he Moon (Latin: Luna) is Earth‘s only natural satellite.[e][f] Although not the largest natural satellite in the Solar System, it is, among the satellites of major planets, the largest relative to the size of the object it orbits (its primary).[g][h] It is the second-densest satellite among those whose densities are known (after Jupiter‘s satellite Io).
The Moon is in synchronous rotation with Earth, always showing the same face with its near side marked by dark volcanic maria that fill between the bright ancient crustal highlands and the prominent impact craters. It is the second-brightest regularly visible celestial object in Earth’s sky (after the Sun), as measured by illuminance on