Earth's only natural satellite, the Moon, is larger relative to its planet than any other satellite in the solar system.During the Apollo program, rocks from the Moon's surface were brought to Earth. Radiometric dating of these rocks has shown that the Moon is 4.53 ± .01 billion years old, formed at least 30 million years after the solar system. New evidence suggests the Moon formed even later, 4.48 ± 0.02 Ga, or 70–110 million years after the start of the Solar System.