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

Astronomers have hoped for the existence of Planet Nine for years. Things were looking promising, but this discovery might ...

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

In 2003, NASA-funded researchers spotted what was then the most distant object discovered in our Solar System. The dwarf ...

Astronomers spotted a baby star displaying the very first signs of planet formation in the zone surrounding it, similar to ...

Just the third-ever confirmed interstellar object has been detected in our solar system. Here's what we know. (Spoiler: It's ...

For now, the outer reaches of our 4.6 billion-year-old solar system continue to be shrouded in mystery, with the classification of objects changing as scientists gain a new understanding of them ...

Peering through a cosmic keyhole at distant baby star, astronomers may have opened a new window on the deep past of our own ...

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 ...

Astronomers witness first moments of planet formation as rock grains crystallize around distant star HOPS-315.

WASHINGTON, May 30 (Reuters) - 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 ...

For now, the outer reaches of our 4.6 billion-year-old solar system continue to be shrouded in mystery, with the classification of objects changing as scientists gain a new understanding of them ...