The moon doesn't rotate on its axis, does it? For many years, scientists have been arguing on this topic, but they do not find an answer that would satisfy everyone. Everyone puts forward their own hypotheses and tries to prove them. To date, 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 people study it together with the Earth, considering it as one whole system.
When the Moon makes its move around the Earth, its position relative to the Sun also changes. The same side always faces our planet. The line that separates the halves is called the terminator. Since the Moon is a satellite, it moves in an ellipsoidal orbit.
During its journey around the Sun, the illuminated side of the Moon appears to change shape. However, the celestial body always remains round, and due to the change in the angle of incidence of the sun's rays on the surface, it seems that its shape has changed. During the month, the moon is visiblefrom the Earth in several different angles. The main ones are:
- new moon;
- first quarter;
- full moon;
- last quarter.
When the moon is new, 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 hit the Moon and, accordingly, does not bounce off, therefore, its half, 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 position is similar, only the left side is illuminated.
Coming into the fourth phase - the full moon, the Moon is in opposition to the Sun, so it completely reflects the light falling on it, and the entire illuminated half is visible from the Earth.
Earth
Back in the 16th century, it was proved that the Earth has its own rotation. However, how it began and what preceded it is unknown. There are several theories about this. For example, during the formation of planets, clouds of dust connected and founded the planet, at the same time they attracted other cosmic bodies. The collision of planets with these bodies could set them in motion, and then it happened by inertia. This is one of the hypotheses that has not found a 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 fact that the body can rotate around its own axis,is the presence of this axis, and the Moon does not have it. The proof of this is presented in this form: The moon is a body that we will break into a large number of points. During rotation, these points will describe the trajectories in the form of concentric circles. That is, it turns out that they are all involved in the rotation. And in the presence of 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 towards the center on the satellite, so the Moon does not spin either.
Movement of a celestial body
Proving the moon's own rotation, scientists use various research methods. One of them remains the consideration of the motion of the Earth's satellite relative to the stars.
They are taken for motionless bodies, from which the countdown is conducted. Using this method, it turns out that the satellite has its own rotation relative to the stars. In this version, when asked why the Moon does not rotate around its axis, the answer will be that it rotates. However, this observation is incorrect. Since the centripetal control of the Moon is determined by the Earth, then it is necessary to study the possibilities of a celestial body relative to the Earth.
Orbit or trajectory
To figure out if the Moon rotates around its axis, consider such concepts as "orbit" and "trajectory". They differ.
Orbit:
- closed and curve;
- shape - round or ellipsoid;
- lying in the same plane;
Trajectory:
- curve with beginning and end;
- straight or curvilinear;
- is in one plane or three-dimensional.
Why doesn't the moon rotate on its axis? It is known that the body can take part in only two types of movement at the same time. The Moon has these two admissible types: 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, we will see a complex curve.
The presence of an orbit is governed by the law of conservation of momentum, but it can change if the angular momentum changes. The orbit is described by the laws of physics, the trajectory is described 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 there is a rotation around it. However, from the point of view of astrophysics, there is no rotation around this center, as can be seen by observing the Moon and the Earth through special modern equipment.
Why doesn't the moon rotate on its axis? Is it true? The rotation of a celestial body is spin-spin and spin-orbital. The moon performs a rotational spin-orbital motion around an axis passing through the center of the Earth.
People on Earth see one side of the Moon all the time and it doesn't change. For practical proof,experiment with a small kettlebell.
Take a weight, tie it to a rope and twist it. 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 him, a person sees only one side of it, that is, people on Earth see one side of the Moon. A second person approaching, standing at a distance, will see all sides of the weight, despite the fact that it does not rotate around its axis. The same thing happens to the Moon, it does not rotate around its axis.
Space Age
For a long time, scientists studied only the visible side of the moon. There was no way to know what the opposite looked like. But with the development of the space age in the middle of the 20th century, humanity was able to see the other side.
As it turned out, the lunar hemispheres are strikingly different from each other. Thus, the surface of the side facing the Earth is covered with bas alt 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 doesn't the moon rotate on its axis? This question has been asked by many scientists for several years and they do not find the right answer unambiguously. Some scientists are sure that rotation still exists, but it is invisible to people, because the periods of rotation of the Moon around its axis and around the Earth coincide. Other scientists deny this fact and recognize the Moon's circulation only aroundSun and Earth.
The question of why the Moon does not rotate around its axis was considered in this article, and with the help of an example (about a weight) it was proved.
