Scientists have discovered a new dwarf planet in our solar system. Far beyond Pluto, 2017 OF201 also orbits the sun in a (huge) orbit. The discovery makes it much less likely that a mysterious ninth planet exists in our solar system.
2017 OF201 is in fact a piece of rock 700 kilometers wide. That makes it just large enough to be considered a dwarf planet, but far too small to be a planet. For comparison: Pluto is almost 2,400 kilometers wide, and the earth about 13,000 kilometers.
The dwarf planet 2017 OF201 takes a total of about 25,000 years for a complete orbit around the sun. The earth does that in a year. The orbit around the sun of the dwarf planet has the shape of an elongated ellipse (see the picture at the bottom of this article).
At its farthest, 2017 OF201 is sixteen hundred times as far from the sun as the earth on average. That puts the dwarf planet at the edge of our solar system. It is certainly part of the solar system, because it clearly moves around the sun, says principal investigator Sihao Cheng. The existence of the dwarf planet has been confirmed by the International Astronomical Union (IAU).
The discovery of 2017 OF201 seems to mean a definitive end to the existence of a ninth planet. Scientists have long wondered if a large, undiscovered planet was located in our solar system. That would explain why other planets and celestial bodies do not move completely as expected. The gravity of 2017 OF201 explains those deviations almost completely, according to the astronomers.