The movement of the moon around the planet Earth in orbit takes about a month. In addition, it moves around its axis. This process takes a little more than 27 days. Since the movement in orbit and rotation around its axis occurs simultaneously, the Moon is always directed to the Earth on one side.
The moon itself does not shine like the sun. It only seems that it is shining, but in fact it only reflects sunlight. As the moon moves around the planet, sunlight falls on its different parts. This is the answer to the question: "Why is the moon different?". From time to time we see a fully illuminated surface of the satellite, and from time to time only its part is illuminated. Therefore, it seems to us that the moon is changing its shape. But this is only a transformation of the star - phases that indicate that we can see its various parts.
Lunar phases, or why the moon is different
The first lunar phase is the new moon. At her moment, the luminary is between the Sun and the Earth. Such a moon is not visible to us. Then comes the phase of the growing moon, in which its side is illuminated by sunlight. This part of it looks like a thin piece of a circle.
Very soon, the side of the moon, on which the sun falls, grows and becomes a semicircle. And this lasts until the moon reaches the last quarter, then the cycle ends and it starts all over again.
Earth and moon
Does the movement of the earth around its axis coincide with the periods of rotation of the moon, or is it just a gravitational effect of one celestial body on another? The answer to this question was sought by many inquiring minds.
It is established that nevertheless gravity becomes the cause of this position of celestial bodies. We all know what the tides that regularly occur in the oceans and raise water by several meters.
And the question “why the moon is different” has a simple answer: the earth from different directions is subjected to lunar gravity in different ways. The side that is turned toward the satellite is more affected than the reverse.
As a result, different parts of the Earth move in the direction of the side at different speeds. The surface, which is directed towards the Moon, swells, in the center of the Earth it shifts less, and the opposite surface completely lags behind, forming a hump. The Earth's crust is reluctant to change shape, and on land tidal forces are invisible. In the sea, under the influence of a satellite, tidal humps form on different sides of the planet.
As the Earth rotates, it turns to the Moon with its different sides, as a result of the tidal hump also moving along its surface. That is why the moon is different.
Scientists calculated that a billion years ago the moon was located much closer to planet Earth. At this time, the day was only 20 hours. Only a few days it took the moon to go around the Earth, and therefore the ebbs and flows were more pronounced. Over time, the satellite’s motion slows down, and after five billion years the Earth will rotate so slowly that it will be turned to the Moon only on one side, and in a year it will be only 9 days, not 365. A year, the Earth’s satellite will make nine revolutions. Consequently, the year will not be 12 months, as it is now, but only 9, and each will have only one day.
