The moon is smaller than the planet Earth. Its diameter is about 2,200 miles. The surface is marked by numerous impact craters. The moon has a weak gravitational field.
The information about the moon's formation is the giant impact hypothesis. This hypothesis says that the moon formed when debris was ejected into space after Theia, a Mars-sized object, collided with the early Earth.
Impact craters, mountains, regolith, and Maria dominate the surface. The impact of space debris forms the impact craters. The moon's mountains are older and more rugged than Earth's. Regolith is fractured rock, dust, and other debris. Maria is a flat plain composed of solidified basaltic lava.
The moon has a thin atmosphere called the exosphere. The sky appears black throughout the day, and there are extreme weather variations. The main gases are helium, argon, and neon.
Exploration of the moon consists of both crewed and robotic missions. One of the most popular moon explorations was the Apollo 11 mission. The Apollo 11 mission was the first time a human landed on the moon in 1969, with the first human, Neil Armstrong, took the first step. Right now, it is planned that in 2026, NASA's Artemis program will have humans return to the moon with the Artemis II mission and Artemis III for landing on the moon.