: Because of the gravitational pull being exerted on the most distant objects in the solar system, astronomers say there could be a ninth planet orbiting beyond Pluto. Using computer simulations and mathematical modeling, Konstantin Batygin and Mike Brown of Caltech have estimated
that so-called Planet Nine has a mass about 10 times that of Earth, orbits the Sun about 20 times farther out than Neptune, and would take 10 000–20 000 years to circle the Sun. In this Forbes
article, Ethan Siegel gives several reasons to be skeptical that such a planet exists and points out the irony that the person “who killed Pluto” may be the one to find the solar system’s “true” ninth planet.