Hey, there might really be another planet out there. A pretty big one, too. Caltech researchers have found evidence of a giant planet tracing a bizarre, highly elongated orbit in the outer solar system. The object, which the researchers have nicknamed Planet Nine, has a mass about 10 times that of Earth and orbits about 20 times farther from the sun on average than does Neptune or nearly 56 billion miles away. It tremendous distance means it would take between 10,000 and 20,000 years to make just one orbit around the sun.
There’s been all sorts of baloney online for the past several years about a planet named Niburu the Destroyer headed for a collision course with Earth. This putative planet is not Niburu, which was never real in the first place but more of a chimera created out of fear of the unknown. And just to be clear, no one has seen Planet Nine. Its existence is inferred through mathematical modeling and computer simulations based on the clustering of six remote asteroids in the Kuiper Belt, a vast repository of icy asteroids and comets beyond Neptune. Planetary scientists Konstantin Batygin and Mike Brown of the California Institute of Technology in Pasadena say there’s only a 0.007% chance or about 1 in 15,000 that the clustering could be a coincidence.
The astronomers’ work appeared in the January 20th edition of the Astronomical Journal.
“Although we were initially quite skeptical that this planet could exist, as we continued to investigate its orbit and what it would mean for the outer solar system, we become increasingly convinced that it is out there,” says Batygin. “For the first time in over 150 years, there is solid evidence that the solar system’s planetary census is incomplete.”
That’s exciting news though I wonder why such a large object wouldn’t have been seen glowing in infrared light (heat) by NASA’s Wide-Field Infrared Survey Explorer (WISE). Still, the data are compelling. All six objects follow elliptical orbits that point in the same direction in physical space.
“It’s almost like having six hands on a clock all moving at different rates, and when you happen to look up, they’re all in exactly the same place,” says Brown. The odds of having that happen are something like 1 in 100, he says. But on top of that, the orbits of the six objects are also all tilted in the same way—pointing about 30 degrees downward in the same direction relative to the plane of the eight known planets. The probability of that happening is about 0.007 percent. “Basically it shouldn’t happen randomly,” Brown says. “So we thought something else must be shaping these orbits.”
And that something’s mass (weight) can be estimated by how the bodies move in their similar-shaped orbits. The potential planet would also provide an explanation for the mysterious orbits that two of the six trace — Sedna, discovered by Brown in 2003 and 2012 VP113. Unlike standard-variety Kuiper Belt objects, which get gravitationally “kicked out” by Neptune and then return back to it, Sedna never gets very close to Neptune. The presence of Planet Nine in its proposed orbit would shepherd objects like Sedna, slowly pulling them away into an orbit less connected to Neptune.
How would such a big planet manage to migrate so far away from the rest of us? The four heavyweights of the solar system are the gas and ice giants Jupiter, Saturn, Uranus, and Neptune. Planet Nine could represent a fifth, and if it got too close to Jupiter or Saturn, could have been ejected into a distant, eccentric orbit.
Brown and other colleagues have begun searching the skies for Planet Nine. Only the planet’s rough orbit is known, not a location. If the planet happens to be close to its perihelion (closest point to the sun), Brown says, astronomers should be able to spot it in images captured by previous surveys. If it’s in the most distant part of its orbit, the world’s largest telescopes will be needed to see it. If, however, Planet Nine is now located anywhere in between, many telescopes have a shot at finding it.
While Brown would love to find it himself, he hopes the publication of the paper will fire up astronomers around the world to look for it. The more the merrier, and the more telescopes applied to the job, the better chance of finding Planet Nine.
“All those people who are mad that Pluto is no longer a planet can be thrilled to know that there is a real planet out there still to be found,” he says. “Now we can go and find this planet and make the solar system have nine planets once again.”
For more information, please see the Caltech new release.