A ninth planet?

[-Velocity-]

1 minute ago, kerbiloid said:

Ganymede and Titan can't understand why so much noise about that tiny homeless trash.

Of course their barycenters lie inside their gas giants, but themselves are bigger thatn those "planets/non-planets". 
Strange to call "double planet" Pluto+Charon but ignore double (by their practical significance) planets Jupiter-Ganymede and Saturn-Titan.

Saturn is like 3500 times more massive than Titan...

[sjbuggs]

The reason the barycenter idea appeals to me is that it goes back to the idea of what a moon is.  Charon doesn't orbit Pluto, but these two Dwarf Planets orbit a shared common point between them.  Yes it can mean that a super-earth orbiting a gas giant would still be a moon.  I'm ok with that, as I'm basing it on what the two objects are doing in relation to each other.  At its heart, a moon is an object that orbits another, so whether a massive moon is bigger than the smallest dwarf doesn't change what it does.  Doesn't make either more or less interesting either.  The Horizons mission was fantastic regardless of whether it flew by the smallest planet, a binary dwarf planet system, or a dwarf planet. 

However, I definitely don't like arbitrary mass cut off points.  What is the significance of 10^23 kg? other than it lies in a sort of dead zone in our solar system?  (Forgot that some of the gas giant moons were that much bigger than Luna and Pluto)

All this actually reminds me of that famous supreme court comment on obscenity along the lines of "I don't know how to define it, but I know it when I see it..."

Edited June 16, 2017 by sjbuggs

[kerbiloid]

1 hour ago, Green Baron said:

Yes, a duke is lesser than a king ... :-)

Nominally - yes.
While the slim and nervous king has a crown pawned in a pawnshop, and fat and lazy duke sends him money to buy some food. (114 Years War, Red&White Roses, so on).

So, if we want just an empty title, Pluto can be a planet, while Ganymede and Titan are just moon.
If we speak about the Solar System usage, Titan and Jupiter's Four are planets, while Pluto and others stay in queue for soup.

1 hour ago, -Velocity- said:

Saturn is like 3500 times more massive than Titan...

If a 0.1 Msun star orbits round a 150 Msun star, it's no more a star?

[Green Baron]

1 hour ago, sjbuggs said:

All this actually reminds me of that famous supreme court comment on obscenity along the lines of "I don't know how to define it, but I know it when I see it..."

lol, that fits. Such empty slogans have a connotation in the topic we shall not talk about and dispensation of law :-), expressing a personal view (or in this case probably the lack of it).

 

As to Planet Nine, there is an update on the blog of the postulaters. A few newly discovered kbos fit right in the postulation. But we have to be patient until the first snapshot, maybe wait for the next generation of telescopes.

 

[kerbiloid]

Pluto, Titan and Ganymede: planets honoris causa.

[Scotius]

28 minutes ago, Green Baron said:

lol, that fits. Such empty slogans have a connotation in the topic we shall not talk about and dispensation of law :-), expressing a personal view (or in this case probably the lack of it).

 

As to Planet Nine, there is an update on the blog of the postulaters. A few newly discovered kbos fit right in the postulation. But we have to be patient until the first snapshot, maybe wait for the next generation of telescopes.

 

And this makes me doubt the existence of 9th planet even more. We find more and more perturbed bodies - but we can't find necessarily much more massive body that messed their orbits? It doesn't add up. Unless of course Number 9 is a teeny-tiny pitch black slab of pure lead - which would be even weirder

[Green Baron]

Planet 9, if it exists, is very far out, much farer than the irritated kbos that are all following the same pattern), between kuiper belt and oort cloud. Scroll a few pages up for the postulated orbit. And, yes, it is assumed to be a dark rock. Its orbit is (if it exists) highly eccentrical, thus it loiters a lot of time far away with little haste. Also it might be responsible for the tilt in the ecliptic of the planets. Like many other eccentrics before, after it was done with disturbing its prissy fellows they sent it off to go play somewhere else :-)

If it exists ...

[sjbuggs]

5 hours ago, Green Baron said:

Planet 9, if it exists, is very far out, much farer than the irritated kbos that are all following the same pattern), between kuiper belt and oort cloud. Scroll a few pages up for the postulated orbit. And, yes, it is assumed to be a dark rock. Its orbit is (if it exists) highly eccentrical, thus it loiters a lot of time far away with little haste. Also it might be responsible for the tilt in the ecliptic of the planets. Like many other eccentrics before, after it was done with disturbing its prissy fellows they sent it off to go play somewhere else :-)

If it exists ...

Right, too lazy to read too much but a quick google placed Sedna (aphelion 936 / peri 76) right now at 90AU.  So it is pretty close comparatively in it's orbit right now.  Betting the others being found are biased towards being near perihelion as well.

The hypothetical planet 9 would have a peri of 200 au and aphelion of 1200.  So even if you take the midpoint, 700 AU out is way further out than Sedna.

 

 

[-Velocity-]

10 hours ago, sjbuggs said:

The reason the barycenter idea appeals to me is that it goes back to the idea of what a moon is.  Charon doesn't orbit Pluto, but these two Dwarf Planets orbit a shared common point between them.  Yes it can mean that a super-earth orbiting a gas giant would still be a moon.  I'm ok with that, as I'm basing it on what the two objects are doing in relation to each other.  At its heart, a moon is an object that orbits another, so whether a massive moon is bigger than the smallest dwarf doesn't change what it does.  Doesn't make either more or less interesting either.  The Horizons mission was fantastic regardless of whether it flew by the smallest planet, a binary dwarf planet system, or a dwarf planet. 

However, I definitely don't like arbitrary mass cut off points.  What is the significance of 10^23 kg? other than it lies in a sort of dead zone in our solar system?  (Forgot that some of the gas giant moons were that much bigger than Luna and Pluto)

All this actually reminds me of that famous supreme court comment on obscenity along the lines of "I don't know how to define it, but I know it when I see it..."

We have to draw the line somewhere, and there will always be objects that fall too close to the line.  Nature doesn't produce planetoids in discrete sizes or with discrete properties.  We're trying to impose an artificial classification scheme.  No, mass isn't a good criterion but it is the least worst one. Does it make sense to have a more massive object deemed a dwarf planet while a less massive object deemed a planet?  Because if you don't make the criterion based on mass, you could have that situation arise.  That is most illogical

9 hours ago, kerbiloid said:

Nominally - yes.
While the slim and nervous king has a crown pawned in a pawnshop, and fat and lazy duke sends him money to buy some food. (114 Years War, Red&White Roses, so on).

So, if we want just an empty title, Pluto can be a planet, while Ganymede and Titan are just moon.
If we speak about the Solar System usage, Titan and Jupiter's Four are planets, while Pluto and others stay in queue for soup.

If a 0.1 Msun star orbits round a 150 Msun star, it's no more a star?

Yes, perhaps we shouldn't have an object being a moon disqualify from being a planet also.   But there is a class of astronomical object (not yet detected to my knowledge)- Pluto/Charon being the closest in our solar system (Earth/Moon being second), where two planetary bodies of near equal mass orbit each other. Which is the moon?  You probably need to reserve "double planet" for those types of bodies.  Maybe Titan and Ganymede can be "planetary moons" or something like that.

Edited June 16, 2017 by -Velocity-

[sjbuggs]

6 minutes ago, -Velocity- said:

Does it make sense to have a more massive object deemed a dwarf planet while a less massive object deemed a planet?  Because if you don't make the criterion based on mass, you could have that situation arise.  That is most illogical

Well, that is admittedly a flaw in the Dwarf planet definition as the whole 'clearing out an orbit' bit is admittedly a bit wonky.  If Earth was in Pluto's orbit it wouldn't be a "planet" either due to the space involved.  Then again, an earth sized object probably wouldn't have formed there in the first place.  Hence, the obscenity rule again.

I do object to the idea of Titan and the like being called planets, dwarf or otherwise as they clearly do orbit a much more massive object.  It's a simple and fundamental definition that works.

 

[Rakaydos]

On 6/16/2017 at 3:30 AM, Green Baron said:

Planet 9, if it exists, is very far out, much farer than the irritated kbos that are all following the same pattern), between kuiper belt and oort cloud. Scroll a few pages up for the postulated orbit. And, yes, it is assumed to be a dark rock. Its orbit is (if it exists) highly eccentrical, thus it loiters a lot of time far away with little haste. Also it might be responsible for the tilt in the ecliptic of the planets. Like many other eccentrics before, after it was done with disturbing its prissy fellows they sent it off to go play somewhere else :-)

If it exists ...

Also, the DIRECTION of it's eccentricity means it spends most of it's orbit backlit by the galactic core. It's hard to make out in the glare.

[-Velocity-]

On 6/18/2017 at 7:42 AM, Rakaydos said:

Also, the DIRECTION of it's eccentricity means it spends most of it's orbit backlit by the galactic core. It's hard to make out in the glare.

Actually, according to Mike Brown, Planet 9's aphelion is in Taurus. So no, it's not towards the galactic center unless we're very unlucky right now (its orbit is so elongated that it is most likely near aphelion right now).  Also, it's not the "glare" that makes planets harder to find if they are near the galactic plane (or especially, galactic core) in the sky, it's the sheer number of faint background stars.

Edited June 22, 2017 by -Velocity-

[YNM]

Maybe, Planet Nine is a massive Russel's Teapot.

[kerbiloid]

Populated by Schroedinger's cats.

[wumpus]

10 hours ago, YNM said:

Maybe, Planet Nine is a massive Russel's Teapot.

I have to wonder how many teapot pictures are hung in front of telescopes on April 1.  I could just see the NASA press release:

We've located absolute proof of the divine.  And she is a trickster goddess.

[Green Baron]

We must wait. Until then:

Tea. Earl Grey. Hot.

[insert_name]

Bringing this somewhat back on topic, another group of researchers thinks there's a different planet 9 in the outer solar system at 55 au

http://gizmodo.com/a-mysterious-mars-sized-object-could-be-hiding-at-the-e-1796343294

[Scotius]

Heh. Another one? Planet 9,5 or Planet 10 this time?

[kerbiloid]

1 hour ago, Scotius said:

Planet 9,5 or Planet 10 this time?

Plan 9 From Outer Space

[YNM]

I bet they must really like tea ! Lots of stranded teapots !

Edited June 23, 2017 by YNM

[Green Baron]

Some point to Russell's teapot with a stern mine, others, wearing a grin, paint Alabama teapots while Picard's aunt Adele is ready to serve the famous ginger tea. A horrible swill that coils up your toenails ... :-)

 

[Vanamonde]

This here is a non-jokey part of the forum. Please stick to the thread's topic. 

[insert_name]

19 hours ago, Scotius said:

Heh. Another one? Planet 9,5 or Planet 10 this time?

Most likely the newly theorized one will be planet 9 and Brown's planet will be planet 10  since it should be easier to discover and closer to the sun

[Cabbink]

My Ideas for Names for Objects(Including Planet 9):

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

Moon 1: Erebos/Erebus: Roman God Of Darkness.

Moon 2: Amphitryon, Hero In Roman Mythology, Who Rescued Thebes from the Teumessian fox.

Moon 3: Branchus, A Son Of Apollo.

Moon 4+: No Idea.

Good Luck to the scientists hunting for Planet 9!

Edited June 25, 2017 by Cabbink

[Green Baron]

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.

 

 

Edited June 26, 2017 by Green Baron