Curious regularities of the Moon, Mercury and Venus

Sometimes one is surprised by the huge number of scientific works and fantastic stories about the Moon, Mercury and Venus. These heavenly bodies have always attracted the attention of scientists and science fiction writers. Maybe because in the solar system some curious regularities of the Moon, Mercury and Venus are observed in movements.

Maybe because in the solar system some curious regularities of the Moon, Mercury and Venus are observed in movements

For example, the Moon in about 28 days makes one revolution around the Earth and within the same period of time makes one revolution around its own axis. Thanks to this amazing regularity, namely the coincidence of the periods of revolution and rotation of the Moon, we always see only one side of it. The question arises: what is the cause of this coincidence and whether this is a regularity?

A curious pattern in motion can also be found in Mercury - the planet closest to the Sun. Mercury completes one revolution around the Sun for 88 terrestrial days, and one revolution around its axis in 59 days. It would seem nothing curious. But the fact is that, according to Kepler's second law, planets move in their elliptical orbits with a variable speed: the closer to the Sun, the faster. It turns out that in Mercury the angular velocity of its own rotation coincides with the angular velocity of its revolution around the Sun at the moment when the planet passes the portion of its orbit closest to the daylight.

An even more surprising regularity is observed in the motion of Venus. Its planet revolves around the Sun for 225 terrestrial days. After every 584 days, Venus is on the line connecting the Sun and Earth. And at this moment Venus is always turned to the Earth by the same side.

What is the cause of all these curious coincidences? It is known that the lunar tides form two "hump" in the water shell and in the solid matter of the Earth, which, when the planet rotates, moves along its surface. These tidal waves move towards the diurnal rotation of the Earth, so they brake it, and the speed of rotation of our planet gradually decreases.

Likewise, in the Moon material, terrestrial tides should occur, but more powerful - because the mass of the Earth is 81 times the mass of the moon. Therefore, the slowing down of the Moon's own rotation took place fairly quickly, as long as the Earth did not stop at all.

The surprising regularity in the coincidence of the angular velocities of rotation and the revolution of Mercury in the point of its orbit nearest to the Sun is also a consequence of the tidal braking caused by solar tides, which for Mercury are strong enough and capable of having a noticeable effect on its rotation.

As for Venus, the reason for its constant orientation toward the Earth during the periods of closest rapprochement remains unclear. It is not known whether this phenomenon is natural.

Generally speaking, such kind of curious patterns in nature are not found often. All because the probability of purely coincidence is extremely small. And if there is any surprising combination of events in nature, then, most likely, it has some hidden regularity.