Sedna is drifting into a part of its path where human technology can finally contemplate catching up, and that window will ...

Planet hunters have grown used to strange worlds, but a handful of discoveries now point to something even more radical: giant planets that loop around their stars on orbits so skewed they almost defy ...

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...

A possible cousin of Pluto seems to be circling the far reaches of the solar system. The dwarf planet candidate 2017 OF201 travels in a superwide orbit, with the sun relatively near one end of its ...