In ancient Greek mythology and religion, Selene is the goddess and personification of the Moon. Also known as Mene, she is traditionally the daughter of the Titans Hyperion and Theia, and sister of the sun god Helios and the dawn goddess Eos. She drives her moon chariot across the heavens. Several lovers are attributed to her in various myths, including Zeus, Pan, and the mortal Endymion. In post-classical times, Selene was often identified with Artemis, much as her brother, Helios, was identified with Apollo. Selene and Artemis were also associated with Hecate and all three were regarded as moon and lunar goddesses, but only Selene was regarded as the personification of the Moon itself.
Detail of Selene from a Roman sarcophagus
Detail of a sarcophagus depicting Endymion and Selene, shown with her characteristic attributes of lunate crown, billowing veil (velificatio) and heavenly chariot, from 3rd century AD, Roman Empire period.
Statue of Selene in white marble, second half of the 3rd century AD
Selene in a flying chariot drawn by two white horses from "Flora, seu florum...", Ferrari 1646.
The Moon is Earth's only natural satellite. It orbits at an average distance of 384,400 km (238,900 mi), about 30 times the diameter of Earth. Over time Earth's gravity has caused tidal locking, causing the same side of the Moon to always face Earth. Because of this, the lunar day and the lunar month are the same length, at 29.5 Earth days. The Moon's gravitational pull – and to a lesser extent, the Sun's – are the main drivers of Earth's tides.
Near side of the Moon, lunar north pole at top
Size comparison of the main moons of the Solar System with Earth to scale. Nineteen moons are large enough to be round, several having subsurface oceans and one, Titan, having a considerable atmosphere.
The thin lunar atmosphere is visible on the Moon's surface at sunrise and sunset with the lunar horizon glow and lunar twilight rays, like Earth's crepuscular rays. This Apollo 17 sketch depicts the glow and rays among the general zodiacal light.
Gene Cernan with lunar dust stuck on his suit. Lunar dust is highly abrasive and can cause damage to human lungs, nervous, and cardiovascular systems.
