MOON

The Moon is the only Earth satellite and is the fifth largest moon in the Solar System. The moon is the largest natural satellite in the Solar System according to the size of the planet it orbits. Among other satellites, the Moon is the second most densely populated satellite after Io (Jupiter's satellite). The moon always shows the same side on the Earth, with the near side marked by dark volcanic currents found between the bright crust highlands and prominent impact craters.

The size of the Moon is relatively large compared to the size of the Earth, which is one quarter of the diameter and 1/81 of the mass of the Earth. The Moon is the largest natural satellite in the Solar System according to the relative size of the planet it orbits, although Charon is larger for the size of the dwarf planet Pluto, which is about 1/9 of the mass of Pluto. Even so, the Earth and the Moon are still regarded as planet-satellite systems, not multiple planetary systems, because the concentrations of these two celestial bodies are located 1,700 km (about a quarter of Earth's radius) beneath the Earth's surface.

In culture, the regular moon phase makes it a very accurate timepiece. The period of emergence and disappearance of the moon in the sky forms the basis for most ancient calendars. The stick of counts of bone artifacts around 20-30,000 years old is believed by some to be a moon phase marker. Thirty days a month is the estimated time of the month cycle. In English, the ”month” noun and the relative word in other Germanic languages ​​come from the Proto-Germanic word which indicates the use of the lunar calendar by the Germanic people (the Germanic calendar) before the adoption of the solar calendar.

Source: https://en.wikipedia.org/wiki/Moon

Picture: Google