A while back I reported on the news that the solar system could--or should--get back its full compliment of nine planets, just as soon as people realized that poor little Pluto deserved better than being called a dwarf. Now, though, comes the possibility that our solar system may in fact have eleven planets. "The possibility of a planet lurking in the outer reaches of the solar system has gained new ground, based on the orbits of recently discovered objects," reports IFLScience. "There is a new twist to the latest evidence, however, with suggestions of not one but two large planets at mind-bending distances from the Sun." For decades astronomers have been looking beyond Neptune for so-called Planet X. Recently, two solar bodies "have been identified with orbits extending to distances hundreds of times further from the Sun than our own." Sedna and the catchily named 2012 VP113.
Although there are several known solar bodies beyond Neptune, many of these are in the Kuiper Belt or Oort Cloud. But Sedna and 2012 VP113 are relatively close neighbors to Earth. "Distant as these orbits are, they are too close to be part of the Oort Cloud, a collection of comets that mostly orbit at distances beyond 5000 AU. Instead it is thought that these objects formed closer to the sun." [Emphasis mine.] "The gravitational influence of a large planet is one explanation of how their orbits changed... Scott Sheppard, of the Carnegie Institution for Science, and the Gemini Observatory's Chad Trujillo noted a clustering in the orbits of the solar system’s most distant known entities, many of which they had discovered. Ten Kuiper Belt Objects, and minor planets Sedna and 2012 VP113, all have orbits that cross the plane of the solar system at angles that range from shallow to steep." It is possible that Neptune is influencing their orbits. "All of these distant objects reach their closest point to the sun just when they are near the plane the planets circle in. The scientists considered this unlikely to be a coincidence, and speculate it might be a sign of a planet influencing all of their orbits. It is too soon to tell if there really are two undiscovered planets out there, and much remains a mystery." David Jewitt of the University of California, Los Angeles told Science News, "The outer solar system can be full of all sorts of unseen and interesting things,” Jewitt says, “but the argument ... for a massive perturber is a bit puzzling." Stephen Luntz writes "Jewitt notes that if the Kuiper Belt Objects in the Trujillo/Sheppard study have a planet keeping them in line, it may well be Neptune. Sedna and 2012 VP113 are too far out for this to be true for them as well, but it is far easier to explain two orbits as coincidences than twelve."
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