Analysis Suggests Solar System Contains Massive Trans-Neptunian Objects

BarbaraHudson writes NBC News reports that at least two planets larger than Earth likely lurk far beyond Pluto, just waiting to be discovered, a new analysis of the orbits of "extreme trans-Neptunian objects" (ETNOs) suggests. The potential undiscovered worlds would be more massive than Earth and would lie about 200 AU or more from the sun — so far away that they'd be very difficult, if not impossible, to spot with current instruments. "The exact number is uncertain, given that the data that we have is limited, but our calculations suggest that there are at least two planets, and probably more, within the confines of our solar system," lead author Carlos de la Fuente Marcos, of the Complutense University of Madrid, said. (Here's the longer version at Space.com.)

Comments

Riiiiight.

[tysonedwards]

Our ability to discern planetary positions has largely been based on our understanding of orbital dynamics and looking for protuberances in the motions of known, directly observed objects that were naked eye observable. This technique has been used since the 16th century and led to discoveries of all Planets, Planetoids, various Asteroids, Comets, and Plutoids ever since without the need of direct imaging; just some very cool math...

Re: Riiiiight.

[Anonymous Coward]

are your protuberances a little bit perturbed?

Re:Riiiiight.

[K. S. Kyosuke]

Yep, but the most recent line of thought has been that all the previously suspicious things about known outer solar system orbits have already been explained away. At least some serious upper bounds have been put on the masses of the potential objects (and lower bounds on their distances). Whether this work on TNOs will withstand close scrutiny is the question to ask.

Re:Riiiiight.

[Anonymous Coward]

Protuberances? That would mean much like Uranus, they are prolapsed.

Re:Riiiiight.

[FrostedWheat]

Most new discoveries are still done through imaging rather than maths. It's fairly automated these days though.

Re:Riiiiight.

[Gravis Zero]

Yep, 400 years the math has been right... and we only discovered Neptune 169 years ago. Pluto varies between 29 AU and 49 AU from Sol, depending on where it is in it's 248 year elliptical orbit. These hypothetical planets are at least 200 AU from the Sol and have very slow and large orbits taking between 1800 and 12000 years to complete.

Our math has worked well for 400 years... but how will it hold up in 400K years?

Re: Riiiiight.

[Will.Woodhull]

Seeing these protuberances on slashdot perturbs me a little. But I would be seriously perturbed to see protuberances of astronomical size.

Re:Riiiiight.

[Solandri]

This technique has been used since the 16th century and led to discoveries of all Planets, Planetoids, various Asteroids, Comets, and Plutoids ever since without the need of direct imaging; just some very cool math...

I don't think orbital dynamics has ever been used to discover an asteroid or comet or trans-Neptunian object. Certainly it's used to confirm their orbits (I've done that myself, freezing my ass off overnight taking a glass photographic plate, then measuring how much a small dot moved night to night). But asteroids have too little mass to to appreciably change the orbits of the larger planets. Ceres (along with a lot of other asteroids in the asteroid belt) in particular was discovered by blind luck by people searching almost at random for another planet between Mars and Jupiter. So to for that matter was Pluto - people were chasing what turned out to be an error in Neptune's calculated mass, and Pluto just happened to be near the spot that error predicted at the time they were looking.

Comets are discovered by (obsessed) people scanning the sky every night for a fuzzy dot that shouldn't be there. It's actually the same process as for asteroids (except now you have a computer do the observation instead of freezing your ass off like I did), and if the orbital calculations say it's a highly elliptical orbit instead of circular, you have a comet. The gas jets from vaporizing material as they approach the sun (which gives them their "tail) are pointed in random directions, and perturbs their orbit enough to make precise orbital calculations useless. Only general calculations like Halley's Comet returning every 86 years work.

Orbital calculations work well for (A) objects which are relatively close together since gravity decreases as the inverse square of distance, and (B) have relatively short orbital periods since this means they move faster and thus generate a larger measurable motion against the background stars. Neither of these hold true for trans-Neptunan objects.

If you subscribe to the theory that the solar system started out as a cloud of matter, and a slightly larger lump somewhere happened to coalesce into the sun by gravity, then it makes sense that the further you go out, the more material there is simply because of geometry. The volume of space (restricted to near the plane of the solar system) goes up as the square of the distance from the sun. While the length of the orbit only goes up proportional to the radius. So there must be more stuff in the outer solar system than in the inner. It's just spread out more.

Re:Riiiiight.

[sysrammer]

...and for all the GN's out there, a protuberance is a special case of a perturbation.

Re:Riiiiight.

[rtb61]

You left out solar wind https://en.wikipedia.org/wiki/... which from the moment of stellar ignition creates a wave which concentrates the dust cloud promoting coalescence into gravitational masses and those masses create turbulence within that dust cloud promoting the formation of comets. So the inner model is planets cores have formed prior to stellar ignition and upon ignition those cores get their final coat. Planets that do not fit that model are shaped by catastrophic impact of one form or another, a very socially uncomfortable viewpoint.

Re:Riiiiight.

[BarbaraHudson]

Try the discovery of Pluto, which was predicted from orbital irregularities of Neptune, which as also predicted because of orbital irregularities of Uranus.

Re: Riiiiight.

[vpness]

Thanks for taking the time to post this. I'm glad your post was modded up. I have a casual, uneducated interest in things in space, and snippets like this are interesting to me. (unlike a lot of /. posts, I'm not being sarcastic)

Re:Riiiiight.

[Pulzar]

Comets are discovered by (obsessed) people scanning the sky every night for a fuzzy dot that shouldn't be there.

I'm completely ignorant on this topic.. but that sounds like something that computers should be able to do easily, no?

Re: Riiiiight.

[jcwayne]

Doesn't the tail of a comet always point directly away from the sun?

Re: Riiiiight.

[605dave]

Don't have mod points, but that would have just qualified as funny to me...

Re:Riiiiight.

[BarbaraHudson]

It's called serendipity. Without the perturbations in Neptune's orbit they wouldn't even have started looking for a "Planet X", so Pluto was indeed found because of perturbations in Neptune's orbit.

Re: Riiiiight.

[Applehu Akbar]

At those distances, comets don't even have tails.

Re:Riiiiight.

[Tablizer]

I think it's only recent that electronic cameras have been sensitive enough at a price amateur comet hunters could afford. Plus, it probably takes a lot of hard-drive space to store comparative images.

Planet X / Nibiru !!!

[Anonymous Coward]

Seriously though, if such a planet did exist and the had an orbit that brought it near our planet once every so many thousnads of years, what effect would it have as it passed near us? Look at the effect the moon has on our planet and think about something larger than Earth passing by.

Re:Planet X / Nibiru !!!

[Urkki]

I think Jupiter makes sure any highly elliptical orbit coming near Jupiter's orbit would not last too many orbits before having it's orbit radically changed, like happens with comets sooner or later if they survive long enough otherwise.

Re:Planet X / Nibiru !!!

[Teun]

If such existed it would have passed us before and left obvious traces.

Re:Planet X / Nibiru !!!

[ArcadeMan]

The obvious traces are everywhere, we just choose to ignore them and think they were man-made.

Re:Planet X / Nibiru !!!

[dbreeze]

Like the records of some ancient civilizations maybe....?

Re:Planet X / Nibiru !!!

[JWSmythe]

Everywhere is relative. There are an estimated 5 trillion habitable planets in the known universe. We've mostly explored one. On our closest neighbors, we've done roughly the equivalent of checking your back yard and saying "There are no whales". Well, unless you happen to have whales in your yard, then we'll say "... no elephants". :)

If there is/was life on other planets, it is very likely not to be in our solar system. Even if there was an species that achieved space travel, and spent millions of years settling on millions of planets, it's *still* not very likely they'd be found on one in our solar system.

Even if we found one, would we know what we're looking at? Since rock seems to be pretty abundant in the tiny speck of space that we've explored, a sand and rock covered hull of a spacecraft would be reasonable. That would help protect from micro-meteors and other hazards. If one crashed on a neighboring planet even 10,000 years ago, would just look like rock. Heck, if one crashed on Earth, it would still look like a rock.

Is this space craft remains, or a natural formation?

No, I don't believe it's a crashed spaceship. It's just a rock. But since we don't exactly do thorough core samples on every large rock on the planet (and under the surface), we wouldn't know if it was.

Re:Planet X / Nibiru !!!

[ArcadeMan]

This looks like a photo of the rough pass of a CNC milling operation that has gone through a very bad resizing routine, probably nearest-neighbor interpolation.

Re:Planet X / Nibiru !!!

[plopez]

"We've mostly explored one"

Not even close to 'mostly'. The land areas often have areas very little understood, we can't find a crashed airliner in the ocean, we know very little of the crust though some discoveries of extremophiles underground hint at some weird biology and chemistry, and can't even get sol microbes into the lab without killling them. Before we try to understand other planets it might be a good idea to understand Earth first.

Re:Planet X / Nibiru !!!

[JWSmythe]

Dude, it's from Close Encounters of the Third Kind. I picked it on purpose, just to show that I wasn't totally serious. Damn, you'd think an obvious landmark from an extremely popular science fiction movie would be a hint to some people.

I'm not saying that it's an alien spacecraft. What I'm saying is, we wouldn't necessarily know if we saw one. Hell, people find all kinds of "lost" things in their own back yards. In the last year, someone found a viking burial site. Someone else literally found buried gold. Would you know if there was an ancient spacecraft buried 20 feet under your house?

I wasn't even trying to propose that alien spacecraft do have rock shielding. What I'm saying is there's a lot we *don't* know. Short of seeing a spacecraft that looks like a spacecraft as we'd expect it, we could easily overlook it.

Re:Planet X / Nibiru !!!

[JWSmythe]

We've explored more of this rock than any other. That's the "mostly".

Finding the lost airliner isn't a matter of lack of exploration. That is, we can't recheck an entire ocean in a short period to see if the airliner is there now. I believe that part of the ocean was already mapped, so it has already been "explored".

Your airplane argument would be like saying you haven't explored your back yard, if someone tossed a beer can over the fence yesterday, and you didn't know about it.

BTW, I tossed a beer can over your fence yesterday, you should go clean it up, your yard is a mess.

Re:Planet X / Nibiru !!!

[Applehu Akbar]

Devils Tower is a volcanic stump, not a butte. A butte forms in sedimentary strata as one of the final steps in the erosion of a dissected plain (cut up by rivers, which deepen into canyons...). When there are softer layers of rock underlying hard layers, they undercut during erosion, forming a 'mesa' with more or less vertical sides. When a mesa becomes thinner than it is tall, it gets classified as a butte.

A volcanic stump forms when a volcano comes up through country rock (no, that has nothing to do with Trisha Yearwood) that is softer than the magma basalt. With enough erosion, the basalt stands alone, cracking into those characteristic hexagonal columns.

Re:Planet X / Nibiru !!!

[ArcadeMan]

Would you know if there was an ancient spacecraft buried 20 feet under your house?

It would certainly explain why my appliances work without being connected.

I still think Pluto is a planet

[HangingChad]

I think Pluto got robbed.

Re:I still think Pluto is a planet

[modmans2ndcoming]

It has not cleared it's orbit of debris and Eris is in the same boat yet LARGER than Pluto.... how is Pluto a planet then?

Re:I still think Pluto is a planet

[Anonymous Coward]

Pluto has tenure.

Re:I still think Pluto is a planet

[michelcolman]

I wonder what they're going to call these new objects, because they'll probably find a reason not to call them planets just like they did for Pluto.

They're too big to be dwarf planets... Maybe elf planets?

Re:I still think Pluto is a planet

[jc42]

It has not cleared it's orbit of debris and Eris is in the same boat yet LARGER than Pluto.... how is Pluto a planet then?

Neither has Earth; there's a rather large, bright rock visible in our sky about half the time. ;-)

Seriously, though, it's probably just a matter of time before a rock bigger than Earth is discovered out in the Kuiper belt and/or the Oort Cloud, and chances are pretty slim that its orbit will be "cleared" of rubble. This will either put an end to the current (somewhat bogus) definition of "planet", or it will cause the debate over what's a planet and what's not to bumble on indefinitely.

The most likely result will be that astronomers will eventually reject the term "planet" entirely. Sorta like how, a few centuries back, they rejected the older term "astrology", due to all its baggage and mis-use by pseudo-scientists and charlatans.

In any case, the big rocks in the sky don't really care how we classify them. They just go about their orbiting, occasionally bashing into each other (and occasionally us) at widely-spaced intervals.

Re: I still think Pluto is a planet

[ilguido]

Troll planets would be nice.

Re: I still think Pluto is a planet

[jd2112]

Troll planets would be nice.

No thanks, we have enough lurking on the Internet. We don't need whole planets of them.

Re:I still think Pluto is a planet

[K. S. Kyosuke]

Actually, Neptune has forced Pluto into a 2:3 orbital resonance, thus Neptune has effectively cleared its orbit of Pluto: Pluto never approaches Neptune more than it aproaches Uranus.

Re: I still think Pluto is a planet

[DeBaas]

Indeed if Elon Musk connects a planet full of them to our internet, we're really fscked .....

Re:I still think Pluto is a planet

[K. S. Kyosuke]

It means that Pluto is gravitationally dominated by Neptune. For the purpose of the definition of "clearing the neighborhood", this is perfectly sufficient, certainly no less then accretion or ejection.

Plus, after all, orbits are not those fancy circles and ellipses; that's only five out of six orbital elements.

Re:I still think Pluto is a planet

[Anonymous Coward]

Why do you say that? I think we can all agree Jupiter is a planet, but due to its size it has an entire category of asteroids (Trojans) which sit at its Lagrange points. Seems to me if the only things in your orbit are there in such a way as to never affect you, and you're that much bigger than them, that's cleared.

Re:I still think Pluto is a planet

[Will.Woodhull]

The most likely result will be that astronomers will eventually reject the term "planet" entirely. Sorta like how, a few centuries back, they rejected the older term "astrology", due to all its baggage and mis-use by pseudo-scientists and charlatans.

You realize that you are implying that the astronomers who voted in the current astronomical definition of planet are all either psuedo-scientists or charlatans?

That raises some very serious thought-provoking questions. IMHO, using only common sense and no optical assistance mechanisms, it looks to me like they are probably pseudo-scientists, and not charlatans.

Re:I still think Pluto is a planet

[Will.Woodhull]

They will be known as "midget planets", I would think.

Except for the ones that are larger than Earth. Those will be taxonomy busters.

Re:I still think Pluto is a planet

[jouassou]

There are mathematically precise ways of defining the difference between planets and dwarf planets. If you check the table of planetary discriminants a little bit down the page, you see that there clearly appears to be two groups of planetoids in the list: those with a planetary discriminant of 10,000-1,000,000 which we call planets, and those with a planetary discriminant of 0.01-1.00 which we now call dwarf planets. Do you still disagree that these two groups, separated by four orders of magnitude in their planetary discriminants, deserve different names?

Re:I still think Pluto is a planet

[Anonymous Coward]

Uh no. Just no. Pluto's orbit does not ever directly intersect Neptune's orbit. It doesn't even sit on the same plane.

Go read some books or something.

Re:I still think Pluto is a planet

[jc42]

The most likely result will be that astronomers will eventually reject the term "planet" entirely. Sorta like how, a few centuries back, they rejected the older term "astrology", due to all its baggage and mis-use by pseudo-scientists and charlatans.

You realize that you are implying that the astronomers who voted in the current astronomical definition of planet are all either psuedo-scientists or charlatans?

That raises some very serious thought-provoking questions. IMHO, using only common sense and no optical assistance mechanisms, it looks to me like they are probably pseudo-scientists, and not charlatans.

Well, they apparently spent some time in meetings of an international organization discussing the definition of "planet", when they could have been doing actual scientific work. ;-)

Of course, sometimes terminology is important scientifically, and it's worthwhile spending time to get it right. But they were mocked by other actual astronomers pointing out that any term that includes both Mercury and Jupiter but not some objects with intermediate properties must be an absolutely worthless term for any scientific purposes. So, at least during the time they spent in such discussions of the definition of "planet", they weren't functioning as scientists. But they were pretending that the terminology involved had scientific value, so it probably did qualify for the term "pseudo-science", in at least one of its common meanings.

Re:I still think Pluto is a planet

[cheesybagel]

Nah those will be the "mighty midget" planets.

Re:I still think Pluto is a planet

[dissy]

Until you can name all hundred thousand of the "planets" in our solar system, we won't be using your definition of planet.

Why do you insist 3rd graders should be able to recite all hundred thousand planets from memory yet refuse to do so yourself even with the Internet as your reference?

Re: I still think Pluto is a planet

[Applehu Akbar]

"Troll planets would be nice."

And because of the latency, the inhabitants would be enable to form coherent ripostes to our posts.

Re:I still think Pluto is a planet

[C0R1D4N]

Is Australia a continent or a very large island?

Re:I still think Pluto is a planet

[david_thornley]

Given the proximity of New Guinea, it's safe to say it isn't a planet.

Re:I still think Pluto is a planet

[ghurlag]

Pretty sure this sums up this whole argument nicely. It's like the Kevin Bacon game, only with planetary and geographical bodies. Where x=( and purple is the new feather.

Planets?

[Sperbels]

At that range, you have to wonder enough time has elapsed since the formation of the solar system for them to have "cleared the neighborhood" around their orbits.

Re:Planets?

[CanEHdian]

Plenty if you assume the orbital period to be around 5,000 years (see e.g. 2012_VP113)

Re:Planets?

[Urkki]

At that range, you have to wonder enough time has elapsed since the formation of the solar system for them to have "cleared the neighborhood" around their orbits.

If they are detected by looking at how they herd the minor bodies in the outer solar system, then I think it is safe to say they are indeed planets.

Re:Planets?

[war4peace]

Interesting point. Let's say a planet orbits the Sun once every 1000 years (Pluto's is almost 248 years). This means roughly 4.6 million planetary "years" from that planet's reference frame. Did Earth clear its orbital neighborhood in 4.6 million years? Probably not.

Re:Planets?

[K. S. Kyosuke]

This is actually a valid question for the transneptunian space. I vaguely recall that between the times and spaces involved, the transneptunian space may not have "aged" to the same extent that the inner parts of the Solar System have. There simply has to be a threshold somewhere where the definition stops making sense, so it's only applicable to those places where something like this is possible.

Re:Planets?

[SharpFang]

I don't exactly know what the "neighborhood" is defined as, but note how its volume (and as result, space that is to be cleared) rises with cube of orbital radius. At 200AU the hypothetical planets have 8,000,000 times more cubic kilometers of space to wipe than Earth does.

Re:Planets?

[Anonymous Coward]

Quantitative work has been done on how difficult it is to scatter crossing orbits and for other smaller bodies into a resonance, and the difficulty doesn't quite scale with volume, but scales with orbit diameter (or semi-major axis for elliptical orbits) to the (3/2) power, while also scaling with the square of the bodies's mass. So in that sense, moving Earth out to a distance of 200 AU would make it roughly 3000 times harder to scatter bodies out of the orbit. But by those estimates, Earth has almost 400 times the necessary mass for the rough threshold in its own orbit, so it would still be plenty to clear out an orbit at 200 AU. However if you look at something like Pluto, its distance and mass give it nearly 10^8 times worse scattering ability, putting it orders of magnitude under the threshold of where a planet would be expected to clear the neighbourhood.

Exciting stuff

[benjfowler]

I hope I'm alive long enough for somebody to build probes that are fast and powerful enough to reach and map these places.

The trouble with present technology, is that most rockets/spacecraft only have enough delta-V to take decades to get out there, and nowhere near enough to actually go into orbit when they get out there.

Hazarding a guess, I would say that that'll only happen when somebody gets around to building nuclear-powered engines. The big question is: who's got the money and balls to pull it off?

Re:Exciting stuff

[7bit]

Whoa whoa big boy!

Before you can send any probes to any such place, the first thing you need to do is find the darn things. And here you are, sending probes to things that haven't been found.

Well humans, at least 49% of us, are all about the probing. Tell us about something we haven't probed before and we'll start working out plans right away for how we WILL probe it. Kinda makes me think those Grey aliens that are busy probing farmers really are us from the future...

Re:Exciting stuff

[7bit]

Whoa whoa big boy!

Before you can send any probes to any such place, the first thing you need to do is find the darn things. And here you are, sending probes to things that haven't been found.

Well humans, at least 49% of us, are all about the probing. Tell us about something we haven't probed before and we'll start working out plans right away for how we WILL probe it. Kinda makes me think those Grey aliens that are busy probing farmers really are us from the future...

Dammit! Must. Remember. To. Click. Anonymous...

Re:Exciting stuff

[SharpFang]

It's nowhere near impossible, it would just require a decent budget.

First, not a single probe but a bunch of them, to cover more of the space. Of course not all at once, but a program of sending a new one every five years or so would be nice.
Next, equip the probes with decent telescopes. Something like Hubble, maybe a little more on the budget side. The number of probes and the time would contribute to more coverage.
And give them some surplus fuel. So that if something is discovered, a probe can be redirected for a closer fly-by.

Re:Exciting stuff

[SharpFang]

If you introduce the change early enough, even little fuel can change the direction a lot. Note there's a bunch of probes so one can always pick one with trajectory pretty close to optimal, and adjust it early enough. The timeframe would certainly be decades too - I'm thinking of something like Voyager 1, except with a lot of modern technology. New Horizons is one of the newer generation, "budget" probes. Small, lightweight and slow. These would still need budget of the class of Cold War era...

Nothing new

[Anonymous Coward]

Alf already predicted this http://alf.wikia.com/wiki/Alvin

Of course!

[__aaclcg7560]

This would explain why SPACE: 1999 had the runaway Moon passing a planet outside the solar system in every episode. For all these years, I thought British SF TV was just weak in the science department.

Re:Of course!

[gronofer]

If I remember correctly, they did have a scientific explanation for that. The explosion that separated the Moon from the Earth was so powerful that its relative velocity was close to the speed of light, so distance was contracted according to the theory of relativity.

However, I don't remember any explanation for how the moon and its inhabitants could survive intact with such a powerful explosion and rapid acceleration. Maybe I need to go and rewatch the series to find out.

Fastest Probe? [Re:Exciting stuff]

[Tablizer]

I wonder what the fastest possible chemically-propelled-rocket probe is? If the probe was made small and compact to do little more than take photos and spectrographic analysis, how fast could the bugger be made to travel using existing rocket tech?

If it records the pass-by data and sends it back later at a slower pace, somewhat like New Horizons, then it doesn't need that big of an antenna.

Re:Fastest Probe? [Re:Exciting stuff]

[stjobe]

I wonder what the fastest possible chemically-propelled-rocket probe is? If the probe was made small and compact to do little more than take photos and spectrographic analysis, how fast could the bugger be made to travel using existing rocket tech?

While not chemically-propelled, Freeman Dyson calculated while working on the Orion project that one of those magnificent bastards could achieve 3.3% of the speed of light (0.03c, 10,000 km/s, or roughly 22 million kph - give or take a few hundred thousand mph - by firing a shaped-charge nuclear bomb behind it every three seconds for ten days straight.

At that speed, Alpha Centauri is just 133 years away, and these ETNOs are really not much farther than down the road to the chemist.

It's a shame that project never came to anything but a few chemical proof-of-concept scale tests.

Re:Fastest Probe? [Re:Exciting stuff]

[Tablizer]

by firing a shaped-charge nuclear bomb behind it every three seconds for ten days straight.

That's a lot of nukes.

Re:Fastest Probe? [Re:Exciting stuff]

[DanielRavenNest]

> I wonder what the fastest possible chemically-propelled-rocket probe is?

Slower than a Nuclear-ion probe. Nuclear in this case means a small nuclear reactor, say in the 1 MW power range. Plasma thrusters have an exhaust velocity of ~ 50 km/s, and it is reasonable to reach 3x exhaust velocity, thus 150 km/s. The mass ratio (propellant to empty mass) would be 20:1 in that case. For any kind of chemical rocket to reach that velocity, it would need a mass ratio of 10 trillion, which is seriously impractical.

150 km/s = 31.6 AU/year, therefore missions to around 300 AU would be reasonable (10 year trip time). 1 MW reactor with radiators would mass ~ 20 tons. 300 AU probe would mass ~ 5 tons. Propellant load would be 25x20 = 500 tons. Propellant flow rate is .57 grams/sec or 49 kg/day. So thrust time is 28 years, which is a bit long. It would help if the reactor could be made lighter.

Re:Fastest Probe? [Re:Exciting stuff]

[stjobe]

Yep. 300,000 1-megaton yield nukes at 1 metric ton each.

The proposed design had a departure mass of 400,000 tons, with a 50,000 ton payload.

Re:Fastest Probe? [Re:Exciting stuff]

[Tablizer]

Nukes carry a lot of politics with them even if price was no object.

What about a solar sail that also uses the big planets as a gravity sling-shot?

New System: Kuiper Planets

[7bit]

I wonder what they're going to call these new objects, because they'll probably find a reason not to call them planets just like they did for Pluto.

They're too big to be dwarf planets... Maybe elf planets?

Perhaps KP's, Kuiper Planets. Which could start a whole new Planetary naming system based on regional distance from a star instead of what we have now. Everything round + blah between the Star and it's local Kuiper Belt type region would be either an Inner Planet or Solar Planet, everything otherwise fitting that definition but within the Kuiper Belt would be a Kuiper Planet and anything further than that would be an Oort Planet.

That might even allow Pluto to be reclassified as a planet again, either a Solar Planet or Kuiper Planet. I really think this system, plus other basic details like roundness etc, could be a more useful system. It would also allow a way to keep the number of planets more manageable since we could mostly focus on the Inner/Solar Planet count for general public use without the number of them being too high to manage.

New Planet types based on Region/Distance from star:

Inner Planet or Solar Planet
Kuiper Planet
Oort Planet

btw: I made a post as anon under the same parent post before this, then thought I should log in and elaborate. The previous post was:

" They'll probably be called KP's. Kuiper Planets."

Re:New System: Kuiper Planets

[SuperKendall]

That seems like a really good idea, sorry I have no mode points to promote.

Re:New System: Kuiper Planets

[Tablizer]

Mort calling Oort. Mort calling Oort. Manu Manu!

Re:New System: Kuiper Planets

[RockDoctor]

There is a general dispute in taxonomy between "lumpers" and splitters" - people who say "this, this and this share these characteristics, and so I lump them together in one taxon" versus those who say "this, this and this differ in these characteristics, and so I split them into these taxa".

You're evidently a splitter. No disrespect about that - it's a defensible position (see above). But being a lumper is also a defensible position (see above).

The important things that you need for designing a taxonomy are to know what questions you want your taxonomy to address - if you're wanting answers to questions of surface gravity, then a taxonomy based on colour is unlikely to be helpful, for example.

Our current taxonomy for planets is based on the observational status of the planets in respect of their neighbours - the "cleared orbital region" criterion. In principle, that is an addressable question - observe the skies, plot the orbiting bodies down to a few percent of the size of the planets of interest, question answered.

Where things are getting confused is that many people project questions of the origin of the planets onto the orbital classification. Which may not be the most logical thing to do, when looked at in the context above. The two questions are not strictly related : Earth, Venus, Uranus and Pluto all appear to have suffered a giant impact in the late stage of their construction, but Pluto does not currently have a cleared orbit to make it a "planet" under the orbital classification. So our believed-to-be-correct models of origin processes do not (necessarily) align with current orbital status. But you can see from the length of my qualifications above that one taxonomy split is based on fairly long chains of cause and implication, and the other on simple Newtonian mechanics. So I can understand why the IAU decided to go with the relatively simple present-day orbital status criterion.

If I were to design a planet taxonomy, I'd use a criterion of sphericity (is the shape within X% of being a simple spheroid) to divide planets from "minor planets" (you can look at it as the interplay of material strength versus object mass, if you like), and at the upper boundary the presence of fusion (separating planets from stars, with a fudge area to deal with brown dwarfs). But that criterion shows my interest in body materials (I'm a geologist by trade), which differs from the interests of astronomers in general.

Nuclear engines exist

[xtal]

And are well understood.

Short on balls to use them, though.

Rediscovering the 1950s

[dorpus]

They said back then that there is a massive "Planet X" that may orbit in the reverse direction from other planets.

We know now that the universe is full of orphan planets, so it would hardly surprise me if there are many such planets randomly drifting toward stars.

Re:Probe

[beelsebob]

1) It's very difficult to get there - Voyager 1 and 2 are the only probes ever to get that far from the sun and still be functional, and they took decades to get there
2) If you hang around in the orbit of the planet, then you'll have the same orbital period as it. Effectively, you'd stay stationary relative to the planet, and as a result never spot it unless you got lucky and landed exactly where the planet was.

Re:Probe

[Anonymous Coward]

Not to mention the orbital speed even if the probes stayed still. IIRC Pluto hasn't circled the Sun once since it was found.

New System: Inner/Outer Planets

[7bit]

Perhaps KP's, Kuiper Planets. Which could start a whole new Planetary naming system based on regional distance from a star instead of what we have now. Everything round + blah between the Star and it's local Kuiper Belt type region would be either an Inner Planet or Solar Planet, everything otherwise fitting that definition but within the Kuiper Belt would be a Kuiper Planet and anything further than that would be an Oort Planet.

That might even allow Pluto to be reclassified as a planet again, either a Solar Planet or Kuiper Planet. I really think this system, plus other basic details like roundness etc, could be a more useful system. It would also allow a way to keep the number of planets more manageable since we could mostly focus on the Inner/Solar Planet count for general public use without the number of them being too high to manage.

New Planet types based on Region/Distance from star:

Inner Planet or Solar Planet
Kuiper Planet
Oort Planet

btw: I made a post as anon under the same parent post before this, then thought I should log in and elaborate. The previous post was:

" They'll probably be called KP's. Kuiper Planets."

It could be simplified even further yet while still retaining the benefit of greater number manageability for the public, which seems to be a concern for those making the definitions, while also giving actual useful information about the planet in its Type name.

Define a Planetary Region around a star, that would apply to all stars (actual distance per star could vary depending on Factors), in which Planetary objects would be called "Inner Planets" and one more region beyond it in distance where such same type objects would be called "Outer Planets". The Type Name of the Planets would instantly give anyone information about its position relative to its star, which is perhaps more important than telling us it's size "Dwarf". This would solve the old problem of non-Sol Planets not technically being "Planets" while also giving the public a common class of Planets to focus on and more easily remember while still being able to address all the other planets if needed.

Inner Planets
Outer Planets

Re:New System: Inner/Outer Planets

[darkain]

This is starting to sound a lot like Sailor Moon with the Inner vs Outer Senshi.

Re:New System: Inner/Outer Planets

[Will.Woodhull]

The alchemists did something like this, on the road to the periodic table of the elements. So it could definitely be a useful way to develop telescopic science.

In a few decades we could then make a distinction between astronomers who accept a rationally based taxonomy of orbital objects, and "alastronomers" whose thought processes are mired in the old school searches for definitions that make distinctions between Pluto, Ceres, etc and Mercury, Mars, etc. Not to mention the hair-splitting the alastronomers use to keep from admitting that the Earth and Moon are a binary planet such that the orbit of either one around Sol has a strong sinusoidal component.

Re:New System: Inner/Outer Planets

[Damarkus13]

Not to mention the hair-splitting the alastronomers use to keep from admitting that the Earth and Moon are a binary planet such that the orbit of either one around Sol has a strong sinusoidal component.

I thought the distinction was that the center of the Earth and Moon's mass was still within the physical circumstance of the planet. While binary planets have that center of mass somewhere between the planet's. That doesn't seem like splitting hairs to me. That seems to be a pretty clear distinction.

Re:New System: Inner/Outer Planets

[Will.Woodhull]

I have read your post and understand that it is, alas, representative of contemporary astronomy's position wrt the pairing of the Earth and Moon as not being significantly different from, say, the pairing of Mars and Phobos.

But I take solace in the fact that the Moon is spiralling away from the Earth and long before the death of the Sun makes all this insignificant, the Earth and Moon will, in fact, become a binary planet. According to the precepts of contemporary astronomy.

It does seem extremely odd that what will become true in the future is considered false at present. Especially as the increase in distance that will make the Earth - Moon a binary planet will also diminish the now powerful effects each has upon the other.

Re:New System: Inner/Outer Planets

[SharpFang]

" the Moon is spiralling away from the Earth and long before the death of the Sun makes all this insignificant, the Earth and Moon will, in fact, become a binary planet."

With growing distance gravitational influence between two bodies gets weaker, that means distant Moon would influence Earth orbit even less than it does now, and the centre of rotation between the two would move even further towards Earth's core.

Re:New System: Inner/Outer Planets

[Ramze]

Modern astronomy is still clinging to the historical method of naming things according to their influence on and by their surroundings. Yes, it's silly. I'd rather a system that describes bodies by their characteristics instead of their locations relative to other objects.

Phobos is just an asteroid captured by Mars, but because it's a satellite of Mars, it is classified as a moon. Some large moons around gas giants like Triton are thought to have once been planets or dwarf planets. Obviously, there's a huge difference between Titan with its large diameter and thick atmosphere and the tiny, irregularly shaped Deimos. Yet, they are both moons. The current system cares nothing for their characteristics or how they were formed.

Your notion regarding the Earth/Moon system having a different classification in the future than it does today is no more relevant than if Mars were to be captured by Jupiter in a few billion years due to orbital instability. We'd then call Mars a moon instead of a planet. Odd, perhaps, but that doesn't mean we should start calling Mars a Jovian moon in the meantime - even if we had mathematical models proving it was going to happen. Even more odd -- if a Jovian moon were to be hurled into deep space, there is no official designation for what to call it at that point. Rogue planet, sub-brown dwarf, and interstellar planetary body are merely suggestions.

To say that the Earth and the Moon have a special relationship is obvious, but it doesn't warrant any extraordinary classification given the absurdity of the current system. The Moon does indeed orbit Earth as evidenced by the barycenter being inside Earth as well as the Earth being the more massive of the two objects. The Moon is also tidally locked to Earth as most moons are. Yes, as you point out, both the Earth and the Moon have a sinusoidal/elliptical orbit around Sol, but I'd argue that it's not only insignificant, but its shape would change entirely if Earth/Moon were a greater distance from Sol. Earth's orbit only shows a tiny wobble while the Moon's is more pronounced, but more importantly - the shape of the Moon's orbit has little to do with the mass of the moon itself. At its current distance from Earth, given the masses and positions of Sol and Earth, any satellite would have a stronger gravitational influence from Sol than from Earth. However, if we moved Earth and the Moon to a distance say... in place of Jupiter, Sol's influence would be less, the barycenter between Earth and the Moon would stay the same, but you'd instead see a true looping orbit path for the Moon around the Earth as Earth's gravity will be significantly stronger than the Sun's at that distance. Some of Neptune's outermost moons also have a sinusoidal path around the sun, but again, it's more to do with the masses and distances to Neptune and Sol than anything unique about the moons in relation to Neptune. Alternatively, over 4 billion years ago, the Earth/Moon system would have had a barycenter closer to Earth's core and the distance between the Earth and Moon was shorter, making Earth's gravitational effect on the Moon much stronger. I haven't done the math, but given the distances, I'd bet the Moon's orbit at that time was more influenced by Earth than Sol as well and took a different shape around Sol.

http://en.wikipedia.org/wiki/D...

Your argument that the Earth and Moon have a special relationship in our solar system is valid, but your argument to classify that relationship as a binary planet is flawed primarily because there currently is no such formal classification. One was proposed for Pluto because the barycenter for it and its moons is outside of Pluto, but that proposal was abandoned. Pluto is a dwarf planet with moons instead of a binary planet or even a binary dwarf planet with Charon. The barycenter idea isn't a rule - it's just an arbitrary argument which wasn't strong enough to convince a committee that it was important enough to warrant

Re:New System: Inner/Outer Planets

[Will.Woodhull]

tl;dr. I did read the first few paragraphs.

Significant findings in what I did read:

Somehow parent poster managed to mistake grand-parent's position with regard to using the innie-or-outie barycenter as a point of distinction between a moon and a binary planet. GP was very definitely saying that such a distinction was pointless. Which seems to also be what PP is trying to argue. Which suggests that much of PP can be ignored; it is preaching to the choir but for some reason its author has been unable to see that. Perhaps his mind, which apparently is pretty clear much of the time when dealing with astronomy, was clouded by his emotions. Which do come through very strongly in PP.

However the following calls for a comment:

To say that the Earth and the Moon have a special relationship is obvious, but it doesn't warrant any extraordinary classification given the absurdity of the current system.

While PP and GP agree on the absurdity of all this, PP is not seeing the importance that GP sees in the affects of promulgating this crap.

GP's concern is that astronomy has a duty (as does every science) to present its truths clearly to everyone outside of its small scientific community. It cannot dismiss absurd representations in its jargon as unimportant by arguing that all astronomers can see the fallacies and just ignore them. That is a travesty; astronomy needs to provide college students, high school students, grade school students, and kindergarteners with an accurate representation of its findings and not some mumbo-jumbo absurdity like what PP has so eloquently described above.

This is all the more poignant since the IAU brought this whole foolish argument up because in the wisdom of their final hours of their last big confab after many members had left to catch the bus home, they expressedly attacked the current state of general understanding of what defines a planet or a moon and replaced it with an even more absurd set of definitions meant for public consumption. To replace what has been taught in the schools. And now through posts like PP the community of astronomers are attempting to backpedal by claiming that none of this makes any difference anyway, since WE all know what we are talking about.

What arrogant bullshit.

IAU: you and you alone have the power to fix this mess that was made on your doorstep, in your name. Figure out what it is that should be taught to the youngsters today who might choose to take advanced astronomy courses tomorrow. Then make that public, with your full support behind it.

Re:New System: Inner/Outer Planets

[Ramze]

No need to begin with tl; dr as it's obvious you either didn't read it or simply have a lack of reading comprehension. Odd that you'd bother to reply without reading and comprehending, though. You clearly missed my point entirely.

My post was a response to yours, not its grandparent, so all references to such are moot. Mostly, I was trying to convey a general sense that modern astronomy lacks clear, descriptive definitions and designations - including one for "binary planet" which you were clearly arguing for.

This gem is what I was specifically replying to:

"But I take solace in the fact that the Moon is spiralling away from the Earth and long before the death of the Sun makes all this insignificant, the Earth and Moon will, in fact, become a binary planet. According to the precepts of contemporary astronomy."

The Earth and Moon will absolutely, emphatically, undeniably NOT be considered a binary planet according to contemporary astronomy because THERE IS NO SUCH DESIGNATION.

I hope this post was short enough and uses small enough words to get the point across for you.

I apologize for attempting to enlighten you on your error while simultaneously agreeing with you that the current system is extremely flawed.

Re:New System: Inner/Outer Planets

[Will.Woodhull]

Yes, "the stupid drama" is probably getting more people to read this stuff than would otherwise be the case.

But the positions that have been expressed are now only being repeated. Let it go. A better astronomical taxonomy will undoubtedly come along in the next few years, possibly at the next IAU convention. Let it go, for now.

Re:Probe

[stjobe]

You recall correctly; Pluto hasn't even made it half a lap around the sun since we discovered it.

It was discovered in 1906, 108 years ago, and it's orbital period is 247.68 years.

Re:Yuggoth

[stjobe]

"Why choose the lesser of two evils? Vote Cthulhu for President 2016"

Re:The correct answer

[gatkinso]

Says the grown up tape worm to the baby human.

Re:Probe

[Anonymous Coward]

You think in another 108 years you'll have mastered the difference between its and it's?

Re:Probe

[Anonymous Coward]

You recall correctly; Pluto hasn't even made it half a lap around the sun since we discovered it.

It was discovered in 1906, 108 years ago, and it's orbital period is 247.68 years.

Incorrect, Pluto was discovered on February 18, 1930 by Clyde W. Tombaugh.

Percival Lowell started looking for trans neptunian objects in 1906 if you read here:

http://en.wikipedia.org/wiki/Pluto

That being said, being a serious Doctor Who fan, I hope that one of these planets the article postulates to exist, when found, is named Cassius so that K-9's statement in the episode "The SunMakers" turns out to be true.

Re:Probe

[SharpFang]

As for 2), if you move in the retrograde orbit, you're bound to encounter the planet twice per its orbital period. Any probes towards the transneptunian objects (except for these with landers) should move in retrograde direction (opposite to how the planets travel), this way they will be able to observe them in reasonable timeframe.

Re:Probe

[AthanasiusKircher]

You recall correctly; Pluto hasn't even made it half a lap around the sun since we discovered it.

It was discovered in 1906, 108 years ago

WTF MODS? This gets "+5 informative"??

Pluto was discovered in 1930, as anyone could verify anywhere. Jesus Christ. This is NOT an obscure fact, particularly for anyone who knows anything about the solar system. I've been reading Slashdot for a long time, and I've seen a lot of crap, but I'm seriously thinking of leaving now. News for "nerds" my ass.

Re:Nibiru!

[Applehu Akbar]

But how does Nibiru get those mind-altering toxins to American air carriers so they can be spread through our pristine skies as chemtrails? At those distances, Paul Craig Roberts would probably still have to invoke a wormhole.

Re:Probe

[beelsebob]

Where by "reasonable timeframe" you mean "once every 2 and a half millennia", plus, getting into a retrograde orbit around the sun increases the fuel bill, and the issue with point 1) even more.

So what?!

[vandamme]

If they're out there, they are cold and dark, and really really far away. As long as they stay there, it makes no difference to us.

Re:Probe

[SharpFang]

Getting into the retrograde orbit necessitates a close Jupiter flyby in order to reverse direction.

two and half millennia per probe per object per flyby (as opposed to observation from a long distance). Nevertheless that's already vastly better than 'never'.