11 Surprising Phenomena That Still Have Experts Scratching Their Heads

Kuiper Belt

Image source: http://images.spaceref.com/

In the area just beyond the former planet Pluto known as the Kuiper Belt, astronomers observed a gap, suggesting that the gravity of an unknown object approximately the size of planet Earth has been pulling debris towards it, creating the said empty space.
Could this be another undiscovered planet lurking at the edge of our solar system?