Given that we now have telescopes that can probe far into the most distant regions of the universe, and are even able to detect the existence of what are known as exoplanets (i.e., planets orbiting stars other than our own Sun), you would think that we would pretty much know everything that exists in our own neighborhood of the solar system.
Hence there has been considerable excitement about the possibility of a new planet in our system. This postulated planet is not a small object like Pluto but has a mass that is ten times that of the Earth. What makes some scientists suspect that it is there? The reasoning is similar to the way in which astronomers Adams and Leverrier predicted the existence of Neptune back in 1846, by observing the anomalous behavior of other celestial objects such of Uranus.
Two researchers from the California Institute of Technology have discovered evidence for a massive planet orbiting the sun far beyond Neptune. Using mathematical and computer models, Michael Brown and Konstantin Batygin looked at objects behaving strangely in the Kuiper belt, a region beyond the eight planets filled with minor planets similar to Pluto, asteroids and other rocky bodies of varying sizes.
They concluded that another planet, which they call “Planet Nine,” must be responsible for these peculiarities. They reported their findings Wednesday in The Astronomical Journal, an open-source publication.
Brown and Batygin built upon the findings of a 2014 paper by a separate team of astronomers. That team discovered an object roaming beyond Neptune with an unusually elliptical orbit, similar to that of the previously discovered minor planet Sedna. They nicknamed their discovery “Biden,” after the vice president, and put forth the idea that the gravitational pull of a large planet could be responsible for the object’s orbit.
Further research by Brown and Batygin showed that at least six objects, including Biden and Sedna, as well as other, smaller bodies, followed similarly aligned oval-shaped orbits. This behavior could not be explained by current models of the solar system and offered strong evidence that an unknown force was at work.
In their current study, Brown and Batygin used computer simulations to work through the various possibilities to explain the peculiar orbits. They considered, and then discarded, scenarios where the gravitational pull of the Kuiper belt itself was responsible for the odd orbits. Also rejected was the theory that a large planet could be encircling all of the objects and influencing them from the outside. They inserted planets of different sizes into their projections, and found that the only way to describe the six Kuiper belt objects’ behavior was a body substantially larger than Earth on a long orbit around the sun passing through the Kuiper belt.
So if it does exist, how could we have missed it for so long? This planet, although much bigger than the Earth, has a very large orbit, at its farthest point being about 1,200 times the distance from the Sun as the Earth is, and its orbit takes about 10,000 to 20,000 Earth years.
This is not the first time that new planets have been suggested but those earlier speculations did not pan out and until there is more direct proof of its existence, this will not enter science textbooks.
Still, it is nice to think that the possibility exists of astronomical treasures still undiscovered in our own backyard.