When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...

The celestial body's unusual orbit “implies that something extraordinary occurred" in the early days of the solar system—and ...

Despite the powerful telescopes that modern astronomers have to work with, the distant reaches of the Solar System are still ...

"It is possible that a planet once existed in the solar system but was later ejected, causing the unusual orbits we see today ...

Observations of the potential Planet Nine are extremely difficult, as it's so far out in the Solar System that it would reflect only the tiniest amount of sunlight.

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory about the possibility of a giant ninth planet. The dwarf planet's existence ...

A tiny object far beyond Pluto, newly discovered by the Subaru Telescope, could reshape our understanding of the early Solar System. Named 2023 KQ14, this rare “sednoid” follows an unusual orbit that ...

Currently, our solar system recognizes 8 planets, with Pluto being demoted to a dwarf planet floating in the Kuiper Belt in 2006. Planet Nine's gravitational pull may explain what keeps the icy ...

Astronomers have found 2023 KQ14, nicknamed Ammonite, a rare sednoid with a unique orbit that challenges the Planet Nine ...

Planet Nine should appear stationary over the course of a single day but show detectable movement over months.

A potential dwarf planet has been discovered in the outer reaches of our solar system, orbiting beyond Neptune. Its presence there challenges the existence of a hypothetical body known as Planet 9 ...

The astronomers observed hot minerals just beginning to solidify – the first specks of planet-forming material, the astronomers said. A gaseous disk surrounding the young star is the first stages of ...