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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
(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).
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(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