One place Planet 9 could be hiding(universetoday.com)
universetoday.com
One place Planet 9 could be hiding
https://www.universetoday.com/165774/theres-one-last-place-planet-9-could-be-hiding/
79 comments
Would it be a bigger surprise if Planet 9 existed, or if Planet 9 doesn't exist? This isn't my field of study, but as I understand there's a good amount of indirect evidence for a Planet 9... and still no direct proof. Assuming we're searching in the right areas, if a scan of the first 80% didn't reveal it, it seems unlikely (but of course not impossible) that we'll find it in the last 20%.
There’s a difference between completing 80% of the work, and ruling out 80% of the options.
We could rule out 80% of the options and still have 99% of the work yet to be completed.
Like if we’re looking for a bacteria on the land surface of the earth, and we rule out 80% of the options, that leaves us with searching an area the size of Africa for a microscopic life form.
We could rule out 80% of the options and still have 99% of the work yet to be completed.
Like if we’re looking for a bacteria on the land surface of the earth, and we rule out 80% of the options, that leaves us with searching an area the size of Africa for a microscopic life form.
Doesn't change the fact that whatever probability you previously assigned to finding Planet 9, it should be one fifth of that now. (Sort of. Not so drastic if you have strong reasons to think there is a Planet 9)
The suggestion is maybe part of the sky is easier to survey, so it was completed cheaply, even though that part wasn't the most likely part. I don't know which way it is, but it's an interesting question, and that's what OP is getting at for understanding the relevant probabilities instead of the relevant area.
Existing would be the bigger surprise. We've ruled out anything of Earth's mass out to distances of 100 AU and Jupiter's mass to 1000 AU, since those would be visible to telescopic searches and have measurable gravitational effects on known objects that we don't see from observation. It's almost certain that there's nothing that would meet the "clearing the neighborhood" definition of a planet. At most there would be more dwarf planets on the size order of Pluto and Eris and Quaoar, which are common, but those are each comparatively tiny, like 0.2% of Earth's mass.
The article says "78% of places have been searched"... but that's a really weirdly imprecise way of saying that. What are "places" here? Like, the sphere out to 100 AU is 78% of the volume out to 120 AU... but that makes no sense, the possible locations go out to 1000 AU or more.
There are indeed lots of claims of some evidence for another planet existing... but all those claims are different with no consensus, and it's largely fairly specious proposals trying to get some funding.
The article says "78% of places have been searched"... but that's a really weirdly imprecise way of saying that. What are "places" here? Like, the sphere out to 100 AU is 78% of the volume out to 120 AU... but that makes no sense, the possible locations go out to 1000 AU or more.
There are indeed lots of claims of some evidence for another planet existing... but all those claims are different with no consensus, and it's largely fairly specious proposals trying to get some funding.
Eh, we ruled that out - within our observable time-frame, but we do not know about exotic, long-term orbits. Like a 50.000 year elipse out into the ort cloud and back in.
“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's long way down the road to the chemist's, but that's just peanuts to space.”
I like to tell people how big space is just by describing how fast voyager 1 is moving and how long it will take to reach 1 light year of travel. Voyager 1 launched back in the 70's and is traveling around 38,210 mph. Even at that speed it will take another approximate 18,500 years for it to reach it's first light year traveled. The closest star is about 4.2 light years away so at it's current speed it would take about 75,000 years for it to reach Alpha Centauri.The more you start getting into the numbers and things like how many light years across the milky way is and how far to the next galaxy and how many galaxies their are you start to see the universe is unimaginably large. I don't think one could fully grasp it's size. Amazing
"Don't Panic."
> continues to search for the elusive Planet Nine (also called Planet X)
In light of Pluto's demotion, surely we should deprecate "Planet X" in favor of "Planet Ix".
In light of Pluto's demotion, surely we should deprecate "Planet X" in favor of "Planet Ix".
I've always thought the idea of planet nine being a primordial black hole was kinda cool, but AFAIK we have no evidence to suggest this.
Unless I'm mistaken if PBHs do exist then one with 2-4 Earth masses is within the plausible range. It'd be about the size of a billiard ball. The existence of lots and lots of PBHs of various sizes is one dark matter candidate.
https://en.wikipedia.org/wiki/Primordial_black_hole
If there were such a thing out there we could send a probe to it. I can't imagine what kinds of interesting physics we could do if we could directly examine a black hole.
It'd be neat if it were actually useful in the far future too, like as a power source to generate and beam energy to interstellar spacecraft. There's even concepts like this:
https://en.wikipedia.org/wiki/Black_hole_starship
A PBH of that mass would not be useful for this but perhaps there'd be a way to leverage the extreme conditions created near the event horizon to generate smaller ones that evaporate quickly... like the extreme physics analog of sourdough starter.
Unless I'm mistaken if PBHs do exist then one with 2-4 Earth masses is within the plausible range. It'd be about the size of a billiard ball. The existence of lots and lots of PBHs of various sizes is one dark matter candidate.
https://en.wikipedia.org/wiki/Primordial_black_hole
If there were such a thing out there we could send a probe to it. I can't imagine what kinds of interesting physics we could do if we could directly examine a black hole.
It'd be neat if it were actually useful in the far future too, like as a power source to generate and beam energy to interstellar spacecraft. There's even concepts like this:
https://en.wikipedia.org/wiki/Black_hole_starship
A PBH of that mass would not be useful for this but perhaps there'd be a way to leverage the extreme conditions created near the event horizon to generate smaller ones that evaporate quickly... like the extreme physics analog of sourdough starter.
The idea of a black hole starship is that you carry the black hole around, just like any other engine. If you want to beam power from it, there isn't anything at all there to gain compared to beaming power from the Sun.
And if you want to carry it with your ship, it weighting 2 Earth masses is kind of a drawback.
And if you want to carry it with your ship, it weighting 2 Earth masses is kind of a drawback.
There was a scifi story decades ago about using small but heavy objects (neutronium, IIRC) as an integral part of space ships. The idea was not to use them to generate energy, but to generate a gravitational field to counteract the effects on humans of high acceleration. The object was held in front of the spacecraft, and would be moved closer when high acceleration was needed.
I guess if the ship was just drifting, you'd have the heavy object at a sufficient distance to cause ~1g gravity.
I don't remember the story's title or author(s), but it likely appeared in Analog.
I guess if the ship was just drifting, you'd have the heavy object at a sufficient distance to cause ~1g gravity.
I don't remember the story's title or author(s), but it likely appeared in Analog.
It's Charles Sheffield, in particular his McAndrew series.
Thank you! With that help, I was able to find the story: "Moment of Inertial." And here's a link to the story: https://www.baen.com/Chapters/067157857X/067157857X__2.htm
If I recall, he used that invention in several stories. They're quite enjoyable. Sheffield, as a writer with a hard science background, came up with some very interesting ideas, such as The Sturm Invocation, and the entire Proteus series was very well-considered. Sometimes I get a taste for the diamond-hard sf and he scratches that itch. Hal Clement, too, if you're into that; Half Life is probably the best novel where the concept of the scientific method itself is at the forefront.
I now have Half Life on order, your fault.
I was intrigued by another Hal Clement title, Trio for Slide Rule and Typewriter. I have a slide rule sitting a few feet from me as I write this, in case of emergency. No typewriter, though.
I was intrigued by another Hal Clement title, Trio for Slide Rule and Typewriter. I have a slide rule sitting a few feet from me as I write this, in case of emergency. No typewriter, though.
Pay especial attention to the General Order and such right at the very start. I literally have incorporated those two ideas into the highest levels of how I solve problems. Hopefully, you will enjoy the book as much as I.
You don't move the blackhole+ship, that's crazy. You'd simply move the universe around your ship.
Which is already possible by shoveling dark matter into an oven, right?
I always wondered why there's no episode where the implications of more than two dark matter engines working at once were explored :)
I always wondered why there's no episode where the implications of more than two dark matter engines working at once were explored :)
How would you move a black hole around?
AFAIK, the most popular answer is to give it an electrical charge.
I really don't know how are you supposed to maintain that change long-term. But then, it's similar to the problem of deciding whether the emissions from the black hole are particles that you can focus around, so I guess it's an open problem.
I really don't know how are you supposed to maintain that change long-term. But then, it's similar to the problem of deciding whether the emissions from the black hole are particles that you can focus around, so I guess it's an open problem.
Just get out and push
There are far more feasible alternatives to deep space propulsion that could actually work now, and all you have to do is detonate a couple of nukes.
https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...
See also its cousin:
https://www.centauri-dreams.org/2012/07/20/medusa-nuclear-pu...
You can even try these in KSP with mods afaik
https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...
See also its cousin:
https://www.centauri-dreams.org/2012/07/20/medusa-nuclear-pu...
You can even try these in KSP with mods afaik
? Are you serious.
We have concepts for light driven probes now. They even can slow down, by ejecting a parabolic lightsail, that bounces light from the opposit direction back to them.
Its all lightweight and - way more feasable, if you abandon the " a human has to go there idea". Communication would be an issue, but otherwise...
We have concepts for light driven probes now. They even can slow down, by ejecting a parabolic lightsail, that bounces light from the opposit direction back to them.
Its all lightweight and - way more feasable, if you abandon the " a human has to go there idea". Communication would be an issue, but otherwise...
Yeah I'm familiar with the old "Devil's pogo stick." Apparently thermonuclear Orion could achieve as high as 10% the speed of light, which would get you to the Centauri system within a single human life span (barely).
> If there were such a thing out there we could send a probe to it.
You might be interested in Ed Witten's paper about this topic: "Searching for a Black Hole in the Outer Solar System", https://arxiv.org/abs/2004.14192
(See also this related comment from the HN discussion back then which puts Witten's paper into context very nicely: https://news.ycombinator.com/item?id=23135031 )
You might be interested in Ed Witten's paper about this topic: "Searching for a Black Hole in the Outer Solar System", https://arxiv.org/abs/2004.14192
(See also this related comment from the HN discussion back then which puts Witten's paper into context very nicely: https://news.ycombinator.com/item?id=23135031 )
It's hard to imagine a scenario in which the solar system captures a wandering black hole. If it comes in it's going to keep going, or take the hyperbola back out the way it came.
It's not impossible and such scenarios can be constructed. But they're really narrow and it's hard to justify putting a lot of effort into looking for wild coincidences.
It's not impossible and such scenarios can be constructed. But they're really narrow and it's hard to justify putting a lot of effort into looking for wild coincidences.
If you draw a box around the solar system, and want a fast moving BH to settle in without rejecting on hyperbolic orbit, you'd just have to throw out another object that's comparable in size, at comparable speed. Momentum conserved.
A near miss with one of Jupiters moons might sling the BH into an orbit at slower pace and throw that moon into, say, earth to create our own moon.
This stuff probably happens more often than we think, on a galactic time scale.
A near miss with one of Jupiters moons might sling the BH into an orbit at slower pace and throw that moon into, say, earth to create our own moon.
This stuff probably happens more often than we think, on a galactic time scale.
Maybe you could elaborate? As the solar system already contains bodies with masses both smaller and larger than the primordial black holes mentioned, what would be the issue?
The relative velocity of stuff that wasn't in the cloud that formed the solar system would almost certainly be really high. So it would take a lot to capture the an extra-solar body. Any bodies from outside the solar system would probably either travel straight through the solar system or do something like what ʻOumuamua did.
all of the stuff I'm the Solar system that we know about probably was here from the beginning, forming out of the same cloud of dust that produced the sun. A black hole would have to wander in from elsewhere and somehow get captured rather than zipping by on a hyperbolic orbit.
A PBH that size would be extremely useful for getting out of (and back into)
our solar system, at least for probes that could survive being slingshot
to a fraction of light speed.
It could be like slingshoting around the sun,
but but at a few miles from the core instead of a million miles.
In that scenario, I'd love to see the kinds of cool relativistic time dilation experiments we could run on those probes.
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Neil deGrasse Tyson, an astrophysicist, claims [0] that if you remove one observatories data, that the anomaly that leads to the conclusion there's a planet 9 disappears.
[0] https://www.youtube.com/shorts/RvNYL5sPItc
[0] https://www.youtube.com/shorts/RvNYL5sPItc
He also tends to be full of hot air. His biggest contributions are in science communications towards younger and non-science oriented people. I'm not saying he is wrong or lying or anything like that, but a youtube short is not a good standin for a scientific hypothesis.
> His biggest contributions are in science communications towards younger and non-science oriented people.
that's a huge contribution and not to be undervalued!
that's a huge contribution and not to be undervalued!
Correct. I'm not saying he is bad for the world, just that he is more focused on soundbites to reel people in than on the detailed discussion being proposed by his video.
What is this reasoning? A scientific hypothesis can fit in one sentence on the back of a napkin, certainly it can in a youtube short too.
Please don't spread YouTube Shorts. It's polluting the internet.
https://www.mrfdev.com/enhancer-for-youtube
This has an option to makes Shorts less objectionable, in addition to allowing control over a lot of the things in the YouTube experience that I find annoying anyway.
This has an option to makes Shorts less objectionable, in addition to allowing control over a lot of the things in the YouTube experience that I find annoying anyway.
Maybe the name of that observatory was too long to fit in that 59 seconds video. Do you have any idea about which observatory it is?
There's a good overview of history of discoveries of planets (and other types of objects) in the solar system: https://www.youtube.com/watch?v=J_KCbyGkNuY
You can arrow through it to just have a look at the slides. At 39 minute presenter talks about extreme orbits that made some of the objects hard to discover for decades.
You can arrow through it to just have a look at the slides. At 39 minute presenter talks about extreme orbits that made some of the objects hard to discover for decades.
This is about a different hypothesised planet beyond Neptune.
How can we spot exoplanets 20M light years away, but not have absolute metaphysical certitude about the number of planets in the solar system?
Not sure where 20M l.y. are coming from, because the farthest exoplaned seems to be 27k l.y. from the Sun: https://en.wikipedia.org/wiki/SWEEPS-11
Regarding your question, perhaps it's harder to perform direct imaging of a planet in the solar system than of an exoplanet against its local star(s). In the first case, relative motion is much higher.
Regarding your question, perhaps it's harder to perform direct imaging of a planet in the solar system than of an exoplanet against its local star(s). In the first case, relative motion is much higher.
1) We spot exoplanets by their influence on the star, which is nearly nil at distances of 100+ AU.
2) We spot exoplanets that have huge volumes and masses, like Neptune or Jupiter size (15x or 100x Earth's mass, or even multiples of Jupiter), but the ones we're talking about beyond the Kuiper belt might be on the order of 0.1 Earth mass or smaller.
3) 20M light years is an exaggeration, most detected planets are within 1000 light years.
2) We spot exoplanets that have huge volumes and masses, like Neptune or Jupiter size (15x or 100x Earth's mass, or even multiples of Jupiter), but the ones we're talking about beyond the Kuiper belt might be on the order of 0.1 Earth mass or smaller.
3) 20M light years is an exaggeration, most detected planets are within 1000 light years.
I wonder if it could be opposite from us, on the other side of the Sun.
Rotating at the same speed and hence never observable?
Rotating at the same speed and hence never observable?
If you mean on the opposite side, in the same orbit(in the earth-sun L3), this has been hypothesised as far back as the presocratic Greeks(https://en.wikipedia.org/wiki/Counter-Earth), but we now have a lot of evidence that it isn't there.
Also, planet 9 was hypothesised in order to explain the orbits of transneptunian objects, which an antiearth wouldn't do.
If you mean behind the sun on a completely different orbit, well it wouldn't stay behind the sun relative to us forever, and likely would only very rarely be obscured by the sun.
Also, planet 9 was hypothesised in order to explain the orbits of transneptunian objects, which an antiearth wouldn't do.
If you mean behind the sun on a completely different orbit, well it wouldn't stay behind the sun relative to us forever, and likely would only very rarely be obscured by the sun.
Have you seen the movie Another Earth (2011)?
That’s the exact plot.
It’s not realistic (space probes would have “seen” the other earth), but does make for an interesting film.
https://en.m.wikipedia.org/wiki/Another_Earth
That’s the exact plot.
It’s not realistic (space probes would have “seen” the other earth), but does make for an interesting film.
https://en.m.wikipedia.org/wiki/Another_Earth
The premise there is also that the other earth developed in exactl synchronism until they discovered each other which is much less realistic :)
If you liked the premise, I can warmly recommend Counterpart. It’s a series with JK Simmons.
It’s much better imo.
https://en.m.wikipedia.org/wiki/Counterpart_(TV_series)
It’s much better imo.
https://en.m.wikipedia.org/wiki/Counterpart_(TV_series)
Yes that was a great series. Though it went a bit off track in the second season with the story all over the place. I wasn't surprised they cancelled it.
We would certainly see something that is six times the mass of the earth sharing our orbit.
The wiki estimates the missing planet to be 6.3 times as massive as the Earth, could be up to 2.3 times more or −1.5 times less than this figure.
"Based on earlier considerations, this hypothetical super-Earth-sized planet would have had a predicted mass of five to ten times that of the Earth, and an elongated orbit 400 to 800 times farther from the Sun than the Earth is."
https://en.wikipedia.org/wiki/Planet_Nine
The wiki estimates the missing planet to be 6.3 times as massive as the Earth, could be up to 2.3 times more or −1.5 times less than this figure.
"Based on earlier considerations, this hypothetical super-Earth-sized planet would have had a predicted mass of five to ten times that of the Earth, and an elongated orbit 400 to 800 times farther from the Sun than the Earth is."
https://en.wikipedia.org/wiki/Planet_Nine
It would have to be orbiting at the same distance as the Earth to have the same speed, which seems unlikely, and only gives it a fairly small amount of space to live in, so I’m sure we’ve checked there.
The hypothetical planet 9 is speculated to be far from the sun, past Pluto.
The hypothetical planet 9 is speculated to be far from the sun, past Pluto.
It couldn't be stable there for very long. It's a three body problem. If it ever existed it would have been ejected billions of years ago.
There are uncoutably many binary star systems,
one (or both) being the size of a sports ball changes nothing.
All our eyes aren’t on Earths orbit
I mean, Pluto is right there man
Pluto needs to up its game and become GRAVITATIONALLY DOMINANT!!!
Yeah, but this is Mike Brown we are talking about. The Don of the "Pluto is not a planet" mafia.
That would be Planet 12 :)
Nah. It should have been grandfathered in as planet 9.
If you want to stand on tradition, planet 9 has to go to Ceres.
Yeah that's where 12 comes from. IIRC it was the 12th known "planet" when it was discovered, if you include spherical, gravitationally differentiated asteroids.
The air quotes are because by the geophysical definition of planet (the only scientifically reasonable definition, fight me) our Moon, the Galilean moons of Jupiter, and Titan are all also planets, and I think they were known at that time.
Our solar system likely contains thousands of planets. I wish people could get excited over that rather get stuck up about tradition and "how will kids ever remember them all?" My kids can name the stats and special powers of 350 Pokemon. They'll be just fine.
The air quotes are because by the geophysical definition of planet (the only scientifically reasonable definition, fight me) our Moon, the Galilean moons of Jupiter, and Titan are all also planets, and I think they were known at that time.
Our solar system likely contains thousands of planets. I wish people could get excited over that rather get stuck up about tradition and "how will kids ever remember them all?" My kids can name the stats and special powers of 350 Pokemon. They'll be just fine.
[deleted]
its in Pluto's orbit. mainly because Pluto is planet 9.
Have you checked across the 8th dimension? Ask any Lectroid, they'll tell you.
Most likely explanation is that Planet 9s population is a higher level civilization that understands the “dark forest” hypothesis. They’re probably nervously eyeing their noisy neighbors