The moon does not rotate around its axis, is that so? For many years, scientists have been arguing on this topic, but they don’t find an answer that would satisfy everyone. Each puts forward his own hypotheses and tries to prove them. Today, there is a controversial situation on this issue.
Moon shape
The study of the surface of the moon is of great interest in the scientific community. Some study it together with the Earth, considering it as one whole system.
When the moon makes its move around the earth, then its position relative to the sun also changes. Our planet is always facing the same side. A line that divides the halves is called a terminator. Since the moon is a satellite, it moves in an orbit whose shape is ellipsoidal.
During its journey around the sun, it seems that the illuminated side of the moon changes shape. However, the celestial body always remains round, and due to a change in the angle of incidence of sunlight on the surface, it seems that its shape has changed. Over the course of a month, the Moon is visible from the Earth in several different angles. The main ones are:
- new moon;
- first quarter;
- full moon;
- last quarter.
With the new moon, the moon is not visible in the sky, since this phase corresponds to the location of the satellite between the Sun and the Earth. Light from the Sun does not fall on the Moon and, accordingly, does not fend off; therefore, half of it, visible from the Earth, is not illuminated.
In the first quarter, the right half of the moon is illuminated by the Sun, since it is at an angular distance of 90 ° from the star. In the last quarter, the situation is similar, only the left side is lit.
Coming to the fourth phase - the full moon, the Moon is in opposition to the Sun, so it fully reflects the light falling on it, and the entire illuminated half is visible from the Earth.
Land
As early as the 16th century, it was proved that the Earth has its own rotation. However, how it began and what preceded it is not known. There are several theories about this. For example, during the formation of the planets, dust clouds connected and formed the planet, at the same time they attracted other cosmic bodies. The collision of the planets with these bodies could set them in motion, and then occurred by inertia. This is one of the hypotheses that has not found clear confirmation. In this regard, another question arises: why does the moon not rotate around its axis? Let's try to answer.
Types of rotation of the moon
A prerequisite for the body to rotate around its own axis is the presence of this axis, but the Moon does not. The proof of this is presented in the following form: The moon is a body that we break into a large number of points. During rotation, these points describe the trajectories in the form of concentric circles. That is, it turns out that they are all involved in rotation. And if there were an axis, some points would remain motionless, and the side visible from the Earth would change. This is not happening.
In other words, there are no centrifugal forces directed toward the center on the satellite, and therefore the moon does not spin.
Motion of the celestial body
To prove their own rotation of the moon, scientists use various research methods. One of them is the consideration of the motion of the Earth’s satellite relative to the stars.
They are mistaken for motionless bodies, from which the reference is made. Using this method, it turns out that relative to the stars, the satellite has its own rotation. In this version, when asked why the moon does not rotate on its axis, the answer will sound like it is spinning. However, this observation is incorrect. Since the centripetal control of the Moon is determined by the Earth, it is necessary to study the capabilities of the celestial body relative to the Earth.
Orbit or trajectory
To understand whether the moon rotates around its axis, we consider concepts such as “orbit” and “trajectory”. They are different.
Orbit:
- closed and curve;
- shape - round or ellipsoidal;
- lies in one plane;
Trajectory:
- a curve having a beginning and an end;
- straight or curved shape;
- is in the same plane or in three-dimensional.
Why does the moon not rotate around its axis? It is known that the body can take part in only two types of movement at a time. On the Moon, these two permissible species are present: around the Earth and around the Sun. Accordingly, there can be no other types of rotation.
If you look at the trajectory of the moon from the earth, you will see a complex curve.
The presence of an orbit is governed by the law of conservation of momentum, however, it can change if the angular momentum changes . Orbit - is described by the laws of physics, the trajectory - by the laws of mathematics.
Earth Moon System
In some manuals, the Moon and the Earth are a single whole system. Mathematically, their common center of mass is calculated, which does not coincide with the center of the Earth, and it is stated that rotation is going on around it. However, from the point of view of astrophysics, any rotation around this center is absent, as can be seen by observing the Moon and the Earth through special modern equipment.
Why doesn't the moon spin around its axis? Is it true? The rotation of the celestial body is spin-spin and spin-orbit. The moon rotates in a spin-orbital motion around an axis passing through the center of the earth.
People on Earth all the time see one side of the moon, and it does not change. For practical evidence, you can experiment with a small weight.
Take the weight, tie it to the rope and twist. In this case, the weight will be the Moon, and the person holding the other end of the rope will be the Earth. Rotating a weight around itself, a person sees only one side of it, that is, people on Earth see one side of the moon. Approaching a second person, standing at a distance, will see all sides of the weight, despite the fact that it does not rotate around its axis. The moon is doing the same thing, it does not rotate on its axis.
Space age
For a long time, scientists studied only the visible side of the moon. It was not possible to find out what the opposite looks like. But with the development of the space age in the middle of the 20th century, mankind was able to see the second side.
As it turned out, the lunar hemispheres are very different from each other. So, the surface of the side facing the Earth is covered with basalt spoons, and the surface of the second hemisphere is dotted with craters. These differences are still of interest to scientists. It is believed that many years ago the Earth had two satellites, one of which collided with the Moon and left such imprints on its surface.
Conclusion
The moon is a satellite whose behavior has not been precisely studied. Why does the moon not rotate around its axis? This question has been asked by many scientists over the course of several years, and they cannot find a definite answer. Some scientists are sure that the rotation does exist, but it is invisible to people, because the periods of rotation of the Moon around its axis and around the Earth coincide. Other scholars deny this fact and recognize the moon’s revolution only around the sun and the earth.
The question of why the Moon does not rotate around its axis was considered in this article, and it is proved using an example (about a weight).