The article describes why the Moon does not fall on the Earth, the reasons for its movement around the Earth and some other aspects of the celestial mechanics of our solar system.
The beginning of the space age
The natural satellite of our planet has always attracted attention. In ancient times, the Moon was the subject of a cult of some religions, and with the invention of primitive telescopes, the first astronomers could not tear themselves away from the contemplation of majestic craters.
A little later, with the discovery in other areas of astronomy, it became clear that such a celestial satellite is present not only on our planet, but also on a number of others. And Jupiter, there are 67 of them! But ours is leading in size throughout the system. But why does the moon not fall to the earth? What is the reason for its movement in the same orbit? We’ll talk about this.
Heavenly mechanics
First, you need to figure out what orbital movement is and why it happens. According to the definition used by physicists and astronomers, orbit is the movement in the gravitational field of another object that is significantly superior in mass. For a long time it was believed that the orbits of the planets and satellites have a circular shape as the most natural and perfect, but Kepler, after unsuccessful attempts to apply this theory to the motion of Mars, rejected it.
As you know from the course of physics, any two objects experience mutual forces of attraction, the so-called gravity. The same forces affect our planet and the moon. But if they are attracted, then why the moon does not fall to the earth, how would it be most logical?
The thing is that the Earth does not stand still, but moves around the Sun in an ellipse, as if constantly “running away” from its satellite. And he, in turn, have an inertial speed, because of which he travels again in an elliptical orbit.
The simplest example that can explain this phenomenon is a ball on a rope. If you untwist it, then the centrifugal force will keep the object in one plane or another, and if you slow down, it will not be enough and the ball will fall. The same forces act on the moon. Earth's gravity carries it along with it, preventing it from standing still, while the centrifugal force developed as a result of rotation holds it, preventing it from approaching a critical distance.
If the question of why the Moon does not fall on the Earth is given an even simpler explanation, then the reason for this is the equal interaction of forces. Our planet attracts the satellite, forcing it to rotate, and centrifugal force repels it, as it were.
The sun
Such laws apply not only to our planet and satellite, they are subject to all other space objects. In general, gravity is a very interesting topic. The movement of the planets around the center of mass is often compared with the clockwork, so it is accurate and calibrated. And most importantly, breaking it is extremely difficult. Even if several planets are removed from it, the others are very likely to change to new orbits, and collapse with a fall to the central star will not occur.
But if our luminary has such a colossal gravitational effect even on the most distant objects, then why does the moon not fall on the sun? Of course, the star is at a much farther distance than the Earth, but its mass, and hence gravity, is an order of magnitude higher.
The thing is that the celestial body and its satellite also move in orbit around the Sun, and the latter does not act separately on the Moon and the Earth, but on their common center of mass. And the moon is affected by the double influence of gravity - stars and planets, and after it the centrifugal force that balances them. Otherwise, all satellites and other objects would have long been burned in a hot star. That is the answer to the frequent question of why the moon does not fall.
Movement of the sun
Another fact worth mentioning is that the sun is also moving! And with it, our entire system, although we are used to believing that outer space is stable and unchanging, with the exception of the orbits of the planets.
If you look more globally, within the framework of systems and their entire clusters, you can see that they also move along their trajectories. In this case, the Sun with its "satellites" revolves around the center of the Milky Way galaxy. If we conditionally present this picture from above, it looks like a spiral with many branches, which are called galactic arms. In one of these arms, along with millions of other stars, our Sun moves.
A fall
But still, if you ask yourself this question and dream up? What are the conditions under which the moon will crash into the Earth or go on a journey to the sun?
This can happen if the satellite stops rotating around the main object and the centrifugal force disappears, also if its orbit changes something and adds speed, for example, a collision with a meteorite.
Well, she will go to the star if she deliberately somehow stops her movement around the Earth and gives the initial acceleration to the sun. But most likely, the Moon will simply gradually rise into a new twisted orbit.
To summarize: the Moon does not fall on the Earth, because, in addition to the attraction of our planet, a centrifugal force also acts on it, which repels it. As a result, these two phenomena balance each other, the satellite does not fly away and does not crash into the planet.