Introduction to the Moon

The Moon is Earth's only natural satellite. At one-quarter the diameter of Earth (comparable to the width of Australia),it is the largest natural satellite in the Solar System relative to the size of its planet, and the fifth largest satellite the Solar System overall (larger than any dwarf planet). According to new research, the Moon is 85 million years younger than scientist once thought. Computer simulations revealed that the Moon formed roughly 4.425 billion years ago.