Far beyond Neptune, strange orbital patterns suggest the Solar System may still contain a massive unseen planet. Planet 9 ...

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 ...

Scientists have discovered a bizarre planetary system where a rocky world orbits farther out than giant gas planets, defying long-standing theories of planet formation. The finding hints that some ...

Add Yahoo as a preferred source to see more of our stories on Google. (Ianm35/iStock/Getty Images Plus) The Solar System is one of the comforting constants of human existence. No matter what else we ...

The new goal of the revamped program was to study the outer solar system and the interstellar medium beyond the sun’s ...

Planetary scientists have long debated where the material that formed Earth comes from. Despite its location in the inner solar system, they consider it likely that 6–40% of this material must have ...