from the searching-for-keys-near-the-streetlight dept.
Ethan Siegel at Starts With A Bang brings to attention the results of the Outer Solar System Origins Survey (OSSOS). The OSSOS project, which started in 2013 (before the Planet Nine hypothesis was proposed) to survey the minor planets of the outer Solar System, has discovered and determined the orbits of well over eight hundred trans-Neptunian objects (TNOs) in its operation. They have recently published a paper that basically puts the kibosh on the Planet Nine hypothesis. Planet Nine was initially proposed to explain an apparent anomalous clustering of orbits of TNOs consistent with them being perturbed by a large planet, but the OSSOS results have found no such anomalous clustering, and are rather seeing a distribution consistent with uniform randomness.
From Forbes' Javascript-required article:
It was perhaps the most exciting idea to come out of science last year: that an undiscovered, giant world exists in our Solar System, far beyond the orbit of Neptune. This wouldn't be some tiny, frozen world like Pluto or Eris, smaller even than Earth's Moon, but a monstrous super-Earth, perhaps ten times as massive as our own world and almost as large as Uranus or Neptune in radius. As the months passed since it was first proposed by Konstantin Batygin and Mike Brown, they compiled additional evidence for it, and things were looking rosy. But a new study by Shankman et al. has turned the evidence on its head, disfavoring the planet's existence and uncovering a bias in the data itself.
[...] what they found was entirely consistent with no Planet Nine, and that the overall case for Planet Nine's existence was substantially weakened by their study. In particular, the clustering in the orientation of each orbit in space (defined by multiple variables, ω and Ω) that earlier studies, like Batygin & Brown and Trujillo & Sheppard, previously noticed simply doesn't exist in this new, unbiased study.
We find no evidence in the OSSOS sample for the ω clustering that was the impetus for the current additional planet hypothesis.
The data from this new study is quite clear that the previously observed correlation, which was the impetus for hypothesizing Planet Nine, doesn't persist into the new sample.
OSSOS also has a Frequently Asked Questions page about these findings. They don't entirely rule out the existence of a substantial (perhaps Mars-sized) planet in the outer reaches of the Solar System, but their data makes it highly improbable that a super-Earth on the scale of Uranus or Neptune might be out there.
Additional reading:
https://www.sciencemag.org/news/2017/06/new-haul-distant-worlds-casts-doubt-planet-nine
Related Stories
A new study of the orbits of extreme trans-Neptunian objects has supported the existence of Planet Nine, just weeks after the Outer Solar System Origins Survey cast doubt on the hypothetical object:
Two astronomers from the Complutense University of Madrid in Spain studied 22 "extreme" TNOs (ETNOs), which orbit the sun at an average distance of at least 150 AU and never get closer than Neptune. (Neptune lies about 30 AU from the sun and orbits on a roughly circular path.) Specifically, the duo analyzed the ETNOs' "nodes," the two points at which the objects cross the plane of the solar system. (Distant bodies such as ETNOs tend not to lie in the same plane as the sun and the solar system's eight officially recognized planets.)
The researchers found that the objects' nodes generally aggregate at certain distances from the sun (as do those of 24 "extreme Centaurs," very distant objects with some characteristics of asteroids and others of comets). In addition, they discovered a correlation between the nodes' positions and an orbital parameter known as inclination.
The new results back the Planet Nine hypothesis, said lead author Carlos de la Fuente Marcos. "Assuming that the ETNOs are dynamically similar to the comets that interact with Jupiter, we interpret these results as signs of the presence of a planet that is actively interacting with them in a range of distances from 300 to 400 AU," he told Spain's Information and Scientific News Service, which is known by its Spanish acronym, SINC. "We believe that what we are seeing here cannot be attributed to the presence of observational bias."
Also at EarthSky.
Evidence for a possible bimodal distribution of the nodal distances of the extreme trans-Neptunian objects: avoiding a trans-Plutonian planet or just plain bias? (DOI: 10.1093/mnrasl/slx106) (DX)
Medieval astronomical records, such as the Bayeux Tapestry, could help narrow down the location (or at least infer the existence) of the hypothetical Planet Nine:
Scientists suspect the existence of Planet Nine because it would explain some of the gravitational forces at play in the Kuiper Belt, a stretch of icy bodies beyond Neptune. But no one has been able to detect the planet yet, though astronomers are scanning the skies for it with tools such as the Subaru Telescope on Hawaii's Mauna Kea volcano.
Medieval records could provide another tool, said Pedro Lacerda, a Queen's University astronomer and the other leader of the project.
"We can take the orbits of comets currently known and use a computer to calculate the times when those comets would be visible in the skies during the Middle Ages," Lacerda told Live Science. "The precise times depend on whether our computer simulations include Planet Nine. So, in simple terms, we can use the medieval comet sightings to check which computer simulations work best: the ones that include Planet Nine or the ones that do not."
Also at Queen's University Belfast.
Related: "Planet Nine" Might Explain the Solar System's Tilt
Planet Nine's Existence Disfavoured by New Data
Study of ETNOs Supports Planet Nine's Existence
Passing Star Influenced Comet Orbits in Our Solar System 70,000 Years Ago
Collective gravity, not Planet Nine, may explain the orbits of 'detached objects'
Bumper car-like interactions at the edges of our solar system—and not a mysterious ninth planet—may explain the the dynamics of strange bodies called "detached objects," according to a new study. CU Boulder Assistant Professor Ann-Marie Madigan and a team of researchers have offered up a new theory for the existence of planetary oddities like Sedna—an icy minor planet that circles the sun at a distance of nearly 8 billion miles. Scientists have struggled to explain why Sedna and a handful of other bodies at that distance look separated from the rest of the solar system. [...] The researchers presented their findings today at a press briefing at the 232nd meeting of the American Astronomical Society, which runs from June 3-7 in Denver, Colorado.
[...] [Jacob] Fleisig had calculated that the orbits of icy objects beyond Neptune circle the sun like the hands of a clock. Some of those orbits, such as those belonging to asteroids, move like the minute hand, or relatively fast and in tandem. Others, the orbits of bigger objects like Sedna, move more slowly. They're the hour hand. Eventually, those hands meet. "You see a pileup of the orbits of smaller objects to one side of the sun," said Fleisig, who is the lead author of the new research. "These orbits crash into the bigger body, and what happens is those interactions will change its orbit from an oval shape to a more circular shape." In other words, Sedna's orbit goes from normal to detached, entirely because of those small-scale interactions.
Also at Popular Mechanics, where Planet Nine proposer Konstantin Batygin disputes the findings:
Batygin, of Caltech, tells Popular Mechanics that any sufficiently strong gravitational encounter could detach an object from Neptune's embrace, but for the distant small bodies of the Kuiper belt to have done so through "self-gravity"—as the CU model proposes—there would need to be about five to ten times the mass of Earth in the outer parts of the Kuiper belt. There isn't.
"Unfortunately, the self-gravity story suffers from the following complications," Batygin says. "Both observational and theoretical estimates place the total mass of the Kuiper belt at a value significantly smaller than that of the Earth [only 1 to 10 percent Earth's mass]. As a consequence, Kuiper belt objects generally behave like test-particles enslaved by Neptune's gravitational pull, rather than a self-interacting group of planetoids."
Related: Planet Nine's Existence Disfavoured by New Data
Medieval Records Could Point the Way to Planet Nine
Another Trans-Neptunian Object With a High Orbital Inclination Points to Planet Nine
Outer Solar System Origins Survey Discovers Over 800 Trans-Neptunian Objects
LSST Could be the Key to Finding New Planets in Our Solar System
Where *Isn't* Planet 9? Search for Planet Nine still continues
Not long ago astronomers Mike Brown and Konstantin Batygin (the two original people proposing the existence of the planet) used the alignments of the TNO orbits to back-calculate the potential location of the unseen planet in space. It's a kind of treasure map to find the planet.
In a new paper they've put that map to use, looking through survey data in a hunt for Planet 9.
[...] Brown and Batygin wrote software that simulates where Planet 9 would be and how bright it would appears for various values of its size, reflectivity, and orbital shape. They created a database of positions and brightnesses for it, and then combed through the [Zwicky Transient Facility (ZTF)] database to look for it, going through the past three or so years of observations since the facility started its survey campaign.
[...] They ran 100,000 simulations of various parameters for the planet, and looked to see if the ZTF would've seen it if it were indeed smaller and closer to us. They determined that it would've been seen in the survey about 56,000 times out of the 100,000, so just looking at that their non-detection indicates the chance it's smaller and closer is now less than 50%, making it more likely it's farther out, bigger, and fainter.
The larger Vera C. Rubin Observatory is expected to find many previously hidden objects in the solar system, and is scheduled to begin full operations in October 2023. It will accumulate all-sky survey data around 10 times faster than the Zwicky Transient Facility.
Also at ExtremeTech.
(Score: 2, Funny) by Anonymous Coward on Tuesday June 27 2017, @08:46AM (6 children)
Pluto is a planet and always will be.
(Score: 0) by Anonymous Coward on Tuesday June 27 2017, @11:22AM (5 children)
(Score: 2) by takyon on Tuesday June 27 2017, @11:52AM
It's OK if kids can't name all of the planets due to there being a thousand of them instead of 8.
But Pluto, Sedna, Eris, etc. are clearly different from Mercury through Neptune in several ways.
We can always revisit the definition after finding any Mars or Neptune sized entities lurking in the outskirts of the solar system. The LSST [wikipedia.org] goes live in 2021. "Planet Nine" is expected to be found before that if it exists. We are about to find hundreds more dwarf planets, some of which will be larger than Pluto (like Triton).
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(Score: 0) by Anonymous Coward on Tuesday June 27 2017, @11:52AM
Except none of those other planet-wannabes have a Disney character named after them. /s
(Score: 3, Insightful) by unauthorized on Tuesday June 27 2017, @12:40PM
Planet is a colloquialism, Astronomers can go ahead and invent your own unique technical terms just like everyone else. I certainly wouldn't go around telling normies that their OS's shell is an app", or that their phone and gaming console are computers.
Domain specific terms should not be hamfisted into common language.
(Score: 0) by Anonymous Coward on Tuesday June 27 2017, @11:44PM (1 child)
It *is* meaningless, there is no clear-cut boundary between big asteroid and "planet"; it's all continuous. If we want a definitive definition, then pick a cutoff diameter. Place Pluto at the lower end, and wallah! you have a relatively clear-cut definition. If we later find hundreds of "planets" bigger than Pluto in our Solar System, so be it.
(Score: 0) by Anonymous Coward on Thursday June 29 2017, @06:25AM
(Score: 0) by Anonymous Coward on Tuesday June 27 2017, @08:48AM
Planet Ex-traego you mean?
(Score: 2) by FatPhil on Tuesday June 27 2017, @09:22AM (1 child)
However, am I the only one who thinks it should be titled "Science, Motherfuckers!"?
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Tuesday June 27 2017, @10:45AM
Yes, I believe you are.
(Score: 2) by FatPhil on Tuesday June 27 2017, @09:38AM (7 children)
That implies that if you're detecting TNOs, you're more likely to detect a TNO that in some kind of larger-than-typical cluster. And that's true whether the cluster is just part of the normal random variation in densities or is actually because of some external influence.
Looking at the shepherding other planets have performed (orbital resonance, and lagrange-point capture) in order to be sure of the existence of a 9th planet, I would hope that the evidence would be more than just a slight trend that can be as refuted as easily as this. But science is science (motherfucker!), and we never (expect when libraries are burnt) get *less* data, so let the issue remain as open as the telescope's apertures.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Tuesday June 27 2017, @12:10PM (6 children)
I'm reminded of the apparent paradox that the average person lives in a larger-than-average town, and also that the average town is smaller than average in population.
Ain't that just a problem with semantics, not a paradox? The meanings of the two "average"s is different.
AverageRandomly-selected person lives in a larger-than-average town.AverageRandomly-selected town is smaller than average in population.Of course, your point about the observational bias still stands :)
(Score: 2) by FatPhil on Tuesday June 27 2017, @02:30PM (4 children)
I view a paradox as a situation where from the same starting point (an assumption about the distribution) and two or more superficially justifiable methods of proceeding (what one selects and how) you can end up with apparently contradictory conclusions (about how typical the thing selected is).
Equivocation, being two superficially justifiable interpretations of a word, fits into that schema quite easily.
When I was just a kid I had a big book of mathematically-oriented paradoxes. Of course, there were the well-known stories based on propositional and predicate logic - to wit barbers, cretans, and the heterological - where all paths lead to an impossibility, which is what many view as the only true "paradoxes", but they were in the minority. Many more were set-theoretic, geometric or probabilistic, and a lot of the weirder ones pertained to the infinite. Of course, to the mathematically astute, for this majority of the examples, there was only one way to approach the problem, and only one correct answer, and therefore they were not paradoxes. However, the *superficially justifiable* approach a layman might be persuaded to use in his state of ignorance did lead to a contradictory conclusion, and so they were acceptable paradoxes by that author's definition. And I always thought that the author was justified in that definition, so I adopted it.
I would be willing to bet that the majority of the authors represented in this list here: https://www.amazon.com/mathematical-paradoxes-Books/s?ie=UTF8&page=1&rh=n%3A283155%2Ck%3Amathematical%20paradoxes also share that definition. Given a publication date of 1972, I presume the Northrop one was the one I had.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by Immerman on Tuesday June 27 2017, @03:50PM (3 children)
Paradox itself has several disparate definitions - as relevant to statements according to Merriam Webster:
a : a statement that is seemingly contradictory or opposed to common sense and yet is perhaps true
b : a self-contradictory statement that at first seems true
c : an argument that apparently derives self-contradictory conclusions by valid deduction from acceptable premises
Mathematicians of course have their own far more rigorous definition - but if we let mathematicians define the language it would mean an end to all conversation for lack of sufficiently ambiguous terminology.
(Score: 2) by KGIII on Tuesday June 27 2017, @06:59PM (1 child)
I'd just point out that 'average' means multiple things.
Then again, I am a mathematician. There is no paradox, just poor understanding.
"So long and thanks for all the fish."
(Score: 2) by FatPhil on Wednesday June 28 2017, @12:17AM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by FatPhil on Wednesday June 28 2017, @12:14AM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by Immerman on Tuesday June 27 2017, @03:44PM
You don't have to go with randomly selected - one of the broadly accepted meanings of average in everyday usage is median - so, you line up everybody according to the size of the city/town they live in and take the median - they'll live in a larger-than-median town because cities skew the sample in their direction. For the same reason, the median-sized town will fall far below the arithmetic average size.
Paradox, noun: a statement that is seemingly contradictory or opposed to common sense and yet is perhaps true
I'd say that qualifies. Moreover, I'd say it also satisfies one of the classic uses of paradox as a means to illustrate profound lessons. The lesson being that 1) "average" is an extremely ambiguous term and 2) that humans are generally *very* bad at properly interpreting statistical information.
Both of which deserve to be driven home regularly, because the sad fact is that statistics competency is appallingly low even among professional researchers - one of the groups who should be the most well versed as literally their entire career is based on using statistics to tease out details of the subject they're investigating, and a misunderstanding of what their statistical tools are telling them (p-values anyone?) can lead to years, even decades of wasted effort and false conclusions, even before you consider the wasted effort of all those others who used their conclusions as a starting point for their own research.
(Score: 3, Interesting) by takyon on Tuesday June 27 2017, @11:43AM (1 child)
http://www.sciencemag.org/news/2017/06/new-haul-distant-worlds-casts-doubt-planet-nine [sciencemag.org]
Of course, Mike Brown and crew have identified a "small" patch of sky that they are imaging to look for the hypothetical planet. Completing that should take at most 2-3 years. If they come up empty, then they will have some explaining to do.
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(Score: 2) by FatPhil on Tuesday June 27 2017, @02:43PM
[* This is the step that many of the less reputable so-called "sciences" unfortunately avoid, sometimes seemingly deliberately.]
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Tuesday June 27 2017, @02:36PM (2 children)
Gay rights in space! Trannies flocking to Neptune! Oh, glorious day! Don't you feel FAHBULOUS?!??!
(Score: 2) by FatPhil on Tuesday June 27 2017, @02:43PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Tuesday June 27 2017, @03:34PM
Gas giants dressing up as rocky planets, the horror, with their makeup craters and fake polar ice caps and disobeying orbit usage signs. It's unnatural! The solar system has gone nova in a hand-basket.