What is the name of Earth's natural satellite?

Earth's natural satellite is the Moon. It is the only astronomical body beyond Earth that humans have visited and the brightest object in our night sky after the Sun.

The leading explanation for the Moon's origin is the giant-impact hypothesis. About 4.5 billion years ago, a Mars-sized body probably struck the young Earth, sending material into orbit that eventually clumped together to form the Moon. Its surface is covered with impact craters, bright highlands, and dark basalt plains called maria.

The Moon is tidally locked to Earth, meaning it rotates once in the same time it orbits our planet. That is why the same lunar hemisphere generally faces Earth. The Moon's gravity drives most ocean tides, although the Sun also contributes.

The familiar phases—from new Moon to full Moon—do not mean that the Moon changes shape. They show different portions of its sunlit half as it travels around Earth. Phobos is a moon of Mars, while Europa and Titan orbit Jupiter and Saturn, respectively.