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 ...

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

Credit: Southwest Research Institute Trans-Neptunian objects (TNO) are some of our solar system's lesser-known objects. They number in the thousands, and they get their name from their orbits.

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 ...

The long-serving space telescope saw the third interloper to enter the solar system from beyond its limits late on Monday ...

A new study reveals the binary nature of a trans-Neptunian object (TNO). A new study authored by Southwest Research Institute scientists Rodrigo Leiva and Marc Buie reveals the binary nature of a ...

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 ...