Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

https://www.space.com/astronomy/solar-system/evidence-of-controversial-planet-9-uncovered-in-sky-surveys-taken-23-years-apart

by spchampion2 • 1 year ago

242 250 1 year ago

space.com

bikenaga• 1 year ago

Original paper: https://arxiv.org/pdf/2504.17288

codethief• 1 year ago

Non-PDF link: https://arxiv.org/abs/2504.17288

DiogenesKynikos• 1 year ago

They forgot to change the title from "Overleaf Example" in their LaTeX source file.

perihelions3• 1 year ago

It's "hello, world!" planetary science with "hello, world!" tooling!

metalman2• 1 year ago

we already have a 9'th planet, but due to the greatest pedantic campain of all time, pluto got demoted. Though given the current situation, ha!, that could change.....perhaps the naming commity will get noticed, and be offered a chance to do a deal, and Make Pluto A Planet Again,(MPAPA)

chess_buster• 1 year ago

Pluto for planet! https://www.planetarium-hamburg.de/en/pluto-for-planet

rini172• 1 year ago

The same happened to Ceres first. To be fair, Make Ceres A Planet Again!

metalman2• 1 year ago

Ya, I know but Ceres is going to get pushed into an intersection with Mars to generate an atmosphere and a hydrological cycle .......testing on fusion rocket drives is ongoing https://newatlas.com/space/pulsar-fusion-rocket-design-slash...

juped3• 1 year ago

Yes, Pluto is the tenth planet.

To discover Planet 9, simply open your ephemerides and look for "Neptune".

echelon• 1 year ago

If planets are required to clear their orbits, what was Jupiter called while the solar system was forming? A dwarf planet? A proto planet? The entire time?

Was earth not a planet shortly before and after collision with Theia?

The naming pedantry seems ridiculous given that we have such a small sample size.

brookst• 1 year ago

This is especially important if it turnes out there is a black hole acting as an additional planet, since it justifies the “Planet X” name.

rollcat• 1 year ago

The definition is pretty arbitrary. It's more interesting, what can we learn by studying that object. Even the trivia, like tidal locking, it was one of my 10000 moments (https://xkcd.com/1053/).

gus_massa• 1 year ago

If you add Pluto, you must add also Eris and a few more, like 5 or more, and perhaps also Ceres.

Here is a nice graphic that excludes Ceres https://en.m.wikipedia.org/wiki/Dwarf_planet#Population_of_d...

ryao2• 1 year ago

We should add those planets to the official list too. Gauss considered Ceres to be a planet and I believe him over living astronomers.

The motivation for this dwarf planet nonsense was to try to keep the official planet list small so children could memorize them with ease, but that is absurd. We do not remove countries from the map to make it easier for children to learn geography and there are over 100 of them.

irrational• 1 year ago

I would add those to the list of official planets, yes. Don’t remove Pluto, add the rest.

jodrellblank• 1 year ago

"If you add Pluto, you must add also Eris"

Nonsense. "Pluto is grandfathered in as a planet, nothing else is a planet". See?

randomtoast2• 1 year ago

I find one theory regarding Planet 9 especially interesting, and that is that it could be a primordial black hole with a Schwarzschild radius on the order of just a few centimeters. So basically, just a golf ball-sized black hole. This would explain why we can see the gravitational effects on the other objects as described in many papers, and it would also explain at the same time why we have no direct observation of this object, because it's simply too tiny and black.

api7• 1 year ago

I really hope this is true, because it would mean there is a black hole close enough it could be examined and studied. This might allow us to test physics ideas that can’t be tested any other way, and maybe even to “finish” physics.

It could also allow gravity and Oberth effect acceleration of small probes to meaningful fractions of the speed of light for interstellar flyby missions. Imagine the Oberth effect boost from thrusting in such a deep gravity well.

TheOtherHobbes• 1 year ago

I really hope it isn't true because if there's one out there, there will be others, and I'd rather not meet one in person.

We don't have enough data to see whether there are unexpected instabilities in detected planetary systems. But it would be an interesting project to look for those.

ednite3• 1 year ago

Honestly, if there is a golf ball–sized black hole out there chilling in the outer solar system, I'm all in.

Let’s fire up a replica of TARS, load up ChatGPT inside (TARS-GPT, patent pending), and yeet it straight toward the Schwarzschild golf ball. It’ll narrate live.

Imagine the livestream:

“Approaching event horizon. Spaghettification at 3%. Mood: stretchy.”

“Entering gravitational lensing zone… wow, even my tokens are redshifting.”

Bonus: With the right timing and Oberth maneuver, TARS-GPT might sling itself into Alpha Centauri before we finish arguing whether Pluto’s a planet again.

Worst case: we lose a robot. Best case: we unlock quantum gravity and get a podcast from inside a black hole.

I'd call that a win.

kiba• 1 year ago

We could use the black hole to power our civilization due to how efficient it is for generating power.

zveyaeyv3sfye• 1 year ago

Not sure I want a black hole in my backyard ;-)

For all it's worth, there's no need to go black hole to explain the lack of visual observation. Objects that far from a star reflect very little if any light and would appear black to a black background.

ajross• 1 year ago

FWIW, the object in the linked article is visible, so while that's an interesting theory it's actually ruled out if this thing turns out to be a planet. The black hole would need to be Planet 10 I guess.

lazide• 1 year ago

At the distances described, available passive light flux is so low, it could be 100% painted with white titanium dioxide paint and we’d be lucky to ever see it. It doesn’t need to be a black hole to be effectively invisible.

perihelions3• 1 year ago

Indeed, it's a doubly inverse-squared law: one 1/d^2 factor for how far it is from the sun, by how much the solar flux is reduced; and one 1/d^2 factor again for how it is from Earth-based observers. 1/d^4, a quartic law.

That's the idea behind this paper (and similar ones like it): since they're looking for the planet's intrinsic emissions, from its internal heat, it's only a single inverse-square law.

With d being ~20 times Neptune's distance and ~140 times Jupiter's, these really are large factors!

Projectiboga• 1 year ago

If it were earth mass it would be ~grapefruit size. This estimate puts object nine at 9 earth mass so maybe vollyball size or melon size? https://www.astronomy.com/science/is-planet-nine-a-black-hol...

tlogan• 1 year ago

If I’m remembering right, compressing all of Earth’s mass would give a Schwarzschild radius of roughly 9 mm. I think Uranus (15x heavier than earth) would be like basketball.

Is my calculation correct?

Qem5• 1 year ago

If it were a blackhole it wouldn't show up in IRAS and AKARI infrared maps.

Dylan168074• 1 year ago

Grapefruit versus volleyball? If you make a black hole 9x as heavy, it gets 9x the radius. 700x the volume.

deadbabe• 1 year ago

Any chance we could use this black hole as a really powerful slingshot by getting very close right before passing the event horizon and then firing off into space?

randomtoast2• 1 year ago

I think one problem for such tiny black holes is the way the gravitation works on objects that come close to it. So for instance, a spaceship could or a human could not reach the event horizon of a tiny black hole in one piece, because it would be torn apart by the gravitational tides. So the question is how close can you come to the event horizon before gravitation rips you apart. My guesstimation would be not close enough to reach a meaningful percentage of c.

interludead5• 1 year ago

A golf ball–sized primordial black hole lurking in the outer solar system sounds like pure sci-fi, but it would neatly explain the gravitational weirdness and the lack of visual detection

goku126• 1 year ago

It would be extremely difficult to observe something that far away from the sun, no matter how voluminous it is. I'm not going to scorn at the idea of a blackhole, but I wonder what process can crush that much mass into such a volume. I don't think it's massive enough to suffer a gravitational collapse.

smolder3• 1 year ago

Primordial black holes can theoretically be much smaller than those formed in the usual way from collapsed stars or neutron star mergers, etc, because the early universe was dense with matter already and perturbations could have caused gravitational collapses for arbitrary volumes. I don't think we've observed any directly, which would be hard as small low-emission masses. They're still a potential piece of the dark matter missing-mass puzzle.

yfontana• 1 year ago

Primordial black holes are black holes that formed right after the big bang. Basically areas where gravity caused the extremely dense matter of the universe's first instants to collapse into black holes before expansion could pull it apart. Their existence has been hypothesized but not confirmed (or definitively rejected) so far.

snowwrestler• 1 year ago

This paper exploring the idea has as Fig 1. a to-scale illustration of a 5-Earth-mass primordial black hole:

https://arxiv.org/pdf/1909.11090

As I recall, it did not get printed this way because the ink would be too expensive, or mess with the paper.

AIPedant5• 1 year ago

I think “15 times further from the Sun than Pluto” is more meaningful for most readers than “700 times further from the Sun than Earth.” If it exists, it’s way way way out there.

ck2• 1 year ago

There's an episode on "Space & Beyond" where they show all the planets in scale to the realworld on an actual football field.

Then to show Planet 9 distance they have to get in a car and drive a few miles.

That worked for me.

7373737373• 1 year ago

My favorite: Cody'sLab's "How far away are the nearest stars": https://youtube.com/watch?v=dCSIXLIzhzk Also gives an intuition for how incredibly bright stars shine

oxidant• 1 year ago

I think Bill Nye has something similar, too.

WillAdams• 1 year ago

Yeah, when the solar system was introduced to my class in grade school, we had an outdoor excursion where the teacher brought out a golfball and place it at one end, then brought out various tiny things (noting scale was very approximate) and paced off each to show the relative distances.

Nevermark• 1 year ago

I have a set of twelve books by an artist, titled "Astronomical" (one book for each letter). The first page shows the sun, then the rest of the books are almost all simply black pages, but with the planets and asteroid belt entities shown with accurate distance and size scale.

It communicates the scales really well, while only taking up a little over a foot of bookshelf space when not being "navigated". I have two heavy metallic retro looking rocket bookends for it.

airstrike• 1 year ago

What is "Space & Beyond"?

1970-01-01• 1 year ago

Yes, also being 10x the mass of Earth that far out hints that it may be an interstellar object captured by the Sun.

nonethewiser3• 1 year ago

Forgive my ignorance but how is that different than the rest of the planets?

water-data-dude• 1 year ago

I wanted to get a sense of what that MEANS relative to the rest of the gas giants. Apparently it’d be roughly the size of Uranus or Neptune.

I guess I’d always put all the gas giants in the same “very, unimaginably big” bucket. I knew Jupiter was the biggest, then Saturn, but I didn’t realize just HOW big they were compared to the rest. At the risk of stating the very, very obvious, Jupiter is huge!!!

Masses of gas giants are: Jupiter, 317.8 earth mass; Saturn, 95.2 earth mass; Neptune, 17.1 earth mass; Uranus, 14.5 earth mass

[0] https://en.m.wikipedia.org/wiki/Earth_mass#Unit_of_mass_in_a...

NikkiA• 1 year ago

I dunno, '700 AU' gelled for me instantly, '15 times the distance to pluto' doesn't even make sense given pluto's orbit isn't anywhere near circular.

doubletwoyou• 1 year ago

I don’t think the vast majority of people will have a good sense of how far away the standard gas giants and pluto are from the sun in terms of AU.

AIPedant5• 1 year ago

It makes even less sense for Earth because Earth's orbit is near-circular, whereas Planet 9's hypothesized orbit is highly eccentric, more so than Pluto.

Most people don't know off-hand that Pluto is ~40-50AU from the sun, so 700AU is hard to conceptualize.

Waterluvian• 1 year ago

On its own it’s a bit of a useless number. You’d have to know how many AU Pluto is to understand context.

But if you got “15x further than Pluto” you have context without needing to know any other trivia-style numbers.

bryant• 1 year ago

New horizons launched 9.5 years before it reached Pluto, and your average reader who has an interest in Planet 9 will likely know it took New Horizons about that long.

15x means no one alive today will see a mission that reaches the planet, and that's more accessible for most readers per above.

nandomrumber3• 1 year ago

The length of 2.1 trillion Olympic swimming pools.

Or 698 trillion bananas.

rkagerer3• 1 year ago

1 hour at Warp 4

rainsford• 1 year ago

It's sort of amazing to me that the Sun can capture objects that far away. Like obviously even at that distance the Sun would be by far the closest massive thing, but it's hard to comprehend the effects of gravity being strong enough at that distance. From "Planet 9" the Sun probably wouldn't significantly stand out from all the other stars in the sky, yet you'd be orbiting it.

fallingknife2• 1 year ago

From 700 AU you would still be only 0.01 ly from the sun, or 400x closer to the sun than the second closest star.

8bitsrule• 1 year ago

That IS better, but I like ~0.011Ly too ... the nearest star is about 4Ly away.

Another perspective on the size of the solar system, like the Pale Blue Dot.

bsdetector• 1 year ago

Would this be far enough out to use the sun's gravitational lensing to image distant planets?

It seems like the idea was to send a bunch of instruments way out and then take pictures in the brief time they were at a useful distance, but if there's a planet out there we can orbit and so stop the instruments at that distance it seems like we could make a permanent super telescope.

fallingknife2• 1 year ago

Probably easier to just put it in solar orbit at that distance. Orbital velocity is only about 1km/s at 700 AU.

codesnik• 1 year ago

orbiting a planet in that case is no different than orbiting a sun on the same orbit as planet. Probably even more cumbersome, all that jiggling around. Or are you talking about making a gravity assist to turn the orbit of the probe into less eccentric?

carbocation• 1 year ago

All 3 points (two from you and one from '8bitsrule) helped me contextualize this:

* 700 times further from the Sun than the Earth

* 15 times further from the Sun than Pluto

* 0.01 lightyear, or 1/400th the distance to the nearest star

washadjeffmad2• 1 year ago

If the Earth is 8 lightminutes from the Sun, Planet X is 3.8 lightdays.

Or, it's the difference between going for a 15 minutes walk and walking from Boston to Orlando (or San Diego to Seattle, for the West Coasters).

AzzyHN• 1 year ago

Most readers probably know Pluto is the... well... it's not the farthest dwarf planet. But they know it's far, but don't realize just how far it is. I certainly didn't until I watched a video about it.

700 further from the Sun than Earth is tangible as "really really far" though.

SecretDreams• 1 year ago

I think both work. The average reader doesn't need to conceptualize these distances. They just need to know they're reallllly far away and realllllllly realllllllly (9x) far away. You can use the earth or pluto distances as relative scales.

nine_k• 1 year ago

700 AU is way past heliopause, firmly in the interstellar space. Same, 15 times farther than Pluto is definitely away from the Solar system "proper". It's about 100 light-hours away from Sun.

I wonder how could this object be counted as a "planet" belonging to the Solar system, even if it were the size of Jupiter. But it's an object "estimated to be 2 to 4 times the radius, and about ten times the mass of the Earth". This must be another class of celestial bodies, some jumbo-sized Oort cloud object.

manquer• 1 year ago

As long it is orbiting the sun, i.e bound by the solar gravitational field then it is in the solar system?

Also depending how elliptical the orbit, is the perigee might be much closer than 700AU, while still being further than Pluto's orbit. For all we know 700 AU is the apogee and say the perigee is 70 AU (1.4x Pluto's apogee ).

smolder3• 1 year ago

I think both comparisons together paint a good picture: 15 times further than Pluto, which itself has an orbit ranging from 30 to 49 AU (the distance between Earth and the sun.)

StopDisinfo9103• 1 year ago

But then why Pluto rather than Eris which is considerably further than Pluto or Sedna which is even further?

Pluto is a fairly unremarkable dwarf planet. I don’t think it really helps to compare things to it.

halgir3• 1 year ago

Because more people know about Pluto than Eris or Sedna. And we know that Pluto is the furthest away planet (sue me). So 15x Pluto is much easier to visualize in context of the entire solar system than 700x Earth. My cosmological knowledge is above average, but I don't know off the top of my head if 700 AU is super-duper far away or still in the range of the gas giants.

interludead5• 1 year ago

Most people have at least a vague sense of Pluto being the edge of the solar system, so hearing that Planet Nine could be way beyond that makes it feel almost interstellar

mbfg• 1 year ago

how about 4 times further than Voyager 1?

snthpy• 1 year ago

I agree. Idk now many AUs Pluto is but I know it's far away and hardly visible until we flew by.

perihelions3• 1 year ago

This cannot be evidence of Planet 9 (the Batygin and Brown hypothesis)—it's outright incompatible with it.

https://bsky.app/profile/plutokiller.com/post/3lnqm2ymbd22r

If those two spots are the same object, that object is on a high-inclination orbit; but the pattern the Planet 9 hypothesis explains is only compatible with a low-inclination object.

sph2• 1 year ago

The guy killed Pluto and still he isn't done :(

Seriously though, is he one of the people responsible for Pluto's demotion to dwarf planet?

ufo• 1 year ago

His team discovered Eris and many other trans-neptunian objects, which did fuel the discussion behind pluto's demotion: greatly increase the number of planets, or demote pluto? They're also behind the Planet 9 theory that's discussed in the article.

db48x5• 1 year ago

Nobody killed Pluto.

Back in the early 1800s children used to memorize the names of the 12 planets: Mercury, Venus, Earth, Ceres, Pallas, Juno, Vesta, Mars, Jupiter, Saturn, Uranus, and Neptune. But then in 1845 astronomers discovered Astraea, and now there were 13. In 1847 three more were discovered: Hebe, Iris, and Flora. Then Metis, Hygiea, Parthenope, and Victoria by 1850. The 100th asteroid was discovered in 1868, and the pace only got quicker from there. Somewhere along that line people started using the words “asteroid” and “asteroid belt” and schoolchildren were mercifully spared the pointless task of memorizing hundreds, and later many thousands, of names of asteroids.

The same thing happened to Pluto. Just as Ceres was the first discovered asteroid, Pluto was the first discovered TNO. There are now hundreds of named TNO and thousands more that are just numbered. Nobody should force schoolchildren to memorize them all. Just tell them that there are an unknown number of objects in the Kuiper belt and the Oort cloud and they’ll know as much as they need to know. Give them bonus points if they know the names Ceres and Pluto, and more if they know why these two were discovered first of all the objects in their class: they’re the biggest. Otherwise there’s nothing special about them.

raverbashing• 1 year ago

Nah, if it is big, and at that distance, and follows an elliptical orbit then yes it will be "Planet 9^W 8"

rozab• 1 year ago

Isn't this exactly how Pluto was discovered? Due to an innacurate estimate of the mass of Neptune (not corrected until Voyager I think), people were hunting for a large planet to explain the discrepancy. After a bunch of searching they happened to find Pluto, but it was not the Planet X they were looking for. The mass estimates for Pluto were gradually downgraded from many Earth masses to 1/500, which is the true reason it was initially classified as a planet.

Qem5• 1 year ago

For a time pluto had good estimates for his small size, but poor constraints on his mass beyond this Neptune mass estimate. So I remember reading a short story were they interpreted the possible high density as signs of a stargate.

philistine2• 1 year ago

Yeah. If Pluto had been slightly heavier, we’d probably have ended up with a definition of a planet that included its mass instead of clearing its orbit to keep Pluto a planet. But Pluto was cooked when we figured out it’s not really heavier than Ceres.

Qem5• 1 year ago

Perhaps searching for Planet 9 we went straight to Planet 10. There was another one and we happened to find it first. Or also it could be a nomadic planet undergoing a close encounter with the solar system.

interludead5• 1 year ago

It's still super interesting if it is a massive trans-Neptunian object, just maybe not that Planet 9

K0balt3• 1 year ago

I hope this turns out to be wrong. I’m still holding out for a primordial back hole Planet X. That would be soooo cool and unbelievably useful.

jsbisviewtiful• 1 year ago

Why useful? Considering how hard of a time astronomers are having to simply find it it’s hard to imagine it being easy to study.

mrshadowgoose• 1 year ago

A black hole in our solar system is basically "in our backyard" in relation to typical interstellar distances.

Sure, we wouldn't be able to get there for many decades, but "within a century" would be feasible.

There are so many unknowns surrounding the nature of black holes. Having one in our backyard would give us a chance to test our guesses.

jiggawatts• 1 year ago

A black hole reachable in a human lifetime with ordinary chemical rockets would be an amazing laboratory for extreme physics.

andrewflnr• 1 year ago

Yeah, finding it is hard, but once you've found it, sending a probe would be totally doable. I think it would be worth it.

K0balt3• 1 year ago

Aside from research, it could be used to provoke time dilation, though I’m not sure how much you could get out of a basketball sized black hole.:8

interludead5• 1 year ago

Not only would it be insanely cool, it'd give us a once-in-a-lifetime chance to study something that might've formed in the first moments of the universe

choudharism• 1 year ago

I mean, if it's there, we can study it as many times as we want in our lifetime.

anthk• 1 year ago

Well, 9front guys now have a fancy release name.

doublerabbit• 1 year ago

Can I move to Planet9? Anywhere is better than this planet.

Qem5• 1 year ago

With current spaceships you would die of old age long before arrival.

rvz• 1 year ago

Even before that since the food on the spaceship is finite and once it runs out; you would stave to death before the first year during the journey.

tiahura• 1 year ago

How can we spot planets in other galaxies when we can’t even be certain how many planets are in our solar system?

userulluipeste• 1 year ago

It has everything to do with the available means that we have, for now. For the record though, we haven't yet been able to spot planets in other galaxies, just in our own Milky Way. The spotted ones just happened to be there when we decided to look, twice. To spot an astral body properly sized to fit the definition of planet, which we yet suspect to orbit around our own star, we should be lucky enough to look exactly at it and not at something else.

bagels• 1 year ago

I thought the same, but amazingly, there are some early results that suggest a transit was observed in another galaxy:

https://science.nasa.gov/universe/exoplanets/exoplanet-disco...

https://en.wikipedia.org/wiki/Extragalactic_planet

rootsudo• 1 year ago

When did Planet X become planet 9? Is it because Pluto was a planet and now no longer is so the X was really a Roman numeral vs a variable (if)?

xattt• 1 year ago

The article explains that Planet X is a possible explanation for the apparent regularity of mass extinction events. Planet 9 is a separate concept to explain the bunching of Kuiper Belt objects, like Sedna.

goku126• 1 year ago

In other words, PlanetX was a hypothetical rogue planet that appeared unexpectedly from the abyss of deep space and ambushed the unsuspecting Earth every once in a while. It has a dormamu vibe. I see why the scientists didn't like it.

vpribish• 1 year ago

I can clearly see the object as a bright group of pixels in the IRAS image, but I don't see a damn thing at the spot they hilight in the AKARI image. Like, are they kidding or is this a crap article with the wrong image or something?

sigmoid10• 1 year ago

You'd have to read the actual paper [1] to understand this. It does not appear as a physical source in the plot because of how the dataset works. The image is only for reference regarding the position.

[1] https://arxiv.org/pdf/2504.17288

Nimitz14• 1 year ago

[flagged]

tomhow• 1 year ago

Please don't complain about tangential annoyances—e.g. article or website formats, name collisions, or back-button breakage. They're too common to be interesting.

https://news.ycombinator.com/newsguidelines.html

_heimdall• 1 year ago

Pluto will always be the 9th planet, I don't care what Neil Degrasse Tyson says.

astar1• 1 year ago

it's a Mass Relay

ForOldHack• 1 year ago

It. Is. Not. A. Planet. Not.

goku126• 1 year ago

By the same celestial laws that stripped Pluto of its planet label, this one would be a planet. Unless you decide to change the rules again.

gitroom• 1 year ago

love how nerdy this whole thread gets - so much hot debate for basically a frozen rock way out there. you think we're ever gonna agree on what counts as a planet or is it always just moving goalposts?

marsten• 1 year ago

This would be a planet by anyone's definition, if it's near the predicted 9 times the mass of the Earth.

By comparison the entire Kuiper belt – including Pluto – is estimated to have a total mass of about 10% of Earth's mass.

interludead5• 1 year ago

Kinda funny how "Planet X" keeps getting rebranded every generation

alex_duf• 1 year ago

700 times further => isn't it farther rather than further?

Non native english speaker here, but last I checked further was a metaphorical distance, when farther was a literal distance. You can push a concept further, but you walk farther right? Or did I miss something?

williamdclt• 1 year ago

You’re right in theory, but in practice further is used a lot for literal distance. I don’t think I ever hear farther used at all actually

dmos62• 1 year ago

If these words have identical etymology (do they?), then the distinction adds no value, in my eyes.

iamthemonster• 1 year ago

You speak English too well - you have surpassed English speakers. None of us know the difference between further and further.

YeGoblynQueenne• 1 year ago

They're the same :P

stevula• 1 year ago

This is, I think, a learned distinction and not universally observed. I only learned this distinction in university.

ashoeafoot2• 1 year ago

is such a excentric orbitting body not like a giant guitar string when it comes to the gravitational influence of "passing bye" solar systems and black holes?

rietta• 1 year ago

My lay scientist feel is still that Pluto is a planet, or at the very least have been grandfathered in. The New Horizons reporting 10 years ago just solidified this in my mind. The geological processes are more telling than having cleared the orbital neighborhood. That would just mean that get far enough out and nothing can be a planet no matter how massive. All that said, this massive of an object that far out is very interesting. It would be a very, very cold out there. Would even a gas giant be a solid at that distance? Are there any geological processes possible?

Evidence of controversial Planet 9 uncovered in sky surveys taken 23 years apart

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