New discoveries of objects in the Kuiper Belt have also presented challenges for the Planet Nine theory. The latest is known ...

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

In a groundbreaking discoverypublished in The Planetary Science Journal, a team of astronomers led by the Center for ...

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

"This is a big step in understanding the outer solar system," team leader Rosemary Pike from the Center for Astrophysics | ...

An oddly tilted object beyond Neptune moves in perfect sync, one orbit for every ten of Neptune’s, and scientists are ...

Researchers participating in the Discovering the Surface Compositions of Trans-Neptunian Objects program, led by the University of Central Florida (UCF), recently studied these dim objects using ...

For reference, Pluto’s average distance from the Sun is about 40 AU, so 2023 KQ14 is quite distant. At 23.4 billion miles (37 ...

Of the 461 objects described for the first time in the new paper, a few stand out. Nine are known as extreme trans-Neptunian objects, which have orbits that swing out at least 150 AUs from the sun.

The trans-Neptunian object Arrokoth, also known as Ultima Thule, which NASA's space probe New Horizons passed on New Year's Day 2019, may have changed its shape significantly in the first 100 ...