A previously unknown giant planet may have been discovered lurking in the outer reaches of our solar system, US scientists announced on Wednesday.
Nicknamed Planet Nine, the object "has a mass about 10 times that of Earth" and follows a "bizarre, highly elongated orbit in the distant solar system," said a statement by researchers at the California Institute of Technology (Caltech).
"In fact, it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the Sun."
The report was published in the Astronomical Journal.
Researchers Konstantin Batygin and Mike Brown say have not yet observed the object directly.
Rather, they found it through mathematical modeling and computer simulations.
The presumed planet has about 5,000 times the mass of Pluto, and scientists believe its gravity has affected the motion of dwarf planets in the outer solar system, essentially perturbing celestial bodies in the field of icy objects and debris beyond Neptune known as the Kuiper Belt.
"Like a parent maintaining the arc of a child on a swing with periodic pushes, Planet Nine nudges the orbits of distant Kuiper Belt objects such that their configuration with relation to the planet is preserved," explained CalTech in a statement.
- Pluto Killer -
Brown, one of the co-authors on the paper, was a leading force in the downgrade of Pluto from planet to dwarf planet in 2006.
He and colleagues had found a dwarf planet called Eris that was more massive than Pluto, and a potential candidate for a 10th planet.
But when the International Astronomical Union decided in 2006, to issue a new definition of "planet," neither Eris nor Pluto made the cut.
"OK, OK, I am now willing to admit," said Brown, who goes by @plutokiller on Twitter.
"I DO believe that the solar system has nine planets."