'Planet Nine'? Cosmic Objects' Strange Orbits May Have a Different Explanation

The bullying presence of a big, undiscovered "Planet Nine" isn't necessary to explain the strange orbits of a handful of objects in the outer reaches of the solar system, new research suggests. Last month, Konstantin Batygin and Mike Brown, both astronomers at the California Institute of Technology (Caltech) in Pasadena, proposed the existence of Planet Nine, a world perhaps 10 times more massive than Earth that orbits far beyond Pluto, completing one lap around the sun every 10,000 to 20,000 Ea