The first step in studying the properties of gravity can be considered the discovery by Johannes Kepler of the laws of planetary motion around the Sun.
Kepler was the first person who managed to discover that the movement of the planets around the Sun occurs in ellipses, i.e. with. elongated circles. He also found out the law of changes in the speed of a planet depending on its position in orbit and discovered a relationship connecting the periods of revolution of planets with their distances from the Sun.
However, Kepler's laws, while making it possible to calculate the future and past positions of the planets, still did not say anything about the nature of those forces that connect the planets and the Sun into a coherent system and do not allow them to dissipate in space. Thus, Kepler's laws provided, so to speak, only a cinematic picture of the solar system.
However, the question of why the planets move and what force controls this movement arose even then. But it was not possible to get an answer to it right away. In those days, scientists mistakenly believed that any movement, even uniform and rectilinear, could only occur under the influence of force. Therefore, Kepler looked for a force in the solar system that “pushes” the planets and prevents them from stopping. The solution came a little later, when Galileo Galilei discovered the law of inertia, according to which the speed of a body on which no forces act remains unchanged, or, to put it in more precise language: in cases where the forces acting on the body are zero, the acceleration of this body is also equal to zero. With the discovery of the law of inertia, it became obvious that in the solar system we must look not for the force that “pushes” the planets, but for the force that turns their rectilinear motion “by inertia” into a curvilinear one.
The law of action of this force, the force of gravity, was discovered by the great English physicist Isaac Newton as a result of studying the movement of the Moon around the Earth. Newton was able to establish that all bodies attract each other with a force proportional to their masses and inversely proportional to the square of the distance between them. This law turned out to be a truly universal law of nature, operating both under the conditions of the Earth and our solar system, and in outer space among cosmic bodies and their systems.
We encounter manifestations of gravity, gravity, literally at every step. The fall of bodies onto the earth, lunar and solar tides, the revolution of planets around the Sun, the interaction of stars in star clusters - all this is directly related to the action of gravitational forces. In this regard, the law of gravity received the name “universal”. His discovery helped to understand a number of phenomena, the causes of which had previously remained unknown.
The quantitative side of the law of gravitation has received numerous confirmations in precise mathematical calculations and astronomical observations. It is enough to recall at least the “theoretical discovery” of Neptune, the eighth planet of the solar system. This new planet was discovered by the French mathematician Le Verrier through a mathematical analysis of the movement of the seventh planet Uranus, which experienced “disturbances” from a then unknown celestial body.
The history of this remarkable discovery is very instructive. As the accuracy of astronomical observations increased, it was noticed that the planets in their movement around the Sun noticeably deviate from Keplerian orbits. At first glance, this seemed to contradict the law of gravity, indicating an inaccuracy or even irregularity. However, not every contradiction disproves the theory.
There are “exceptions” that are in fact themselves a direct consequence of the law. They represent one of its manifestations, which for the time being eludes our attention and only once again testifies to its justice. There is even a catchphrase: “The exception confirms the rule.” The study of such “exceptions” advances scientific knowledge and allows for a deeper study of this or that natural phenomenon.
This is exactly what happened with the movement of the planets. The study of incomprehensible deviations of planetary paths from Keplerian orbits ultimately led to the creation of modern “celestial mechanics” - a science capable of pre-calculating movements celestial bodies.
If there were one single planet moving around the Sun, its path would exactly coincide with the orbit calculated on the basis of the law of gravity. However, in reality, nine large planets revolve around our daylight, interacting not only with the Sun, but also with each other. This mutual attraction of the planets leads to the very deviations mentioned above. Astronomers call them "disturbances."
IN early XIX V. Astronomers knew only seven planets orbiting the Sun. But in the movement of the seventh planet Uranus, terrible “disturbances” were discovered, which could not be explained by attraction from the known six planets. It remained to assume that an unknown “suburanian” planet was acting on Uranus. But where is it located? Where in the sky should we look for it? The French mathematician Le Verrier set out to answer these questions.
The new planet, the eighth from the Sun, has never been observed by any person. But despite this, Le Verrier had no doubt that it existed. The scientist spent many long days and nights working on his calculations. If earlier astronomical discoveries were made only in observatories, as a result of observations of the starry sky, then Le Verrier searched for his planet without leaving his office. He clearly saw it behind the orderly rows of mathematical formulas, and when, according to his instructions, Galle actually discovered the eighth planet, named Neptune, Le Verrier, they say, did not even want to look at it through a telescope.
Having been born, celestial mechanics quickly won a place of honor in space research. It is today one of the most accurate sections of astronomical science.
It is enough to mention at least the precalculation of solar moments and lunar eclipses. Do you know, for example, when the next total eclipse of the Sun will occur in Moscow? Astronomers can give a completely accurate answer. This eclipse will begin at about 11 o'clock on October 16, 2126. Celestial mechanics helped scientists look 167 years into the future and accurately determine the moment when the Earth, Moon and Sun will take such a position relative to each other that the lunar shadow will fall on the territory of Moscow. What about calculations of the movement of space rockets and artificial celestial bodies created by human hands? They are again based on the law of gravity.
The movement of any celestial body is ultimately completely determined by the force of gravity acting on it and the speed that it possesses. It can be said that in current state system of celestial bodies clearly determines its future. Therefore, the main task of celestial mechanics is that, knowing relative position and the speed of any celestial bodies, calculate their future movements in space. Mathematically, this problem is very difficult. The fact is that in any system of moving cosmic bodies there is a constant redistribution of masses, and due to this, the magnitude and direction of the forces acting on each body changes. Therefore, even for the simplest case of motion of three interacting bodies, there is still no complete mathematical solution. An exact solution to this problem, known in “celestial mechanics” as the “three-body problem,” can be obtained only in certain cases, when it is possible to introduce a certain simplification. A similar case occurs, in particular, when the mass of one of the three bodies is negligible compared to the masses of the others.
But this is exactly the situation when calculating rocket orbits, for example, in the case of a flight to the Moon. The mass of the spacecraft is so small compared to the masses of the Earth and Lupe that it can be ignored. This circumstance makes accurate calculations of rocket orbits possible.
So, the law of action of gravitational forces is well known to us, and we successfully use it to solve a number of practical problems. But what natural processes determine the attraction of bodies to each other?
Why won’t the Moon be attracted to the Sun, since its gravitational force is 2 times greater??? and got the best answer
Answer from Uncle Fedor[guru]
It’s actually complete nonsense about “doubled strength”...
The Moon is attracted to the Sun. And the Earth is also attracted to the Sun. Thanks to this attraction, the Earth and Moon move in orbit around the Sun, rather than flying away along a straight path.
Reply from Nikolay Gorelov[guru]
Before answering this question, you need to recognize it as nonsense.
Reply from Vladimir Medvedev[newbie]
The question comes from the fact that there are two givens - the Earth and the Sun, and the Moon must choose between them, which one to be attracted to.
If the attraction is more towards the Earth, you will rotate around the Earth, if it is more towards the Sun, you will rotate around the Sun - or even fall onto it.
The implicit assumption here is that the Earth and the Sun themselves are fixed at certain points in space, since they are considered as two different bases, one of which the Moon must belong to. At least the influence of the Earth and the Sun on each other is not considered.
But in fact, this influence exists. And just as the Sun attracts the Moon, it also attracts the Earth just as strongly, and even more strongly.
Accordingly, they are attracted in tandem and “fall” towards the Sun. But the rotation of the Earth-Moon system around the Sun allows the centrifugal force and the gravitational force of the Sun to balance.
Reply from Anatoly Nizgodinsky[guru]
It is necessary to consider not the Moon separately, but the Earth-Moon pair! And don’t forget that they ROTATE around the sun!!!
Reply from Konstantin Okhotnik[guru]
Yes, you don’t need to look at the answers, but read a scientific book, at least a school textbook.
Don't worry, the Moon is attracted by both the Sun and the Earth! And it falls on both the Earth and the Sun, but it just can’t get there.
Why does the Sun act on the Moon with double force?
Reply from Evgeniy Yurtaev[expert]
then why don’t leaves or dust swirl around us? Logically, we have more iron inside and dust should be our companion 😀
Reply from Vlada Shatrova[active]
The earth is closer to the moon and the gravity is greater, but the sun is further away and the force of gravity decreases. So it turns out that the Moon “hangs” between the Sun and the Earth.
Reply from White Rabbit[guru]
Uncle Fyodor has the correct answer.
ALL bodies in the gravitational field move the same way, including the Moon and the Earth; if we consider the Earth-Moon system, then we can temporarily forget about the Sun
This is a consequence of the fact that there is actually no POWER of attraction (not twice as much, but NONE at all :)
Reply from Danilochkin Fedor[guru]
The earth doesn't let go. Do not forget about the mutual attraction of the earth and the moon.
Reply from 3 answers[guru]
Hello! Here is a selection of topics with answers to your question: Why won’t the Moon be attracted to the Sun, because its gravitational force is 2 times greater???
The Earth, like other planets, revolves around the Sun in its orbit, which has the shape of an ellipse. Well acquainted with school curriculum The law of gravity states about the mutual attraction of such huge astronomical bodies as the Sun and the Earth.
Moreover, the body with less mass moves towards the body with more mass. According to this law, our Earth must fall towards the Sun. Let's find out why doesn't the earth fall into the sun, and due to what restraining force this does not happen!
The force that keeps planet Earth from falling into the Sun
It turns out that the fall itself exists, and constantly! Yes, the Earth is in a constant state of falling towards the Sun. And if the Earth did not revolve around the Sun, this would have happened long ago.
The counteracting force that prevents the fall is nothing more than the centrifugal force that arises as a result of the movement of the Earth in its orbit around the Sun.
And this force, as you may have guessed, is always equal to the force of gravity. That is, the speed of 30 km/s with which the Earth moves in its orbit creates a force that constantly deviates the Earth's flight path from a perpendicular fall towards the Sun.
Think about how fine-tuned this mechanism is, creating this constant balance of forces that has existed for more than 5 billion years. If the speed were greater, we would constantly deviate from the Sun, and if it decreases, exactly the opposite.
Calculation of the gravitational force between the Earth and the Sun
Is it possible to calculate this very force of attraction that arises between the Earth and the Sun? Certainly. To do this, it is enough to know their masses, mutual distances from each other and the constant gravitational constant. It is worth noting that the distances between the planets and the Sun are averaged in reference books. In fact, due to the elliptical shapes of the orbits, this distance during the year is different for each planet relative to the Sun.
The same effect forces other planets of the solar system to be in their orbits. The difference is only in the forces of attraction. Each planet has its own orbital speed, which creates an opposing centrifugal force equal strength attraction.
Why doesn't the Earth-Moon system fall into the Sun?
Attraction by the Sun systems Earth-Moon very large.
Why doesn't this system fall into the Sun?
After all, the mass of the Sun is 329,000 times greater than the total mass of the Earth and the Moon.
Tides, caused by the mutual attraction of the Earth and the Moon, are stronger than solar ones. The Sun also causes relatively weak tides in the Earth-Moon system, stretching the Moon's orbit around the Earth and compressing it laterally.
Tidal actions from the Sun are weak because they depend on the DIFFERENCE of forces acting on the near and far sides of attracting objects, and the sizes of these objects are small compared to the distance to the Sun.
At the same time, the attraction of the Sun for the WHOLE Earth-Moon SYSTEM is very great.
Why doesn't it fall on the Sun? After all, the mass of the Sun is 329,000 times greater than the total mass of the Earth and the Moon. Of course, it would fall directly into the Sun if the Earth stopped in orbit, and did not move, as it does now, around the Sun at a speed of 30 kilometers per second. (At this speed, you can drive to Samara in 7 seconds!). And if not for the gravity of the Sun, the Earth would fly away tangentially to its orbit. The sun prevents this and causes all the bodies of the solar system to revolve around it.
Why do the bodies of the Solar System rotate in orbits at such high speeds?
Because the solar system was formed from a rapidly rotating cloud. The increase in its angular velocity was a consequence of the gravitational compression of the cloud towards its center of mass, in which the Sun was subsequently formed. Even before compression, the cloud already had an angular and forward speed. Therefore, the solar system not only rotates, but also moves in the direction of the constellation Hercules at a speed of 20 kilometers per second. And the Earth and the Moon also participate in this movement.
What is the reason for the translational and rotational movements of the cloud before its gravitational compression begins? “Our” cloud is a small part of one of the huge gas and dust complexes that fill our Galaxy. Of the numerous reasons that cause the complex movement of these complexes, we will name a few of the main ones.
Non-solid rotation of the Galaxy. Galaxy - no solid. The rotation speed of that part of the complex that is closer to the center of the Galaxy is greater than that which is further away; a pair of forces arises that rotate the gas and dust complex.
Magnetic fields of the Galaxy. The gas component contains ions, and the dust component contains iron and other metals. Interacting with complex galactic fields, the complexes move along magnetic field lines.
Supernova explosions. The supernova substance ejected during the explosion accelerates the surrounding gas and dust material at speeds of thousands of kilometers per second. “Novae” and other stars that shed their atmospheres are less effective.
Star wind. Hot giant stars, with their stellar wind, disperse the gas and dust matter from which they were formed,
There are many reasons. In the Galaxy, all objects have their own rotational and translational speeds.
The problem discussed in this note relates to the problems of cosmogony. Scientists have puzzled over it since the general understanding of the structure of our Solar system. This problem has been around for at least three hundred years. Now, in general, the problem has been qualitatively solved. Rakhil Menashevna wrote an informative note about this.
However, many mysteries still remain, especially in the quantitative calculation of the parameters of the Solar system. We have already written about some of these riddles. Some of them were described by Rakhil Menashevna. For example, why there is a lot of water on Earth, and how this water got to us.
I would really like to understand how the formation of our Sun and Solar System occurred. But this problem may never be completely resolved. The period of revolution of the Sun around the center of the Galaxy is approximately 250 million years. During the lifetime of the Sun, which is approximately 4.5 billion years, the Sun made 16-17 revolutions. During this time, apparently, our Sun diverged very far from its sisters, who were born with it. Therefore, in order to understand the initial conditions, it would be necessary to establish which stars are sisters to our Sun. But, unfortunately, we cannot do this yet. But it would be great to say - that star over there was born from the same cloud as the Sun, but this one was next to it at the time of birth.
For example, within a radius of 15 light years from the Sun there are two systems with a white dwarf. These are Sirius and Procyon. These systems are similar to each other. Were they born with the Sun or not?
Your unexpected question I was also interested. I think that the assumption about the formation of Sun, Sirius and Procyon from one common cloud is true.
I also found in the reference book P.G. Kulikovsky that these stars have rather small relative radial velocities: they approach the Sun at speeds of 8 and 3 km/s, respectively, while most radial velocities of stars lie in the range of 20 - 30 km/s. Perhaps these stars still rotate together around the center of the Galaxy.
The purpose of my short articles is to explain the essence of the phenomena under consideration. I could supplement them with many details, but I try not to do this; even more details could be taken from the literature, and even more, as you rightly noted, are unknown to science.
Dear RMR_stra! Very interesting information! I've had an idea for quite some time!
Let's assume that Sirius or Procyon were born with Sun from the same cloud. We know the age of the Sun. This is about 4.5 billion years. This is approximately half the lifespan of the Sun. White dwarfs cannot have a mass greater than twice the mass of the Sun. More likely somewhere around 1.5 solar masses. But stars with a mass two to one and a half times that of the Sun and live the same number of times less than the Sun, approximately, of course. But this means that white dwarfs in the Saturn and Procyon systems appeared quite recently. It is possible that our ancestors saw the shedding of the shells of these stars in the form of some kind of grandiose celestial fireworks. There is a so-called disk of Nebry. It is estimated to be about 5,000 years old. It has some arcs in the starry sky. The discarded shell should have looked like such sparkling arcs in the Earth's sky. On the disk, the arcs are believed to be adjacent to the seven stars of the Pleiades. And they are located in almost the same sector of the sky as Sirius and Procyon.
Moreover, one can even assume that the ejected shell reaching the Solar System several hundred years after the ejection could cause increased condensation of moisture in the Earth’s atmosphere (due to an increase in the flow of charged particles), i.e. rain. Such rain could last the entire time during which the central part of the shell passes the Earth. And this time should be calculated in several tens of days.
Indeed, it is strange: the Sun, with its enormous gravitational forces, holds the Earth and all the other planets of the solar system near itself, preventing them from flying into outer space. It would seem strange that the Earth holds the Moon near itself. There are gravitational forces between all bodies, but the planets do not fall on the Sun because they are in motion, this is the secret. Everything falls down to the Earth: raindrops, snowflakes, a stone falling from a mountain, and a cup overturned from the table. And the Moon? It revolves around the Earth. If it were not for the forces of gravity, it would fly off tangentially to the orbit, and if it suddenly stopped, it would fall to Earth. The Moon, due to the gravity of the Earth, deviates from a straight path, all the time as if “falling” to the Earth. The movement of the Moon occurs along a certain arc, and as long as gravity acts, the Moon will not fall to the Earth. It’s the same with the Earth - if it stopped, it would fall into the Sun, but this will not happen for the same reason. Two types of motion - one under the influence of gravity, the other due to inertia - add up and result in curvilinear motion.
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