Pluto resurrected

[Timsup2nothin]

Okay, not exactly. Maybe Pluto, the sequel. Is being at nine planets really important?

The story.

 

[dutchfire]

Funny, we're looking for dark matter and we can't even find all the planets in our solar system....

 

[Timsup2nothin]

Heck, a lot of humanity can't find their own ass with both hands.

 

[Serutan]

Saw that. Will be interesting when they spot it. And if so, is there any chance New Horizons could be re-routed there?

 

[wolfigor]

Funny, we're looking for dark matter and we can't even find all the planets in our solar system....

Both the alleged planet and dark matter are not find by direct observation.
We look at effects, at deviations from the orbits we expect, a lot small clues that reveal there is something out there.
It's like to find a needle in a haystack by looking at from far at the disturbance in the hay.

Saw that. Will be interesting when they spot it. And if so, is there any chance New Horizons could be re-routed there?

"There" where?
Scientists have seen a "disturbance" in the path of several objects which could be explained by the planet.
They have no clue where the planet really is (if it exists at all).

The other point is that the possible orbit brings the alleged planet at a whopping 600 AU of distance!
Pluto orbit is between 30 & 50 AU.

 

[Timsup2nothin]

The other point is that the possible orbit brings the alleged planet at a whopping 600 AU of distance!
Pluto orbit is between 30 & 50 AU.

I think that 600 AU might be the mean. The theoretical orbit is substantially elongated, with the nearest approach at "only" 200 AU.

 

[uppi]

I think that 600 AU might be the mean. The theoretical orbit is substantially elongated, with the nearest approach at "only" 200 AU.

If that planet exists, it is very unlikely to be anywhere near that point at the moment. A body with a highly elliptical orbit spends only a small fraction of that orbit near perihelion and lurks far away from the sun most of the time. And if it was close, it would have been almost certainly detected by now.

Keep in mind that there is not one theoretical orbit, but a lot of possible orbits that could fit this planet. That increases the difficulty of finding it, because it could be anywhere in a very large region of the sky.

 

[Timsup2nothin]

If that planet exists, it is very unlikely to be anywhere near that point at the moment. A body with a highly elliptical orbit spends only a small fraction of that orbit near perihelion and lurks far away from the sun most of the time. And if it was close, it would have been almost certainly detected by now.

Keep in mind that there is not one theoretical orbit, but a lot of possible orbits that could fit this planet. That increases the difficulty of finding it, because it could be anywhere in a very large region of the sky.

Agreed on all counts.

Additionally...depending on composition, given the distance it most likely is from the sun reflected light may be very close to zero. We look up and see planets as among the brightest objects in the sky. This thing won't be visible to anything but the highest end of telescopes, if that.

 

[Flying Pig]

My understanding was that Pluto doesn't count as a planet because planets initially form as matter is thrown out from the centre of the solar system - in other words, they should decrease in density as they get further from the sun. Since Pluto is a rock, and not gas, it cannot have been formed along with the other planets, and so must simply be the first of the many big rocks that make up the Kuiper Belt, which we realised when we started finding more. Is there anything different about this one?

EDIT: I see that it's supposedly a gas giant, and suspect that explains something. The position might be a bit like somebody who announced that anything beyond Mars would have to be part of the asteroid belt.

 

[uppi]

Agreed on all counts.

Additionally...depending on composition, given the distance it most likely is from the sun reflected light may be very close to zero. We look up and see planets as among the brightest objects in the sky. This thing won't be visible to anything but the highest end of telescopes, if that.

Yes, you would need a very sensitive telescope to detect it. Highest end telescopes should be able to easily spot it, if they were pointed at it. The problem is that these telescopes have a very narrow field of view, so they would need to be very precisely adjusted to the position of the potential planet to spot it. But they do not know where it is, so they would have to be very lucky with these telescopes.

There is at least one telescope that is more suited for this purpose, because it is sensitive enough and has a wide field of view. The authors of the paper are already using that one to search for that planet, but they say it is going to take at least 5 years to survey the relevant portion of the sky.

My understanding was that Pluto doesn't count as a planet because planets initially form as matter is thrown out from the centre of the solar system - in other words, they should decrease in density as they get further from the sun. Since Pluto is a rock, and not gas, it cannot have been formed along with the other planets, and so must simply be the first of the many big rocks that make up the Kuiper Belt, which we realised when we started finding more. Is there anything different about this one?

EDIT: I see that it's supposedly a gas giant, and suspect that explains something. The position might be a bit like somebody who announced that anything beyond Mars would have to be part of the asteroid belt.

The hypothesis is that it formed like Uranus and Neptune but then got thrown out by these two. And it is supposed to have a mass that is 5-15 times the mass of the earth. So it would clearly be something different than Pluto and all the other dwarf planets. But it would be clearly different compared to the other planets. At that distance it would be outside of the heliosphere and thus in interstellar space. I expect the discussions about the definition of a planet to flare up again if this new potential planet would be detected.

 

[Perfection]

At that distance it would be outside of the heliosphere and thus in interstellar space. I expect the discussions about the definition of a planet to flare up again if this new potential planet would be detected.

I wouldn't think so.

By the IAU definition:

A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

By this metric the hypothesized body would definitely qualify as a planet and I don't think anyone could make a convincing case that it's anything else.

Seems more likely that plasma physicists won't get to say that space probes have left the solar system anymore when they exit the heliosphere. Or they'll have to qualify that statement.

 

[El_Machinae]

Funny, we're looking for dark matter and we can't even find all the planets in our solar system....

Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.

 

[Aea]

Entirely tangental but:

If something knocked Mercury hard enough for it to start flying through the Solar System and intersecting other orbits would be cease to be a planet? The current IAU definition seems to demand both state and behavior so I assume it would.

 

[Flying Pig]

I think they would revise the definition in that case: the point of 'cleared its orbit' was to avoid giving the title to the biggest asteroid in a ring of them, which is what they decided Pluto, essentially, was.

 

[hobbsyoyo]

Entirely tangental but:

If something knocked Mercury hard enough for it to start flying through the Solar System and intersecting other orbits would be cease to be a planet? The current IAU definition seems to demand both state and behavior so I assume it would.

If it was entirely knocked out of the solar system, it would be considered a 'rogue planet'. I'm not sure if there is a rigorous definition for those as there is for 'planet', namely because we haven't found any yet. They are exceedingly hard to spot.

I just read an article where they discovered that the one rogue planet they had discovered turned out to be in the orbit of a very distant (to the planet) and dim brown dwarf and so is no longer a 'rogue'.

 

[Timsup2nothin]

If it was entirely knocked out of the solar system, it would be considered a 'rogue planet'. I'm not sure if there is a rigorous definition for those as there is for 'planet', namely because we haven't found any yet. They are exceedingly hard to spot.

I just read an article where they discovered that the one rogue planet they had discovered turned out to be in the orbit of a very distant (to the planet) and dim brown dwarf and so is no longer a 'rogue'.

So it's a reformed planet?

 

[Agent327]

If that planet exists, it is very unlikely to be anywhere near that point at the moment. A body with a highly elliptical orbit spends only a small fraction of that orbit near perihelion and lurks far away from the sun most of the time. And if it was close, it would have been almost certainly detected by now.

Keep in mind that there is not one theoretical orbit, but a lot of possible orbits that could fit this planet. That increases the difficulty of finding it, because it could be anywhere in a very large region of the sky.

Firstly, it's not an 'if'. Secondly, you won't find it in the sky. It's too far out - even at the closest part of its ellips - to reflect sunlight.

Which makes it a bit odd that the Caltech video ends with request for telescope viewing. It's unviewable by telescope.

 

[Timsup2nothin]

Firstly, it's not an 'if'. Secondly, you won't find it in the sky. It's too far out - even at the closest part of its ellips - to reflect sunlight.

Which makes it a bit odd that the Caltech video ends with request for telescope viewing. It's unviewable by telescope.

WOW.

That was quite an impressive list of facts!

Call CalTech immediately!

Firstly, even the guys proposing that it is there recognize that their calculated probability is far from a certainty. I'm sure they would flat out fall down in gratitude at your providing confirmation.

Secondly, no one but you has any clue regarding composition, so for anyone else determination of reflectivity would be impossible. I expect they will be eager to have you tell them the value to plug in there.

 

[hobbsyoyo]

Firstly, it's not an 'if'. Secondly, you won't find it in the sky. It's too far out - even at the closest part of its ellips - to reflect sunlight.

Which makes it a bit odd that the Caltech video ends with request for telescope viewing. It's unviewable by telescope.

I explained this in another thread (I think in OT) but this is not proven by a long shot, so it still is an 'if'.

And they most definitely could image it with the telescopes available if it exists and it is as massive as predicted. It won't be a pretty image - maybe just a few pixels - but it could be done. We are already capable of directly imaging planets in other solar systems under the right circumstances. This would be much, much easier than that.

 

[uppi]

Firstly, it's not an 'if'.

The case they make for a planet is the best in a long time, but its existence is far from certain and still a long shot.

Secondly, you won't find it in the sky. It's too far out - even at the closest part of its ellips - to reflect sunlight.

Which makes it a bit odd that the Caltech video ends with request for telescope viewing. It's unviewable by telescope.

The discovery of the collection of rocks that provided the evidence for this potential planet proves that small objects can be imaged by telescope even that far out. In fact, astronomers already know that this planet cannot be near its perihelion, because if it was, it would be so bright that it would have shown up on some image already.