A newly discovered object orbiting far beyond Neptune has its closest approach to the Sun pointed in the opposite direction from every other known body like it, weakening one of the central ...

The hunt for Planet Nine continues as new discoveries make the Solar System’s biggest mystery even harder to solve. Is there ...

What is Planet Nine, and where is it? The question has fascinated astronomers for years. Scientists believe a massive undiscovered planet may exist in the outer Solar System. Although no telescope has ...

On a clear night, it dominates the sky, bright enough to cast shadows and large enough for dark patches and surface features ...

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all our efforts to spot it. Some astronomers ...

While life on Mars (and Venus) has long been an obsession for those wondering if we're alone, there are other places in our ...

Some researchers see in this population the manifestation of an invisible presence, a new planet not yet discovered in the dark and cold confines of our solar system. Others, however, think that there ...

There may be another world lurking between the orbital lines of our solar system. Astronomers in Japan have published their theory of an “Earth-like planet,” dubbed Planet Nine, that’s hiding in plain ...

A village in Kent is home to what is thought to be the world's largest scale model of the solar system and beyond, created to ...