Caltech Astronomers Say a Ninth Planet Lurks Beyond Pluto (sciencemag.org)

sciencehabit writes: The solar system may have a new ninth planet. Today, two scientists announced evidence that a body nearly the size of Neptune — but as yet unseen — orbits the sun every 15,000 years. During the solar system's infancy 4.5 billion years ago, they say, the giant planet was knocked out of the planet-forming region near the sun. Slowed down by gas, the planet settled into a distant elliptical orbit, where it still lurks today. Here's a link to the full academic paper published in The Astronomical Journal.

Comments

Waiting for Nibiru / Planet X morons....

[phishybongwaters]

To tell us how this planet oscillates the chemtrails so the 911 nuclear aliens can open up communications with the illuminati and space lizards to bring on the new world order and force us into fema camps.

Re:Ninth, mofo.

[frovingslosh]

Yea, Dwarf planets are not planets any more than dwarf people are people.

Re:Ninth, mofo.

[Rei]

Sorry, but many of us feel that the IAU's redefinition was a huge mistake. Including for example most of the New Horizons team. Heck, even when you press supporters of the concept of defining planets based on orbital characteristics rather than hydrostatic equilibrium you find that even most of them will admit that the definition as it stands is a mess and should be revisited. It's self-contradictory, vague, full of holes and creates more linguistic confusion than it solves.

It's worth adding that if we go by the IAU's definition, this thing - despite being 10 times bigger than the Earth - would almost certainly not be considered a planet, due to its distant elliptical orbit.

Re:Well, I guess we'll know in a few thousand year

[xxxJonBoyxxx]

Again, from TFA, we could perform a narrow infrared scan of the possible path until we find it. (We just did one ruling out "Saturn-sized" objects nearby, but this planet is smaller.) The authors expect discovery and confirmation within about 5 years.

Re:Well, I guess we'll know in a few thousand year

[Rei]

Not really. There's going to be some very powerful telescopes involved in survey work coming online over the course of the next decade that should dramatically increase our detection capability. My favorite is the LSST which should, for example, move from our current knowledge of about 1% of 100km+ KBOs to nearly 100%. And one can expect even more powerful telescopes in the decades after that.

Next decade, whenever anything is detected, we'll also have James Webb to get a better look at it.

Pluto can be a planet again

[voislav98]

Step 1: Rename Pluto
Step 2: Name the new planet Pluto
Step 3: Profit!

Dear Ethan

[Anonymous Coward]

Please read TFA and consider it a good example of how to write something informative, accessible and entertaining, but most importantly not hosted on forbes.

Re:Well, I guess we'll know in a few thousand year

[fahrbot-bot]

Next decade, whenever anything is detected, we'll also have James Webb to get a better look at it.

If we're lucky, James will bring his telescope. :-)

Re:Ninth, mofo.

[xxxJonBoyxxx]

>> Dwarf planets are not planets any more than dwarf people are people.

Dwarf planets are not planets any more than daddy long-legs spiders are not spiders.
Dwarf planets are not planets any more than Komodo dragons are not dragons.
Dwarf planets are not planets any more than Fool's Gold is not gold.

I think we can agree that English isn't the best language for science. Where are we going with this?

I KNEW IT!

[Anonymous Coward]

This finally explains all the times my horoscope wasn't entirely accurate. With this new input, I'm sure that I will be able to use my horoscope to see what the stars have for me and I will be able to intelligently make life-decisions knowing how they are arranged.

N.B. - I started the above in jest, but let's observe a moment of silence for the poor folks who actually feel that way.

Does it count as "evidence"

[necro81]

A computer model that predicts the existence of a ninth planet (of substantial mass, ejected into a distant orbit, early in the solar system) does not, by the usual scientific method, constitute evidence. Evidence of its existence would be certain observables that others could also observe and verify: perturbations in the orbits of other planets, detection in a telescope, etc.

This is a prediction by a hypothesis - nothing more. I could create a model that predicts the existence of dragons that fart nerve gas - that does not count as "evidence of an impending apocalypse," although that would surely generate many clicks.

Re:Does it count as "evidence"

[mothlos]

It is a hypothesis which is supported by evidence. The existence of Jupiter is also a hypothesis which is supported by evidence, although much stronger evidence than the evidence for this planet. Epistemology is frequently at odds with our every day feelings about knowledge.

Re:Does it count as "evidence"

[avgjoe62]

You really need to read the articles. To quote from one of them:

But the real kicker for the researchers was the fact that their simulations also predicted that there would be objects in the Kuiper Belt on orbits inclined perpendicularly to the plane of the planets. Batygin kept finding evidence for these in his simulations and took them to Brown. "Suddenly I realized there are objects like that," recalls Brown. In the last three years, observers have identified four objects tracing orbits roughly along one perpendicular line from Neptune and one object along another. "We plotted up the positions of those objects and their orbits, and they matched the simulations exactly," says Brown. "When we found that, my jaw sort of hit the floor."

"When the simulation aligned the distant Kuiper Belt objects and created objects like Sedna, we thought this is kind of awesome—you kill two birds with one stone," says Batygin. "But with the existence of the planet also explaining these perpendicular orbits, not only do you kill two birds, you also take down a bird that you didn't realize was sitting in a nearby tree."

Re:Does it count as "evidence"

[pz]

If you read the article (I know, I know), you'll learn that there are, in fact, observables involved. There are a handful of Kuiper Belt objects that have an odd level of similarity among them, so odd that the only ready explanation is that there is an as-yet unseen object shepherding them. The Caltech group created a simulation of the kind of object that might produce such a result and found that it ALSO would be expected to shepherd a second set of smaller objects into orbits orthogonal to the ecliptic. Very, very strange. So they made that prediction, and LO! found objects that fit the bill.

They created a theory based on observational evidence. The theory made a prediction that was tested, and found correct. The body itself has not been observed, yet, but I'd expect that the Japanese will find it (given that, according to other news articles), they have just the right sort of telescope to perform the search.

Re:Ninth, mofo.

[bondsbw]

I'm not sure why you inserted "not" before the predicates of the subordinate clauses in your sentences. You changed the structure of the analogy.

Re:Ninth, mofo.

[bondsbw]

It's kind of like the term "marriage". Its meaning is different depending on who you ask. Some believe it is a religious concept, some believe it is a legal concept, and some feel it is both.

I think we can all agree that the proper term for Pluto is "gay planet".

Well...

[denzacar]

It IS Planet Nine from outer space.

Re:Ninth, mofo.

[Ken D]

It's actually a trans planet. Trans-neptunian that is.

Re:Ninth, mofo.

[Rei]

Assuming it exists, it orbits the sun, it is large enough to be round, and it's big enough it probably has "cleared its neighborhood"

It has as mentioned a semi-major axis of around 700AU. That's 23 times more than Neptune. It has a mass of about 10Me, or 58% of Neptune. Its Margot discriminant would be less than a tenth of Mars' (lowest in the solar system). Plus, it's highly elliptical (e=0.6), meaning it has a far broader neighborhood to clear (something not taken into account in the discriminant).

Hydrostatic equilibrium is part of the definition.

  Planetary scientists wanted a definition based solely around hydrostatic equilibrium; the main group pushing for an orbital dynamics definition was astrophysicists. The original draft was based around hydrostatic equilibrium, so many of them left, content that they'd either get a hydrostatic equilibrium definition or no definition at all.

Re:I hope its true

[Rei]

Its perihelion is over 1100 AU. Sedna was discovered at 90AU. Wee bit of a difference there. Also, the degree of the solar system we've searched varies greatly in detection ability, some areas much better studied than others. It's estimated that we've only found about 1% of KBOs larger than 100km.

Some thoughts

[Rei]

An interesting thought. Even at its perihelion (1100 AU), helium won't be getting cold enough to condense out. But hydrogen probably will, condensing to planetwide hydrogen seas. Meaning that - combined with its lower mass - its atmospheric density at perihelion on top of that is probably surprisingly low. However, at aphelion its only about 400AU. That's probably not cold enough to condense hydrogen. So every 15000 years it would go from having hydrogen oceans and low atmospheric pressure to an ice surface under crazy pressures.

What the heck do you call a planet like that?

Such a large planet would certainly have the internal heat for tectonics and volcanism. But I'm still so baffled from trying to picture what such a planet would be like just from that first aspect that I can't even begin to imagine what effect the latter would have on it.

Certainly a lot of energy in play here.

Re:Some thoughts

[Rei]

More thoughts.

1) The atmosphere would be pure - 100% pure helium. The only thing that could contaminate it would be hydrogen, so if it's cold enough for it to be fully condensed out (no hydrogen clouds/rain), then it'll be a monoatomic gas. No clouds.

2) The hydrogen seas would also be pure. There's almost nothing that can float in hydrogen - pretty much just foams gassed with helium, and that doesn't sound likely.

3) Weird nuclear properties: helium is a perfect neutron moderator - it never undergoes neutron capture. It can undergo high energy reactions, but at lower energies, any neutron in helium will become fully thermalized, which - at those temperatures - would make everything interact with it at a very high cross section. Since only helium would be in the atmosphere, that would most likely be 3He. So I would expect 3He depletion.

4) The day length would change when the hydrogen condensed out (like a ballerina pulling her arms in). I'm not sure off the top of my head of the effects of this mass redistribution on any orbital bodies, although I could picture, say, enhanced tidal heating due to the mass redistribution.

5) There's an awful lot of potential non-hydrogen liquids which could exist under the liquid hydrogen (or under the H2/He atmosphere near aphelion) - nitrogen, carbon monoxide, methane and other hydrocarbons, neon, even water. It all depends on the pressure and temperature curves, which one couldn't even begin to speculate on at this point. Most of the latter could potentially form eutectics, but hydrogen is not prone to forming eutectics, so would make its own distinct surface layer.

6) Lava flows of any type (silicate, cryolavas, whatever) would happen underneath the hydrogen ocean. Meaning pillowing. The boiloff of hydrogen could then expose these structures. What do pillow cryolavas formed under hydrogen look like? I haven't the foggiest.

7) Any hot lavas (such as silicates) erupting into liquid hydrogen might have unusual chemistry (metal hydrides and the like? extensive hydrocarbon formation? silanes, stabilized by the low temperatures?). This would then be left exposed on the surface when the hydrogen boils off. That surface could be a really bizarre place.

Any other thoughts?

Re:Some thoughts

[neo-mkrey]

Still sounds like a better place to live than Flint, Michigan, USA.

Re:Ninth, mofo.

[Applehu Akbar]

We prefer the term 'compact planet'.

Re:Ninth, mofo.

[Rei]

The whole "cleared the neighborhood" thing is based on a lie anyway. The vast majority of planets didn't clear their neighborhods. Jupiter**, and to a lesser extent Saturn, did. Mars' lack of influence on its neighborhood can be seen by how low of a percentage of asteroids are in a resonance with it.

Can we stop with the pretending that planets like Mars are responsible for sweeping their orbits clean? No models support this.

It's funny, but you see almost the exact same reason given by everyone interviewed who voted for the IAU definition - always a variant of "I don't want my daughter to have to memorize the names of 50 planets". As if that's even remotely any sort of scientific argument, as if we should say there's only 8 rivers in the world or 8 bones in the human body and all others are "dwarf rivers" and "dwarf bones" that aren't really rivers and bones, in order to make it easier for schoolkids.

They had their preconceived concept - they wanted a low, memorizeable number of planets - and tried to create a definition to fit it. And failed miserably at it. Now we've got a definition where a "Dwarf X" is not an X, despite the fact that in astronomy (and almost everywhere else) "Dwarf X" always denotes a type of X - dwarf stars, dwarf galaxies, etc. We've got a definition based on poorly defined concepts like "neighborhood". We've got a definition that arbitrarily excludes exoplanets from being planets, which is a terminology disaster. We have a definition that runs contrary to what people associate with the word "planet" - they expect "big round object floating through space around a star" - if it's pulled itself into a sphere, they think "planet", if it's lumpy then they think "not a planet".

We had a perfectly good dividing line: hydrostatic equilibrium. It's not just what the public expects the word to mean. Collapse into hydrostatic equilibrium produces altered minerals, releases of energy, fluids, and all sorts of things - they're the place you'd go to study planetary evolution, search for life, etc. Bodies that have not collapsed into hydrostatic equilibrium are where you'd go to study primordial materials, the origins of the solar system, etc. They're fundamentally different bodies.

And for that matter, what sort of nonsensical grouping is it that says that Mercury is more like Jupiter than it is Ceres? Want to pinch off some bodies from the list of planets? Go all the way. We have the inner planets, we have the gas giants, we have the ice giants.... IMHO I really like Stern's multi-classification approach. You have an adjective which describes the size and whether it's in hydrostatic equlibrium - say, superdwarf, dwarf, giant, supergiant, etc; you have a compositional term, such as terrestrial, gas/hydrogen, ice, etc - and you have an orbital term, such as "planet" (body that orbits around a star), "moon" (body that orbits around a planet"), and so forth. When describing a body, you can use as many or as few of the components as you need to.

(** Hell, if I really wanted to nitpick, I could point out that the definition requires planets orbit the sun. Jupiter orbits the Sun-Jupiter barycentre, which is not inside the sun. You can say "close enough", but where do you draw the cutoff line?)

Re:counting is fun

[Rei]

The concept that dark matter wasn't normal matter wasn't arrived upon easily, it took until the 80s to really accept it. The thing is, even small objects still interact with EM radiation and such, and this has effects if you want to have enough of them to account for the missing mass. And these interactions just aren't observed, no matter what size bodies you assume. The closest you can get out of conventional matter is a hypothesis is for hypothetical objects called "macros", which is basically like tiny neutron stars.

Honestly, dark matter doesn't bother me at all. What's so weird about the concept of particles having little to no interaction with certain fields? Now dark energy, that's some evil sorcery there....

Re:Ninth, mofo.

[DahGhostfacedFiddlah]

I think we can agree that English isn't the best language for analogies. Where are we going with this?

Re:Ninth, mofo.

[pugugly]

Yeah that was the first thing that went through my mind - Under current planetary evolution theories, despite it's size it has almost certainly not cleared it's neighborhood.

Which is of course the *exact* problem many people had with the definition, and I really hope this turns out to be real and they have to deal with a 'Dwarf Planet' ten times Earth Mass.