In 2005, space nerds everywhere were disappointed when Pluto was ruled a non-planet. Scientific bodies deemed it too small to qualify; you can see its scale versus Earth below, in this exclusive image obtained by Core77.
Now, however, researchers at the California Institute of Technology have deduced that we do in fact have a ninth planet in our solar system, and it's about ten times the mass of Earth. (Or, as schoolchildren will delight in repeating, roughly the size of Uranus.) The reason "Planet Nine," as they've cleverly named it, took so long to discover is partly because astronomers are lazy and primarily because this previously-unknown planet occupies "a bizarre, highly elongated orbit in the outer solar system" that is not co-planar with the orbits of the other eight planets.
The thing is, no one's actually seen this drunkenly-orbiting planet yet. The Caltech researchers deduced its existence by studying six objects in the Kuiper Belt, a gathering of non-planetary bodies spinning around beyond Neptune; unable to explain their trajectories, they began figuring out what types of nearby bodies would or wouldn't cause them to move that way. According to Phys.org,
That left them with the idea of a planet. Their first instinct was to run simulations involving a planet in a distant orbit that encircled the orbits of the six Kuiper Belt objects, acting like a giant lasso to wrangle them into their alignment. [Researcher Konstantin] Batygin says that almost works but does not provide the observed eccentricities precisely. "Close, but no cigar," he says.
Then, effectively by accident, Batygin and [fellow researcher Mike] Brown noticed that if they ran their simulations with a massive planet in an anti-aligned orbit—an orbit in which the planet's closest approach to the sun, or perihelion, is 180 degrees across from the perihelion of all the other objects and known planets—the distant Kuiper Belt objects in the simulation assumed the alignment that is actually observed.
"Your natural response is 'This orbital geometry can't be right. This can't be stable over the long term because, after all, this would cause the planet and these objects to meet and eventually collide,'" says Batygin. But through a mechanism known as mean-motion resonance, the anti-aligned orbit of the ninth planet actually prevents the Kuiper Belt objects from colliding with it and keeps them aligned.
Batygin and Brown have released their findings in an Astronomical Journal article entitled "Evidence for a Distant Giant Planet in the Solar System." Their hope is that they, or others who read the paper and have access to telescopes, will eventually spot Planet Nine, as they've cleverly named it.
Getting eyes on Planet Nine will be of supreme importance, and I hope Earth's governments will collaborate to find it. As we all learned last month, having unobserved planets floating around out there can be one of the greatest dangers to the galaxy.
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Comments
I wouldn't go as far as to say a planet has been difinitely discovered, only that the strongest models which explain kuiper belt orbits calls for the existence of a large body that is far enough out that it's conceivablefor it to have gone un-noticed thus far.
Rain, I think some of your articles leave more people in stitches than your vintage sewing machines ever have. Thanks for the daily humor.
I am stich-less . Thank you for the article.