Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously ...

For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something ...

The newly identified cluster of Kuiper Belt objects lies about 4 billion miles from the Sun, offering fresh clues about how ...

There have been questions about a mysterious ninth planet in our solar system for nearly a decade. Pluto was unseated as number nine in 2006. Now, a group of international researchers say they may ...

After studying thousands of computer simulations of the solar system, researchers at Rice University and the Planetary Science Institute think there’s a 40% chance an elusive “Planet Nine” or “Planet ...

In the remote outer reaches of planetary systems, far beyond the orbit of known planets, enormous and mysterious worlds silently loop around their stars. Some drift as far as 10,000 times the distance ...

A team of scientists at the Institute for Advanced Study School of Natural Sciences in Princeton, New Jersey, might have found a new dwarf planet, potentially leading to more evidence of a theoretical ...

In the cold, distant reaches of the Solar System, far beyond Pluto, astronomers have just identified what could be a new dwarf planet. It's called 2017 OF 201, a rock that appears to be some 700 ...

The outer reaches of our Solar System continue to reveal a complex dynamical environment where the interplay of gravitational forces shapes the orbits of a myriad of distant bodies. Research in this ...

The Sun's formation caused temperature differences in the surrounding disk of gas and dust. Inner, hotter regions formed rocky planets from less volatile elements. Outer, colder regions allowed ...