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.

Worlds with liquid water could have formed just 200 million years after the big bang from the remains of the earliest ...

Although it's being mistakenly promoted as a "rare planetary alignment," one of the best "planet parades" in half a century ...

per hour on this large gaseous planet, located in our Milky Way galaxy approximately 520 light-years from Earth in a tight ...

Last year was the hottest year in history – on average more than 1.55 degrees higher than pre-industrial temperatures. The ...

Planetary alignments aren't rare, but they can be when they involve six of the eight planets in our solar system.

The new moon of January will be at 7:36 a.m. Eastern Time on Jan. 29, according to the U.S. Naval Observatory, and two days ...

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.