The Moon, also known as Luna, is Earth’s only natural satellite. It is believed to have formed about 4.5 billion years ago from debris after a giant impact on earth. It is a rocky body with a diameter of 2,159 miles and is tidally locked so the same side always faces Earth. Surface temperatures range from -280°F at night to 260°F in daylight. The average distance from Earth is 238,855 miles.