Callisto, the third largest moon in the entire solar system, orbits Jupiter from about 1.2 million miles away. The rocky ...

Though the planets are always “aligned,” seeing more than four in the sky is more uncommon. February’s lineup is a chance to ...

Two planets stand side by side as the evening twilight continues to delight and colorful stars shine in the sky this week.

Earth's Moon: NASA's Galileo spacecraft took this image of Earth's Moon on Dec. 7, 1992, on its way to explore the Jupiter system in 1995-97. The Moon is Earth's only natural satellite.

Here's when and how to watch the next full moon and February's rare planetary parade across Pennsylvania skies, starting with ...

Then Mars and Jupiter will rule the nighttime skyline, with a pop-in from Mercury and a fainter view of Saturn. Here's all about February's full moon and how to watch the planetary parade.

Then Mars and Jupiter will rule the nighttime skyline, with a pop-in from Mercury and a fainter view of Saturn. Here's all about February's full moon and how to watch the planetary parade.