NASA's Mars Curiosity rover has made consistent and puzzling findings while roaming the barren surface of the planet's Gale Crater: mysterious puffs of methane gas that only appear at night and ...

The hunt for Planet Nine—the solar system’s ghostly gravitational troll—is longstanding, and is based on the peculiar clustering of rocky bodies in the Kuiper Belt beyond the orbit of Neptune.

Scientists find "strongest evidence yet" of life in space 01:04. Astronomers announced Thursday that they had detected the most promising "hints" of potential life on a planet beyond our solar ...

Astronomers have found what they claim are the most promising—but also tentative—signs of possible life on the distant planet K2-18b.

A possible new dwarf planet has been discovered at the edge of our solar system, so far-flung that it takes around 25,000 years to complete one orbit around the sun. The object, known as 2017 ...

For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.