The solar system moves in space. solar system

Universe (space)- this is the entire world around us, limitless in time and space and infinitely varied in the forms that eternally moving matter takes. The boundlessness of the Universe can be partially imagined on a clear night with billions of different sizes of luminous flickering points in the sky, representing distant worlds. Rays of light at a speed of 300,000 km/s from the most distant parts of the Universe reach the Earth in about 10 billion years.

According to scientists, the Universe was formed as a result of “ Big Bang» 17 billion years ago.

It consists of clusters of stars, planets, cosmic dust and other cosmic bodies. These bodies form systems: planets with satellites (for example. solar system), galaxies, metagalaxies (clusters of galaxies).

Galaxy(late Greek galaktikos- milky, milky, from Greek gala- milk) - extensive star system, which consists of many stars, star clusters and associations, gas and dust nebulae, as well as individual atoms and particles scattered in interstellar space.

There are many galaxies in the Universe various sizes and shapes.

All stars visible from Earth are part of the Milky Way galaxy. It got its name due to the fact that most stars can be seen on a clear night in the form of the Milky Way - a whitish, blurry stripe.

In total, the Milky Way Galaxy contains about 100 billion stars.

Our galaxy is in constant rotation. The speed of its movement in the Universe is 1.5 million km/h. If you look at our galaxy from its north pole, the rotation occurs clockwise. The Sun and the stars closest to it complete a revolution around the center of the galaxy every 200 million years. This period is considered to be galactic year.

Similar in size and shape to the Milky Way galaxy is the Andromeda Galaxy, or Andromeda Nebula, which is located at a distance of approximately 2 million light years from our galaxy. Light year- distance, passable by light per year, approximately equal to 10 13 km (the speed of light is 300,000 km/s).

To visualize the study of the movement and location of stars, planets and other celestial bodies, the concept of the celestial sphere is used.

Rice. 1. Main lines of the celestial sphere

Celestial sphere is an imaginary sphere of arbitrarily large radius, in the center of which the observer is located. The stars, Sun, Moon, and planets are projected onto the celestial sphere.

The most important lines on the celestial sphere are: the plumb line, zenith, nadir, celestial equator, ecliptic, celestial meridian, etc. (Fig. 1).

Plumb line- a straight line passing through the center of the celestial sphere and coinciding with the direction of the plumb line at the observation point. For an observer on the Earth's surface, a plumb line passes through the center of the Earth and the observation point.

A plumb line intersects the surface of the celestial sphere at two points - zenith, above the observer's head, and nadire - diametrically opposite point.

The great circle of the celestial sphere, the plane of which is perpendicular to the plumb line, is called mathematical horizon. It divides the surface of the celestial sphere into two halves: visible to the observer, with the vertex at the zenith, and invisible, with the vertex at the nadir.

The diameter around which the celestial sphere rotates is axis mundi. It intersects with the surface of the celestial sphere at two points - north pole of the world And south pole of the world. The north pole is the one from which the celestial sphere rotates clockwise when looking at the sphere from the outside.

The great circle of the celestial sphere, the plane of which is perpendicular to the axis of the world, is called celestial equator. It divides the surface of the celestial sphere into two hemispheres: northern, with its summit at the north celestial pole, and southern, with its peak at the south celestial pole.

The great circle of the celestial sphere, the plane of which passes through the plumb line and the axis of the world, is the celestial meridian. It divides the surface of the celestial sphere into two hemispheres - eastern And western.

The line of intersection of the plane of the celestial meridian and the plane of the mathematical horizon - noon line.

Ecliptic(from Greek ekieipsis- eclipse) is a large circle of the celestial sphere along which the visible annual movement of the Sun, or more precisely, its center, occurs.

The plane of the ecliptic is inclined to the plane of the celestial equator at an angle of 23°26"21".

To make it easier to remember the location of stars in the sky, people in ancient times came up with the idea of ​​combining the brightest of them into constellations.

Currently, 88 constellations are known, which bear the names of mythical characters (Hercules, Pegasus, etc.), zodiac signs (Taurus, Pisces, Cancer, etc.), objects (Libra, Lyra, etc.) (Fig. 2).

Rice. 2. Summer-autumn constellations

Origin of galaxies. The solar system and its individual planets still remain an unsolved mystery of nature. There are several hypotheses. It is currently believed that our galaxy was formed from a gas cloud consisting of hydrogen. On initial stage During the evolution of the galaxy, the first stars formed from the interstellar gas-dust medium, and 4.6 billion years ago - the Solar system.

Composition of the solar system

The set of celestial bodies moving around the Sun as a central body forms Solar system. It is located almost on the outskirts of the Milky Way galaxy. The solar system is involved in rotation around the center of the galaxy. The speed of its movement is about 220 km/s. This movement occurs in the direction of the constellation Cygnus.

The composition of the Solar System can be represented in the form of a simplified diagram shown in Fig. 3.

Over 99.9% of the mass of matter in the Solar System comes from the Sun and only 0.1% from all its other elements.

Rice. 3. Composition of the Solar System

Sun

Sun- this is a star, a giant hot ball. Its diameter is 109 times greater than the diameter of the Earth, its mass is 330,000 times greater than the mass of the Earth, but average density small - only 1.4 times the density of water. The Sun is located at a distance of about 26,000 light years from the center of our galaxy and revolves around it, making one revolution in about 225-250 million years. The orbital speed of the Sun is 217 km/s—so it travels one light year every 1,400 Earth years.

Rice. 4. Chemical composition of the Sun

The pressure on the Sun is 200 billion times higher than at the surface of the Earth. The density of solar matter and pressure quickly increase in depth; the increase in pressure is explained by the weight of all overlying layers. The temperature on the surface of the Sun is 6000 K, and inside it is 13,500,000 K. The characteristic lifetime of a star like the Sun is 10 billion years.

Table 1. General information about the sun

The chemical composition of the Sun is about the same as that of most other stars: about 75% hydrogen, 25% helium and less than 1% all others chemical elements(carbon, oxygen, nitrogen, etc.) (Fig. 4).

The central part of the Sun with a radius of approximately 150,000 km is called the solar core. This is the zone nuclear reactions. The density of the substance here is approximately 150 times higher than the density of water. The temperature exceeds 10 million K (on the Kelvin scale, in terms of degrees Celsius 1 °C = K - 273.1) (Fig. 5).

Above the core, at distances of about 0.2-0.7 solar radii from its center, is radiant energy transfer zone. Energy transfer here is carried out by absorption and emission of photons by individual layers of particles (see Fig. 5).

Rice. 5. Structure of the Sun

Photon(from Greek phos- light), elementary particle, capable of existing only by moving at the speed of light.

Closer to the surface of the Sun, vortex mixing of the plasma occurs, and energy is transferred to the surface

mainly by the movements of the substance itself. This method of energy transfer is called convection, and the layer of the Sun where it occurs is convective zone. The thickness of this layer is approximately 200,000 km.

Above the convective zone is the solar atmosphere, which constantly fluctuates. Both vertical and horizontal waves with lengths of several thousand kilometers propagate here. Oscillations occur with a period of about five minutes.

The inner layer of the Sun's atmosphere is called photosphere. It consists of light bubbles. This granules. Their sizes are small - 1000-2000 km, and the distance between them is 300-600 km. About a million granules can be observed on the Sun at the same time, each of which exists for several minutes. The granules are surrounded by dark spaces. If the substance rises in the granules, then around them it falls. The granules create a general background against which large-scale formations such as faculae, sunspots, prominences, etc. can be observed.

Sunspots- dark areas on the Sun, the temperature of which is lower than the surrounding space.

Solar torches called bright fields surrounding sunspots.

Prominences(from lat. protubero- swell) - dense condensation of relatively cold (compared to ambient temperature) substances that rise and are held above the surface of the Sun by a magnetic field. Towards the emergence magnetic field The sun may be driven by the fact that the different layers of the sun rotate with at different speeds: internal parts rotate faster; The core rotates especially quickly.

Prominences, sunspots and faculae are not the only examples of solar activity. It also includes magnetic storms and explosions, which are called flashes.

Above the photosphere is located chromosphere- the outer shell of the Sun. The origin of the name of this part of the solar atmosphere is associated with its reddish color. The thickness of the chromosphere is 10-15 thousand km, and the density of matter is hundreds of thousands of times less than in the photosphere. The temperature in the chromosphere is growing rapidly, reaching tens of thousands of degrees in its upper layers. At the edge of the chromosphere there are observed spicules, representing elongated columns of compacted luminous gas. The temperature of these jets is higher than the temperature of the photosphere. The spicules first rise from the lower chromosphere to 5000-10,000 km, and then fall back, where they fade. All this happens at a speed of about 20,000 m/s. Spi kula lives 5-10 minutes. The number of spicules existing on the Sun at the same time is about a million (Fig. 6).

Rice. 6. The structure of the outer layers of the Sun

Surrounds the chromosphere solar corona — outer layer atmosphere of the Sun.

The total amount of energy emitted by the Sun is 3.86. 1026 W, and only one two-billionth of this energy is received by the Earth.

Solar radiation includes corpuscular And electromagnetic radiation.Corpuscular fundamental radiation- this is a plasma flow that consists of protons and neutrons, or in other words - sunny wind, which reaches near-Earth space and flows around the entire magnetosphere of the Earth. Electromagnetic radiation- This is the radiant energy of the Sun. It reaches the earth's surface in the form of direct and diffuse radiation and provides the thermal regime on our planet.

In the middle of the 19th century. Swiss astronomer Rudolf Wolf(1816-1893) (Fig. 7) calculated quantitative indicator solar activity, known throughout the world as the Wolf number. Having processed the observations of sunspots accumulated by the middle of the last century, Wolf was able to establish the average I-year cycle of solar activity. In fact, the time intervals between years of maximum or minimum Wolf numbers range from 7 to 17 years. Simultaneously with the 11-year cycle, a secular, or more precisely 80-90-year, cycle of solar activity occurs. Uncoordinatedly superimposed on each other, they make noticeable changes in the processes taking place in the geographical shell of the Earth.

The close connection of many terrestrial phenomena with solar activity was pointed out back in 1936 by A.L. Chizhevsky (1897-1964) (Fig. 8), who wrote that the overwhelming majority of physical and chemical processes on Earth are the result of the influence of cosmic forces. He was also one of the founders of such science as heliobiology(from Greek helios- sun), studying the influence of the Sun on living matter geographic envelope Earth.

Depending on solar activity, such physical phenomena occur on Earth as: magnetic storms, frequency of auroras, amount of ultraviolet radiation, intensity of thunderstorm activity, air temperature, Atmosphere pressure, precipitation, level of lakes, rivers, groundwater, salinity and activity of the seas, etc.

The life of plants and animals is associated with the periodic activity of the Sun (there is a correlation between solar cyclicity and the period growing season in plants, reproduction and migration of birds, rodents, etc.), as well as humans (diseases).

Currently, the relationships between solar and terrestrial processes continue to be studied using artificial satellites Earth.

Terrestrial planets

In addition to the Sun, planets are distinguished as part of the Solar System (Fig. 9).

By size, geographical indicators and chemical composition planets are divided into two groups: planets terrestrial group And giant planets. The terrestrial planets include, and. They will be discussed in this subsection.

Rice. 9. Planets of the Solar System

Earth- the third planet from the Sun. A separate subsection will be devoted to it.

Let's summarize. The density of the planet’s substance, and taking into account its size, its mass, depends on the location of the planet in the solar system. How
closer planet towards the Sun, the higher its average density of matter. For example, for Mercury it is 5.42 g/cm\ Venus - 5.25, Earth - 5.25, Mars - 3.97 g/cm3.

The general characteristics of the terrestrial planets (Mercury, Venus, Earth, Mars) are primarily: 1) relatively small sizes; 2) high temperatures on the surface and 3) high density substances of planets. These planets rotate relatively slowly on their axis and have few or no satellites. In the structure of the terrestrial planets, there are four main shells: 1) a dense core; 2) the mantle covering it; 3) bark; 4) light gas-water shell (excluding Mercury). Traces of tectonic activity were found on the surface of these planets.

Giant planets

Now let's get acquainted with the giant planets, which are also part of our solar system. This , .

Giant planets have the following general characteristics: 1) large size and weight; 2) rotate quickly around an axis; 3) have rings and many satellites; 4) the atmosphere consists mainly of hydrogen and helium; 5) in the center they have a hot core of metals and silicates.

They are also distinguished by: 1) low temperatures on a surface; 2) low density of planetary matter.

You sit, stand or lie reading this article and do not feel that the Earth is spinning on its axis at a breakneck speed - approximately 1,700 km/h at the equator. However, the rotation speed does not seem that fast when converted to km/s. The result is 0.5 km/s - a barely noticeable blip on the radar, compared to other speeds around us.

Just like other planets in the solar system, the Earth revolves around the Sun. And in order to stay in its orbit, it moves at a speed of 30 km/s. Venus and Mercury, which are closer to the Sun, move faster, Mars, whose orbit passes behind the Earth’s orbit, moves much slower.

But even the Sun does not stand in one place. Our Milky Way galaxy is huge, massive and also mobile! All stars, planets, gas clouds, dust particles, black holes, dark matter- all this moves relative general center wt.

According to scientists, the Sun is located at a distance of 25,000 light years from the center of our galaxy and moves in an elliptical orbit, making a full revolution every 220–250 million years. It turns out that the speed of the Sun is about 200–220 km/s, which is hundreds of times higher than the speed of the Earth around its axis and tens of times higher than the speed of its movement around the Sun. This is what the movement of our solar system looks like.

Is the galaxy stationary? Not again. Giant space objects have a large mass, and therefore create strong gravitational fields. Give the Universe some time (and we've had it for about 13.8 billion years), and everything will start moving in the direction of greatest gravity. That is why the Universe is not homogeneous, but consists of galaxies and groups of galaxies.

What does this mean for us?

This means that the Milky Way is pulled towards it by other galaxies and groups of galaxies located nearby. This means that massive objects dominate the process. And this means that not only our galaxy, but also everyone around us is influenced by these “tractors”. We are getting closer to understanding what is happening to us in outer space, but we are still missing facts, for example:

• what were the initial conditions under which the Universe began;
• how the different masses in the galaxy move and change over time;
• how the Milky Way and surrounding galaxies and clusters were formed;
• and how it is happening now.

However, there is a trick that will help us figure it out.

The Universe is filled with cosmic microwave background radiation with a temperature of 2.725 K, which has been preserved since the Big Bang. Here and there there are tiny deviations - about 100 μK, but the overall temperature background is constant.

This is because the universe was formed by the Big Bang 13.8 billion years ago and is still expanding and cooling.

380,000 years after the Big Bang, the Universe cooled to such a temperature that the formation of hydrogen atoms became possible. Before this, photons constantly interacted with other plasma particles: they collided with them and exchanged energy. As the Universe cooled, there were fewer charged particles and more space between them. Photons were able to move freely in space. CMB radiation is photons that were emitted by the plasma towards the future location of the Earth, but escaped scattering because recombination had already begun. They reach the Earth through the space of the Universe, which continues to expand.

You can “see” this radiation yourself. The noise that occurs on a blank TV channel if you use simple antenna, similar to hare's ears, are 1% caused by cosmic microwave background radiation.

Still, the temperature of the relict background is not the same in all directions. According to the results of research by the Planck mission, the temperature differs slightly in the opposite hemispheres of the celestial sphere: it is slightly higher in parts of the sky south of the ecliptic - about 2.728 K, and lower in the other half - about 2.722 K.

This difference is almost 100 times larger than other observed temperature variations in the CMB, and is misleading. Why is this happening? The answer is obvious - this difference is not due to fluctuations in the cosmic microwave background radiation, it appears because there is movement!

When you approach a light source or it approaches you, the spectral lines in the source's spectrum shift towards short waves (violet shift), when you move away from it or it moves away from you, the spectral lines shift towards long waves (red shift).

CMB radiation cannot be more or less energetic, which means we are moving through space. The Doppler effect helps determine that our Solar System is moving relative to the CMB at a speed of 368 ± 2 km/s, and the local group of galaxies, including the Milky Way, the Andromeda Galaxy and the Triangulum Galaxy, is moving at a speed of 627 ± 22 km/s relative to the CMB. These are the so-called peculiar velocities of galaxies, which amount to several hundred km/s. In addition to them, there are also cosmological velocities due to the expansion of the Universe and calculated according to Hubble’s law.

Thanks to residual radiation from the Big Bang, we can observe that everything in the Universe is constantly moving and changing. And our galaxy is only part of this process.

This is a system of planets, at the center of which is bright Star, source of energy, heat and light - the Sun.
According to one theory, the Sun was formed along with the solar system about 4.5 billion years ago as a result of the explosion of one or more supernovas. Initially, the Solar System was a cloud of gas and dust particles, which, in motion and under the influence of their mass, formed a disk in which a new star, the Sun, and our entire Solar System arose.

At the center of the solar system is the Sun, around which nine large planets revolve in orbit. Since the Sun is displaced from the center of planetary orbits, during the cycle of revolution around the Sun the planets either approach or move away in their orbits.

There are two groups of planets:

Terrestrial planets: And . These planets small size With a rocky surface, they are closest to the Sun.

Giant planets: And . These are large planets, consisting mainly of gas and characterized by the presence of rings consisting of icy dust and many rocky pieces.

And here does not fall into any group, because, despite its location in the Solar System, it is located too far from the Sun and has a very small diameter, only 2320 km, which is half the diameter of Mercury.

Planets of the Solar System

Let's begin a fascinating acquaintance with the planets of the Solar System in order of their location from the Sun, and also consider their main satellites and some other space objects (comets, asteroids, meteorites) in the gigantic expanses of our planetary system.

Rings and moons of Jupiter: Europa, Io, Ganymede, Callisto and others...
The planet Jupiter is surrounded by a whole family of 16 satellites, and each of them has its own unique features...

Rings and moons of Saturn: Titan, Enceladus and others...
Not only the planet Saturn has characteristic rings, but also other giant planets. Around Saturn, the rings are especially clearly visible, because they consist of billions of small particles that revolve around the planet, in addition to several rings, Saturn has 18 satellites, one of which is Titan, its diameter is 5000 km, which makes it the largest satellite in the solar system...

Rings and moons of Uranus: Titania, Oberon and others...
The planet Uranus has 17 satellites and, like other giant planets, there are thin rings surrounding the planet that have practically no ability to reflect light, so they were discovered not so long ago in 1977, completely by accident...

Rings and moons of Neptune: Triton, Nereid and others...
Initially, before the exploration of Neptune by the Voyager 2 spacecraft, two satellites of the planet were known - Triton and Nerida. Interesting fact that the Triton satellite has the opposite direction of orbital motion; strange volcanoes were also discovered on the satellite that erupted nitrogen gas, like geysers, spreading a dark-colored mass (from liquid state into steam) many kilometers into the atmosphere. During its mission, Voyager 2 discovered six more moons of the planet Neptune...

An important role in the formation of ideas about the structure of the solar system was also played by the laws of planetary motion, which were discovered by Johannes Kepler (1571-1630) and became the first natural science laws in their modern understanding. Kepler's work created the opportunity to generalize the knowledge of mechanics of that era in the form of the laws of dynamics and the law universal gravity, formulated later by Isaac Newton. Many scientists up to early XVII V. believed that the movement of celestial bodies should be uniform and occur along the “most perfect” curve - a circle. Only Kepler managed to overcome this prejudice and establish the actual shape of planetary orbits, as well as the pattern of changes in the speed of movement of planets as they revolve around the Sun. In his searches, Kepler proceeded from the belief that “number rules the world,” expressed by Pythagoras. He looked for the relationship between different quantities characterizing the movement of planets - the size of the orbits, the period of revolution, speed. Kepler acted virtually blindly, purely empirically. He tried to compare the characteristics of the movement of the planets with the patterns of the musical scale, the length of the sides of the polygons described and inscribed in the orbits of the planets, etc. Kepler needed to construct the orbits of the planets, move from the equatorial coordinate system, indicating the position of the planet on the celestial sphere, to a coordinate system, indicating its position in the orbital plane. He used his own observations of the planet Mars, as well as many years of determinations of the coordinates and configurations of this planet carried out by his teacher Tycho Brahe. Kepler considered the Earth's orbit (to a first approximation) to be a circle, which did not contradict observations. In order to construct the orbit of Mars, he used the method shown in the figure below.

Let us know the angular distance of Mars from the point of the vernal equinox during one of the planet's oppositions - its right ascension "15 which is expressed by the angle g(gamma)Т1М1, where T1 is the position of the Earth in orbit at this moment, and M1 is the position of Mars. Obviously, after 687 days (this is the sidereal period of Mars’ orbit), the planet will arrive at the same point in its orbit.

If we determine the right ascension of Mars on this date, then, as can be seen from the figure, we can indicate the position of the planet in space, more precisely, in the plane of its orbit. The Earth at this moment is at point T2, and, therefore, the angle gT2M1 is nothing more than the right ascension of Mars - a2. By repeating similar operations for several other Mars oppositions, Kepler obtained another whole line points and, drawing a smooth curve along them, constructed the orbit of this planet. Having studied the location of the obtained points, he discovered that the speed of the planet’s orbit changes, but at the same time the radius vector of the planet describes in equal intervals equal areas. Subsequently, this pattern was called Kepler's second law.

The radius vector is called in this case a segment of variable size connecting the Sun and the point in the orbit in which the planet is located. AA1, BB1 and CC1 are the arcs that the planet traverses in equal periods of time. The areas of the shaded figures are equal to each other. According to the law of conservation of energy, the total mechanical energy closed system bodies between which gravitational forces act remains unchanged for any movements of the bodies of this system. Therefore, the sum of kinetic and potential energy of a planet that moves around the Sun is constant at all points in its orbit and is equal to its total energy. As a planet approaches the Sun, its speed increases, kinetic energy, but due to the decrease in distance to the Sun, the potential energy decreases. Having established the pattern of changes in the speed of motion of the planets, Kepler set out to determine the curve along which they revolve around the Sun. He was faced with the need to choose one of two possible solutions: 1) assume that the orbit of Mars is a circle, and assume that in some parts of the orbit the calculated coordinates of the planet diverge from observations (due to observation errors) by 8"; 2) assume that the observations do not contain such errors, and the orbit is not a circle, confident in the accuracy of Tycho Brahe's observations, Kepler chose the second solution and found that the best way The position of Mars in its orbit coincides with a curve called an ellipse, while the Sun is not located at the center of the ellipse. As a result, a law was formulated, which is called Kepler's first law. Each planet revolves around the Sun in an ellipse, with the Sun at one focus.

As is known, an ellipse is a curve in which the sum of the distances from any point P to its foci is a constant value. The figure shows: O - center of the ellipse; S and S1 are the foci of the ellipse; AB is its major axis. Half of this value (a), which is usually called the semimajor axis, characterizes the size of the planet’s orbit. Point A closest to the Sun is called perihelion, and point B farthest from it is called aphelion. The difference between an ellipse and a circle is characterized by the magnitude of its eccentricity: e = OS/OA. In the case when the eccentricity is equal to O, the foci and the center merge into one point - the ellipse turns into a circle.

It is noteworthy that the book in which Kepler published the first two laws he discovered in 1609 was called “New Astronomy, or Physics of the Heavens, Set forth in the Investigations of the Motion of the Planet Mars...”. Both of these laws, published in 1609, reveal the nature of the motion of each planet separately, which did not satisfy Kepler. He continued his search for “harmony” in the movement of all planets, and 10 years later he managed to formulate Kepler’s third law:

T1^2 / T2^2 = a1^3 / a2^3

The squares of the sidereal periods of revolution of the planets are related to each other, like the cubes of the semimajor axes of their orbits. This is what Kepler wrote after the discovery of this law: “What 16 years ago I decided to look for,<... >finally found, and this discovery exceeded all my wildest expectations...” Indeed, the third law deserves the highest praise. After all, it allows you to calculate the relative distances of the planets from the Sun, using the already known periods of their revolution around the Sun. There is no need to determine the distance from the Sun for each of them; it is enough to measure the distance from the Sun of at least one planet. The magnitude of the semi-major axis of the earth's orbit - the astronomical unit (AU) - became the basis for calculating all other distances in the solar system. Soon the law of universal gravitation was discovered. All bodies in the Universe are attracted to each other with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them:

F = G m1m2/r2

Where m1 and m2 are the masses of bodies; r is the distance between them; G - gravitational constant

The discovery of the law of universal gravitation was greatly facilitated by the laws of planetary motion formulated by Kepler and other achievements of astronomy in the 17th century. Thus, knowledge of the distance to the Moon allowed Isaac Newton (1643 - 1727) to prove the identity of the force that holds the Moon as it moves around the Earth and the force that causes bodies to fall to the Earth. After all, if the force of gravity varies in inverse proportion to the square of the distance, as follows from the law of universal gravitation, then the Moon, located from the Earth at a distance of approximately 60 of its radii, should experience an acceleration 3600 times less than the acceleration of gravity on the Earth's surface, equal to 9. 8 m/s. Therefore, the acceleration of the Moon should be 0.0027 m/s2.

The force that holds the Moon in orbit is the force of gravity, weakened by 3600 times compared to that acting on the surface of the Earth. You can also be convinced that when the planets move, in accordance with Kepler’s third law, their acceleration and the gravitational force of the Sun acting on them are inversely proportional to the square of the distance, as follows from the law of universal gravitation. Indeed, according to Kepler’s third law, the ratio of the cubes of the semi-major axes of the orbits d and the squares of the orbital periods T is a constant value: The acceleration of the planet is equal to:

A= u2/d =(2pid/T)2/d=4pi2d/T2

From Kepler's third law it follows:

Therefore, the acceleration of the planet is equal to:

A = 4pi2 const/d2

So, the force of interaction between the planets and the Sun satisfies the law of universal gravitation and there are disturbances in the movement of the bodies of the Solar System. Kepler's laws are strictly satisfied if the motion of two isolated bodies (the Sun and the planet) under the influence of their mutual attraction is considered. However, there are many planets in the Solar System; they all interact not only with the Sun, but also with each other. Therefore, the motion of planets and other bodies does not exactly obey Kepler's laws. Deviations of bodies from moving along ellipses are called perturbations. These disturbances are small, since the mass of the Sun is much greater than the mass of not only an individual planet, but also all planets as a whole. The greatest disturbances in the movement of bodies in the solar system are caused by Jupiter, whose mass is 300 times greater than the mass of the Earth.

The deviations of asteroids and comets are especially noticeable when they pass near Jupiter. Currently, disturbances are taken into account when calculating the positions of planets, their satellites and other bodies of the Solar System, as well as trajectories spacecraft, launched for their research. But back in the 19th century. calculation of disturbances made it possible to make one of the most famous discoveries in science “at the tip of a pen” - the discovery of the planet Neptune. Conducting another survey of the sky in search of unknown objects, William Herschel in 1781 discovered a planet, later named Uranus. After about half a century, it became obvious that the observed motion of Uranus does not agree with the calculated one, even when taking into account disturbances from all known planets. Based on the assumption of the presence of another “subauranian” planet, calculations were made of its orbit and position in the sky. This problem was solved independently by John Adams in England and Urbain Le Verrier in France. Based on Le Verrier's calculations, the German astronomer Johann Halle on September 23, 1846 discovered a previously unknown planet - Neptune - in the constellation Aquarius. This discovery became the triumph of the heliocentric system, the most important confirmation of the validity of the law of universal gravitation. Subsequently, disturbances were noticed in the movement of Uranus and Neptune, which became the basis for the assumption of the existence of another planet in the solar system. Her search was crowned with success only in 1930, when, after viewing large quantity photographs of the starry sky, Pluto was discovered.

Since ancient times, humanity has been interested in the visible movements of celestial bodies: the Sun, Moon and stars. It's hard to imagine Our own solar system seems too big, stretching more than 4 trillion miles from the Sun. Meanwhile, the Sun is only one hundredth of a billion of the other stars that make up the Milky Way galaxy.

Milky Way

The galaxy itself is a huge wheel that rotates, made of gas, dust and more than 200 billion stars. Between them lie trillions of miles of empty space. The sun is anchored on the outskirts of the galaxy, shaped like a spiral: from above, the Milky Way looks like a huge rotating hurricane of stars. Compared to the size of the galaxy, the Solar System is extremely small. If we imagine that the Milky Way is the size of Europa, then the solar system will be no larger in size than a walnut.

solar system

The Sun and its 9 satellite planets are scattered in one direction from the center of the galaxy. Just as planets revolve around their stars, stars also revolve around galaxies.

It will take the Sun about 200 million years at a speed of 588,000 miles per hour to complete a revolution around this galactic carousel. Our Sun is no different from other stars in anything special, except that it has a satellite, a planet called Earth, inhabited by life. Planets and smaller celestial bodies called asteroids revolve around the Sun in their orbits.

First observations of luminaries

Man observes the visible movements of celestial bodies and cosmic phenomena for at least 10,000 years. For the first time, records in the chronicles about celestial bodies appeared in ancient Egypt and Sumer. The Egyptians were able to distinguish three types of bodies in the sky: stars, planets, and “stars with tails.” At the same time, celestial bodies were discovered: Saturn, Jupiter, Mars, Venus, Mercury and, of course, the Sun and Moon. The visible movements of celestial bodies are the movement of these objects perceived from the Earth relative to the coordinate system, regardless of daily rotation. Real movement is their movement in outer space, determined by the forces acting on these bodies.

Visible galaxies

Looking into the night sky, you can see our closest neighbor - - in the form of a spiral. The Milky Way, despite its size, is just one of 100 billion galaxies in space. Without using a telescope, you can see three galaxies and part of ours. Two of them are called the Large and Small Magellanic Clouds. They were first seen in southern waters in 1519 by the expedition of the Portuguese explorer Magellan. These small galaxies orbit around milky way, therefore, are our closest cosmic neighbors.

The third galaxy visible from Earth, Andromeda, is approximately 2 million light years away from us. This means that starlight from Andromeda takes millions of years to get closer to our Earth. Thus, we contemplate this galaxy as it was 2 million years ago.

In addition to these three galaxies, you can see part of the Milky Way at night, represented by many stars. According to the ancient Greeks, this group of stars is milk from the breast of the goddess Hera, hence the name.

Visible planets from Earth

Planets are celestial bodies orbiting the Sun. When we observe Venus glowing in the sky, this is because it is illuminated by the Sun and reflects part of sunlight. Venus is the Evening Star or Morning Star. People call it differently because it is in different places in the evening and in the morning.

How the planet Venus revolves around the Sun and changes its location. Throughout the day, visible movement of celestial bodies occurs. The celestial coordinate system not only helps to understand the location of the luminaries, but also allows you to compile star maps, navigate in the night sky by constellations and study the behavior of celestial objects.

Laws of planetary motion

By combining observations and theories about the movement of celestial bodies, people have deduced the patterns of our galaxy. Scientists' discoveries have helped decipher the visible movements of celestial bodies. discovered were among the first astronomical laws.

The German mathematician and astronomer became the pioneer of this topic. Kepler, having studied the work of Copernicus, calculated the most better shape, which explains the visible movements of celestial bodies - the ellipse, and brought to light the patterns of planetary movement known in scientific world like Kepler's laws. Two of them characterize the movement of the planet in orbit. They read:

Any planet rotates in an ellipse. The Sun is present in one of its focuses.

Each of them moves in a plane passing through the middle of the Sun, while over the same periods the radius vector between the Sun and the planet outlines equal areas.

The third law connects the orbital data of planets within a system.

Lower and upper planets

Studying the visible movements of celestial bodies, physics divides them into two groups: the lower ones, which include Venus, Mercury, and the upper ones - Saturn, Mars, Jupiter, Neptune, Uranus and Pluto. The movement of these celestial bodies in the sphere occurs in different ways. In the process of the observed movement of the lower planets, they experience a change of phases like the Moon. When moving the upper planets, you can notice that they do not change phases; they are constantly facing people with their bright side.

The Earth, along with Mercury, Venus and Mars, belongs to the group of so-called inner planets. They revolve around the Sun in internal orbits, unlike the large planets, which revolve in external orbits. For example, Mercury, which is 20 times smaller in its innermost orbit.

Comets and meteorites

In addition to the planets, spinning around the Sun are billions of ice blocks consisting of frozen solid gas, small stones and dust - comets that fill the Solar System. The visible movements of celestial bodies, represented by comets, can only be seen when they approach the Sun. Then their tail begins to burn and glows in the sky.

The most famous of them is Halley's comet. Every 76 years it leaves its orbit and approaches the Sun. At this time it can be observed from Earth. Even in the night sky, you can contemplate meteorites in the form of flying stars - these are clumps of matter that move throughout the Universe at enormous speed. When they fall into the Earth's gravitational field, they almost always burn up. Due to extreme speed and friction with air envelope Earth's meteorites become hot and break up into small particles. The process of their combustion can be observed in the night sky in the form of a luminous ribbon.

The astronomy curriculum describes the apparent movements of celestial bodies. 11th grade is already familiar with the patterns according to which the complex movement of planets occurs, the change lunar phases and the laws of eclipses.