto. So I don’t think a name associating it with Pluto would be appropriate.
For what it’s worth, while Niven’s “The Borderland of Sol” included Persephone as a trans-Neptunian planet, he also conjectured several more named for the rounds of the ninth circle of Hell in Dante’s Inferno: Caina, Antenora, Ptolemea, and Judecca.
But according to the IAU’s naming guidelines, “Objects, including dwarf planets, far beyond the orbit of Neptune are expected to be given the name of a deity or figure related to creation; for example Makemake, the Polynesian creator of humanity and god of fertility, and Haumea, the Hawaiian goddess of fertility and childbirth.” Granted, Persephone is the personification of vegetation and fertility, so she could count as a deity related to creation.
@17/NomadUK: Shouldn’t it be Proserpina? All the other planets have Roman names too.
Sagan. Call it Sagan. Because from this planet what would Earth look like? It would be… with perhaps some photographic enhancement… a pale blue dot.
JanaJansen@19: Good point, but who am I to second-guess Clarke and Niven? I think the thing is, everyone (well, everyone who’s brushed up against the classics at some point or another) knows who Persephone is, but her Roman equivalent is just not as well known. Doesn’t sound as nice, either.
ChristopherLBennett@18: Yeah, it’ll never happen. But the thing is likely to be a lot bigger than the average Kuiper Belt object, a proper planet, so it should follow the conventional naming of the others — with, of course, the Greek name rather than the Roman one for the reasons I mention above. I contradict myself? Very well, then, I contradict myself. I am large; I contain multitudes.
@21/NomadUK: You’re probably right. It just seems so untidy.
@21/NomadUK: Even if it does follow the classical planet-naming convention, that doesn’t make Persephone an inevitable choice. I still say it’s inappropriate for a planet like this, one that’s not similar to or connected with Pluto in any scientifically meaningful way. I’d go with something like, ohh, Erebus, the god of darkness. Too bad there’s already a Plutonian moon named after his mate Nyx, the goddess of night (with the spelling changed to Nix to avoid confusion with the asteroid Nyx).
See, that’s the other problem with Latin or Greek names — we’ve pretty much used them all up on moons and asteroids and such, to the point that we’re even repeating some. That’s why new objects like Sedna and Makemake and Haumea get names from other mythologies. It’s not about cultural inclusiveness, it’s just that we’ve run out of Eurocentric names.
THEY WANT TO CALL IT PERSEPHONE
The foofooraw over the term “dwarf planet” is misplaced; English noun compounds just aren’t that straightforward. Everyone agrees that a tree frog is a kind of frog, but a stone lion isn’t a lion, just a piece of stone carved to look like a lion. And of course a birdbrain isn’t a kind of brain at all.
As for the name “Planet 9 from Outer Space”, it’s possible but unlikely that Nine was captured from another solar system during a close encounter between the Sun and another star. Much more probable is that it formed in the inner system and was ejected before it could grow into a gas or ice giant. In which case it would only work in outer space, holding down those KPOs, but would be from Iowa just like all the other children of the Sun.
KBOs, of course. Too much time spent dealing with Key Performance Objectives.
@25/John Cowan: “The foofooraw over the term “dwarf planet” is misplaced; English noun compounds just aren’t that straightforward. Everyone agrees that a tree frog is a kind of frog, but a stone lion isn’t a lion, just a piece of stone carved to look like a lion. And of course a birdbrain isn’t a kind of brain at all.”
But we’re not comparing different adjectives; we’re comparing uses of the same adjective in the same context — the way the prefix “dwarf” is used when applied to astronomical objects. A dwarf star is still a star; a dwarf galaxy is still a galaxy. By analogy, put the word “tree” in front of most words and it will consistently mean a version associated with a tree — tree frog, tree fungus, tree surgeon, tree house. The issue isn’t the general use of adjectives, but the definition of one specific adjective. General and specific argument are two very different things.
And resorting to slang is a non sequitur, because we’re talking about a formal definition.
@18 Can we call it Rupert? Surely someone can come up with a heart-warming story about some astronomers parrot?
Although the things I really want to rename are KBOs. I refuse to call any of them cubewanos, but what about Albionoids?
Surely Pluto is a Dog Planet?
Just remembered this video essay, if anyone is interested: Planet Nine: Quest for the Exile World
”Sized somewhere between Earth and Neptune”….isn’t that a little like saying something is sized somewhere between a paperclip and an elephant? Not overly informative.
@31/KatherineMW: Our system contains no known planets between Earth and Neptune in size. Earth is the largest known terrestrial planet and Neptune is the smallest giant planet (by radius — Uranus is smallest by mass). So it is informative, because discovering a planet in that size range in our own system — whether a superterrestrial without a hydrogen atmosphere or a “mini-Neptune”/gas dwarf with one — would be a major discovery, adding a whole new category of Solar planet.
https://en.wikipedia.org/wiki/List_of_Solar_System_objects_by_size#List_of_objects_by_radius
Also, Neptune is only a bit under 4 times Earth’s radius and a bit over 17 times its mass, so it’s not that huge a difference — more like a sea lion and an elephant, or a paper clip and an AA battery.
Actually, it’s been theorized since January 2015 (five years ago) that there may be two planets beyond Neptune’s orbit, and I’m a proponent of this derivative hypothesis:
https://www.usatoday.com/story/news/world/2015/01/17/two-planets-beyond-pluto/21912521/
The first (Planet Nine) is expected to have a semi-major axis of around 200 astronomical units and a mass between that of Mars and Saturn. I want it to be named “Hyperion”, but sadly, this name is taken by a moon of Saturn if you didn’t already know. My second choice is “Nox” after the Roman goddess of the night.
Hyperion/Nox itself is expected to be in an orbital resonance with another planet even further out, with a mass of 10 Earth masses and a semi-major axis of 250 astronomical units. This time, I’m not fully sure on what to name that second planet (Vulcan is unfitting because he is a fire deity; Oceanus is unfitting too because it was proposed by the egocentric fringe astronomer Thomas Jackson Jefferson See, Minerva as also unfitting because she has nothing much to do with the underworld*).
So for me, including Pluto, there are eleven planets, in order from the Sun:
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, Hyperion, Arnold
Terrestrial planets: Mercury, Venus, Earth, Mars (Mars is less dense than the other terrestrial planets) (possibly the Moon?)
Icy terrestrial planets: Pluto (a Kuiper Belt object)
Gas giant planets: Jupiter and Saturn
Ice giant planets: Uranus and Neptune
Terrestrial giant planets or super-Earths: Hyperion/Nox and Arnold
*Minerva is also taken by asteroid #93.