In 2016, scientists proposed that our solar system is home to a ninth planet with an orbit beyond those of Neptune and Uranus. Known as Planet 9 and located in the farthest reaches of the solar system, it is a shocking 400 to 800 times farther from the Sun than Earth and it would take 15,000 years to complete one orbit. But in a recent stunning revelation, two scientists now believe that Planet 9 is not a planet at all but could actually be a tiny black hole. Learn more from SciShow Space.