Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the ...

The newly discovered world — a "sednoid" — challenges what planetary scientists thought they knew about the edge of the solar ...

A rare celestial object beyond Neptune, 2020 VN40, moves in sync with Neptune, offering new insights into the outer solar system and fueling the search for Planet Nin ...

Every once in a while, space gives us something totally unexpected. Well this time, the solar system is surprising us with a ...

Astronomers have discovered "Ammonite," a mysterious object on the solar system’s edge whose unusual orbit challenges current ...

NASA's New Horizons spacecraft made history by flying past Pluto, sending back groundbreaking data that would change our ...

Typically, telescopes are synonymous with bringing far-off objects close, but the newest member of the solar system was ...

Theories about Planet Nine have been swirling for years, but this newly discovery planet might put those theories to bed for good.

Season 6, episode 5—the perfectly titled "Why We Fight"—brings an unlikely alliance that could change the fate of the galaxy.

The discovery was made by astronomers using the Subaru Telescope, which is situated atop a dormant volcano in Hawaii.

Astronomers discover Ammonite, a rare icy object beyond Pluto, challenging Planet Nine theory and offering clues to the solar ...

Japanese astronomers have discovered a potential dwarf planet, nicknamed Ammonite, orbiting the Sun far beyond Neptune, challenging the existence of the theorized Planet Nine.