Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...

A newly discovered warp in the outer Solar System may have been created by a small, rocky world, much closer to the Sun than the hypothesized Planet Nine. According to a new measurement of the Kuiper ...

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 ...

Add Yahoo as a preferred source to see more of our stories on Google. An illustration showing Planet Nine, a hypothetical, undiscovered planet in our solar system. New research now suggests the ...

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 ...

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 ...

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all our efforts to spot it. Some astronomers ...

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 ...

What can rocky planets orbiting in the outer parts of a solar system teach scientists about planetary formation and evolution? This is what a recent study published in Science hopes to address as a ...

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 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 dubbed ...