A ninth planet?

[kerbiloid]

Also there are Tartar dwellers: cyclopes and hekatonkheires. They have names, too.

[Cabbink]

11 hours ago, Green Baron said:

Traditionally naming an object is the task of the discoverers. Since nothing is discovered until now no names were officially given. Also doubts have been expressed that the newly proposed object ("Planet 9.5" :-)) that might warp the kuiper belt fullfills the definition of a full-featured planet.

@Cabbink: Erebos and Amphitryon were Greek.

 

 

Woops. Sorry About That. I found them in a Roman Mythology Dictionary.  

[Green Baron]

No problem, just for completeness :-)

Romans actually populated much of their pantheon with disused Greek deities, renamed them and / or assigned them to new competences, so the book was probably not totally wrong.

 

Edited June 26, 2017 by Green Baron

[Mitchz95]

Arthur C. Clarke's books mention a tenth planet (ninth being Pluto) called Persephone. I wouldn't mind that becoming Planet Nine's official name, even though it's Greek rather than Roman.

[wumpus]

56 minutes ago, Mitchz95 said:

Arthur C. Clarke's books mention a tenth planet (ninth being Pluto) called Persephone. I wouldn't mind that becoming Planet Nine's official name, even though it's Greek rather than Roman.

It is certainly better than less-serious SF writer Robert Anton Wilson's naming planets 10-11 (Pluto was still a planet) "Mickey" and "Goofy".  RAW's main claim to space fame was writing a theme song for the proposed High Orbital Mini Earth.  It went "HOME, HOME, on Lagrange..."

[Sigma88]

On 6/25/2017 at 11:34 PM, Cabbink said:

Planet 9: Terminus, Roman God of Bounds Or Boundaries.

being a huge Asimov fan, and also of names from Roman Mythology (instead of Greek) for planets, I would love to see Planet9 get named like that

[Mitchz95]

12 hours ago, Sigma88 said:

being a huge Asimov fan, and also of names from Roman Mythology (instead of Greek) for planets, I would love to see Planet9 get named like that

Only problem is, what if there's a Planet Ten beyond it?

[Bill Phil]

On 6/26/2017 at 5:06 PM, wumpus said:

It is certainly better than less-serious SF writer Robert Anton Wilson's naming planets 10-11 (Pluto was still a planet) "Mickey" and "Goofy".  RAW's main claim to space fame was writing a theme song for the proposed High Orbital Mini Earth.  It went "HOME, HOME, on Lagrange..."

That's called the L5 song, and as far as I'm aware it's by William S. Higgins and Barry D. Gehm... As a reference to the Space Settlements envisioned by Gerard O'Neill and others.

Naming the ninth planet? I'm thinking another Greco-Roman god... or some other figure.

On 6/26/2017 at 4:06 PM, Mitchz95 said:

Arthur C. Clarke's books mention a tenth planet (ninth being Pluto) called Persephone. I wouldn't mind that becoming Planet Nine's official name, even though it's Greek rather than Roman.

Uranus is Greek. Or at least a romanization of Ouranos. The Roman equivalent is Caelus.

And Persephone may make more sense then you'd think. Being queen of the underworld (or, in this case, the outer solar system). 

[Xemina]

I would call it Agina after the god of Invisibilty.

Though its greek, it doesn't matter!

[Green Baron]

On 13/07/2017 at 1:03 AM, Bill Phil said:

And Persephone may make more sense then you'd think.

Too late ...

Edit: link corrected

Edited August 13, 2017 by Green Baron

[Silavite]

Surprised no one has posted these yet.

http://www.findplanetnine.com/2017/06/status-update-part-1.html

http://www.findplanetnine.com/2017/07/status-update-part-2.html

[Bill Phil]

2 hours ago, Green Baron said:

Too late ...

Edit: link corrected

What about 1036 Ganymed? 

What you are referring to is 399 Persephone, not just the name Persephone. Besides, two solar system bodies can share the same name. It's not much of an issue.

[Mitchz95]

2 hours ago, Green Baron said:

Too late ...

Edit: link corrected

There's an asteroid named Europa. They don't have to be exclusive.

EDIT: Ninja'd by half a second!

Edited August 13, 2017 by Mitchz95

[Green Baron]

31 minutes ago, Bill Phil said:

 two solar system bodies can share the same name

Oh, i didn't know that ...

2 hours ago, Silavite said:

Surprised no one has posted these yet.

http://www.findplanetnine.com/2017/06/status-update-part-1.html

http://www.findplanetnine.com/2017/07/status-update-part-2.html

@kunok linked the site at the beginning of the thread ;-)

 

Edited August 13, 2017 by Green Baron

[kerbiloid]

They even have a subcontinent on the Earth named after a Jupiter's moon.

[Green Baron]

Since people are talking about a probe to planet 9 in another i thread it came to me look at the blog of the "postulator" for news.

Actually there are: http://www.findplanetnine.com/2017/10/theory.html

I find too things remarkable: first the link to Karl Popper and his work. I think it would be a good idea if people had a look at this great science philosopher's work. The two sentences in the beginning of the blog point out the direction: do not make claims that can't be falsified !

I know i am talking terribly old and should maybe even touch my own wrinkly nose :-)

 

Second: that they strongly expect to find planet 9 in the course of the next decade. This is falsifiable.

 

Edit: oh, well met :-)

Edited November 13, 2017 by Green Baron

[James Kerman]

Researchers at the University of Cambridge and the American University of Beirut have proposed an alternate theory for the orbital anomalies that do not require a massive trans-Neptunian object.

Quote

“The Planet Nine hypothesis is a fascinating one, but if the hypothesised ninth planet exists, it has so far avoided detection,” said co-author Antranik Sefilian, a PhD student in Cambridge’s Department of Applied Mathematics and Theoretical Physics. “We wanted to see whether there could be another, less dramatic and perhaps more natural, cause for the unusual orbits we see in some TNOs. We thought, rather than allowing for a ninth planet, and then worry about its formation and unusual orbit, why not simply account for the gravity of small objects constituting a disc beyond the orbit of Neptune and see what it does for us?”

Professor Jihad Touma, from the American University of Beirut, and his former student Sefilian modelled the full spatial dynamics of TNOs with the combined action of the giant outer planets and a massive, extended disc beyond Neptune. The duo’s calculations, which grew out of a seminar at the American University of Beirut, revealed that such a model can explain the perplexing spatially clustered orbits of some TNOs. In the process, they were able to identify ranges in the disc’s mass, its ‘roundness’ (or eccentricity), and forced gradual shifts in its orientations (or precession rate), which faithfully reproduced the outlier TNO orbits.

“If you remove planet nine from the model and instead allow for lots of small objects scattered across a wide area, collective attractions between those objects could just as easily account for the eccentric orbits we see in some TNOs,” said Sefilian, who is a Gates Cambridge Scholar and a member of Darwin College.

Earlier attempts to estimate the total mass of objects beyond Neptune have only added up to around one-tenth the mass of the Earth. However, in order for the TNOs to have the observed orbits and for there to be no Planet Nine, the model put forward by Sefilian and Touma requires the combined mass of the Kuiper Belt to be between a few to ten times the mass of the Earth.

“When observing other systems, we often study the disc surrounding the host star to infer the properties of any planets in orbit around it,” said Sefilian. “The problem is when you’re observing the disc from inside the system, it’s almost impossible to see the whole thing at once. While we don’t have direct observational evidence for the disc, neither do we have it for Planet Nine, which is why we’re investigating other possibilities. Nevertheless, it is interesting to note that observations of Kuiper belt analogues around other stars, as well as planet formation models, reveal massive remnant populations of debris.

“It’s also possible that both things could be true – there could be a massive disc and a ninth planet. With the discovery of each new TNO, we gather more evidence that might help explain their behaviour.”

https://www.cam.ac.uk/research/news/mystery-orbits-in-outermost-reaches-of-solar-system-not-caused-by-planet-nine-say-researchers

The Paper: Shepherding in a Self-Gravitating Disk of Trans-Neptunian Objects

 

[Green Baron]

An alternative ! I love alternatives, the discussion is on :-)

 

The Planet 9 protagonists on their blog site have replied:

http://www.findplanetnine.com/2019/01/is-planet-nine-just-ring-of-icy-bodies.html

tl, dr: they find the existence of a massive eccentric and inclined ring improbable but concede that it may exist.

 

My 5 cents: The counterargument for the new hypothesis here is parsimony (archaeologist speaking :-)). Such a ring, stable over billions of years and with more mass than the hypothetical Planet 9, is imo more difficult to explain than a single body in the proposed orbit. Besides, the total mass of all things TNO (excluding Planet 9) is estimated to be magnitudes lower than what is necessary for the ring. But estimations can be corrected ...

What do you guys think ?

 

Edited January 26, 2019 by Green Baron

[James Kerman]

As at December 2017, there are around 2400 observed trans Neptunian objects.  Modeling predicts billions to trillions of these objects so, as per the GB mantra, I think we need moar data.

Core region (38–49 AU): inclination (left) and eccentricity (right) vs. semi-major axis (a)

Full region on a logarithmic scale from 30 to 1000 AU: inclination (left) and eccentricity (right).

Images: https://commons.wikimedia.org/wiki/User:Rfassbind

 

[kerbiloid]

Spoiler

On 1/26/2019 at 5:05 PM, James Kerman said:

“If you remove planet nine from the model and instead allow for lots of small objects scattered across a wide area"

They did it... No more Planet Nine.

 

 

[James Kerman]

Spoiler

38 minutes ago, kerbiloid said:

They did it... No more Planet Nine.

I believe 'It's either Alderaan debris or the Death Star is planet 9' was the alternate title of the paper. (just kidding)

 

Edited January 30, 2019 by James Kerman
grammar

[Shpaget]

Some news on this front:

https://theconversation.com/why-astronomers-now-doubt-there-is-an-undiscovered-9th-planet-in-our-solar-system-127598

tl;dr, These guys think there might not be a planet nine considering the new data and reinterpretation of the old. They made more observation and found new Kuiper belt objects that indicate strong bias in previous observations. Supplemented with data from newly found objects, there is no longer the indication of a big object out there.

[insert_name]

Dubious candidate found in old IRAS data, doesn't show up in later surveys and not a great orbit though

https://www.sciencealert.com/historical-data-reveals-what-may-be-a-decades-old-detection-of-planet-nine

full paper

https://arxiv.org/pdf/2111.03831.pdf