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.

They thought Mars and Jupiter were too ... of the planets in the outer solar system. Nevertheless, because it orbited the Sun like a planet, it was classified as a planet and named Pluto, after ...

"It could be an icy, rocky Earth, or a super-Pluto ... argue that an unseen planet several times larger than Earth could be "shepherding" smaller objects in the solar system.

Data gathered in 1983 shows signs of what a British astronomer believes to be possible evidence of a ninth planet in our solar system ... who are still upset over Pluto’s demotion to dwarf ...

Computer simulations of the gravitational interactions of solar system bodies suggest that a hypothetical Earth-like planet explains all of those ... which it had before Pluto’s demotion in ...

This 'Kuiper Belt' of minor planets beyond Neptune revolutionised our understanding of the solar system's formation and finally explained the origin of the enigmatic outer planet Pluto. This is the ...

Carbon Dioxide and Hydrogen Peroxide on Pluto's Moon Charon Oct ... Gigantic Asteroid Impact Shifted the Axis of Solar System's Biggest Moon Sep. 3, 2024 — Around 4 billion years ago, an ...