Moon

Moon dust is razor-sharp. Earth's sand is worn smooth by water and wind, but lunar dust has never been weathered, leaving it jagged like broken glass. Apollo astronauts' suits were visibly abraded within days. Dust control is now a key engineering challenge for Artemis.

The Moon drifts 3.8 cm farther from Earth every year, about the rate fingernails grow. Two hundred million years ago, in the dinosaur era, the Moon was closer and Earth's spin faster: a day lasted about 23 hours. Apollo 11 retroreflectors let lasers measure the retreat.

Cleopatra lived closer in time to the Moon landing than to the construction of the Great Pyramid of Giza. The pyramid was finished around 2560 BC, Cleopatra was born in 69 BC, and Apollo 11 landed in 1969 AD. To her, the pyramids were already a 2,500-year-old relic.

In Greek mythology, Artemis was the goddess of both the moon and childbirth. When a child was born, Greeks offered round cakes shaped like the moon to thank Artemis — believed to be the origin of eating cake on birthdays.

The Moon's orbit doesn't spiral around Earth as most people imagine. Because the Earth-Moon distance is tiny compared to the Earth-Sun distance, the Moon's actual path through space is nearly circular, traveling alongside Earth around the Sun.