Known as the giant-impact hypothesis, this proposed event involves a collision between Earth and a hypothetical Mars-sized ...

As one of Earth’s most familiar sights in the sky, the moon has inspired billions of people to gaze upward in wonder. Early in humanity’s history, we constructed myths about this silvery orb, and ...

Hovering alongside Earth for millennia, the moon has been a familiar sight in the night sky—a silent witness to the unfolding of human history. On August 1, 1971, some of that history was written on ...