The unusual orbit of a possible dwarf planet, known as 2017 OF201, makes it less likely that our solar system contains a ...

Joseph channels his inner Carl Sagan to find out if discovering the mysteries of space is worth all the work, in his review ...

If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.

A ninth planet the size of Neptune may be hidden in the far reaches of the solar system, but the evidence has left some experts skeptical.

This week, an old astronomical controversy is renewed as researchers present new evidence for a hidden "Planet X" in our solar system.

With Pluto having been classed as the ninth planet for many years, the hunt was on for Planet X. With the demotion of Pluto in 2006, the idea of Planet Nine was first proposed in 2016 by ...