Planetary systems such as our solar system take hundreds of millions of years to evolve. Since humanity has only existed for a sliver of that time, astronomers have only observed planetary systems at ...

If you examine our solar system’s giant planets, you’ll notice right away that they’ve all got moons—a lot of moons. While ...

Although astronomers have found thousands of exoplanets, the number of confirmed exomoons—and exorings—is still zero. But ...