Scientists have recently spotted a huge object far away in the cold outer reaches of our solar system. This ...

OF201 spends only 1% of its orbital time close enough to us to be detectable. The presence of this single object suggests ...

As explained in a pre-press paper [PDF] titled “Discovery of a dwarf planet candidate in an extremely wide orbit: 2017 OF201” ...

Less than 1% of this dwarf planet candidate's orbit is close enough to detect, which means astronomers are lucky to have ...

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the ...

Learn about the recently discovered trans-Neptunian object that may eventually join Pluto as a dwarf planet, found at the ...

U.S. astronomers hunting for "Planet Nine" have instead stumbled on what appears to be a new dwarf planet in the solar system's outer reaches.

Astronomers have just discovered a new celestial body in our solar system that could challenge major space theory. 2017 OF201 ...

It is an evocative idea: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all ...

The International Astronomical Union’s Minor Planet Center, which catalogs new moons and other small bodies in the solar ...

A new member of the solar system has been detected, the second-largest of its kind, suggesting there may be more like it ...

Almost 20 years after Pluto was infamously downgraded from its status as a planet, scientists now believe they have ...