If Earth has gotten just a bit too weird for you lately and you’re fearing an impending Trump/Palin White House, there’s some good news. A whole lot of new real estate just opened up. Researchers at Caltech have found evidence of a new planet in the outer solar system. For now, it’s nicknamed Planet Nine, although the Plutocrats might have something to say about that.
Planet Nine is estimated to have a mass of 10 times that of Earth, so there won’t be a similar fight to Pluto’s over its planet-worthiness. The reason Planet Nine has stayed undiscovered until now is that its orbit is about 56 billion miles from the sun. It’s average year is somewhere between 10,000 and 20,000 earth years. Compare that to Neptune, the furthest known planet from the sun, which orbits at 2.8 billion miles and whose year equals about 165 Earth years.
Although the planet has yet to be directly observed, Konstantin Batygin and Mike Brown announced the discovery in Astronomical Journal using mathematical evidence and simulation. Direct observation is difficult. While its elliptical orbit has been plotted, we don’t quite know where in its orbit Planet Nine is. If its at its perihelion, or the point in its orbit closest to the sun, astronomers may have already captured it in images of other objects. If it’s at the most distant point of its orbit, only the largest telescopes in the world, like those at Mauna Kea, would be able to spot it.
Being so far out from the core solar system, Planet Nine is believed to have the greatest region of gravitational influence of any our planets. It was discovered when objects in the Kuiper Belt (a large, outer belt of asteroids that surrounds the core solar system) were observed behaving unexpectedly. Their orbits were tilted 30 degrees downward compared to the plane of the eight known planets in our solar system. The probability of that occurring randomly is 0.007 percent, which means a different gravity is effecting them.
The presence of such a strange planet as Planet Nine would seem odd, but it would actually make our own solar system more closely resemble those we’ve identified around other stars. Its origin also wouldn’t be difficult to explain. The gas giants whose gravity protects the inner, rocky planets like Earth were early cores that grabbed most of the gas in our solar system. There’s no reason there couldn’t have been five early cores instead of four. As for its distant orbit, Planet Nine wouldn’t be the first object thrown out of the inner system by the gravity of Jupiter or Saturn.
What would Planet Nine be like? At its mass, it’s most likely a gas giant. Earth is the rocky planet in our solar system with the most mass. Uranus is the gas giant with the least, at 14.5 times Earth’s mass. At 10 times Earth’s mass, Planet Nine would be a slightly more modest gas giant than the ones we already know about. We’re not talking about a new Jupiter, whose mass is 318 times that of Earth.
As for gravity, that’s anyone’s guess. You can’t walk on the surface of a gas giant because you’d sink right through the clouds. But let’s say you could. Although Neptune is less massive than Saturn, it has a higher “surface” gravity because it’s more dense.
There’s still a lot to learn about Planet Nine. We have yet to even see the first images of it. The images here are all artists’ conceptions. The search is underway, though. The truth is out there.