This undiscovered planet may be lurking on the very edges of our solar system, and it's not the first time astronomers have suggested that a planet might be out there -- although they've been proven wrong in the past, according to a National Geographic report.
This latest study from Caltech suggests that they may have indeed found a large world somewhere out there, due to the oddly sculpted orbits of some icy bodies circling the sun that would seem to only be explained with a large graviational influence like a planet.
This planet would be distant if exists, circling at four times the orbit of far-away Pluto. Which is why it may be very difficult for scientists to find, if it exists. Such an orbit could take thousands of years to complete, so it will be like looking for a needle in a haystack to find out where it would be in its orbit.
To be defined a planet, it would have to be round, orbit the sun, and be the bully of its own orbit. Pluto didn't fulfill the last category, which is why it was dropped as a planet.
This planet would certainly fit the bill if it exists, however, as it may have 10 Earth masses, so it will certainly be round, and it would be orbiting the sun. And not only is it the king of its own orbit, it is altering the orbits of other objects.
If the planet exists, it would be very cold at 200 times farther from the sun than Earth at its closest, and up to 1,200 times further out at its farthest.