This video explores the long-standing mystery of a potential ninth planet

Anyone with any knowledge of astronomy knows about Pluto. The ninth planet was demoted to a dwarf planet several years ago and has since caused quite some controversy.

Pluto was first discovered in 1930, but 26 years later, in 2006, it was reassigned to the category of a dwarf planet. Pluto was first spotted because Uranus' orbit could not be explained by Neptune alone.

So an additional ninth planet beyond Neptune was hypothesized, and today, since Pluto does not seem to be that planet, the question remains: is there actually a ninth planet out there we have yet to discover?

Its existence would definitely explain the orbits of the seventh and eighth planets and would make sense of our small universe. Indeed, something heavy seems to be interfering with the orbits of Uranus and Neptune, and the jury is still out on exactly what that might be.

So does a ninth planet exist? If so, why haven't we spotted it yet? Is our universe so massive that it could hide a planet large enough to influence Uranus and Neptune? When might it be finally discovered, and what tools would we need to see it? This video explores all these questions and informs on this long-standing mystery.