The moon is the only satellite of the earth. The first person who examined her was Galileo. The same scientist also owns the first discoveries regarding the Earth’s satellite: its approximate sizes, craters and valleys on the surface. Now everyone can make Galileo's discoveries simply by using binoculars.
Moon and planets of the solar system: comparison
The volume of the Moon is 21.99 * 10 9 km 3 . Its mass is 7.35 * 10 22 kg. Knowing these values, we can compare the sizes of the Moon and the Earth. The volume of the Earth is 10.8321 * 10 11 km 3 . Its mass is 5.9726 * 10 24 kg. Thus, the volume of the moon is 0.020 of the volume of the Earth, and the mass is 0.0123. You can also compare the size of the moon and Mars. The volume of the red planet is 6.083 * 10 10 km, mass - 3.33022 * 10 23 kg. Consequently, Mars is approximately twice as large.
The moon in many ways differs from other satellites of the planets of the solar system, not only in size, but also in other parameters. It is believed that the "moons" of other planets could be formed as a result of one of two processes. The first way is their collection from distributed dust and gas and their further attraction to the planet by its gravitational field. The second way - other satellites of the planets of our system could simply be flying past celestial bodies, accidentally falling into the field of gravity. Scientists believe that this is how Mars appeared two satellites called Deimos and Phobos.
How did the moon form?
But the characteristics of the moon cannot be explained by these two options. Astronomers are sure that it appeared as a result of a powerful cataclysm in the solar system. As a result, a huge amount of space debris and young planets, which were worn in space, formed. And one of these celestial bodies collided with the Earth. Several fragments of the Earth were thrown into the surrounding space. Some of them gradually began to attract and formed themselves the moon.
Moon compared to satellites of other planets
The moon is a fairly large satellite. In size it is surpassed only by such satellites of other planets as Io, Callisto, Ganymede, Titan. Thus, the size of the moon allows this celestial body to occupy fifth place among the 91 satellites of the entire solar system.
The appearance of the moon and its surface
The lunar surface undergoes very little change. After all, the era of active meteor showers remained for her in the distant past. Neither tectonic nor volcanic activity is also observed on the surface of the Earth’s satellite. The Moon does not have a dense atmosphere and water, which is also two more reasons why the lunar appearance remains unchanged for humans. Mainland areas on the lunar surface are lighter in color. They have a large number of craters. It used to be that they could be of volcanic origin, but now the meteorite theory prevailed. On the moon were found their mountains, crevices, gorges.
Lunar mountains are called the same as the terrestrial. Here you can see the Carpathians, the Alps, and the Caucasus. These names also gave them Galileo. And the seas are named after the old belief that the Moon controls human emotions and weather on Earth. For example, on a satellite map you can see the sea of Tranquility, Crisis, Rains, Clarity, as well as the ocean of Storms.
Amazing matches
Scientists have discovered many striking coincidences in the structure of the solar system. One of them is the following: between the Earth and the Moon, you can fit all the other planets of the system. The distance from the satellite to the Earth is about 384,400 km. In other words, the moon is not so far from the earth. NASA experts decided to figuratively "push" all the remaining planets between the Moon and the Earth. To astronomers' surprise, they fit in almost exactly, with only small gaps.
Now scientists can only guess: is this fact a coincidence or not. In addition, this wonderful case is not the only one. The size of the moon is selected in a very special way, and the distance from the sun, it would seem, is measured to the nearest centimeter. After all, if the Moon is between the Earth and the Sun, then it completely blocks it. So it turns out a solar eclipse. If the size of the moon were slightly larger or, conversely, smaller, people would not be able to observe this amazing natural phenomenon.
The angular size of the moon
This is simply its apparent size from the surface of the Earth. For example, the angular size of the satellite of our planet and the Sun is approximately the same, because it seems to people that these celestial bodies are equal. But in fact, the linear dimensions of the moon and the sun differ by almost 400 times. Here you can observe another amazing coincidence.
The sun is about 400 times the size of the Earth’s satellite. But the Moon is 400 times closer to the Earth than the Sun. The radius of the solar system is about 696 thousand km. The size of the moon, more precisely, its radius is 1737 km. This situation is unique in the entire solar system. This fact is especially surprising when you consider that there are 8 planets and 166 satellites in the Solar System. As a result of this coincidence, the apparent size of the moon and the sun is almost the same.
Moon and life on earth
The moon not only made others the appearance of the starry sky for the inhabitants of the Earth. This celestial body also made the appearance of life on our planet the most probable. The fact is that each planet oscillates during rotation, because of this, on other planets, the climate is constantly subject to change. With any unstable climate of the emerging life, it is very difficult to gain a foothold on the celestial body. The size of the moon is not so small as not to affect the climate. The moon contributes to the fact that the oscillations of the Earth during its rotation are softened.