The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

Planet Nine", dubbed, has fascinated scientists for its ability to account for "anomalous" motions of objects located faraway ...

chances are you grew up learning about our solar system’s nine planets. Of course, unless you’ve been living under a rock since 2006, you also know that now we only have eight planets.

While the composition of gas and dust in a molecular cloud is fairly uniform, everything changes once a star begins to form.

Stargazers will be treated to a dazzling six-planet "alignment" this January.

It's a six-planet parade! Tap HERE to track clouds for viewing opportunities with our interactive satellite. When to look: Mid and late January, but best visibility may be the night of Jan. 17 and 18.

Casper, Wyo. - The stars are aligning. A rare occurrence of a planetary alignment is about to happen. Having 2-3 planets on ...