<p>I came across post in quora where somebody said that "most astronomers no longer think Planet 9 exists" and being somewhat shocked by that, I did a google search and found a <a href="https://www.forbes.com/sites/startswithabang/2018/09/14/this-is-why-scientists-think-planet-nine-doesnt-exist/#5ba235c76e77" rel="noreferrer">fairly recent article that claims exactly that</a>.</p>

<p>It can take several years to prove a negative within pretty good certainty, as opposed to a discovery which can be checked pretty quickly.   Because I don't want to wait several years, I wanted to ask if the general consensus is that Planet 9 probably doesn't exist?  Or is there still a respectable amount of belief among astronomers in the original evidence and any new evidence that's followed?</p>

<p>If it ends up not existing, I'll be sorry to hear it.   It was a fun story when it lasted.  </p>

CC BY-SA 4.0
2019-01-27T21:29:19.193Z
I thought planet 9 neatly explained the tilt of the ecliptic with respect to the Sun's equator, so I too would be sorry to hear of planet 9's demise.
BillDOe
CC BY-SA 4.0
2019-01-27T21:36:31.753Z
@BillDOe The tilt could just as easily be explained by a similar sized planet that is no longer in orbit around the sun, so I don't think that was every a strong argument in favor.
userLTK
CC BY-SA 4.0
2019-01-27T21:40:59.067Z
@userTLK, granted, but I thought the explanation involved a relatively small force acting over billions of years, so if a similar planet was ejected from the solar system, it would have had to have occurred recently in an astronomical time scale.
BillDOe
CC BY-SA 4.0
2019-01-31T06:42:48.843Z
@BillDOe That might make a good separate question.   I don't see why that would be necessary, but maybe it is.
userLTK
CC BY-SA 4.0
2019-01-31T20:32:07.107Z
What would make a separate question: whether planet 9 may hypothetically be responsible for the tilt of the ecliptic or if such a planet would have taken billions of years to accomplish the tilt?
BillDOe
CC BY-SA 4.0
2019-01-31T23:47:34.950Z
@BillDOe whether it would take billions of years to explain the tilt.   I think the problem with a single gravity assist is that it would only effect the 2 planets that pass close to each other, but over a lot of time, one large planet (probably Jupiter) with a high tilt probably effects the others.  To my understanding, Planet 9 could cause the tilt whether it was ejected or not.  But that's essentially the question, whether the tilt is evidence of planet 9 still being in the solar system or if it's evidence of a planet that was once close, that may have been ejected.  I lean towards Option 2
userLTK
<planet>
3 years later, how strong is the evidence for planet 9?
userLTK
# 3 years later, how strong is the evidence for planet 9?

(Asked by: username_0 on 2019-01-27)

I came across post in quora where somebody said that "most astronomers no longer think Planet 9 exists" and being somewhat shocked by that, I did a google search and found a [fairly recent article that claims exactly that](https://www.forbes.com/sites/startswithabang/2018/09/14/this-is-why-scientists-think-planet-nine-doesnt-exist/#5ba235c76e77).

It can take several years to prove a negative within pretty good certainty, as opposed to a discovery which can be checked pretty quickly. Because I don't want to wait several years, I wanted to ask if the general consensus is that Planet 9 probably doesn't exist? Or is there still a respectable amount of belief among astronomers in the original evidence and any new evidence that's followed?

If it ends up not existing, I'll be sorry to hear it. It was a fun story when it lasted.

**Tags:** planet
> **Comments:**
> **username_1**: I thought planet 9 neatly explained the tilt of the ecliptic with respect to the Sun's equator, so I too would be sorry to hear of planet 9's demise.  
> **username_0**: @BillDOe The tilt could just as easily be explained by a similar sized planet that is no longer in orbit around the sun, so I don't think that was every a strong argument in favor.  
> **username_1**: @userTLK, granted, but I thought the explanation involved a relatively small force acting over billions of years, so if a similar planet was ejected from the solar system, it would have had to have occurred recently in an astronomical time scale.  
> **username_0**: @BillDOe That might make a good separate question.   I don't see why that would be necessary, but maybe it is.  
> **username_1**: What would make a separate question: whether planet 9 may hypothetically be responsible for the tilt of the ecliptic or if such a planet would have taken billions of years to accomplish the tilt?  
> **username_0**: @BillDOe whether it would take billions of years to explain the tilt.   I think the problem with a single gravity assist is that it would only effect the 2 planets that pass close to each other, but over a lot of time, one large planet (probably Jupiter) with a high tilt probably effects the others.  To my understanding, Planet 9 could cause the tilt whether it was ejected or not.  But that's essentially the question, whether the tilt is evidence of planet 9 still being in the solar system or if it's evidence of a planet that was once close, that may have been ejected.  I lean towards Option 2  

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## 0 answers

