In 2016, Batygin and Brown first outlined in detail how the orbits of six of these objects could be explained by a specific Planet Nine. They predicted this world must have a mass at least 10 ...

But in recent years, astronomers have proposed that a ninth world, imaginatively nicknamed "Planet Nine," could be hiding in ...

Known as Planet Nine or Planet X, it is a hypothetical planet that has long been rumoured to exist in the outer solar system. Although "several claims to have found an extra planet have been made ...

The idea regarding the possible existence of a ninth planet, called Planet Nine/Planet X, in the solar system started with Caltech professors Mike Brown and Konstantin Batygin looking far out ...

Scientists have observed a huge planet approximately nine times the mass of Jupiter at a remarkably early stage of formation, describing it as still in the womb, in a discovery that challenges ...