In 1820, French astronomer Alexis Bouvard noticed something strange. The gravity of the inner planets couldn't account for the orbital movement of the outermost planet, Uranus. His hypothesis: There must be a massive object influencing it. That eventually led mathematicians to correctly calculate the location of our eighth planet, Neptune. This discovery fueled a mad hunt to discover more planets using this method.

Unfortunately, since then, no major planet in our solar system has been found. But in the past few decades, modern telescopes have discovered thousands of objects beyond Neptune, and their orbits have made some scientists think that a massive ninth planet might actually exist. This mysterious planet is often referred to as Planet Nine and its existence would, in fact, make our solar system similar to the majority of other planetary systems we have observed so far in other parts of the universe. 

In this exciting talk, astrophysicist Dr. Malena Rice takes us to the edge of our solar system, unfolding the anomalies we observe and sharing what we know so far about this mysterious, elusive, planet.  

Why do we think this planet should be there? And If Planet Nine exists, why has no one seen it?