Planet Nine: does it exist?

[SpookyZalost]

Just saying if the planet is a super earth in mass the core of the missing 5th gas planet would make sense and it's near destruction would explain a lot of other oddities like Venus spinning backwards and Uranus being tilted on it's side, as well as the possible origin of the asteroid belt.

[Kyng]

Just saying if the planet is a super earth in mass the core of the missing 5th gas planet would make sense and it's near destruction would explain a lot of other oddities like Venus spinning backwards and Uranus being tilted on it's side, as well as the possible origin of the asteroid belt.

Possibly - although, I always thought the Asteroid Belt was a 'failed' planet that was pulled apart by Mars and Jupiter? Or is my knowledge on that 20 years out of date?

(It could very easily be - since it was ages since I heard that, and astronomy is one of those fields where our knowledge seems to shift rapidly )

[SpookyZalost]

@ Kyng that is the prevailing theory yes, but it's still entirely possible that it was destroyed by other forces, don't forget Jupiter wasn't always where it is today so it's possible Jupiter and mars are preventing it from reforming after a cataclysm.

[Kyng]

@ Kyng that is the prevailing theory yes, but it's still entirely possible that it was destroyed by other forces, don't forget Jupiter wasn't always where it is today so it's possible Jupiter and mars are preventing it from reforming after a cataclysm.

Yeah, I was assuming that Mars and Jupiter were closer to one another (and, indeed, to this failed planet) when they pulled it apart.

Although, even if that was the case, I expect it'd take a lot of energy (and perhaps a lot of time) to put all the pieces back together. It's hardly surprising that they haven't re-formed on their own .

[SpookyZalost]

well here's hoping they find it so they can throw an ion probe at it and study it.

[Kyng]

Just posting a bit of an update to this.

One of the main pieces of evidence was a mathematical simulation of the early Solar System, which showed that the motion of planets might have been best explained if there was a fifth gas giant (which, in some simulations, was ejected out into space). However, that model has been refined - and it now works equally well with either four or five gas giants (and, if anything, it works slightly better with only four):

https://www.inverse.com/science/nice-model-planet-nine

Doesn't kill the idea of 'Planet Nine', but it does make the case for it a little less compelling. (Although, if it was ejected from the Solar System, I wonder where it is now - and whether we'll ever find it?)

[Kyng]

It still hasn't been found, but the range of locations where it might be has been narrowed down considerably:

https://www.independent.co.uk/space/nine...00389.html

Hopefully that means we'll soon find it - or be able to conclude that it doesn't exist (although I'd personally prefer the former option!).

[Kyng]

Another study of the orbits of objects in the outer Solar System has strengthened the case for the existence of Planet Nine:

https://www.astronomy.com/science/new-ev...anet-nine/

Of course, none of this is definitive proof (nobody's actually found this hypothetical planet yet ), but the case for it is building!