The monsters are multiplying. Just months after astronomers announced hints of a giant "Planet X" lurking beyond Pluto, a team in Spain says there may actually be two supersized planets hiding in the outer reaches of our solar system.
When potential dwarf planet 2012 VP113 was discovered in March, it joined a handful of unusual rocky objects known to reside beyond the orbit of Pluto. These small objects have curiously aligned orbits, which hints that an unseen planet even further out is influencing their behaviour. Scientists calculated that this world would be about 10 times the mass of Earth and would orbit at roughly 250 times Earth's distance from the sun.
Now Carlos and Raul de la Fuente Marcos at the Complutense University of Madrid in Spain have taken another look at these distant bodies. As well as confirming their bizarre orbital alignment, the pair found additional puzzling patterns. Small groups of the objects have very similar orbital paths. Because they are not massive enough to be tugging on each other, the researchers think the objects are being "shepherded" by a larger object in a pattern known as orbital resonance.
For instance, we know that Neptune and Pluto are in orbital resonance – for every two orbits Pluto makes around the sun, Neptune makes three ( via newscientist.com ).