The moon is, as everyone knows, the only and very large satellite of our planet. Even in ancient written sources that existed to this day, including in the Bible, it is referred to as the "night light". And not in vain - because in the visible firmament this object is the second in brightness and magnitude after the Sun. The diameter of the moon is about four times smaller than the earth's. Its volume is only about two percent of the same indicator of the "blue planet". The strength of gravity on the "night light" is six times less than on Earth. Accordingly, the acceleration of free fall on its surface is 16.7% of that to which we are accustomed. In particular, this is indirectly confirmed by the stories of astronauts who have visited this unusual natural satellite.
Between the Moon and the Earth there is a gravitational attraction, which is facilitated by the distance between them and the ratio of their masses. One of the consequences of this phenomenon on our planet is the ebb and flow. They are noticeable on virtually all of its aqueous coatings. In turn, the energy of interaction of the Earth and the moon is absorbed because of the tides. Thanks to this, the distance between our planet and its companion constantly increases by about four centimeters per year. But this is not all, because of this interaction, the movement of the Earth around its own axis is constantly slowed down. Because of this, for every hundred years the duration of the day increases by a certain fraction of a second, and, in addition, the period of circulation of the "cold star" around our planet or, as they say, the cycle of the moon increases. Now it is just over 27 days and 13 hours.
In our time, the average distance to the Moon is about 384,401 km. This is almost 60 equatorial radii of our planet. The diameter of the moon is much smaller than the earth's, as already mentioned above. Its volume is 2.03% of the same index of our planet. In numerical terms, the diameter of the Moon corresponds to 3476 km. The light from it is 500,000 times weaker than from the Sun. It reaches the Earth in just 1.3 seconds. This is the largest satellite in the solar system, the size of which is larger than that of the planet Pluto.
Interestingly, the moon has its own seas. There are a lot of them, and scientists, having investigated the surface of the "night luminary", managed to give them all a name. But, if the area of the Earth is covered by waters more than 70%, then on the Moon the basins of the seas occupy 30-40% of its entire visible surface. Its atmosphere is characterized by high sparsity. This is the reason for frequent and sharp temperature changes - from the strongest cold, which does not set any chance for life, up to +120 degrees. In view of the fact that there is no shell from the ozone or other gas above the Moon, the sky from its surface always appears black. From there you can see only that part of the Earth that is illuminated by the Sun.
In our time, much is known about this satellite: the diameter of the moon, the distance to it, its mass is calculated approximately. However, there are also "white spots" in the knowledge of scientists. Until now, the structure of its nucleus is not known for certain. However, according to some researches of scientists, it is, most likely, analogous to the terrestrial and represents a huge red-hot metal ball.