Far beyond Neptune, something heavy appears to be tugging on the outer solar system, bending the paths of distant icy worlds ...

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

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 ...

There may be a warp in the Kuiper Belt, possibly caused by “Planet Y” — a Mercury-to-Earth-sized world that orbits the sun way beyond the orbit of Neptune. Is there a mysterious “Planet Y” orbiting ...

AMES, Iowa – An international team of astronomers has used nearly three years of high precision data from NASA’s Kepler spacecraft to make the first observations of a planet outside our solar system ...

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 ...

Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be ...

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

LONDON — The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper's authors have ...