Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, ...

Stars that pass close to the solar system could pull planets out of alignment, sending them hurtling into the sun or out into ...

This week, an old astronomical controversy is renewed as researchers present new evidence for a hidden "Planet X" in our ...

Warmer climates than Earth’s could accelerate life’s development, potentially increasing the number of planets with more ...

For years, astronomers have been searching for a ninth planet in our solar system (after giving Pluto the old heave-ho and demoting it to a dwarf planet) and now researchers say they’ve found a ...

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

For years, astronomers have toyed with the idea that the Sun hides an extra planet so distant and dim that even the best ...

Is frozen water scattered in systems around other stars? Astronomers have long expected it is, partially based on previous ...

"Rings are mostly made of ice and small rocks," said William Saunders, a planetary scientist at NASA's Langley Research ...