A ninth planet may be lurking on the icy outer edges of the solar system, Nasa has said.

The American space agency suspects that new evidence points to the existence of a “super-Earth”.
Scientists say that it is now more likely than not that such a planet is hiding 20 times further from the Sun than Neptune, at present the farthest-flung recognised planet. Its gravitational influences may be causing the entire solar system to tilt.
Konstantin Batygin, 31, an astrophysicist at California Institute of Technology (Caltech), is leading a search party. “If you were to imagine Planet Nine does not exist, then you generate more problems than you solve. All of a sudden, you have five puzzles and you must come up with five theories…