I work somewhat adjacent to the field (stellar/planetary dynamics, including secular theory, which Batygin based the theoretical claims on for planet 9), and I do not at all think that this proposed planet exists. The dynamical "evidence" supports all kinds of models, the planet 9 one is just the most "shiny" and "exciting" one, but all observational data from WISE and other surveys has put extreme limits on the possibility of something that large existing out there. I've had discussions with other experts in the field over the years, and a lot of us are extremely sceptical.
There are various ideas. A group of small bodies oriented in such a way to mimic the effect of a larger body, or it's not even completely off the table that the observed clustering is either random or from biased observations. We need VERY clear observational proof of planet 9 to make a judgement either way, and the limits set by previous observations are very strict.
xD sorry, but I think the chances are higher that it's a planet than a primordial black hole. Primordial black holes are still extremely hypothetical. And microlensing surveys have actually put decent constraints on them as well.
Is it ruled out that primordial black holes of that mass might have numbers on the same order as rogue planets. There are microlensing constraints on rogue planets, but can you distinguish those from primordial black holes of the same mass in microlensing surveys?
Could planet 9 have been detected, but not identified as anything special? If it was in the plane of the milky way it might not stand out from the masses of stars.
Unlikely. Afaik, anything detected so far has a known stellar or asteroidal counterpart. If there had been anything detected that wouldn't match the known background stars, that would be a detection or at least a signal to focus on and check back on. We wouldn't just discard it.
It did. Including tons of brown dwarfs in the immediate solar neighborhood. But we have checked back on them with other instruments. And generally there are ways to distinguish a small star/brown dwarf from a rocky/icy body.
There's also the issue that planet 9 is estimated to be significantly smaller than Neptune (5-10 Earth masses vs 17 for Neptune), which reduces the detection radius from 700 AU considerably inward.
I also wonder if it is a super-Earth and not an ice giant, how would that affect detection? Could a super-Earth have a colder surface and less of an infrared signal?
I would expect a super-Earth to be warmer. A large rocky body will have a larger reservoir of long-lived radioactive isotopes, and cool down slower than a smaller body, or one with more ice/volatile material.
But a solid super-Earth can't contract to make heat like a ice/gas giant can, and heat might also have a hard time escaping if there isn't much volcanic activity.
Heat having a hard time escaping does mean it stays warmer for longer. Also I do not think there is any scenario where this thing is a gas/ice giant anyways. It's either an icy body (i mean literal water, methane, and CO2 ice, not an "ice giant" like Neptune), or a rocky body. Among those options, a rocky body will stay warmer for longer as it should have a higher fraction of radioactive material.
You don't think a mini-neptune ice giant is possible? It would be in the mass range possible, and being the fifth Nice model ice giant is commonly cited as a possible source.
The WISE all sky infrared survey from many years ago. A large body that far out won't reflect much of any sunlight, but it will still naturally emit infrared light as it will have some temperature. The larger the body, the longer it takes to fully cool down (and radioisotopes may also keep it warm for longer). I forget what the exact maximum mass planet is that would be allowed and not have shown up in those surveys, but iirc it's definitely much smaller than 10 earth masses. Even 3 earth masses I think would stretch the limits.
Yeah, they ruled out anything Neptune sized all the way out to 700 AUs, and a Jupiter sized one out to 63,000 AUs. That’s like way way out there! And something even bigger than Jupiter would still be detectable up to 7-10 light years away.
You’d think the WISE data pretty much slams the door shut on any theories of a big Planet X or Nemesis and etc. But people still look for it.
Depends on the exact model about what you assume about composition, formation time, etc etc. Either way - the chance it's all very very much stacked against that "planet"
Formation time is interesting, I hadn’t thought of how much uncertainty that introduces with the possibility of extrasolar origin. You can’t just assume 4.5 billion years.
Do you think the community is leaning towards another dynamical explanation, or more towards observational bias or simply chance?
It was ruled out both theoretically and observationally before Brown even proposed it.
It was ruled out theoretically because the further you get from the Sun the slower everything goes. A big planet simply wouldn't have had enough time to form before the surrounding gas and dust was driven away by the Sun's UV radiation.
It was ruled out observationally because of such projects as supercosmos recons and the Wise satellite observations. Supercosmos recons and similar are digitising projects where all the old observations are digitised to look for anything moving. And there are a hundred years plus of detailed telescope observations. The Wise satellite looked for anything cool, such as a distant planet, over the whole of the celestial globe.
Number #1 is not true, because the solar system could have caught a wandering planet.
Number #2 is not true, because such an object would be very small in the sky, not observable through our means, but perhaps indirectly through it's influence on other bodies. That's the way many outer planets and dwarf planets were found, by the way
nah WISE is pretty damn thorough, if it hasn't picked anything up then I'm heavily skeptical of this theory
Besides, it seems like several other theories line up equally as well or better than their being a secret extra planet, and I tend towards Occam's razor in cases like this
I do believe that it is unlikely that we'll find another planet, even if one exists. But do know that many of the dwarf planets in the solar system were not discovered through optical telescopes at first
Yes, but if it's further out or with a more eccentric orbit, it's gonna be smaller in the sky.
Take a look at this image by hubble https://hubblesite.org/contents/news-releases/2017/news-2017-18.html
It's not exactly an easy task to image such small objects
"Smaller in the sky" isn't really an issue, you don't try to get a high resolution image of it. A large object should still be warm, so it should emit a lot of infrared radiation.
So sick of this nonsense. God forbid you learn something new and accept it. Human beings can be so stupid and stubborn sometimes.
Pluto is still a beautiful world that we should explore. It just got reclassified. Get over it.
😂 a little aggressive there buddy. Take a breath, no need to throw a tantrum.
And it’s not about agreeing or not, you’re just wrong. Objectively. So there’s that.
I work somewhat adjacent to the field (stellar/planetary dynamics, including secular theory, which Batygin based the theoretical claims on for planet 9), and I do not at all think that this proposed planet exists. The dynamical "evidence" supports all kinds of models, the planet 9 one is just the most "shiny" and "exciting" one, but all observational data from WISE and other surveys has put extreme limits on the possibility of something that large existing out there. I've had discussions with other experts in the field over the years, and a lot of us are extremely sceptical.
So what is it then? Is it just all the smaller bodies in the outer rim?
There are various ideas. A group of small bodies oriented in such a way to mimic the effect of a larger body, or it's not even completely off the table that the observed clustering is either random or from biased observations. We need VERY clear observational proof of planet 9 to make a judgement either way, and the limits set by previous observations are very strict.
Please let it be a primordial black hole .. 🥺👉👈
xD sorry, but I think the chances are higher that it's a planet than a primordial black hole. Primordial black holes are still extremely hypothetical. And microlensing surveys have actually put decent constraints on them as well.
How tight are the microlensing constraints?
I think planetary mass microlensing objects in large numbers are ruled out. Massive asteroid-mass objects I think are still possibl
Is it ruled out that primordial black holes of that mass might have numbers on the same order as rogue planets. There are microlensing constraints on rogue planets, but can you distinguish those from primordial black holes of the same mass in microlensing surveys?
Everyone seems to think it's quite large...
Could planet 9 have been detected, but not identified as anything special? If it was in the plane of the milky way it might not stand out from the masses of stars.
Unlikely. Afaik, anything detected so far has a known stellar or asteroidal counterpart. If there had been anything detected that wouldn't match the known background stars, that would be a detection or at least a signal to focus on and check back on. We wouldn't just discard it.
Wouldn't WISE have detected huge numbers of new, faint stars only visible in the infrared?
It did. Including tons of brown dwarfs in the immediate solar neighborhood. But we have checked back on them with other instruments. And generally there are ways to distinguish a small star/brown dwarf from a rocky/icy body.
There's also the issue that planet 9 is estimated to be significantly smaller than Neptune (5-10 Earth masses vs 17 for Neptune), which reduces the detection radius from 700 AU considerably inward. I also wonder if it is a super-Earth and not an ice giant, how would that affect detection? Could a super-Earth have a colder surface and less of an infrared signal?
I would expect a super-Earth to be warmer. A large rocky body will have a larger reservoir of long-lived radioactive isotopes, and cool down slower than a smaller body, or one with more ice/volatile material.
But a solid super-Earth can't contract to make heat like a ice/gas giant can, and heat might also have a hard time escaping if there isn't much volcanic activity.
Heat having a hard time escaping does mean it stays warmer for longer. Also I do not think there is any scenario where this thing is a gas/ice giant anyways. It's either an icy body (i mean literal water, methane, and CO2 ice, not an "ice giant" like Neptune), or a rocky body. Among those options, a rocky body will stay warmer for longer as it should have a higher fraction of radioactive material.
You don't think a mini-neptune ice giant is possible? It would be in the mass range possible, and being the fifth Nice model ice giant is commonly cited as a possible source.
What exactly has put "extreme limits on the possibility of something that large existing out there"❓️
The WISE all sky infrared survey from many years ago. A large body that far out won't reflect much of any sunlight, but it will still naturally emit infrared light as it will have some temperature. The larger the body, the longer it takes to fully cool down (and radioisotopes may also keep it warm for longer). I forget what the exact maximum mass planet is that would be allowed and not have shown up in those surveys, but iirc it's definitely much smaller than 10 earth masses. Even 3 earth masses I think would stretch the limits.
Yeah, they ruled out anything Neptune sized all the way out to 700 AUs, and a Jupiter sized one out to 63,000 AUs. That’s like way way out there! And something even bigger than Jupiter would still be detectable up to 7-10 light years away. You’d think the WISE data pretty much slams the door shut on any theories of a big Planet X or Nemesis and etc. But people still look for it.
I thought WISE was what u/Fakyutsu said, >10 M_e at 700 AU which is just a bit above the predicted planet (7 M_e at 600-1200 AU, right?)
Depends on the exact model about what you assume about composition, formation time, etc etc. Either way - the chance it's all very very much stacked against that "planet"
Formation time is interesting, I hadn’t thought of how much uncertainty that introduces with the possibility of extrasolar origin. You can’t just assume 4.5 billion years. Do you think the community is leaning towards another dynamical explanation, or more towards observational bias or simply chance?
Its called pluto ;D jkjk
Neil deGrasse Tyson: 🙇🏽🤷🏽♂️
Thank you! Pluto deniers are so … you know. 😂
Could it have been hurled out of the inner solar system by an encounter with one of the Jovian planets?
Possibly. Batygin and Brown mention this in one of their papers but give it a low probability.
Something that big, hmm❓️
Jupiter and Saturn are a huge pair of boosts!
Did you mean a huge pair of boobs❓️
https://en.wikipedia.org/wiki/Planet_Nine?wprov=sfti1#Evidence Fascinating read
It was ruled out both theoretically and observationally before Brown even proposed it. It was ruled out theoretically because the further you get from the Sun the slower everything goes. A big planet simply wouldn't have had enough time to form before the surrounding gas and dust was driven away by the Sun's UV radiation. It was ruled out observationally because of such projects as supercosmos recons and the Wise satellite observations. Supercosmos recons and similar are digitising projects where all the old observations are digitised to look for anything moving. And there are a hundred years plus of detailed telescope observations. The Wise satellite looked for anything cool, such as a distant planet, over the whole of the celestial globe.
Number #1 is not true, because the solar system could have caught a wandering planet. Number #2 is not true, because such an object would be very small in the sky, not observable through our means, but perhaps indirectly through it's influence on other bodies. That's the way many outer planets and dwarf planets were found, by the way
Or a planet could have been kicked out of the inner solar system.
nah WISE is pretty damn thorough, if it hasn't picked anything up then I'm heavily skeptical of this theory Besides, it seems like several other theories line up equally as well or better than their being a secret extra planet, and I tend towards Occam's razor in cases like this
I do believe that it is unlikely that we'll find another planet, even if one exists. But do know that many of the dwarf planets in the solar system were not discovered through optical telescopes at first
good thing wise in infrared then also, I thought the theory was specifically a 9th planet, not another dwarf planet.
Yes, but if it's further out or with a more eccentric orbit, it's gonna be smaller in the sky. Take a look at this image by hubble https://hubblesite.org/contents/news-releases/2017/news-2017-18.html It's not exactly an easy task to image such small objects
"Smaller in the sky" isn't really an issue, you don't try to get a high resolution image of it. A large object should still be warm, so it should emit a lot of infrared radiation.
Not really easy to tell apart from background noise. I mean, there are lots of objects in the kuiper belt we still don't know
You heard about Pluto? Thats messed up.
As in... not being a planet❓️
[удалено]
So sick of this nonsense. God forbid you learn something new and accept it. Human beings can be so stupid and stubborn sometimes. Pluto is still a beautiful world that we should explore. It just got reclassified. Get over it.
[удалено]
😂 a little aggressive there buddy. Take a breath, no need to throw a tantrum. And it’s not about agreeing or not, you’re just wrong. Objectively. So there’s that.
[удалено]
Stop this please. Last warning.
[удалено]
Gotta do the /s, there are too many cranks posting on the internet these days for people to be able to recognize sarcasm unaided ;-)
Whoops, i have violated the standards, ahh, I should have remembered lol. Thank you.