Have you heard the news? Looks like the planet count in the solar system may be back up to nine. Sadly, the ninth planet is not Pluto, the celestial object that previously held the spot. Scientists have found evidence for an entirely different, much larger planet that lies way beyond Pluto’s orbit.
Caltech astronomers Konstantin Batygin and Mike Brown recently published a paper entitled “Evidence for a Distant Giant Planet in the Solar System,” detailing their argument for the existence of the planet.
Brown is actually the man who originally killed Pluto. In 2005, he discovered Eris, an object only slightly larger than the tiny, innocent ball of icy rock we used to call a planet. Eris was initially thought to be the tenth planet, but eventually, it came to be classified as a dwarf planet. But if Eris was a dwarf planet, so too were other objects like it, including our dearest Pluto. Because of Brown’s discovery, Pluto was tragically declassified as a planet in 2006.
So how do astronomers know there’s another planet out there? After all, nobody’s seen it. And if Pluto’s not a planet, then why should any other object deserve the title?
A planet, by definition, should be massive enough to dominate surrounding objects with its gravitational pull. That’s why Pluto was stripped of its classification — Neptune has too much control over its orbit.
While it’s true that no one has directly observed a ninth planet yet, Batygin and Brown have observed the behavior of several small objects that lie beyond the Kuiper — rhymes with “hyper” — Belt, which is a field of icy debris that lies beyond Neptune’s orbit.
These objects are clustered together, tilted with strange, elliptical orbits that all swing in one direction. After running computer simulations to check the math, the pair from Caltech has no doubt that these strange orbits are a result of the influence of a massive planet’s interference.
So What Is This New Planet?
It is estimated the new planet could be between two to 10 times the size of Earth and is probably less massive than Neptune, making it the fifth largest planet in the solar system. It is thought to be an icy gas giant similar to planets like Neptune and Uranus. Its orbit, however, is very different from that of other nearby planets.
As this diagram shows, the ninth planet — referred to here as Planet X — has an orbit that is not only massively longer and wider than any other planet orbiting the sun but is also elliptical in shape. This orbit is about 20 times longer than that of Neptune, with one trip around the sun clocking in at anywhere from 10,000 to 20,000 years. The ninth planet is estimated to be about 60 billion miles away from the sun.
What Else Is Out There?
When poor little Pluto was demoted, it was because of the discovery of previously unknown objects in the solar system. Now with “Planet 9” possibly less than five years away from being spotted, scientists remind us that what we think we know about the solar system is limited by what we’ve seen so far. There could be a tenth planet — maybe even more.
While the future probably won’t ever return Pluto to its former glory, there are certainly many more discoveries to come.