The idea of the existence of a planet X is an old one. In fact, planets
that we now know of in our solar system were once called "Planet X" themselves before discovery.

In 1846, Adams and Leverrier used unexpected irregularities in the
motion of Uranus to deduce the existence of an
unseen planet and predicted its position with amazing accuracy. It was extremely easy to find once they knew where to look for it. Today, we call this planet Neptune.

Later, Percival Lowell set Clyde Tombaugh out to look for
a planet that he predicted by using unexpected deviations in the motion of Neptune. In 1930 the plant Pluto was found.
Unfortunately, Pluto is much too small to perturb a massive planet such as Neptune, leading to the suspicion that there is still a "Planet X" remaining to be discovered.

Today, it is accepted and understood that the
deviations in the motion of Neptune were simply errors of measurement, with no evidence for unexplained deflections of the planets by Planet X.

Unfortunately, because of it's accidental discovery, Pluto
was automatically labeled a planet. Today, we now know and appreciate Pluto more clearly as the largest known Kuiper Belt Object.

This does not meant that Planet X does not exist, although
their is no convincing evidence that it does. "Absence of evidence is not the evidence of absence." Planet X could still exist provided it is small enough or far enough away to have little impact on the solar system as we know it.

New telescope technologies are making it more and more
possible for us to search for these hidden planets. It will take a lot of luck to find something without a location to go by, but it's certainly possible.

Find out what it could mean for the future of OUR planet if the existence of Planet X is real...