A new study has revealed that our understanding of the South Pole-Aitken basin was quite literally back-to-front, meaning ...

Something called a "quasi-moon" was discovered in August, and now many are wondering if we should count our new neighbor as a second moon.

Learn how the Moon’s phases form, why it changes shape in the sky each night, and what each stage — from new moon to full moon — actually means.

When Earth is opposite Mars from the sun, it will appear full because you’re looking directly on the daylit side. But ...