Our solar system has eight planets but in recent years, astronomers have theorised there could well be a ninth planet that's hiding in our solar system we've not been able to see yet.

Astronomers have narrowed down on the possible location in the Solar System where the elusive planet nine may be hiding, an advance that could shed more light on the evolution of our abode in the ...

The scientists think that the yet unseen ninth planet may be a “rogue,” which entered out solar system not at its inception, but long after the fact. The theory of Planet Nine was born out of ...

However, this year a powerful new telescope is coming online that could prove once and for all that there really is a ninth planet in our Solar System. The same year that Pluto was ignominiously ...

This mysterious ninth planet could be found within the next ... There are eight official planets (sorry, Pluto) in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and ...

We may soon find out. Is there a 9th planet out there? We may soon find out. Earth is a geological oddball in our solar system. This is why. Earth is a geological oddball in our solar system.

In 1930, a systematic search revealed what seemed to be a 9th planet ... than any of the planets in the outer solar system. Nevertheless, because it orbited the Sun like a planet, it was ...

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 ...

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – ...

Mars, Venus, Jupiter, Saturn, Uranus and Neptune will appear together in a row throughout the start of February – although Neptune and Uranus will only be visible with binoculars or a telescope.