Pluto resurrected

[dutchfire]

Agent, have you heard about Vulcan?

 

[Timsup2nothin]

Sooooooo....

A question that has perked up in my mind during all this.

Let us posit a proto planet pinballing around in the forming solar system. There were probably plenty of those. Some managed to establish themselves in near circular orbits that keep them from interacting too much with each other and settled in for the long haul. At least one, theoretically, got booted into this distant somewhat elongated orbit where it could visit the Oort cloud occasionally and stir up some action out there. Others, again theoretically, would have been beaten up so badly by the big bullies on the block that they got booted out entirely and became rogues.

But...

What if one or more of these potential rogues got booted with something just short of sufficient energy to actually escape the sun?

Would such an object not have fallen into a hugely extended elliptical path? A path where it spends millions of years traveling out into the galaxy while slowing down, followed by millions more years regaining velocity in its long "fall" back towards the sun?

So with that in mind, what would be the period of a not quite rogue planet with an apogee somewhere close to the most extreme range from the sun that it could achieve without wandering off, and a perigee of say, just for convenience, 1 AU? What would be the velocity of such a not quite rogue at perigee?

 

[uppi]

That doesn't follow. Anyway, what I gathered from the article is that they ruled out these other hypotheses. Otherwise, presenting their conclusion would indeed be cherry picking. (As in, we pick this hypothesis because we like it best.) We can rule this out, as the article wouldn't even be fit for publication, scientifically speaking.

I'm still waiting for a better argument. Until then I stick with: Planet 9 exists.

Perhaps I should give an analogy. For quite some time our solar system had X number of planets. Then planet Y was discovered, followed by planet Z. But until that time: our solar system has X planets was a true statement - even though factually incorrect, this was the knowledge of the time.

Perhaps this analogy is unnecessary, but one likes to be thorough. I could extend the analogy, but I don't think that's necessary either.

They did not completely rule out alternative hypotheses, partly because it is impossible to do. If the hypothesis is interesting enough, it would be published even if it has a low chance of being right. A paper gets published when it is interesting and not obviously wrong, but whether it is right or not is not a criterion. So that it has been published just means that the referees found no fault with the hypothesis, but that does not necessarily mean they believe that the planet actually exists.

In science there has to be plenty room for multiple opinions. Adding new ideas that could be tested is as valuable as testing and eliminating some of them.

In case y'all have it too easy to fall asleep at night, imagine if the lost planet comes back and knocks the Earth off from the orbit.

I wonder what would happen when the scientists gathered out that this is going to happen. Would they start to plan death star to blow it off before it comes near? Or would they start a crazy sex and drugs infused bacchanal?

It would depend on how much time there still is and how much correction would be needed, but I doubt that we would even have the ability to veer something like that off course. I think the better strategy would be a serious effort to leave this planet.

Would such an object not have fallen into a hugely extended elliptical path? A path where it spends millions of years traveling out into the galaxy while slowing down, followed by millions more years regaining velocity in its long "fall" back towards the sun?

Exactly.

So with that in mind, what would be the period of a not quite rogue planet with an apogee somewhere close to the most extreme range from the sun that it could achieve without wandering off, and a perigee of say, just for convenience, 1 AU? What would be the velocity of such a not quite rogue at perigee?

Calculating the extreme range is a tricky multi-body problem and it would depend in which direction the object would have been slung. I would guess that you could probably get a stable orbit at 2 light years. For special orbits you might get another factor of 2, but I doubt there are stable orbits beyond that.

So lets take 2 light years. The orbital period would be 45 million years. That would mean about 100 orbital periods in the lifetime of the solar system. I would think that if such a planet would exist, it would have knocked a few planets off course already and the solar system would look quite differently.

The orbital velocity at 1 AU would be 42 km/s, not that much more than the 30 km/s of the earth. For that it actually would not matter much where the planet would be coming from. 100 AU or 100 light years would also result in 42 km/s.

 

[Michkov]

Wouldn't such an orbit be very sensitive to disturbances of close stars etc? Especially considering the little time it would spend near the sun.

 

[Timsup2nothin]

Calculating the extreme range is a tricky multi-body problem and it would depend in which direction the object would have been slung. I would guess that you could probably get a stable orbit at 2 light years. For special orbits you might get another factor of 2, but I doubt there are stable orbits beyond that.

So lets take 2 light years. The orbital period would be 45 million years. That would mean about 100 orbital periods in the lifetime of the solar system. I would think that if such a planet would exist, it would have knocked a few planets off course already and the solar system would look quite differently.

The orbital velocity at 1 AU would be 42 km/s, not that much more than the 30 km/s of the earth. For that it actually would not matter much where the planet would be coming from. 100 AU or 100 light years would also result in 42 km/s.

Thanks for doing the math. I was feeling lazy. It does seem like a hundred passes would have left enough catastrophic evidence to rule that out, but it was an interesting brief speculation.

 

[uppi]

Wouldn't such an orbit be very sensitive to disturbances of close stars etc? Especially considering the little time it would spend near the sun.

Sure. As I said, it would be a tricky problem to find the most extreme orbit that is still stable.

 

[Agent327]

They did not completely rule out alternative hypotheses, partly because it is impossible to do. If the hypothesis is interesting enough, it would be published even if it has a low chance of being right. A paper gets published when it is interesting and not obviously wrong, but whether it is right or not is not a criterion. So that it has been published just means that the referees found no fault with the hypothesis, but that does not necessarily mean they believe that the planet actually exists.

If that is the case, they should have presented their findings in another way.

 

[Timsup2nothin]

If that is the case, they should have presented their findings in another way.

So that science believers who don't bother to make sure they understand before they fly off on a tangent wouldn't embarrass themselves by calling people who do understand wrong? How is that their responsibility?

 

[uppi]

If that is the case, they should have presented their findings in another way.

I read the paper when it was published. They presented it as they should. They cannot do anything at all about the misinformation that gets spread by science journalism. And they can do even less about people, who never bothered to read the paper, misunderstanding them.

 

[Agent327]

That's not what I said though. Presentation isn't just publication. If their publication is just a listing of probably explanations, that does not conform with the accompanying video at all. And it hardly justifies a call to 'go look with telescopes'. That's redundant from the viewpoint of probable explanations alone already.

 

[hobbsyoyo]

Link to video.

But hold the phone — no planet has been discovered yet. In a video released by NASA, Jim Green, NASA's director of planetary science, cautions that it is still too early to claim that Earth's solar system has nine planets (again).

"The idea of a new planet is certainly an exciting one for me as a planetary scientist, and I think for all of us," Green said in the video. "It is not, however, the detection of a new planet. It's too early to say with certainty that there is a so-called 'Planet X' out there."

 

[Agent327]

Yes, thanks - I already watched that video. So... why the request to go look with telescopes again?

 

[Flying Pig]

In order to leverage something exciting in the news into more people interested in astronomy?

 

[hobbsyoyo]

Because that's the easiest, surest way to tell if the theory is correct - which is currently not known to be the case. I don't know why you insist everyone repeat themselves.

Edit: Also, because if it exists it can be seen despite your protestations and mischaracterizations.

 

[uppi]

Yes, thanks - I already watched that video. So... why the request to go look with telescopes again?

Because there is this thing called the scientific method. Once you have established a reasonable hypothesis based on current data, the next step is to collect more data that can test this hypothesis. The only way to gather data on this particular issue is...to look with telescopes!

A telescope could find nothing, it could find the planet itself, or it could find other objects that fit or do not fit the hypothesis. This could be used to confirm, refine, or dismiss the hypothesis - the scientific method in action.

 

[Flying Pig]

Edit: Also, because if it exists it can be seen despite your protestations and mischaracterizations.

Can it? I thought it was too far away, even given its size, to be seen from earth with a telescope. At least if I've understood this correctly, that is.

 

[Timsup2nothin]

Can it? I thought it was too far away, even given its size, to be seen from earth with a telescope. At least if I've understood this correctly, that is.

That's kind of dependent on the telescope. No one is suggesting that I should be out in my backyard looking, though I do have a nice scope for looking at moon craters and such.

 

[hobbsyoyo]

Can it? I thought it was too far away, even given its size, to be seen from earth with a telescope. At least if I've understood this correctly, that is.

As Tim pointed out, that comic really depends on what kinds of telescopes we use. Your amateur telescope, not so much; but the big flagship observatories, certainly.

It's also been pointed out here that this theory rests on the direct observation of several KBO's which are far, far smaller than Planet X. Additionally, we can see planets in other solar systems which are much, much further away than Planet X. With the right telescopes, we could certainly see it if it exists, no problem whatsoever.

 

[Timsup2nothin]

As Tim pointed out, that comic really depends on what kinds of telescopes we use. Your amateur telescope, not so much; but the big flagship observatories, certainly.

It's also been pointed out here that this theory rests on the direct observation of several KBO's which are far, far smaller than Planet X. Additionally, we can see planets in other solar systems which are much, much further away than Planet X. With the right telescopes, we could certainly see it if it exists, no problem whatsoever.

Well, no problem IF we know exactly where to look. I really like the line about trying to find a grain of sand on the kitchen floor by looking through a straw.

 

[hobbsyoyo]

That's an apt comparison!