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Is Planet Nine Alone in the Outer System?
- RajT88 1y agoI hope when we finally catch a glimpse of it, it does not look like an 8 ball.
- rdtsc 1y agoPrevious discussion https://news.ycombinator.com/item?id=43874641 https://news.ycombinator.com/item?id=43874641 Link to the paper:https://arxiv.org/pdf/2504.17288 https://arxiv.org/pdf/2504.17288
- Qem 1y ago> Brown argues that this object is not likely to be Planet Nine because its orbit would be far more tilted than what is predicted for the undiscovered world. In other words, a planet in this position would not have the observed effects on the Solar System. In fact, a planet in this orbit would make the calculated Planet Nine orbit itself unstable, which would eliminate Planet Nine altogether. Is there an entirely different planet out there? Future observations will have to sort this out. There's also an alternative lesser known proposal for an undetected massive object in the outer solar system, by Lykawka and Mukai[1], ofter confounded with the planet nine hypothesis, but it is actually an independent proposal from the object predicted by Batygin and Brown. I wonder if despite not being compatible with the more known planet nine proposal, the recent finding may be compatible with the one from Lykawka et al, or it may even be the case that the former acts in tandem with the later, and we actually have two real objects making the work of the virtual single planet proposed by B&B. [1] https://iopscience.iop.org/article/10.1088/0004-6256/135/4/1161/pdf https://iopscience.iop.org/article/10.1088/0004-6256/135/4/1...
- watersb 1y agoThis linked paper is a textbook chapter; it's intense. 40 pages of two-column astrophysical journal survey and analysis. I can see why it must be required reading for a discussion of TNO dynamics. Wow.
- eth0up 1y agoI'm going with little black hole
- schrectacular 1y agoI mean how else would the aliens have gotten here?
- andrewflnr 1y agoOnly mostly joking: I think the most likely way aliens could be in the solar system is a relict machine civilization from a life-bearing phase of Mars or Venus. Crazy? Yes. More likely than successful interstellar travel? Still yes.
- jaggederest 1y agoI mean, interstellar travel isn't outside the realm of possibility. We see all kinds of weird junk in the deep background, quasars 13 billion years old. Even for a type 1+ civilization, let alone a dyson sphere, the energy requirements are not insane. Couple hundred thousand tons of antimatter and matter, specific impulse in the millions, get there. Time dilation solves all your "being alive to see the sights" issues, and as long as you don't leave anyone behind that you care about and bring enough antimatter all the other problems are solvable.
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- dataflow 1y agoHow does the mechanics of antimatter propulsion work? Is the idea that the momentum of the released photons is enough to push you in the opposite direction at relativistic speeds? And that you presumably somehow shield yourself from that radiation through a perfect paraboloidic reflector of some sort?
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- xhrpost 1y ago> The authors say that the 570 megapixel Dark Energy Camera (DECam) may be useful for follow-up observations. I was curious what kind of resolution you'd have at this distance but not sure I did the math right. The camera has a resolution of 0.27"/pixel[1] which is 0.000075 degrees. Then to get size at 500AU -> tan((pi/180) * 0.000075)(500 149597870700) ~98megameters, which is like 8 earth diameters. Is this right? [1]: https://www.darkenergysurvey.org/the-des-project/instrument/the-camera/ https://www.darkenergysurvey.org/the-des-project/instrument/...
- georgeburdell 1y agoSub pixel resolution is possible by observing the space over time
- DoingIsLearning 1y agoIn astronomy how is image registration done? Is there some sort of astronomic dead reckoning system? Or is it just image based with some kind of Homography technique?
- ddahlen 1y agoMost images are registered by finding the location of known stars from a high resolution catalog such as GAIA. So you fit centroids of all stars in an image, then do a search of Gaia sources in that location and do some sort of linear or higher order polynomial mapping of pixel space to the celestial sphere reference coordinates ICRF. Astrometry.net is a service that does an approximate version of this on the web. I am glossing over many details here, but this is roughly what happens.
- DoingIsLearning 1y agoVery cool to learn about other areas of knowledge. Astrometry.net really made this quite visual thanks. For the curious wanting to go down this rabbit hole here seems to be an ESA archive dataset of 'GAIA Data Release 3' (released 3 June 2022) : https://cdn.gea.esac.esa.int/Gaia/gdr3/ https://cdn.gea.esac.esa.int/Gaia/gdr3/
- adrian_b 1y agoThe fact that many trans-Neptunian bodies have weird orbits is not a correct argument for the existence of an extra big planet beyond them in the present time. It is only evidence that at some moment in the past there was something big out there, which has perturbed their orbits. In 2024 there have been published a few papers which propose that a star has passed close to the Solar System in the past and its passage has caused all the unusual orbits that we see in the outer Solar System. This seems more plausible than an undiscovered big planet. https://www.nature.com/articles/s41550-024-02349-x https://www.nature.com/articles/s41550-024-02349-x https://iopscience.iop.org/article/10.3847/2041-8213/ad63a6 https://iopscience.iop.org/article/10.3847/2041-8213/ad63a6
- Qem 1y ago> This seems more plausible than an undiscovered big planet. Both are plausible, both are intriguing. To determine what in fact happened there's no way around looking up and searching until we exhaust the possibilities. Kudos for Terry Phan and his team for putting in the work, regardless of what hypothesis it ends strenghtening.
- adrian_b 1y agoEvidence for a currently existing outer planet would be provided only when we would see changes in the orbits of the known bodies. Unusual values of the orbital parameters are only evidence for something that has happened in the past.
- willvarfar 1y agoBut were a search to _find_ planet 9, would you still be holding out for changes?
- andrewflnr 1y agoIf you made a direct detection, the orbits vs changes question would become immaterial.
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- putpoointheloo 1y ago[flagged]
- cratermoon 1y agoI thought we decided that Pluto was the largest of many trans-Neptunian objects.
- andrewflnr 1y agoI'm not sure it's even the largest. Eris and Sedna are pretty close. But that's not really relevant here.
- yellowapple 1y agoThe worst part of Pluto's demotion from "planet" to "dwarf planet" is the sheer disrespect toward what's arguably the most interesting planet that's not Earth. The second-worst part is that we can't call this hypothetical trans-Plutonian planet "Planet X" anymore.
- gs17 1y agoI can settle for Planet 9 From Outer Space.
- invalidlogin 1y agoThe film The operating system The planet The legend
- caulkboots 1y agoPlanet X is Eris.
- globular-toast 1y ago"Planet X" was used before Pluto was discovered. The X didn't mean 10. In fact, Pluto was thought to be Planet X before they realised it was much, much smaller than that.
- yellowapple 1y agoThe people now calling it Planet 9 instead of Planet X, as in the article, evidently didn't get that memo.
- glimshe 1y agoWhy do sites hijack scrolling? Reading this on my laptop is painful.
- autoexec 1y agoI'll give the website some credit for being perfectly readable and painless to view with javascript disabled.
- Hobadee 1y agoPlanet 9 is Pluto! Fight me!
- WalterBright 1y agoI saw a documentary where Duck Dodgers found Planet X, I'm sure he could also find Planet 9.
- soufron 1y agoIt's "Earth in Upheaval" all over again. What is the proposed timeline of the passing of that other star?
- ArthurStacks 1y agoThis group have been banging on about this for decades
- codethief 1y agoOP quotes a Science article that, in turn, quotes Mike Brown (who came up with Planet 9) but the article fails to provide a source, even though it's right here on the internet and quite the interesting read: https://bsky.app/profile/plutokiller.com/post/3lnqm2ymbd22r https://bsky.app/profile/plutokiller.com/post/3lnqm2ymbd22r
- p0w3n3d 1y agoSounds to me like `Plan 9 From Outer Space`
- hulitu 1y ago> Is Planet Nine Alone in the Outer System? This reminds me of "lone rangers"