Gravity is the most mysterious force in the universe. Scientists do not know until the end of its nature. It is she who keeps the planets of the solar system in orbit. It is a force that occurs between two objects and depends on mass and distance.

Gravity is called the force of attraction or gravitation. With the help of it, the planet or other body pulls objects to its center. Gravity keeps the planets in orbit around the sun.

What else does gravity do?

Why do you land on the ground when you jump up instead of floating away into space? Why do items fall when you drop them? The answer is an invisible force of gravity that pulls objects towards each other. Earth gravity is what keeps you on the ground and makes things fall.

Everything that has mass has gravity. The power of gravity depends on two factors: the mass of objects and the distance between them. If you pick up a stone and a feather, let them go from the same height, both objects will fall to the ground. A heavy stone will fall faster than a feather. The feather will still hang in the air, because it is lighter. Objects with more mass have a greater force of attraction, which becomes weaker with distance: the closer objects are to each other, the stronger their gravitational attraction.

Gravity on Earth and in the Universe

During the flight of the aircraft, people in it remain in place and can move as if on the ground. This happens because of the flight path. There are specially designed aircraft in which there is no gravity at a certain height, weightlessness is formed. The aircraft performs a special maneuver, the mass of objects changes, they briefly rise into the air. After a few seconds, the gravitational field is restored.

Considering the force of gravity in space, it is greater than most of the planets on the globe. It is enough to look at the movement of astronauts during landing on planets. If we walk calmly on the ground, then there the astronauts seem to soar in the air, but do not fly away into space. This means that this planet also has a gravitational force, just a little different than that of the planet Earth.

The force of attraction of the Sun is so great that it holds nine planets, numerous satellites, asteroids and planets.

Gravity plays a crucial role in the development of the universe. In the absence of gravity, there would be no stars, planets, asteroids, black holes, galaxies. Interestingly, black holes are not actually visible. Scientists determine the signs of a black hole by the degree of power of the gravitational field in a certain area. If it is very strong with the strongest vibration, this indicates the existence of a black hole.

Myth 1. There is no gravity in space

Watching documentaries about astronauts, it seems that they are hovering above the surface of the planets. This is due to the fact that gravity on other planets is lower than on Earth, so astronauts walk as if floating in the air.

Myth 2. All bodies approaching a black hole are torn apart.

Black holes have a powerful force and form powerful gravitational fields. The closer an object is to a black hole, the stronger the tidal forces and the power of attraction become. Further development of events depends on the mass of the object, the size of the black hole and the distance between them. A black hole has a mass directly opposite to its size. Interestingly, the larger the hole, the weaker the tidal forces and vice versa. In this way, not all objects are torn apart when they enter the field of a black hole.

Myth 3. Artificial satellites can orbit the Earth forever

Theoretically, one could say so, if it were not for the influence of secondary factors. Much depends on the orbit. In a low orbit, a satellite will not be able to fly forever due to atmospheric braking; in high orbits, it can remain in an unchanged state for quite a long time, but the gravitational forces of other objects come into force here.

If only the Earth existed of all the planets, the satellite would be attracted to it and practically not change the trajectory of movement. But in high orbits, the object is surrounded by many planets, large and small, each with its own gravity.

In this case, the satellite would gradually move away from its orbit and move randomly. And, it is likely that after some time, it would have crashed to the nearest surface or moved to another orbit.

Some facts

1. In some corners of the Earth, the force of gravity is weaker than on the entire planet. For example, in Canada, in the Hudson Bay region, gravity is lower.
2. When astronauts return from space to our planet, at the very beginning it is difficult for them to adapt to the gravitational force of the globe. Sometimes it takes several months.
3. Black holes have the most powerful gravitational force among space objects. One ball-sized black hole has more power than any planet.

Despite the ongoing study of the force of gravity, gravity remains undiscovered. This means that scientific knowledge remains limited and humanity has a lot to learn.

Since ancient times, mankind has thought about how the world around us works. Why does grass grow, why does the Sun shine, why can't we fly... The latter, by the way, has always been of particular interest to people. Now we know that the reason for everything is gravity. What it is, and why this phenomenon is so important on the scale of the Universe, we will consider today.

Introduction

Scientists have found that all massive bodies experience mutual attraction to each other. Subsequently, it turned out that this mysterious force also determines the movement of celestial bodies in their constant orbits. The very same theory of gravity was formulated by a genius whose hypotheses predetermined the development of physics for many centuries to come. Developed and continued (albeit in a completely different direction) this teaching was Albert Einstein - one of the greatest minds of the past century.

For centuries, scientists have observed gravity, trying to understand and measure it. Finally, in the last few decades, even such a phenomenon as gravity has been put at the service of mankind (in a certain sense, of course). What is it, what is the definition of the term in question in modern science?

scientific definition

If you study the works of ancient thinkers, you can find out that the Latin word "gravitas" means "gravity", "attraction". Today, scientists so call the universal and constant interaction between material bodies. If this force is relatively weak and acts only on objects that move much more slowly, then Newton's theory is applicable to them. If the opposite is the case, Einstein's conclusions should be used.

Let's make a reservation right away: at present, the very nature of gravity itself has not been fully studied in principle. What it is, we still do not fully understand.

Theories of Newton and Einstein

According to the classical teaching of Isaac Newton, all bodies are attracted to each other with a force that is directly proportional to their mass, inversely proportional to the square of the distance that lies between them. Einstein, on the other hand, argued that gravity between objects manifests itself in the case of curvature of space and time (and the curvature of space is possible only if there is matter in it).

This idea was very deep, but modern research proves it to be somewhat inaccurate. Today it is believed that gravity in space only bends space: time can be slowed down and even stopped, but the reality of changing the shape of temporary matter has not been theoretically confirmed. Therefore, the classical Einstein equation does not even provide for a chance that space will continue to influence matter and the emerging magnetic field.

To a greater extent, the law of gravity (universal gravitation) is known, the mathematical expression of which belongs precisely to Newton:

\[ F = γ \frac[-1.2](m_1 m_2)(r^2) \]

Under γ is understood the gravitational constant (sometimes the symbol G is used), the value of which is 6.67545 × 10−11 m³ / (kg s²).

Interaction between elementary particles

The incredible complexity of the space around us is largely due to the infinite number of elementary particles. There are also various interactions between them at levels that we can only guess at. However, all types of interaction of elementary particles among themselves differ significantly in their strength.

The most powerful of all the forces known to us bind together the components of the atomic nucleus. To separate them, you need to spend a truly colossal amount of energy. As for electrons, they are “tied” to the nucleus only by ordinary ones. To stop it, sometimes the energy that appears as a result of the most ordinary chemical reaction is enough. Gravity (what it is, you already know) in the variant of atoms and subatomic particles is the easiest kind of interaction.

The gravitational field in this case is so weak that it is difficult to imagine. Oddly enough, but it is they who “follow” the movement of celestial bodies, whose mass is sometimes impossible to imagine. All this is possible due to two features of gravity, which are especially pronounced in the case of large physical bodies:

• Unlike atomic ones, it is more noticeable at a distance from the object. So, the Earth's gravity keeps even the Moon in its field, and the similar force of Jupiter easily supports the orbits of several satellites at once, the mass of each of which is quite comparable to the Earth's!
• In addition, it always provides attraction between objects, and with distance this force weakens at a low speed.

The formation of a more or less coherent theory of gravitation occurred relatively recently, and precisely on the basis of the results of centuries-old observations of the motion of planets and other celestial bodies. The task was greatly facilitated by the fact that they all move in a vacuum, where there are simply no other possible interactions. Galileo and Kepler, two outstanding astronomers of the time, helped pave the way for new discoveries with their most valuable observations.

But only the great Isaac Newton was able to create the first theory of gravity and express it in a mathematical representation. This was the first law of gravity, the mathematical representation of which is presented above.

Conclusions of Newton and some of his predecessors

Unlike other physical phenomena that exist in the world around us, gravity manifests itself always and everywhere. You need to understand that the term "zero gravity", which is often found in pseudo-scientific circles, is extremely incorrect: even weightlessness in space does not mean that a person or a spacecraft is not affected by the attraction of some massive object.

In addition, all material bodies have a certain mass, expressed in the form of a force that was applied to them, and an acceleration obtained due to this impact.

Thus, gravitational forces are proportional to the mass of objects. Numerically, they can be expressed by obtaining the product of the masses of both considered bodies. This force strictly obeys the inverse dependence on the square of the distance between objects. All other interactions depend quite differently on the distances between two bodies.

Mass as the cornerstone of theory

The mass of objects has become a particular point of contention around which Einstein's entire modern theory of gravity and relativity is built. If you remember the Second, then you probably know that mass is a mandatory characteristic of any physical material body. It shows how an object will behave if force is applied to it, regardless of its origin.

Since all bodies (according to Newton) accelerate when an external force acts on them, it is the mass that determines how large this acceleration will be. Let's look at a clearer example. Imagine a scooter and a bus: if you apply exactly the same force to them, they will reach different speeds in different times. All this is explained by the theory of gravity.

What is the relationship between mass and attraction?

If we talk about gravity, then the mass in this phenomenon plays a role completely opposite to that which it plays in relation to the force and acceleration of an object. It is she who is the primary source of attraction itself. If you take two bodies and see with what force they attract a third object, which is located at equal distances from the first two, then the ratio of all forces will be equal to the ratio of the masses of the first two objects. Thus, the force of attraction is directly proportional to the mass of the body.

If we consider Newton's Third Law, we can see that he says exactly the same thing. The force of gravity, which acts on two bodies located at an equal distance from the source of attraction, directly depends on the mass of these objects. In everyday life, we talk about the force with which a body is attracted to the surface of the planet as its weight.

Let's sum up some results. So, mass is closely related to acceleration. At the same time, it is she who determines the force with which gravity will act on the body.

Features of acceleration of bodies in a gravitational field

This amazing duality is the reason why, in the same gravitational field, the acceleration of completely different objects will be equal. Suppose we have two bodies. Let's assign a mass z to one of them, and Z to the other. Both objects are dropped to the ground, where they fall freely.

How is the ratio of forces of attraction determined? It is shown by the simplest mathematical formula - z / Z. That's just the acceleration they receive as a result of the force of gravity, will be exactly the same. Simply put, the acceleration that a body has in a gravitational field does not depend in any way on its properties.

What does the acceleration depend on in the described case?

It depends only (!) on the mass of objects that create this field, as well as on their spatial position. The dual role of mass and the equal acceleration of various bodies in a gravitational field have been discovered for a relatively long time. These phenomena have received the following name: "Principle of equivalence". This term once again emphasizes that acceleration and inertia are often equivalent (to a certain extent, of course).

On the importance of G

From the school physics course, we remember that the acceleration of free fall on the surface of our planet (Earth's gravity) is 10 m / s² (9.8 of course, but this value is used for ease of calculation). Thus, if air resistance is not taken into account (at a significant height with a small fall distance), then the effect will be obtained when the body acquires an acceleration increment of 10 m / s. every second. Thus, a book that has fallen from the second floor of a house will move at a speed of 30-40 m/sec by the end of its flight. Simply put, 10 m/s is the "speed" of gravity within the Earth.

Acceleration due to gravity in the physical literature is denoted by the letter "g". Since the shape of the Earth is to a certain extent more like a tangerine than a sphere, the value of this quantity is far from being the same in all its regions. So, at the poles, the acceleration is higher, and on the tops of high mountains it becomes less.

Even in the mining industry, gravity plays an important role. The physics of this phenomenon sometimes saves a lot of time. Thus, geologists are especially interested in the ideally accurate determination of g, since this allows exploration and finding of mineral deposits with exceptional accuracy. By the way, what does the gravity formula look like, in which the value we have considered plays an important role? There she is:

Note! In this case, the gravitational formula means by G the "gravitational constant", the value of which we have already given above.

At one time, Newton formulated the above principles. He perfectly understood both unity and universality, but he could not describe all aspects of this phenomenon. This honor fell to Albert Einstein, who was also able to explain the principle of equivalence. It is to him that mankind owes a modern understanding of the very nature of the space-time continuum.

Theory of relativity, works of Albert Einstein

At the time of Isaac Newton, it was believed that reference points can be represented as some kind of rigid "rods", with the help of which the position of the body in the spatial coordinate system is established. At the same time, it was assumed that all observers who mark these coordinates would be in a single time space. In those years, this provision was considered so obvious that no attempts were made to challenge or supplement it. And this is understandable, because within our planet there are no deviations in this rule.

Einstein proved that the accuracy of the measurement would be really significant if the hypothetical clock was moving much slower than the speed of light. Simply put, if one observer, moving slower than the speed of light, follows two events, then they will happen for him at the same time. Accordingly, for the second observer? the speed of which is the same or more, events can occur at different times.

But how is the force of gravity related to the theory of relativity? Let's explore this issue in detail.

Relationship between relativity and gravitational forces

In recent years, a huge number of discoveries in the field of subatomic particles have been made. The conviction is growing stronger that we are about to find the final particle, beyond which our world cannot be divided. The more insistent is the need to find out exactly how the smallest “bricks” of our universe are affected by those fundamental forces that were discovered in the last century, or even earlier. It is especially disappointing that the very nature of gravity has not yet been explained.

That is why, after Einstein, who established the "incapacity" of Newton's classical mechanics in the area under consideration, researchers focused on a complete rethinking of the data obtained earlier. In many ways, gravity itself has undergone a revision. What is it at the level of subatomic particles? Does it have any meaning in this amazing multidimensional world?

A simple solution?

At first, many assumed that the discrepancy between Newton's gravity and the theory of relativity can be explained quite simply by drawing analogies from the field of electrodynamics. It could be assumed that the gravitational field propagates like a magnetic one, after which it can be declared a "mediator" in the interactions of celestial bodies, explaining many inconsistencies between the old and the new theory. The fact is that then the relative velocities of propagation of the forces under consideration would be much lower than the speed of light. So how are gravity and time related?

In principle, Einstein himself almost succeeded in constructing a relativistic theory based on just such views, only one circumstance prevented his intention. None of the scientists of that time had any information at all that could help determine the "speed" of gravity. But there was a lot of information related to the movements of large masses. As you know, they were just the generally recognized source of powerful gravitational fields.

High speeds strongly affect the masses of bodies, and this is not at all like the interaction of speed and charge. The higher the speed, the greater the mass of the body. The problem is that the last value would automatically become infinite in the case of movement at the speed of light or higher. Therefore, Einstein concluded that there is not a gravitational, but a tensor field, for the description of which many more variables should be used.

His followers came to the conclusion that gravity and time are practically unrelated. The fact is that this tensor field itself can act on space, but it is not able to influence time. However, the brilliant modern physicist Stephen Hawking has a different point of view. But that's a completely different story...

Even a person who is not interested in space has at least once seen a film about space travel or read about such things in books. In almost all such works, people walk around the ship, sleep normally, and do not experience problems with eating. This means that these - fictional - ships have artificial gravity. Most viewers perceive this as something completely natural, but this is not at all the case.

artificial gravity

This is the name of the change (in any direction) of gravity familiar to us by applying various methods. And this is done not only in fantastic works, but also in very real earthly situations, most often for experiments.

In theory, the creation of artificial gravity does not look so difficult. For example, it can be recreated with the help of inertia, more precisely, the need for this force did not arise yesterday - it happened immediately, as soon as a person began to dream of long-term space flights. The creation of artificial gravity in space will make it possible to avoid many problems that arise during prolonged stay in weightlessness. The astronauts' muscles weaken, the bones become less durable. Traveling in such conditions for months, you can get atrophy of some muscles.

Thus, today the creation of artificial gravity is a task of paramount importance, without this skill it is simply impossible.

materiel

Even those who know physics only at the level of the school curriculum understand that gravity is one of the fundamental laws of our world: all bodies interact with each other, experiencing mutual attraction / repulsion. The larger the body, the greater its force of attraction.

Earth for our reality is a very massive object. That is why, without exception, all the bodies around it are attracted to it.

For us, this means which is usually measured in g, equal to 9.8 meters per square second. This means that if we had no support under our feet, we would fall at a speed that increases by 9.8 meters every second.

Thus, only thanks to gravity we are able to stand, fall, eat and drink normally, understand where is up and down. If the attraction disappears, we will find ourselves in weightlessness.

Astronauts who find themselves in space in a state of soaring - free fall are especially familiar with this phenomenon.

In theory, scientists know how to create artificial gravity. There are several methods.

Big mass

The most logical option is to make it so large that artificial gravity arises on it. It will be possible to feel comfortable on the ship, since orientation in space will not be lost.

Unfortunately, this method with the modern development of technology is unrealistic. To build such an object requires too many resources. In addition, it will require an incredible amount of energy to lift it.

Acceleration

It would seem that if you want to achieve g equal to the earth's, you just need to give the ship a flat (platform) shape and make it move perpendicular to the plane with the desired acceleration. In this way, artificial gravity will be obtained, and - ideal.

However, in reality, everything is much more complicated.

First of all, it is worth considering the fuel issue. In order for the station to constantly accelerate, it is necessary to have an uninterruptible power supply. Even if an engine suddenly appears that does not eject matter, the law of conservation of energy will remain in force.

The second problem lies in the very idea of ​​constant acceleration. According to our knowledge and physical laws, it is impossible to accelerate to infinity.

In addition, such transport is not suitable for research missions, since it must constantly accelerate - fly. He will not be able to stop to study the planet, he will not even be able to slowly fly around it - he must accelerate.

Thus, it becomes clear that such artificial gravity is not yet available to us.

Carousel

Everyone knows how the rotation of the carousel affects the body. Therefore, an artificial gravity device according to this principle seems to be the most realistic.

Everything that is in the diameter of the carousel tends to fall out of it at a speed approximately equal to the speed of rotation. It turns out that a force acts on the body, directed along the radius of the rotating object. This is very similar to gravity.

So, a ship that has a cylindrical shape is required. At the same time, it must rotate around its axis. By the way, artificial gravity on a spaceship, created according to this principle, is often shown in science fiction films.

A barrel-shaped ship, rotating around the longitudinal axis, creates a centrifugal force, the direction of which corresponds to the radius of the object. To calculate the resulting acceleration, you need to divide the force by the mass.

In this formula, the result of the calculation is acceleration, the first variable is the nodal speed (measured in radians per second), the second is the radius.

According to this, in order to obtain the usual g, it is necessary to correctly combine the radius of space transport.

A similar problem is highlighted in films such as Intersolach, Babylon 5, 2001: A Space Odyssey and the like. In all these cases, artificial gravity is close to the terrestrial free fall acceleration.

No matter how good the idea is, it is quite difficult to implement it.

Problems of the carousel method

The most obvious problem is highlighted in A Space Odyssey. The radius of the "space carrier" is about 8 meters. In order to get an acceleration of 9.8, the rotation must occur at a rate of approximately 10.5 revolutions every minute.

With these values, the "Coriolis effect" is manifested, which consists in the fact that a different force acts at a different distance from the floor. It directly depends on the angular velocity.

It turns out that artificial gravity in space will be created, but too fast rotation of the case will lead to problems with the inner ear. This, in turn, causes imbalances, problems with the vestibular apparatus and other - similar - difficulties.

The emergence of this barrier suggests that such a model is extremely unsuccessful.

You can try to go from the opposite, as they did in the novel "The World-Ring". Here the ship is made in the form of a ring, the radius of which is close to the radius of our orbit (about 150 million km). At this size, its rotation speed is enough to ignore the Coriolis effect.

You may assume that the problem is solved, but it is not at all the case. The fact is that a complete rotation of this structure around its axis takes 9 days. This makes it possible to assume that the loads will be too large. In order for the structure to withstand them, a very strong material is needed, which we do not have at our disposal today. In addition, the problem is the amount of material and the construction process itself.

In games of a similar theme, as in the movie "Babylon 5", these problems are somehow solved: the rotation speed is quite sufficient, the Coriolis effect is not significant, it is hypothetically possible to create such a ship.

However, even such worlds have a drawback. It's called momentum.

The ship, rotating around its axis, turns into a huge gyroscope. As you know, it is extremely difficult to make the gyroscope deviate from the axis due to the fact that its quantity does not leave the system. This means that it will be very difficult to set the direction for this object. However, this problem can be solved.

Solution

Artificial gravity on a space station becomes available when the "O'Neill top hat" comes to the rescue. To create this design, identical cylindrical ships are needed, which are connected along the axis. They should rotate in different directions. The result of such an assembly is zero angular momentum, so there should be no difficulty in giving the ship the necessary direction.

If it is possible to make a ship with a radius of about 500 meters, then it will work exactly as it should. At the same time, artificial gravity in space will be quite comfortable and suitable for long flights on ships or research stations.

Space Engineers

How to create artificial gravity is known to the creators of the game. However, in this fantasy world, gravity is not the mutual attraction of bodies, but a linear force designed to accelerate objects in a given direction. The attraction here is not absolute, it changes when the source is redirected.

Artificial gravity on the space station is created by using a special generator. It is uniform and equidirectional in the area of ​​the generator. So, in the real world, if you get hit by a ship that has a generator installed, you would be pulled to the hull. However, in the game, the hero will fall until he leaves the perimeter of the device.

To date, artificial gravity in space, created by such a device, is inaccessible to mankind. However, even gray-haired developers do not stop dreaming about it.

Spherical generator

This is a more realistic version of the equipment. When installed, gravity has a direction towards the generator. This makes it possible to create a station, the gravity of which will be equal to the planetary one.

Centrifuge

Today, artificial gravity on Earth is found in various devices. They are based, for the most part, on inertia, since this force is felt by us similarly to gravitational influence - the body does not distinguish what causes acceleration. As an example: a person going up in an elevator experiences the effect of inertia. Through the eyes of a physicist: lifting an elevator adds to the acceleration of free fall the acceleration of the car. When the cabin returns to a measured movement, the “gain” in weight disappears, returning the usual sensations.

Scientists have long been interested in artificial gravity. The centrifuge is used for these purposes most often. This method is suitable not only for spacecraft, but also for ground stations in which it is required to study the effect of gravity on the human body.

Study on Earth, apply in…

Although the study of gravity began from space, it is a very earthly science. Even today, achievements in this area have found their application, for example, in medicine. Knowing whether it is possible to create artificial gravity on the planet, you can use it to treat problems with the motor apparatus or nervous system. Moreover, the study of this force is carried out primarily on Earth. This makes it possible for astronauts to conduct experiments while remaining under the close attention of doctors. Another thing is artificial gravity in space, there are no people there who can help astronauts in case of an unforeseen situation.

Bearing in mind complete weightlessness, one cannot take into account a satellite in near-Earth orbit. These objects, albeit to a small extent, are affected by gravity. The force of gravity generated in such cases is called microgravity. Real gravity is experienced only in an apparatus flying at a constant speed in outer space. However, the human body does not feel this difference.

You can experience weightlessness during a long jump (before the canopy opens) or during a parabolic descent of the aircraft. Such experiments are often done in the USA, but on an airplane this feeling lasts only 40 seconds - this is too short for a full-fledged study.

Back in 1973, the USSR knew whether it was possible to create artificial gravity. And not only created it, but also changed it in some way. A striking example of an artificial decrease in gravity is dry immersion, immersion. To achieve the desired effect, you need to put a dense film on the surface of the water. The person is placed on top of it. Under the weight of the body, the body sinks under water, only the head remains above. This model demonstrates the low gravity support that is characteristic of the ocean.

There is no need to go into space to feel the effect of the opposite force of weightlessness - hypergravity. During takeoff and landing of a spacecraft, in a centrifuge, overload can not only be felt, but also studied.

Gravity treatment

Gravitational physics studies, among other things, the impact of weightlessness on the human body, seeking to minimize the consequences. However, a large number of achievements of this science can be useful to ordinary inhabitants of the planet.

Physicians place great hopes on the study of the behavior of muscle enzymes in myopathy. This is a serious illness leading to early death.

With active physical exercises, a large amount of the enzyme creatinophosphokinase enters the blood of a healthy person. The reason for this phenomenon is unclear, perhaps the load acts on the cell membrane in such a way that it “perforates”. Patients with myopathy get the same effect without exercise. Observations of astronauts show that in weightlessness the flow of the active enzyme into the blood is significantly reduced. This discovery suggests that the use of immersion will reduce the negative impact of factors leading to myopathy. Animal experiments are currently underway.

The treatment of some diseases is already being carried out today using data obtained from the study of gravity, including artificial. For example, cerebral palsy, strokes, Parkinson's are treated by using load suits. The studies of the positive impact of the support - the pneumatic shoe - are practically completed.

Will we go to Mars?

The latest achievements of the astronauts give hope for the reality of the project. There is experience of medical support for a person during a long stay away from the Earth. Research flights to the Moon, on which the force of gravity is 6 times less than our own, have also brought a lot of benefits. Now astronauts and scientists are setting themselves a new goal - Mars.

Before you stand in line for a ticket to the Red Planet, you should know what the body expects already at the first stage of work - on the way. On average, the road to the desert planet will take a year and a half - about 500 days. On the way, you will have to rely only on your own strength, there is simply nowhere to wait for help.

Many factors will undermine strength: stress, radiation, lack of a magnetic field. The most important test for the body is the change in gravity. On the journey, a person will “get acquainted” with several levels of gravity. First of all, these are overloads during takeoff. Then - weightlessness during the flight. After that - hypogravity at the destination, because the gravity on Mars is less than 40% of the earth.

How do you cope with the negative impact of weightlessness on a long flight? It is hoped that developments in the field of creating artificial gravity will help solve this issue in the near future. Experiments on rats traveling on Kosmos-936 show that this technique does not solve all problems.

OS experience has shown that the use of training complexes capable of determining the necessary load for each astronaut individually can bring much more benefit to the body.

So far, it is believed that not only researchers will fly to Mars, but also tourists who want to establish a colony on the Red Planet. For them, at least at first, the sensations of being in weightlessness will outweigh all the arguments of doctors about the dangers of prolonged exposure to such conditions. However, in a few weeks they will also need help, which is why it is so important to be able to find a way to create artificial gravity on a spaceship.

Results

What conclusions can be drawn about the creation of artificial gravity in space?

Among all the options currently under consideration, the rotating structure looks the most realistic. However, with the current understanding of physical laws, this is impossible, since the ship is not a hollow cylinder. Inside it there are overlaps that interfere with the embodiment of ideas.

In addition, the radius of the ship must be so large that the Coriolis effect does not have a significant effect.

To control something like this, the O'Neill cylinder mentioned above is required, which will make it possible to control the ship. In this case, the chances of using a similar design for interplanetary flights with providing the team with a comfortable level of gravity increase.

Before humanity succeeds in making their dreams come true, I would like to see a little more realism and even more knowledge of the laws of physics in science fiction.

Every person in his life has come across this concept more than once, because gravity is the basis of not only modern physics, but also a number of other related sciences.

Many scientists have been studying the attraction of bodies since ancient times, but the main discovery is attributed to Newton and is described as a story known to everyone with a fruit that fell on his head.

What is gravity in simple words

Gravity is the attraction between several objects throughout the universe. The nature of the phenomenon is different, as it is determined by the mass of each of them and the length between, that is, the distance.

Newton's theory was based on the fact that both the falling fruit and the satellite of our planet are affected by the same force - attraction to the Earth. And the satellite did not fall on the earth space precisely because of its mass and distance.

Gravity field

The gravitational field is a space within which bodies interact according to the laws of attraction.

Einstein's theory of relativity describes the field as a certain property of time and space, which is characteristically manifested when physical objects appear.

gravity wave

This is a certain kind of change in the fields that are formed as a result of radiation from moving objects. They break away from the subject and propagate in a wave effect.

Theories of gravity

The classical theory is Newtonian. However, it was not perfect and alternative options subsequently appeared.

These include:

• metric theories;
• non-metric;
• vector;
• Le Sage, who first described the phases;
• quantum gravity.

Today, there are several dozen different theories, all of which either complement each other or consider phenomena from the other side.

It is worth noting: there is no perfect solution yet, but ongoing developments are opening up more answers regarding the attraction of bodies.

The force of gravitational attraction

The basic calculation is as follows - the force of gravity is proportional to the multiplication of body mass by another, between which it is determined. This formula is also expressed as follows: the force is inversely proportional to the distance between objects squared.

The gravitational field is potential, which means that kinetic energy is conserved. This fact simplifies the solution of problems in which the force of attraction is measured.

Gravity in space

Despite the delusion of many, there is gravity in space. It is lower than on Earth, but still present.

As for the astronauts, who at first glance fly, they are actually in a state of slow fall. Visually, it seems that they are not attracted by anything, but in practice they experience gravity.

The strength of attraction depends on the distance, but no matter how large the distance between objects, they will continue to reach for each other. Mutual attraction will never be equal to zero.

Gravity in the solar system

In the solar system, not only the Earth has gravity. The planets, as well as the Sun, attract objects towards them.

Since the force is determined by the mass of the object, the Sun has the highest value. For example, if our planet has an indicator equal to one, then the indicator of a luminary will be almost twenty-eight.

The next, after the Sun, in gravity is Jupiter, so its force of attraction is three times higher than that of the Earth. Pluto has the smallest parameter.

For clarity, let's denote it like this, in theory, on the Sun, an average person would weigh about two tons, but on the smallest planet in our system - only four kilograms.

What determines the gravity of the planet

Gravitational pull, as mentioned above, is the power with which the planet pulls objects located on its surface towards itself.

The force of attraction depends on the gravity of the object, the planet itself and the distance between them. If there are many kilometers, gravity is low, but it still keeps objects connected.

A few important and fascinating aspects related to gravity and its properties that are worth explaining to a child:

1. The phenomenon attracts everything, but never repels - this distinguishes it from other physical phenomena.
2. There is no zero indicator. It is impossible to simulate a situation in which pressure does not act, that is, gravity does not work.
3. The Earth is falling at an average speed of 11.2 kilometers per second, reaching this speed, you can leave the planet's attraction well.
4. The fact of the existence of gravitational waves has not been scientifically proven, this is just a guess. If ever they become visible, then many mysteries of the cosmos related to the interaction of bodies will be revealed to mankind.

According to the theory of basic relativity of a scientist like Einstein, gravity is a curvature of the basic parameters of the existence of the material world, which is the basis of the universe.

Gravity is the mutual attraction of two objects. The force of interaction depends on the gravity of the bodies and the distance between them. So far, not all the secrets of the phenomenon have been revealed, but today there are several dozen theories describing the concept and its properties.

The complexity of the studied objects affects the time of the study. In most cases, the dependence of mass and distance is simply taken.

Don DeYoung

Gravity (or gravity) keeps us firmly on the ground and allows the earth to revolve around the sun. Thanks to this invisible force, rain falls to the ground, and the water level in the ocean rises and falls every day. Gravity keeps the earth in a spherical shape and also keeps our atmosphere from escaping into space. It would seem that this force of attraction, observed every day, should be well studied by scientists. But no! In many ways, gravity remains the deepest mystery to science. This mysterious power is a wonderful example of how limited modern scientific knowledge is.

What is gravity?

Isaac Newton was interested in this issue back in 1686 and came to the conclusion that gravity is an attractive force that exists between all objects. He realized that the same force that causes the apple to fall to the ground is in its orbit. In fact, the force of gravity of the Earth causes the Moon to deviate from its straight path by about one millimeter every second during its rotation around the Earth (Figure 1). Newton's Universal Law of Gravity is one of the greatest scientific discoveries of all time.

Gravity is the "string" that keeps objects in orbit

Picture 1. An illustration of the moon's orbit not drawn to scale. In every second, the moon moves about 1 km. Over this distance, it deviates from the straight path by about 1 mm - this is due to the gravitational pull of the Earth (dashed line). The moon constantly seems to fall behind (or around) the earth, just as the planets around the sun also fall.

Gravity is one of the four fundamental forces of nature (Table 1). Note that of the four forces, this force is the weakest, and yet it is dominant relative to large space objects. As Newton showed, the attractive gravitational force between any two masses gets smaller and smaller as the distance between them gets larger and larger, but it never completely reaches zero (see The Design of Gravity).

Therefore, every particle in the entire universe actually attracts every other particle. Unlike the forces of the weak and strong nuclear forces, the force of attraction is long-range (Table 1). The magnetic force and the electrical interaction force are also long-range forces, but gravity is unique in that it is both long-range and always attractive, which means that it can never run out (unlike electromagnetism, in which forces can either attract or repel).

Beginning with the great creationist scientist Michael Faraday in 1849, physicists have constantly searched for the hidden connection between the force of gravity and the force of the electromagnetic force. Currently, scientists are trying to combine all four fundamental forces into one equation or the so-called "Theory of Everything", but, without success! Gravity remains the most mysterious and least understood force.

Gravity cannot be shielded in any way. Whatever the composition of the barrier, it has no effect on the attraction between two separated objects. This means that in the laboratory it is impossible to create an anti-gravity chamber. The force of gravity does not depend on the chemical composition of objects, but depends on their mass, known to us as weight (the force of gravity on an object is equal to the weight of that object - the greater the mass, the greater the force or weight.) Blocks made of glass, lead, ice, or even styrofoam, and having the same mass, will experience (and exert) the same gravitational force. These data were obtained during experiments, and scientists still do not know how they can be theoretically explained.

Design in Gravity

The force F between two masses m 1 and m 2 located at a distance r can be written as the formula F = (G m 1 m 2) / r 2

Where G is the gravitational constant, first measured by Henry Cavendish in 1798.1

This equation shows that gravity decreases as the distance, r, between two objects gets larger, but never fully reaches zero.

The inverse-square nature of this equation is simply breathtaking. After all, there is no necessary reason why gravity should act in this way. In a disordered, random, and evolving universe, arbitrary powers such as r 1.97 or r 2.3 would seem more likely. However, accurate measurements showed an exact power to at least five decimal places, 2.00000. As one researcher said, this result seems "too precise".2 We can conclude that the force of attraction indicates an accurate, created design. In fact, if the degree were to deviate even slightly from 2, the orbits of the planets and the entire universe would become unstable.

Links and notes

1. Technically speaking, G = 6.672 x 10 –11 Nm 2 kg –2
2. Thompsen, D., "Very accurate about gravity", science news 118(1):13, 1980.

So what exactly is gravity? How is this force able to act in such a vast, empty outer space? And why does it even exist? Science has never been able to answer these basic questions about the laws of nature. The force of attraction cannot come slowly through mutation or natural selection. It has been active since the very beginning of the existence of the universe. Like any other physical law, gravity is undoubtedly a wonderful evidence of a planned creation.

Some scientists have tried to explain gravity in terms of invisible particles, gravitons, that move between objects. Others talked about cosmic strings and gravitational waves. Recently, scientists with the help of a specially created laboratory LIGO (Eng. Laser Interferometer Gravitational-Wave Observatory) only managed to see the effect of gravitational waves. But the nature of these waves, how physically objects interact with each other at vast distances, changing their shape, still remains a big question for everyone. We simply do not know the nature of the origin of the force of gravity and how it holds the stability of the entire universe.

Gravity and Scripture

Two passages from the Bible can help us understand the nature of gravity and physical science in general. The first passage, Colossians 1:17, explains that Christ “There is first of all, and everything is worth it to Him”. The Greek verb stands (συνισταω sunistao) means: to cling to, to be kept or held together. The Greek use of this word outside of the Bible means vessel containing water. The word used in the book of Colossians is in the perfect tense, which usually indicates a present ongoing state that has arisen from a completed past action. One of the physical mechanisms used in question is obviously the force of attraction, established by the Creator and unmistakably maintained today. Just imagine: if the force of gravity ceased to act for a moment, chaos would undoubtedly ensue. All celestial bodies, including the earth, moon, and stars, would no longer be held together. All that hour would be divided into separate, small parts.

The second Scripture, Hebrews 1:3, declares that Christ "holds all things with the word of his power." Word keeps (φερω pherō) again describes the maintenance or conservation of everything, including gravity. Word keeps used in this verse means much more than just holding a weight. It includes control over all ongoing movements and changes within the universe. This endless task is carried out through the almighty Word of the Lord, through which the universe itself came into being. Gravity, the "mysterious force" that remains poorly understood even after four hundred years of research, is one of the manifestations of this amazing divine care for the universe.

Distortions of time and space and black holes

Einstein's general theory of relativity considers gravity not as a force, but as a curvature of space itself near a massive object. Light that traditionally follows straight lines is predicted to bend as it travels through curved space. This was first demonstrated when astronomer Sir Arthur Eddington discovered a change in the apparent position of a star during a total eclipse in 1919, believing that light rays were bent by the sun's gravity.

General relativity also predicts that if a body is dense enough, its gravity will warp space so badly that light can't pass through it at all. Such a body absorbs light and everything else that its strong gravity has captured, and is called a Black Hole. Such a body can only be detected by its gravitational effects on other objects, by the strong curvature of light around it, and by the strong radiation emitted by matter that falls on it.

All matter inside a black hole is compressed at the center, which has infinite density. The "size" of the hole is determined by the event horizon, i.e. a boundary that surrounds the center of a black hole, and nothing (not even light) can escape from it. The radius of the hole is called the Schwarzschild radius, after the German astronomer Karl Schwarzschild (1873–1916), and is calculated as R S = 2GM/c 2 , where c is the speed of light in a vacuum. If the sun were to fall into a black hole, its Schwarzschild radius would be only 3 km.

There is solid evidence that once the nuclear fuel of a massive star runs out, it can no longer resist collapsing under its own enormous weight and falls into a black hole. Black holes with a mass of billions of suns are believed to exist at the centers of galaxies, including our galaxy, the Milky Way. Many scientists believe that super-bright and very distant objects called quasars use the energy that is released when matter falls into a black hole.

According to the predictions of general relativity, gravity also distorts time. This has also been confirmed by very accurate atomic clocks, which run a few microseconds slower at sea level than in areas above sea level, where Earth's gravity is slightly weaker. Near the event horizon, this phenomenon is more noticeable. If we watch the clock of an astronaut who is approaching the event horizon, we will see that the clock is running slower. While in the event horizon, the clock will stop, but we will never be able to see it. Conversely, the astronaut will not notice that his clock is running slower, but he will see that our clock is running faster and faster.

The main danger to an astronaut near a black hole would be tidal forces, caused by gravity being stronger on parts of the body that are closer to the black hole than on parts further away from it. In terms of their power, the tidal forces near a black hole that has the mass of a star are stronger than any hurricane and easily tear into small pieces everything they come across. However, while gravitational attraction decreases with the square of distance (1/r 2), tidal activity decreases with the cube of distance (1/r 3). Therefore, contrary to popular belief, the gravitational force (including tidal force) is weaker on the event horizons of large black holes than on small black holes. So tidal forces at the event horizon of a black hole in observable space would be less noticeable than the gentlest breeze.

The dilation of time by gravity near the event horizon is the basis of the creationist physicist Dr. Russell Humphreys' new cosmological model, which he discusses in his book Starlight and Time. This model may help solve the problem of how we can see the light of distant stars in a young universe. In addition, today it is a scientific alternative to the non-biblical one, which is based on philosophical assumptions that go beyond the scope of science.

Note

Gravity, the "mysterious force" that, even after four hundred years of research, remains poorly understood...

Isaac Newton (1642–1727)

Photo: Wikipedia.org

Isaac Newton (1642–1727)

Isaac Newton published his discoveries about gravity and the motion of celestial bodies in 1687, in his famous work " Mathematical beginnings". Some readers quickly concluded that Newton's universe left no room for God, since everything can now be explained with equations. But Newton did not think so at all, as he said in the second edition of this famous work:

"Our most beautiful solar system, planets and comets can only be the result of the plan and domination of an intelligent and strong being."

Isaac Newton was not only a scientist. In addition to science, he devoted almost his entire life to the study of the Bible. His favorite Bible books were Daniel and Revelation, which describe God's plans for the future. In fact, Newton wrote more theological works than scientific ones.

Newton was respectful of other scientists such as Galileo Galilei. By the way, Newton was born in the same year that Galileo died, in 1642. Newton wrote in his letter: “If I saw further than others, it was because I stood on shoulders giants." Shortly before his death, probably reflecting on the mystery of gravity, Newton modestly wrote: “I don’t know how the world perceives me, but to myself I seem to be only a boy playing on the seashore, who amuses himself by looking for a pebble more colorful than others, or a beautiful shell, while a huge ocean of unexplored truth."

Newton is buried in Westminster Abbey. The Latin inscription on his tomb ends with the words: “Let mortals rejoice that such an ornament of the human race lived among them”.