When is the next leap year? Here are some fascinating leap year facts, along with all the details about why leap day always falls on Feb. 29.

The moon's ascending node (the point in the sky where its orbit crosses the ecliptic from south to north) is moving westward ...

September opens with Venus hosting winter constellations in the eastern predawn sky. West of the planet, the bright star Procyon, in Canis Minor, the little dog, rises at almost the same time as ...