I. Kepler spent his whole life trying to prove that our solar system is some kind of mystical art. Initially, he tried to prove that the structure of the system is similar to regular polyhedra from ancient Greek geometry. At the time of Kepler, six planets were known to exist. It was believed that they were placed in crystal spheres. According to the scientist, these spheres were located in such a way that polyhedrons of the correct form fit exactly between the neighboring spheres. Between Jupiter and Saturn there is a cube inscribed in the external environment in which the sphere is inscribed. Between Mars and Jupiter is a tetrahedron, and so on. After many years of observing celestial objects, Kepler's laws appeared, and he disproved his theory of polyhedra.
Laws
The geocentric Ptolemaic system of the world was replaced by the system of the heliocentrictype created by Copernicus. Still later, Kepler discovered the laws of motion of the planets around the Sun.
After many years of observations of the planets, Kepler's three laws appeared. Consider them in the article.
First
According to Kepler's first law, all the planets in our system move along a closed curve called an ellipse. Our luminary is located in one of the foci of the ellipse. There are two of them: these are two points inside the curve, the sum of the distances from which to any point of the ellipse is constant. After lengthy observations, the scientist was able to reveal that the orbits of all the planets in our system are located almost in the same plane. Some celestial bodies move in elliptical orbits close to a circle. And only Pluto and Mars move in more elongated orbits. Based on this, Kepler's first law was called the law of ellipses.
Second Law
Studying the movement of bodies allows the scientist to establish that the speed of the planet is greater during the period when it is closer to the Sun, and less when it is at its maximum distance from the Sun (these are the points of perihelion and aphelion).
Kepler's second law says the following: each planet moves in a plane passing through the center of our star. At the same time, the radius vector connecting the Sun and the planet under study describes equal areas.
Thus, it is clear that the bodies move around the yellow dwarf unevenly, and having a maximum speed at perihelion, and a minimum speed at aphelion. In practice, this can be seen from the movement of the Earth. Annually at the beginning of Januaryour planet, during the passage through perihelion, moves faster. Because of this, the movement of the Sun along the ecliptic is faster than at other times of the year. In early July, the Earth moves through aphelion, which causes the Sun to move more slowly along the ecliptic.
Third Law
According to Kepler's third law, a connection is established between the period of revolution of the planets around the star and its average distance from it. The scientist applied this law to all the planets of our system.
Explanation of laws
Kepler's laws could be explained only after Newton's discovery of the law of gravity. According to it, physical objects take part in gravitational interaction. It has universal universality, which affects all objects of the material type and physical fields. According to Newton, two stationary bodies act mutually with each other with a force proportional to the product of their weight and inversely proportional to the square of the gaps between them.
Indignant movement
The motion of the bodies of our solar system is controlled by the force of gravity of the yellow dwarf. If bodies were attracted only by the force of the Sun, then the planets would move around it exactly according to the laws of Kepler's motion. This type of movement is called unperturbed or Keplerian.
In fact, all objects of our system are attracted not only by our luminary, but also by each other. Therefore, none of the bodies can move exactly along an ellipse, a hyperbola, or a circle. If a body deviates from Kepler's laws during motion, then thisis called perturbation, and the motion itself is called perturbed. That is what is considered real.
Orbits of celestial bodies are not fixed ellipses. During attraction by other bodies, the orbit ellipse changes.
Contribution of I. Newton
Isaac Newton was able to deduce from Kepler's laws of planetary motion the law of universal gravitation. Newton used universal gravitation to solve cosmic-mechanical problems.
After Isaac, progress in the field of celestial mechanics was the development of the mathematical science used to solve the equations expressing Newton's laws. This scientist was able to establish that the gravity of the planet is determined by the distance to it and the mass, but such indicators as temperature and composition have no effect.
In his scientific work, Newton showed that the third Keplerian law is not entirely accurate. He showed that when calculating it is important to take into account the mass of the planet, since the movement and weight of the planets are related. This harmonic combination shows the relationship between Keplerian laws and Newton's law of gravity.
Astrodynamics
The application of the laws of Newton and Kepler became the basis for the emergence of astrodynamics. This is a branch of celestial mechanics that studies the movement of artificially created cosmic bodies, namely: satellites, interplanetary stations, and various ships.
Astrodynamics is engaged in calculations of the orbits of spacecraft, and also determines what parameters to launch, which orbit to launch, what maneuvers are needed,planning the gravitational effect on ships. And these are by no means all the practical tasks that are put before astrodynamics. All the results obtained are used in a wide variety of space missions.
Astrodynamics is closely related to celestial mechanics, which studies the movement of natural cosmic bodies under the influence of gravity.
Orbits
Under the orbit understand the trajectory of a point in a given space. In celestial mechanics, it is commonly believed that the trajectory of a body in the gravitational field of another body has a much larger mass. In a rectangular coordinate system, the trajectory may be in the form of a conic section, i.e. be represented by a parabola, ellipse, circle, hyperbola. In this case, the focus will coincide with the center of the system.
For a long time it was believed that orbits should be round. For quite a long time, scientists tried to choose exactly the circular version of the movement, but they did not succeed. And only Kepler was able to explain that the planets do not move in a circular orbit, but in an elongated one. This made it possible to discover three laws that could describe the movement of celestial bodies in orbit. Kepler discovered the following elements of the orbit: the shape of the orbit, its inclination, the position of the plane of the body's orbit in space, the size of the orbit, and the timing. All of these elements define an orbit, regardless of its shape. In calculations, the main coordinate plane can be the plane of the ecliptic, galaxy, planetary equator, etc.
Multiple studies show thatthe geometric shape of the orbit can be elliptical and rounded. There is a division into closed and open. According to the angle of inclination of the orbit to the plane of the earth's equator, orbits can be polar, inclined and equatorial.
According to the period of revolution around the body, orbits can be synchronous or sun-synchronous, synchronous-diurnal, quasi-synchronous.
As Kepler said, all bodies have a certain speed of movement, i.e. orbital speed. It can be constant throughout the entire circulation around the body or change.
