How can fission-powered propulsion help advance deep space exploration, specifically to the outer planets like Jupiter, ...

The core of the Red Planet may be filled with sulfur. New experiments have shown that the core of Mars formed much faster ...

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

For decades it was thought that water was prevalent in the outer reaches of the Solar System early in its history, with ...

A potential new dwarf planet has been discovered in the outer reaches of the solar system, and its existence poses the ...

A recently discovered celestial body is rewriting our knowledge of the Kuiper Belt and maybe challenging the existence of the ...

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

There’s a new object in the distant reaches of our solar system, and it might just offer clues to a long-standing cosmic ...

A new dwarf planet, discovered beyond Neptune and described as Pluto's 'cousin,' could void the hypothesis of a Planet X in ...

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

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

WASHINGTON - Scientists have identified an object about 435 miles (700 km) wide inhabiting the frigid outer reaches of our solar system that might qualify as a dwarf planet, spotting it as it travels ...