Mike Brown is an astronomer at Caltech who has been a leading figure in the search for Planet Nine. He told Live Science: “It's really difficult to explain the solar system without Planet Nine ...

Astronomers believe that our solar system may still hold surprises, with ongoing efforts to find a hidden ninth planet, often referred to as Planet Nine or Planet X. If confirmed, this discovery ...

Pluto, considered the ninth planet in our solar system until it was reclassified to dwarf planet status in 2006, is thought to have undergone an impact that broke off the largest of its five moons ...