Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

An alternate explanation that fits the evidence is that Vesta was once part of a planet – but which planet that might been ...

For years, astronomers have been searching for a ninth planet in our solar system (after giving Pluto the old heave-ho and demoting it to a dwarf planet) and now researchers say they’ve found a ...

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

A new look through decades-old data has unveiled some of the most compelling evidence yet of a hidden ninth planet in the far reaches of our solar system, far beyond the bounds of Neptune and the ...

Over the past decade or so, astronomers have speculated about the characteristics of rogue planets in the Milky Way galaxy. These "free-floating" worlds don't orbit stars, but instead roam the ...

Astronomers claim to have discovered a new ninth planet in our Solar System. Planet Nine, also known as Planet X, is a hypothetical celestial object that would distantly orbit our Sun – but ...

For nearly a decade, scientists have been on the hunt for Planet Nine – a hypothetical celestial object on the edge of our Solar System. Now, astronomers claim to have discovered this ninth ...