jordmånen

Jordmånen, commonly referred to as Earth's Moon, is the natural satellite of the planet Earth. It orbits Earth at an average distance of about 384,400 kilometers and completes a sidereal orbit in roughly 27.3 days. Because of tidal locking, the same hemisphere faces Earth, while the far side remains largely hidden from view.

With a diameter of about 3,474 kilometers and a mass of 7.35×10^22 kilograms, the Moon has a surface gravity of about 1.62 m/s². It lacks a significant atmosphere and possesses only a tenuous exosphere. The surface features include basaltic plains called maria, rugged highlands, and numerous impact craters, all coated by a fine regolith from billions of years of space weathering.

Most scientists attribute its origin to a giant impact about 4.5 billion years ago, when a Mars-sized body named Theia collided with the early Earth. Debris coalesced to form the Moon, which differentiated into crust, mantle, and a small core. Lunar volcanism filled some basins with basalt, creating the maria.

Jordmånen has been studied extensively by robotic missions and, historically, by human missions during the Apollo program (1969–1972). Data from orbiters and landers continue to inform models of planetary formation and the early Solar System. The Moon remains a focus for future exploration and science, including plans to support long-term human presence on the Moon and potential future missions to Mars.