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

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.

Be sure to check out our best telescopes for viewing planets guide and our more general ... Mercury — passes superior conjunction with the sun on Feb. 9 and enters the evening sky.

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 ...