New evidence for existence of Planet Nine

May 21, 2018 by Bob Yirka, Phys.org report
A visual representation of the orbit of 2015 BP519, plotted with the other ETNOs as comparisons. For each orbit, the darker regions on the curve denote where an object falls below the plane of the solar system. 2015 BP519 has the highest inclination of any extreme TNO discovered to date. The full, interactive 3D orbit visualization can be found at smillholland.github.io/BP519/ . Credit: arXiv:1805.05355 [astro-ph.EP]

A large international team of researchers has found what they are describing as more evidence of the existence of Planet Nine. In their paper posted on the arXiv preprint server, the group describes the behavior of a newly discovered distant object as suggestive of an influence of a large planet.

It was just two years ago that astronomers at Caltech proposed the possible existence of a large planet circling the sun—which would make it the ninth known planet in our solar system. The researchers made their prediction based on observations of icy objects that exist at the edge of the solar system—their orbits were clearly being warped by a gravitational mass. They suggested a very distant planet roughly four times the size of Earth, but with 10 times its mass, could account for the odd behavior. If such a planet does exist, it would be quite distant, taking from 10,000 to 20,000 years to make one trip around the sun. Since announcing their initial findings, the team at Caltech has published papers offering more evidence of the planet—the possibility that it could have played a role in tilting the other planets in our solar system, for example. They have also suggested it as an explanation for why objects in the Kuiper Belt orbit in an opposite direction to everything else.

In this new effort, the researchers suggest the behavior of a certain Trans-Neptunian could very well be due to gravity from Planet Nine. The object, called 2015 BP519 (Caju for short), was first noted approximately three years ago, but it was only recently that the shape of its orbit was found to be very unusual—it lies nearly perpendicular to the plane established by the known . What makes the find so compelling is that the team of researchers who first proposed the existence of Planet Nine created a simulation that predicted the orbital angle of just such an object. And it just happened to match with what has been found.

The researchers report that after Caju was first discovered, attempts were made to calculate its , but they all failed. Then they added a large planet to the simulations, which resolved the discrepancies. All that is needed now, they suggest, is for someone to actually find the planet.

Explore further: In search of the ninth planet

More information: Discovery and Dynamical Analysis of an Extreme Trans-Neptunian Object with a High Orbital Inclination, arXiv:1805.05355 [astro-ph.EP] arxiv.org/abs/1805.05355

Abstract
We report the discovery and dynamical analysis of 2015 BP519, an extreme Trans-Neptunian Object detected detected by the Dark Energy Survey at a heliocentric distance of 55 AU and absolute magnitude Hr= 4.3. The current orbit, determined from a 1110-day observational arc, has semi-major axis a≈ 450 AU, eccentricity e≈ 0.92 and inclination i≈ 54 degrees. With these orbital elements, 2015 BP519 is the most extreme TNO discovered to date, as quantified by the reduced Kozai action, which is is a conserved quantity at fixed semi-major axis a for axisymmetric perturbations. We discuss the orbital stability and evolution of this object in the context of the known Solar System, and find that 2015 BP519 displays rich dynamical behavior, including rapid diffusion in semi-major axis and more constrained variations in eccentricity and inclination. We also consider the long term orbital stability and evolutionary behavior within the context of the Planet Nine Hypothesis, and find that BP519 adds to the circumstantial evidence for the existence of this proposed new member of the Solar System, as it would represent the first member of the population of high-i, ϖ-shepherded TNOs.

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Mark Thomas
2.7 / 5 (10) May 21, 2018
Astronomer Mike Brown said he thought "Planet 9" would be found by the Spring of 2018, so that prediction has one more month of shelf life. I am of the opinion that Mike Brown will be proven wrong here, i.e., Planet 9 does not exist.

"A star is expected to pass through the Oort Cloud every 100,000 years or so. An approach as close or closer than 52,000 AU (Scholz's Star) is expected to occur about every 9 million years."

https://en.wikipe...z's_Star

That means Mike Brown's simulation failed to account for any one of the approximately 45 thousand close encounters since the solar system was formed. This is a gigantic, gaping hole in Mike Brown's simulation. This also ignores the arguably far more interesting story of exchange of materials during these close encounters like asteroid 2015 BZ509, which is apparently of interstellar origin.

https://phys.org/...lar.html
Scolar_Visari
5 / 5 (2) May 21, 2018
Batygin & Brown's, "Evidence for a Distant Giant Planet in the Solar System" was not the only paper producing evidence for the proposed Planet Nine. Indeed, Trujillo & Sheppard's, "A Sedna-like body with a perihelion of 80 astronomical units" Nature 2014 gets that honor, and they did address several earlier papers on the subject of stellar encounters and disruptions of the outer Solar System; and this was also mentioned in "Evidence for a Distant Giant Planet".

Furthermore, disruptions of the Oort Cloud by stellar encounters are simply not mutually exclusive with a massive planet doing the same to the same family of objects or others. Marcos, Marcos & Aarseth's, "Where the Solar system meets the solar neighbourhood: patterns in the distribution of radiants of observed hyperbolic minor bodies" MNRAS 2018 noted that while particular observations could be attributed to stellar encounters (including Scholz's Star), others could still be attributed to, "one or more unseen perturbers."
Mark Thomas
4 / 5 (1) May 21, 2018
disruptions of the Oort Cloud by stellar encounters are simply not mutually exclusive with a massive planet doing the same to the same family of objects or others.


That makes obvious sense to you and me, at least at the start of the analysis when one cannot readily distinguish between the effects of a close stellar pass and a Planet 9. However, Batygin & Brown concluded the only remaining possibility was Planet 9.

Unless you want to argue all the searches for Planet 9 since the Batygin & Brown announcement have been completely useless, the chances of Planet 9 hiding out there in some unsearched corner grow increasingly slim with time.

Another possibility is that Planet 9 existed at one point in time, but was later removed by a close stellar pass or series of close stellar passes. This is yet another scenario Batygin & Brown did not consider at all when they concluded that Planet 9 currently exists in the outer solar system as they specified.
Mark Thomas
5 / 5 (1) May 21, 2018
Scolar_Visari, here is my predicted answer, which has not changed since no later than April, 2016:

There is no Planet 9 because the outer solar system is far more dynamic over geological time scales than we had previously thought. The simulation of Batygin & Brown is fundamentally flawing for ignoring this fact. Eventually Batygin & Brown will conclude the same thing.

https://phys.org/...net.html

JongDan
5 / 5 (3) May 21, 2018
There's a slight difference between a single stellar pass, and a body in orbit that consistently perturbs. Additionally, ~45k close encounters would mean that one would expect ~45k different configurations of perturbed orbits (I'm assuming that orbits this distant are stable enough not to change much, but here almost all of them seem to be perturbed in the same way.
Scolar_Visari
5 / 5 (2) May 21, 2018
Planet Nine's existence was supported by Batygin & Brown because there was strong evidence that the perturbed bodies are maintained, and that automatically precludes a removed planetary body. Batygin & Morbidelli's, "Dynamical Evolution Induced By Planet Nine" Astronomical Journal 2017 goes into further detail on the subject.

Additionally, the paper which this article is addressing, "Discovery and dynamical analysis of an extreme tran-Neptunian object with a high orbital inclination" also mentioned non-Planet Nine alternatives in detail (including stellar encounters) and still concluded an unseen planet is the best fit for the data.

Despite the reality that a hypothetical Planet Nine hasn't been observed, it's still the best hypothesis for the problem in question. You haven't really cited any papers contradicting this, and I'm not even sure you've read the papers supporting Planet Nine's existence before deciding that Brown (really Batygin & Brown) were wrong.
granville583762
3 / 5 (6) May 21, 2018
A Definition of a planet is a planet has cleared its orbit. Earth has not cleared its orbit, the other way round. The moon is clearing its orbit increasing its orbital radius. The earth joins PLUTO in a class of dwarf planets.
Planet Nine's existence is Pluto, were looking for planet 10, knowing what we now know about Pluto it would still be planet 9.
Mark Thomas
5 / 5 (2) May 21, 2018
The closest and most recent stellar passes might have the most noticeable effects on current Kuiper Belt, Scattered Disk and Oort Cloud orbits. Close passes by other stellar objects are potentially messy encounters with extended portions of a passing solar system and ours potentially coming into relatively close contact. Unlike some papers that described these outer portions of our solar system as containing "pristine" objects, the amount of chaos and mixing by tens of thousands of close passes must be profound. For example, I would expect to find objects with a great diversity of origins that formed under a great diversity of conditions, including much higher temperatures than typical for their areas of space. Add this to the mountain of reasons to keep exploring the solar system.
yaridanjo
1 / 5 (6) May 21, 2018
I think Planet Nine has already been found in 2002 - 2004. Astronomer Forbes almost found in 1880. Madam Blavatsky sensed it around 1900 and told us how to find it and called it 'Vulcan'. You can find its mass and orbital parameters here:

http://barry.warm...led.html
VULCAN REVEALED
A Dangerous New Jovian Sized Body In Our Solar System
Scolar_Visari
4.2 / 5 (5) May 21, 2018
@granville583762
Clearing one's orbit DOES NOT mean being the only object within said orbit as you're implying. To quote Jean-Luc Margot's, "A Quantitative Criterion for Defining Planets" The Astronomical Journal 2015, "What the IAU intended is not the impossible standard of impeccable orbit clearing; rather the standard is analogous to what Soter (2006, 2008) described as a dynamical-dominance criterion".

Prior to completely reversing his views, Alan Stern also co-wrote a paper with Harold Levison, "Regarding the Criteria for Planethood and Proposed Planetary Classification Schemes" Highlights of Astronomy 2002 that noted, "The largest planetary bodies dynamically control the region surrounding them. Nearby small bodies are on unstable, transient orbits, or are locked in mean motion resonances or in satellite orbits."
Mark Thomas
5 / 5 (2) May 21, 2018
Scolar_Visari, a number of professional astronomers have questioned Batygin & Brown's conclusions. Considering B&B have argued since 2016 that Planet 9 exists, but nothing has been found, I would say the burden of proof is on them more than ever to make their case. To my knowledge, B&B have not proven their case is better than the close stellar passes case and the single paragraph in section 4.2.1 of the paper here is not exactly a tour-de-force on this subject.

I would also note that the simulation in the paper is with Planet 9 at a very convenient 700 AU, but that area of space has arguably already been ruled out by existing surveys. I find it hard to believe a 10 Earth mass planet is lurking unseen a mere 700 AU away, resisting all attempts to locate it, including NASA's WISE mission.
Scolar_Visari
5 / 5 (2) May 21, 2018
@Mark Thomas
I can't think of any relevant papers that actually assume the outer Solar System is dynamically, "pristine" by any understanding of the term. All the papers cited thus far addressing Planet Nine, as a matter of fact, immediately expect scattering of the entire system as a consequence of neighboring stars, the known planets and possibly ejected planets from the very birth of the Sun. Yet those and the additional possibility of perturbations from more recent stellar encounters have little bearing on the maintained perturbations already observed that have only been reliably modeled by accepting an unseen planet.

I would recommend reading some of the peer reviewed work supporting Planet Nine, as a lot of your objections were actually addressed in the cited texts.
Scolar_Visari
5 / 5 (2) May 21, 2018
Unless you provide a reference, there's no reason to accept your claim that, "a number of professional astronomers have questioned Batygin & Brown's conclusions" as any more or less accurate than arguing that an even larger number have supported their conclusions. This also goes for your argument that Planet Nine's hypothetical position at 700 AU has been ruled out. The latter claim is particularly odd, as you appear to be using a proposed semi-major axis instead of the more useful aphelion and perihelion figures.

While the stellar encounters haven't been modeled in great detail, this isn't really a problem given that there is strong evidence that the perturbation in question is being actively maintained.

And why bring up burden of proof? No one's disputing the possibility that Planet Nine may not exist. The issue is that it's the only hypothesis modeled thus far with evidence to its credit, and you've not really provided much to contradict this.
granville583762
3.7 / 5 (3) May 21, 2018
Scolar_Visari> @granville583762
Clearing one's orbit DOES NOT mean being the only object within said orbit as you're implying. To quote Jean-Luc Margot's, "A Quantitative Criterion for Defining Planets" The Astronomical Journal 2015, "What the IAU intended is not the impossible standard of impeccable orbit clearing; rather the standard is analogous to what Soter (2006, 2008) described as a dynamical-dominance criterion".

Prior to completely reversing his views, Alan Stern also co-wrote a paper with Harold Levison, "Regarding the Criteria for Planethood and Proposed Planetary Classification Schemes" Highlights of Astronomy 2002 that noted, "The largest planetary bodies dynamically control the region surrounding them. Nearby small bodies are on unstable, transient orbits, or are locked in mean motion resonances or in satellite orbits."

Continuing to redefine planets will result in this search not be 9 but 8 so PLUTO still stands a planet.
Scolar_Visari
3.7 / 5 (3) May 21, 2018
@granville583762
Amusingly, the Stern & Levison paper I cited precluded Pluto from being grouped in with the eight planets for the very same reason you allege Earth would not be a planet.

Though I'm getting the impression you really don't care how actual astronomers categorize objects.
granville583762
3.7 / 5 (3) May 21, 2018
Scolar_Visari> @granville583762
Clearing one's orbit DOES NOT mean being the only object within said orbit as you're implying..

Prior to completely reversing his views, Alan Stern also co-wrote a paper with Harold Levison, "Regarding the Criteria for Planethood and Proposed Planetary Classification Schemes"

granville583762> Continuing to redefine planets will result in this search not be 9 but 8 so PLUTO still stands a planet

A test of a system for defining planets comes with the human element, mainly one always leaves the status quo, nobody minds the definition for planets of new planets, it is not the done thing old boy – Pluto is still a planet especially what we now know about Pluto because we're only going to find more of the same as PLUTO – just in various sizes, PLUTO is as good as it gets!
granville583762
3.7 / 5 (3) May 21, 2018
Beyond PLUTO the solar system has run out of planets
Scolar_Visari> @granville583762
Amusingly, the Stern & Levison paper I cited precluded Pluto from being grouped in with the eight planets for the very same reason you allege Earth would not be a planet.

Though I'm getting the impression you really don't care how actual astronomers categorize objects.

Beyond PLUTO the solar system has run out of planets that can even match a planet of PLUTOS complexity being defined as dwarf – in fact any dwarf planet further than PLUTO can only be less complex as a planet.
granville583762
3.7 / 5 (3) May 21, 2018
Scolar_Visari> @granville583762

Though I'm getting the impression you really don't care how actual astronomers categorize objects.

You do keep treading on toes - it is not the done thing old boy.
Scolar_Visari
3 / 5 (4) May 21, 2018
@granville583762
Pluto is not a planet under the definition of the IAU, and your claiming otherwise won't change the minds of publishing astronomers and planetary scientists who now and have routinely mention it as a dwarf planet distinct from the eight known planets.

Likewise, it is quite possible for a body, such as the proposed Planet Nine, to be massive enough to clear its orbit. Its vague, "complexity" is irrelevant. Planets are defined by hydrostatic equilibrium and their dynamical characteristics and have been for centuries, and the modern definition is simply a clarification of that. In spite of your claims, the IAU et al. were indeed retaining the status quo by excluding Pluto so as to exclude the increasing number of similar bodies.
granville583762
3.7 / 5 (3) May 21, 2018
Scolar_Visari:- Questioning a theory does not mean ones belief is diminished in the dwarf definition as I was not saying it was not valid; it should have been used with a bit more discretion!
granville583762
3.7 / 5 (3) May 21, 2018
Scolar_Visari:- Questioning a theory does not mean ones belief is diminished in the dwarf definition as I was not saying it was not valid; it should have been used with a bit more discretion!

Which comes to the search of plants as complex of plants of the stature of PLUTO, the end result from this endeavour in all likely hood will result in a new class of planets of a sub class below a dwarf planet less complex than PLUTO.
Scolar_Visari
5 / 5 (1) May 21, 2018
The classification of Pluto is not a matter of theory or belief. It's a matter of professional convenience that, quite frankly, your own opinion has no bearing on. Don't like it? Too bad. I'm simply pointing out that you visibly don't understand how the current definition works (or simply don't care) and that you aren't making any sense elsewhere. Typing Pluto in all caps is not helping your case.

As for finding more planets, Planet Nine's proposed maximum mass of ten Earths is more than enough to include it as a planet in spite of your claims. Again, your vague mentions of complexity ignore how astronomers actually classify planets.
Mark Thomas
5 / 5 (3) May 21, 2018
"Right now, any good scientist is going to be skeptical, because it's a pretty big claim." – Mike Brown

https://www.pbs.o...presence

I read Astronomer David Jewitt and others had questioned the existence of Planet 9. If I get a chance I will look for some of the articles I read before.

In any case, you have ignored:

1. Mike Brown's prediction that it would be found by the Spring of 2018 is about to fail.
2. Nothing has been found, even though many have looked, limiting the area where Planet 9 could be found.
3. The 700 AU figure came from the paper, not me.
4. Nobody has done a great job simulating the effects of all those close stellar passes probably because it is a tremendously difficult task due to the chaotic nature of all the close encounters.

A agree that the odds are what is happening out there is not a coincidence, but that does not make B&B right.
Mark Thomas
not rated yet May 21, 2018
I give it about a 1% chance of turning out to be real," says astronomer JJ Kavelaars, of the Dominion Astrophysical Observatory in Victoria, Canada.


http://www.scienc...net-nine

Indeed, Paul Delaney, an astronomer at York University, notes that the effects attributed to Planet Nine could be explained by other phenomena or by simple chance — however remote.


https://www.thest...uto.html
Scolar_Visari
5 / 5 (1) May 21, 2018
1. So what if Brown's Magic 8-Ball level prediction is wrong? The video from early 2016 itself ignores developments made since that time and Jewitt's doubts regarding Planet Nine were also expressed in 2016.

2. Having not found Planet Nine hasn't really had anything to do with the other claims you've made regarding its general validity. Despite the lack of direct observation, we're probably farther from dismissing Planet Nine now than we were it was first brought up. There have been several papers published since then.

3. From what paper?

4. That stellar encounters haven't been modeled in detail isn't that big a problem in this particular case given that we already have a good fit for an unseen planet in the data.

No one is saying Brown et al. are correct (particularly since nothing has been found!), but that they present the most likely solution. What we personally think of them is not really relevant.
eric96
not rated yet May 22, 2018
This mystery is the very reason why we need 4 telescopes around earth (2 at poles) and 4 telescopes around Neptune (2 at poles). Obviously we can count the ground ones if they sit at either poles or the equator. When you're talking a distance 40x greater then pluto, its a big ass sky, and our view is rather limited compared to Neptunes.
RealityCheck
3.7 / 5 (6) May 22, 2018
@Scolar_Visari.

I can't help wondering: Given the voluminous past and present stellar observations data, and especially the more recent 'planet hunting' efforts (using dedicated planet-hunting scopes/instruments capable of detecting the very small stellar radiation 'drop' when planets pass across our line-of-sight to the host stars), shouldn't we have detected by now Planet Nine (in our own outer solar system) passing across our line-of-sight to whichever distant stars it would be 'eclipsing' totally?

ie, IF the (postulated) Planet Nine moved along its orbital arc so far observed, there should be a detectable 'serial eclipsing' of a 'line' of stars normally visible along that arc-line in the sky.

Have you (or anyone else) seen any papers/comments anywhere in the literature considering/pursuing this particular line of enquiry/observation/logic? If so, I would be much obliged for any link(s) to same.

Thanks, SV. :)
Shootist
1 / 5 (1) May 22, 2018
what this forum needs is Oliver Manuel, Ph. D.

granville583762
3.7 / 5 (3) May 22, 2018
Theories are all in the mind when they come crashing down when your theories fall flat
Scolar_Visari> The classification of Pluto is not a matter of theory or belief. It's a matter of professional convenience that, quite frankly, your own opinion has no bearing on. Don't like it?

For a planet that's been around for 4billion years and only in 1/4billionth of that time as has its status downgraded to a dwarf, when it has been holding its own for over 4billion years and your suddenly getting high horsy and almighty as though the only opinion that counts is your good self and no one's else's
Your arrogance is breathtaking, and you go on to say any one contradicting your view you have taken upon yourself - that everyone else visibly don't understand how the current definition works (or simply don't care) and that we aren't making any sense.

That is some Ivory Tower you are constructing for you self old bean, when it comes crashing down!
granville583762
3.7 / 5 (3) May 22, 2018
A PLANETS status, a dwarf does not make

Let's get into us simply not understanding Scolar_Visari shall we
You simply do not understand Scolar_Visari, it matters not one jot of difference Scolar_Visari that PLUTO is a dwarf or what it has been for the last 4billion years namely A Planet.

Changing in a planets status does not change PLUTO, nothing has changed, it is the same planet it was a planet one femto-second before the vote as it is the the same planet one femto-second after the vote!

If it was different after the vote, I could understand your angst.
granville583762
3.7 / 5 (3) May 22, 2018
But Scolar_Visari it is not different after the vote is it Scolar_Visari.

It is still the same planet as astronomers were happy to designate PLUTO a planet upon its discovery.
The very same astronomers are still quite happy to designate that bright orb rising on those clear evenings a MOON and their in lies the distinction Scolar_Visari, we have a system when a PLANET stops being a planet and becomes other celestial bodies, as in this case a Planets Moon!
granville583762
3.7 / 5 (3) May 22, 2018
Other solar systems planets are visible but not further out from Pluto
RealityCheck> @Scolar_Visari, I can't help wondering: Given the voluminous past and present stellar observations data, and especially the more recent 'planet hunting' efforts (using dedicated planet-hunting scopes/instruments capable of detecting the very small stellar radiation 'drop' when planets pass across our line-of-sight to the host stars), shouldn't we have detected by now Planet Nine

Exactly the impression I have been implying to Scolar_Visari but a planet status is clouding the view.

The fact that if we accept Pluto's new found status, all be it a bit late after 4buillion years, the fact we are uncovering planets on solar systems of other Suns, and we cannot see Planets (polite cough, dwarf planets) a little further out from PLUTO – well why not, even fully fledged planets, speaks volumes!
eric96
5 / 5 (2) May 22, 2018
Perspective

No planet, discovered to date, has been discovered by direct observation.
Even the closest star, its planets are a combination of (too far, too small, too dim, too cold) to observe directly we current technology. The furthest object in our solar system that we have observed sits at 103 AU, and has a radius of about 300 km. Planet 9 has a radius of 13,000 km, but is anywhere between 200 to 1200 AU. Pluto is about 50 AU, Eris is about 97 AU and the same size of pluto. Eris was discovered using the 1.2 m Samuel Oschin Schmidt telescope at Palomar Observatory. No object has been classified beyond 103 AU. So what does this all mean? It means none of the 13 of the largest optical telescopes with a 8 m mirror have been utilized to catalogue our solar system; absolutely stupid but true. There's just no demand for "almost nothing" of which most of the observation time with these telescopes would yield because nobody is interested in asteroids. Continued.
eric96
5 / 5 (1) May 22, 2018
You may also think size is king, but that is only true if the planet is close to its parent star and planet 9 as you know is the exact opposite. Planet 9 is likely a rock or ice planet with virtually no atmosphere. Such a planet would be very dim and very cold and even at 400 AU that's still 8X farther than pluto. You would need those 13 telescopes to have any hope in detecting it. Nearly all observations in history would fail to illustrate it even as a dot.
Anonym
1 / 5 (3) May 22, 2018
Hard to believe the name hasn't come up yet. So here it is:
velikovsky
Mark Thomas
5 / 5 (3) May 22, 2018
These papers directly or indirectly conclude passing stars can affect the orbits of outer solar system objects and make them less circular and/or move them out of the plane of the solar system.

"We ran a grid of simulations for a flyby star . . . The effect on the disc is slight but clear starting at 40 AU, where particles reach an eccentricity up to 0.1"
https://arxiv.org...2412.pdf

https://arxiv.org...2644.pdf
https://arxiv.org...02.00778
https://arxiv.org...01.10254
https://arxiv.org...02.04655
https://www.acade.../7212353
Mark Thomas
5 / 5 (2) May 22, 2018
1. So what if Brown's Magic 8-Ball level prediction is wrong?
Obviously this increases the desirability for a new hypothesis to explain the strange orbits of the bodies B&B were looking at.

2. Having not found Planet Nine hasn't really had anything to do with the other claims you've made regarding its general validity.
Wrong, the more we look and don't find, the more likely B&B's simulation is a either wrong or a red herring .

3. From what paper?
See some of them above.

4. That stellar encounters haven't been modeled in detail isn't that big a problem in this particular case given that we already have a good fit for an unseen planet in the data.
You can't simply conclude that makes it right, especially when the evidence is going the other way.

No one is saying Brown et al. are correct
- Good, because I am saying there is a good chance they are incorrect.

granville583762
3.7 / 5 (3) May 22, 2018
eric96> No planet, discovered to date, has been discovered by direct observation.
Even the closest star, its planets are a combination of (too far, too small, too dim, too cold) to observe directly we current technology. The furthest object in our solar system that we have observed sits at 103 AU, and has a radius of about 300 km. Planet 9 has a radius of 13,000 km, but is anywhere between 200 to 1200 AU. Pluto is about 50 AU, Eris is about 97 AU and the same size of pluto. Eris was discovered using the 1.2 m Samuel Oschin Schmidt telescope at Palomar Observatory. No object has been classified beyond 103 AU. None of the 13 of the largest optical telescopes with a 8 m mirror have been utilized to catalogue our solar system; nobody is interested in asteroids

Just what's been said. PLUTO is as good as it gets!
Da Schneib
not rated yet May 22, 2018
@Mark one of the points @Visari is making is that multiple encounters with extra-Solar System objects are required to give the results, which can be explained by only one large planet. The former are much less likely than the latter. This is a form of Ockham's Razor. If we're betting money I'm going with the Razor.
granville583762
3.7 / 5 (3) May 23, 2018
Nothing of note since PLUTO
Pluto Discovered February 18, 1930 by Clyde William Tombaugh, the result of all that hard work now appears to be a dwarf planet.
Clyde William Tombaugh secondary discovery of note asteroid 1604 Tombaugh, discovered in 1931 isv32 kilometres in diameter.
It all so appears no more planets have been found now totalling 88years
The asteroid 1604 Tombaugh, discovered in 1931, named after him. He discovered hundreds of asteroids, beginning with 2839 Annette in 1929, mostly as a by-product of his search for Pluto and his searches for other celestial objects
Mark Thomas
5 / 5 (2) May 23, 2018
multiple encounters with extra-Solar System objects are required to give the results


I have read this before, but I have not seen convincing evidence this is true. If a star were to pass by or through our solar system it's gravity would change the orbits of the closest bodies in the solar system, as mentioned in a number of the papers I cited. A single stellar encounter would be enough to permanently change these orbits.

If Planet 9 does not exist, we need to consider other alternatives. It is possible that stellar encounters may not be source of effects B&B identified, but if a star has passed through the Oort Cloud every 100,000 years they are certain to have a significant effect at least in the Oort Cloud.
granville583762
3.7 / 5 (3) May 23, 2018
The application of Tact.
Demoting PLUTO lost that spark of interest and with it the prestigious telescopes of the astronomical community
Maybe if we had not diminished PLUTO'S status, retaining its status and the images from PLUTO'S flyby it would have retained that spark of interest and the great telescopes of the world would be training their long held interest in PLUTO and beyond!
granville583762
3.7 / 5 (3) May 23, 2018
We have to get over it - Planet 9 is Pluto we are looking for planet 10
Mark Thomas> If Planet 9 does not exist, we need to consider other alternatives

The 9th planet already exists in Pluto. Pluto is as good as it gets, whether a larger or smaller planet, is also whatever status we give Pluto, when the 10th planet is found is has the same status as Pluto.
By demoting the ninth planet Pluto to a dwarf is demoting planet 10 to a dwarf!
granville583762
3.7 / 5 (3) May 23, 2018
The Obfuscation of a Planet – the ninth planet
We have 9 planets so we demote one, then we search to restore are ninth planet by obfuscation - by renaming are designation of a planet to enable us to search for one the same to call what Pluto was namely the ninth plant for one the same – the ninth planet!
Mark Thomas
4.4 / 5 (5) May 23, 2018
granville, a planet is a sub-stellar, celestial body at least 2,000 kilometers in diameter. Or at least by my personal definition it is. By that definition, we have ten known planets in the solar system including Pluto and Eris.

Although it is not perfect, I would put my personal planet definition up against the IAU's any day of the week. Orbiting the sun, or anything else for that matter, is not required, neither is "clearing the neighborhood."
granville583762
3.7 / 5 (3) May 23, 2018
In one's orbit
It would be useful to get a clear precise definition of clearing ones orbit - does that include Saturn's rings and Jupiter's moons.
granville583762
3.7 / 5 (3) May 23, 2018
In fact
Mark Thomas> "clearing the neighborhood."

Is a slightly different meaning than clearing one's orbit as an orbit encompasses the Sun where as "clearing the neighbourhood" means the back garden to the planet, already there are two definitions to start the ball rolling.
Mark Thomas
4 / 5 (4) May 23, 2018
granville, if you would like, consider my definition, I think it works pretty well.

"A planet is a sub-stellar, celestial body at least 2,000 kilometers in diameter."
granville583762
3.8 / 5 (4) May 23, 2018
A planet at 2000km diameter is sufficiently diverse as a planet
I am thinking of considering, I am considering, I have considered – Pluto at 2400km is a planet!
Mark Thomas> granville, if you would like, consider my definition, I think it works pretty well.
"A planet is a sub-stellar, celestial body at least 2,000 kilometers in diameter."

A small planet is not a dwarf planet, there is a distinction -
There is a wide variety of features to distinguish a small planet from simply a lump of rock, it has all the characteristics of a planet which cannot justifiably be described as a dwarf planet, if Pluto was in a goldilocks zone inhabited by Plutonium's, they would not take kindly to some Earthling's calling their planet a dwarf planet! A small planet may be! But definitely not a dwarf as they inhabit the world of goblins and trolls!
granville583762
4 / 5 (4) May 23, 2018
A planet is a sub-stellar, celestial body at least 2,000 km in diameter
It would also solve this eternal problem created by demoting Pluto as it comes within the 2000km diameter.
It would show Tact and Diplomacy in retaining Pluto and we would not have to look for a planet to replace a ninth planet that does not exist as it only exists in Pluto the ninth planet.
Mark Thomas
5 / 5 (3) May 23, 2018
I feel like this definition cuts the proverbial Gordian Knot. The difficulty of precisely defining the high end of the range is set aside for now by selecting "sub-stellar." "Celestial body," similarly eliminates other natural and artificial objects. Because the vast multitude of objects out there must constitute a continuum, an arbitrary, but precise number is probably the best choice. The 2,000 km limit is nice round number easy to use and remember, although we may have to consider it an average. There is a nice gap in objects in our solar system between Makemake and Eris, so nothing is close to the cutoff. Having ten planets is also a nice round number. More subtly, this definition encourages us to send a probe to Eris as the last remaining unexplored planet in the solar system.

I also like how exoplanets and rogue planets are now simply planets too. So an object that is an "Earth twin" would still be a planet regardless whether it orbited another star or no star at all.
Mark Thomas
5 / 5 (4) May 23, 2018
One remaining problem is how to deal with the question of where to draw the line between a large moon and a double or multiple planet. I haven't figured that one out.

At the high end, science may eventually give us a better answer, such as less than 13 Jupiter masses, etc.

Maybe someday we will know so much about so many planets that we will be able to select a better number for where planetary processes begin, but for the moment, a 2,000 kilometer diameter is probably very reasonable given what we know.
granville583762
4.2 / 5 (5) May 23, 2018
Earthlings see common sense, order and stability in tradition

What we're trying to do is overturn thousands of years of how we as millions of earthlings define a planet, a moon, and asteroids at stroke with a handful of people having a show of hands when we should have left well alone. You cannot have a few people dictating what millions of people have arrived at as distinctions of celestial body's over 10thousand years. It is a recipe for confusion and disaster.

I might seem to be able to tweeze confusion and obfuscation out a flea and turn it into a mountain, but only to people who persist in not seeing confusion and obfuscation in their actions as in this example, demoting a century's held view of Pluto as a planet and summarily demoting Pluto at a stroke where the average earthlings are the ones who made up these traditional disdinctions but arenot allowed to vote on Pluto's future.
Mark Thomas
3.4 / 5 (5) May 23, 2018
BTW, this definition would also correct the mistake Mike Brown made in taking pride in killing Pluto's status as a planet and give him the credit he deserves for discovering our tenth planet, Eris. This will also give Mike Brown some solace for when his predicted "Planet 9" fails to materialize.

granville583762
4 / 5 (4) May 24, 2018
Mike Brown: best known as the man who killed Pluto removing 2 planets from our solar system

ERIS is practically identically the same size as PLUTO; where as Clyde William Tombaugh received the credit for discovering our ninth planet PLUTO and asteroid 1604 in his name. Mike Brown receives no credit for finding our identically sized 10th planet ERIS!

And it gets worse, not only does he receive no credit, he shot himself in the proverbial foot by killing the definition of planet thereby preventing himself receiving due credit for finding our 10th planet.
And it gets even worse, after removing 2 planets from our solar system he still want the credit for finding a planet which he defines as a planet – the arrogance of the man is staggering. He doesn't want any planet he wants one the size of NEPTUNE

The end result is Mike Brown consequently has discovered no planets
How appropriately ironic!
granville583762
4 / 5 (4) May 24, 2018
Here in lies Mike Brown's dilemma: "He doesn't want any planet he wants one the size of NEPTUNE"
Planets come in a range of sizes - MERCURY, VENUS, MARS, EARTH, JUPITER, SATURN, URANUS, NEPTUNE, PLUTO and ERIS -
If only Mike Brown had adopted the philosophy of planetary sizes, Mike Brown would not inhabit the world of OGHRES TROLLS AND DWARFS, he would be in inhabiting the world of Celebrities, Nobel Prizes and well done old chap for discovering our 10th Planet ERIS!
maholmes1
3.7 / 5 (3) May 27, 2018
granville, a planet is a sub-stellar, celestial body at least 2,000 kilometers in diameter. Or at least by my personal definition it is. By that definition, we have ten known planets in the solar system including Pluto and Eris.

Although it is not perfect, I would put my personal planet definition up against the IAU's any day of the week.


Yeah. It *was* the IAU's definition--their proposed one, anyway--until a few hundred of them hijacked the system and manipulated the situation to force through the flawed definition we have today. There are geophysical planets that are smaller, like Ceres and Makemake, but at 2000 kilometers diameter a planet is massive enough to hold on to an atmosphere--for example, Pluto.
savvys84
1 / 5 (1) May 28, 2018
Lol, so nibiru exists after all
gmh
5 / 5 (1) May 28, 2018
Not an astronomer, but have a question. Could the egos of certain posters be adversely affecting the planets orbits?
sascoflame
3.7 / 5 (3) May 28, 2018
Planet nine is Pluto. In a power play certain astronomers played some dirty politics to get Pluto voted off the list but the truth is not based on a vote.
milnik
not rated yet May 29, 2018
The first logical conclusion is that no celestial body from the other solar system can have a closed path (ellipse) around the other solar system. That is, if there are planets 9, it must belong to our solar system. But it is a big question: how can such a large planet be forced to circle around our sun at a distance of 700 AU? Secondly, how did those experts calculate or measure the size of the eccentricity, when they do not know the position of perihel and afel?
Thirdly, if such a planet exists, the perianth of the solar system would not lie in the sun itself, then the sun would have its rotation around the pericent at a distance greater than the radius of the sun. How would the sun behave?

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