Planets of the Solar System: eight and one. Natural satellites of the planets of the solar system

Saturn's moons and rings Saturn's moons are the natural satellites of the planet Saturn. Saturn has 62 known natural satellites with a confirmed orbit, 53 of which have their own named ... Wikipedia

Bodies belonging to the solar system orbiting around a planet, and with it around the sun. Instead of S., the word moon is sometimes used in the common sense. Currently known 21 S. Near the ground 1; Mars has 2; Jupiter has 5; y... ... Encyclopedia of Brockhaus and Efron

This is what Venus would look like, according to the artist, if it had a satellite. Moons of Venus hypothetical celestial bodies natural origin, I draw... Wikipedia

Comparative sizes of the six most famous moons of Uranus. From left to right: Puck, Miranda, Ariel, Umbriel, Titania and Oberon. The moons of Uranus are the natural satellites of the planet Uranus. There are 27 known satellites. Sun... Wikipedia

Bodies belonging to the solar system orbiting around a planet, and with it around the Sun. Instead of S., the word moon is sometimes used in the common sense. Currently, 21 C is known. The Earth has 1; Mars has 2; Jupiter has 5; u... ... encyclopedic Dictionary F. Brockhaus and I.A. Ephron

Stability assessment problem solar system one of the oldest qualitative problems in celestial mechanics. Within the framework of Newton's theory of gravity, a system of two bodies is stable, but already in system of three movement of bodies is possible, leading, for example, to... ... Wikipedia

According to modern ideas, the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant interstellar molecular cloud. Most of the matter ended up in gravitational... Wikipedia

The table below provides a visual history of the discovery of the planets of the solar system and their moons. Historically, the names of some planets and their natural satellites do not always correspond to those assigned to them at the time of discovery. In the table... ... Wikipedia

The style of this article is non-encyclopedic or violates the norms of the Russian language. The article should be corrected according to Wikipedia's stylistic rules. See also: Colonization of the Solar System ... Wikipedia

Imaginary space station"Stanford Torus", view from the inside Satellites of the planets Colonization of the Solar System, a particular and most realistic area of ​​​​space colonization, is one of the topics of science fiction. However, it is believed that... ... Wikipedia

Books

• Lectures on the Solar System
• Lectures on the Solar System, S. A. Yazev. Tutorial, dedicated to the presentation of modern data about the objects that make up the Solar System, using information obtained using astronautics methods. Considered...
• Lectures on the Solar System: Textbook / Ed. V. G. Surdina. 2nd ed., rev. and additional , Yazev S.A.. A textbook dedicated to the presentation of modern data about the objects that make up the Solar System, using information obtained using astronautics methods. Considered...

The Earth is a satellite of the Sun in cosmic space, forever circling around this source of heat and light, which makes life on Earth possible. The brightest celestial objects we constantly observe, besides the Sun and Moon, are our neighboring planets. They belong to those nine worlds (including the Earth) that revolve around the Sun (and its radius is 700 thousand km, i.e. 100 times the radius of the Earth) at distances reaching several billion kilometers. A group of planets together with the Sun makes up the Solar System. Although the planets appear similar to stars, they are actually much smaller and darker. They are visible only because they reflect sunlight, which appear very bright because planets are much closer to Earth than stars. But if we moved our most powerful telescopes to the nearest star, then even with their help we would not be able to see these satellites of the Sun.

In addition to the planets, the solar “family” includes satellites of the planets (including our satellite, the Moon), asteroids, comets, meteoroids, and the solar wind. The planets are arranged in the following order: Mercury, Venus, Earth (one satellite - the Moon), Mars (two satellites - Phobos and Deimos), Jupiter (15 satellites), Saturn (16 satellites), Uranus (5 satellites), Neptune (2 satellites ) and Pluto (one satellite). The Earth is forty times closer to the Sun than Pluto and two and a half times farther than Mercury. It is possible that there are one or more planets beyond Pluto, but searching for them among the many stars weaker than 15th magnitude is too painstaking and does not justify the time spent on them. Perhaps they will be discovered “at the tip of the pen,” as has already been the case with Uranus, Neptune and Pluto. There should be planets around many other stars, but there is no direct observational data about them, and there are only some indirect indications.

Since 1962, planets and their satellites have been successfully studied by spacecraft. The atmospheres and surface of Venus and Mars were studied, the surface of Mercury, the cloud cover of Venus, Jupiter, Saturn, and the entire surface of the Moon were photographed, images of the satellites of Mars, Jupiter, Saturn, and the rings of Saturn and Jupiter were obtained. Descent spacecraft investigated physical and chemical rock properties, making up the surface of Mars, Venus, and the Moon (samples of lunar rocks were brought to Earth and carefully studied).

By physical characteristics planets are divided into two groups: planets earth type(Mercury, Venus, Earth, Mars); giant planets (Jupiter, Saturn, Uranus, Neptune). Little is known about Pluto, but it appears to be closer in structure to the terrestrial planets.

On March 13, 1781, English astronomer William Herschel discovered the seventh planet of the solar system - Uranus. And on March 13, 1930, American astronomer Clyde Tombaugh discovered the ninth planet of the solar system - Pluto. By the beginning of the 21st century, it was believed that the solar system included nine planets. However, in 2006, the International Astronomical Union decided to strip Pluto of this status.

There are already 60 known natural satellites of Saturn, most of which were discovered using spacecraft. Most of the satellites consist of rocks and ice. The largest satellite, Titan, discovered in 1655 by Christiaan Huygens, is larger than the planet Mercury. The diameter of Titan is about 5200 km. Titan orbits Saturn every 16 days. Titan is the only moon to have a very dense atmosphere, 1.5 times that of Earth, and consisting mainly of 90% nitrogen, with moderate methane content.

The International Astronomical Union officially recognized Pluto as a planet in May 1930. At that moment, it was assumed that its mass was comparable to the mass of the Earth, but later it was found that Pluto’s mass was almost 500 times less than the Earth’s, even less than the mass of the Moon. Pluto's mass is 1.2 x 10.22 kg (0.22 Earth's mass). Pluto's average distance from the Sun is 39.44 AU. (5.9 to 10 to 12 degrees km), radius is about 1.65 thousand km. The period of revolution around the Sun is 248.6 years, the period of rotation around its axis is 6.4 days. Pluto's composition is believed to include rock and ice; the planet has subtle atmosphere, consisting of nitrogen, methane and carbon monoxide. Pluto has three moons: Charon, Hydra and Nix.

At the end of XX and beginning of XXI centuries, many objects have been discovered in the outer solar system. It has become obvious that Pluto is only one of the largest Kuiper Belt objects known to date. Moreover, at least one of the belt objects - Eris - is a larger body than Pluto and is 27% heavier. In this regard, the idea arose to no longer consider Pluto as a planet. August 24, 2006 at XXVI General Assembly The International Astronomical Union (IAU) has decided to henceforth call Pluto not a “planet”, but a “ dwarf planet".

At the conference, a new definition of a planet was developed, according to which planets are considered bodies that revolve around a star (and are not themselves a star), have a hydrostatically equilibrium shape and have “cleared” the area in the area of ​​their orbit from other, smaller objects. Dwarf planets will be considered objects that orbit a star, have a hydrostatically equilibrium shape, but have not “cleared” the nearby space and are not satellites. Planets and dwarf planets are two different classes objects of the solar system. All other objects orbiting the Sun that are not satellites will be called small bodies of the Solar System.

Thus, since 2006, there have been eight planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. The International Astronomical Union officially recognizes five dwarf planets: Ceres, Pluto, Haumea, Makemake, and Eris.

On June 11, 2008, the IAU announced the introduction of the concept of "plutoid". It was decided to call celestial bodies revolving around the Sun in an orbit whose radius is greater than the radius of Neptune’s orbit, and whose mass is sufficient to gravitational forces gave them an almost spherical shape, and which do not clear the space around their orbit (that is, many small objects revolve around them).

Since it is still difficult to determine the shape and thus the relationship to the class of dwarf planets for such distant objects as plutoids, scientists recommended temporarily classifying all objects whose absolute asteroid magnitude (brilliance from a distance of one astronomical unit) is brighter than +1 as plutoids. If it later turns out that an object classified as a plutoid is not a dwarf planet, it will be deprived of this status, although the assigned name will be retained. The dwarf planets Pluto and Eris were classified as plutoids. In July 2008, Makemake was included in this category. On September 17, 2008, Haumea was added to the list.

The material was prepared based on information from open sources

Planets of the solar system - a little history

Previously, a planet was considered to be any body that orbits a star, glows with light reflected from it, and is larger than an asteroid.

Also in Ancient Greece mentioned seven luminous bodies that move across the sky against the background of fixed stars. These cosmic bodies were: the Sun, Mercury, Venus, Moon, Mars, Jupiter and Saturn. The earth was not included in this list, since the ancient Greeks considered the earth to be the center of all things.

And only in the 16th century Nicolaus Copernicus in his scientific work entitled "On Appeal" celestial spheres“came to the conclusion that it is not the Earth, but the Sun that should be at the center of the planetary system. Therefore, the Sun and Moon were removed from the list, and the Earth was added to it. And after the advent of telescopes, Uranus and Neptune were added, in 1781 and 1846, respectively.
Pluto was considered the last discovered planet in the solar system from 1930 until recently.

And now, almost 400 years after Galileo Galilei created the world's first telescope for observing stars, astronomers have come to the following definition of a planet.

Planet- This heavenly body, which must satisfy four conditions:
the body must revolve around a star (for example, around the Sun);
the body must have sufficient gravity to have a spherical or close to it shape;
the body should not have other large bodies near its orbit;
the body should not be a star.

In turn, the polar star is a cosmic body that emits light and is a powerful source of energy. This is explained, firstly, by the thermonuclear reactions occurring in it, and secondly, by the processes of gravitational compression, as a result of which a huge amount of energy is released.

Planets of the Solar System today

solar system is a planetary system that consists of a central star - the Sun - and all the natural space objects orbiting around it.

So, today the solar system consists of eight planets: four inner, so-called terrestrial planets, and four outer planets, called gas giants.
The terrestrial planets include Earth, Mercury, Venus and Mars. All of them consist mainly of silicates and metals.

The outer planets are Jupiter, Saturn, Uranus and Neptune. Gas giants are composed mainly of hydrogen and helium.

The sizes of the planets of the Solar System vary both within groups and between groups. Thus, gas giants are much larger and more massive than terrestrial planets.
Mercury is closest to the Sun, then as it moves away: Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

It would be wrong to consider the characteristics of the planets of the Solar System without paying attention to its main component: the Sun itself. Therefore, we will start with it.

The sun planet is the star that gave rise to all life in the solar system. Planets, dwarf planets and their satellites, asteroids, comets, meteorites and cosmic dust revolve around it.

The Sun arose about 5 billion years ago, is a spherical, hot plasma ball and has a mass that is more than 300 thousand times the mass of the Earth. The surface temperature is more than 5000 degrees Kelvin, and the core temperature is more than 13 million K.

The sun is one of the largest and most bright stars in our galaxy, which is called galaxy Milky Way. The Sun is located at a distance of about 26 thousand light years from the center of the Galaxy and makes a full revolution around it in about 230-250 million years! For comparison, the Earth makes a full revolution around the Sun in 1 year.

Mercury planet

Mercury is the smallest planet in the system, which is closest to the Sun. Mercury has no satellites.

The surface of the planet is covered with craters that arose about 3.5 billion years ago due to massive bombings meteorites. The diameter of the craters can range from a few meters to more than 1000 km.

The atmosphere of Mercury is very thin, consists mainly of helium and is inflated by the solar wind. Since the planet is located very close to the Sun and does not have an atmosphere that would retain heat at night, the surface temperature ranges from -180 to +440 degrees Celsius.

By earthly standards, Mercury completes a full revolution around the Sun in 88 days. But a Mercury day is equal to 176 Earth days.

Venus planet

Venus is the second planet closest to the Sun in the solar system. Venus is only slightly smaller in size than Earth, which is why it is sometimes called “Earth’s sister.” Has no satellites.

The atmosphere consists of carbon dioxide with admixtures of nitrogen and oxygen. The air pressure on the planet is more than 90 atmospheres, which is 35 times more than on Earth.

Carbon dioxide and, as a consequence, Greenhouse effect, dense atmosphere, as well as proximity to the Sun allow Venus to bear the title of “hottest planet.” The temperature on its surface can reach 460°C.

Venus is one of the brightest objects in the earth's sky after the Sun and Moon.

Planet Earth

Earth is the only planet known today in the Universe on which there is life. The earth has largest sizes, mass and density among the so-called inner planets Solar system.

The age of the Earth is about 4.5 billion years, and life appeared on the planet about 3.5 billion years ago. The Moon is a natural satellite, the largest of the satellites of the terrestrial planets.

The Earth's atmosphere is fundamentally different from the atmospheres of other planets due to the presence of life. Most of the atmosphere consists of nitrogen, but also includes oxygen, argon, carbon dioxide and water vapor. Ozone layer and the Earth's magnetic field, in turn, weaken the life-threatening influence of solar and cosmic radiation.

Due to the carbon dioxide contained in the atmosphere, the greenhouse effect also occurs on Earth. It is not as pronounced as on Venus, but without it the air temperature would be about 40°C lower. Without an atmosphere, temperature fluctuations would be very significant: according to scientists, from -100°C at night to +160°C during the day.

About 71% of the Earth's surface is occupied by the world's oceans, the remaining 29% are continents and islands.

Mars planet

Mars is the seventh largest planet in the solar system. "Red Planet", as it is also called due to the presence large quantities iron oxide in the soil. Mars has two satellites: Deimos and Phobos.
The atmosphere of Mars is very thin, and the distance to the Sun is almost one and a half times greater than that of the Earth. That's why average annual temperature on the planet is -60°C, and temperature changes in some places reach 40 degrees during the day.

Distinctive features of the surface of Mars are impact craters and volcanoes, valleys and deserts, and polar ice caps similar to those on Earth. Mars has the most high mountain in the solar system: the extinct volcano Olympus, whose height is 27 km! And also the largest canyon: Valles Marineris, whose depth reaches 11 km and length – 4500 km

Jupiter planet

Jupiter is the most big planet Solar system. It is 318 times heavier than the Earth, and almost 2.5 times more massive than all the planets in our system combined. In its composition, Jupiter resembles the Sun - it consists mainly of helium and hydrogen - and emits a huge amount of heat, equal to 4 * 1017 W. However, in order to become a star like the Sun, Jupiter must be 70-80 times heavier.

Jupiter has as many as 63 satellites, of which it makes sense to list only the largest - Callisto, Ganymede, Io and Europa. Ganymede is the largest moon in the solar system, even larger than Mercury.

Due to certain processes in the inner atmosphere of Jupiter, many vortex structures appear in its outer atmosphere, for example, stripes of clouds in brown-red shades, as well as the Great Red Spot, a giant storm known since the 17th century.

Saturn planet

Saturn is the second largest planet in the solar system. Business card Saturn is, of course, its ring system, which consists mainly of icy particles different sizes(from tenths of a millimeter to several meters), as well as rocks and dust.

Saturn has 62 moons, the largest of which are Titan and Enceladus.
In its composition, Saturn resembles Jupiter, but in density it is inferior even to ordinary water.
The planet's outer atmosphere appears calm and uniform, which is explained by a very dense layer of fog. However, wind speeds in some places can reach 1800 km/h.

Uranus planet

Uranus is the first planet discovered by telescope, and the only planet in the Solar System that orbits the Sun on its side.
Uranus has 27 moons, which are named after Shakespearean heroes. The largest of them are Oberon, Titania and Umbriel.

The composition of the planet differs from gas giants in the presence of a large number of high-temperature modifications of ice. Therefore, along with Neptune, scientists have classified Uranus as an “ice giant.” And if Venus has the title of “hottest planet” in the solar system, then Uranus is the most cold planet With minimum temperature about -224°C.

Neptune planet

Neptune is the most distant planet in the solar system from the center. The story of its discovery is interesting: before observing the planet through a telescope, scientists used mathematical calculations to calculate its position in the sky. This happened after the discovery of inexplicable changes in the movement of Uranus in its own orbit.

Today, 13 satellites of Neptune are known to science. The largest of them, Triton, is the only satellite that moves in the direction opposite to the rotation of the planet. The fastest winds in the solar system also blow against the rotation of the planet: their speed reaches 2200 km/h.

Neptune's composition is very similar to Uranus, therefore it is the second “ice giant”. However, like Jupiter and Saturn, Neptune has internal source heat and emits 2.5 times more energy than it receives from the Sun.
The blue color of the planet is given by traces of methane in the outer layers of the atmosphere.

Conclusion
Pluto, unfortunately, did not manage to get into our parade of planets in the solar system. But there is absolutely no need to worry about this, because all the planets remain in their places, despite changes in scientific views and concepts.

So, we answered the question how many planets are there in the solar system. There are only 8 .

Our solar system consists mainly of the Sun and eight planets. Of course, people are primarily fascinated by the Earth's neighbors - Mars, Jupiter, Saturn... However, the moons revolving around them are also quite interesting.

10. Ganymede is the largest satellite

At first glance, Ganymede is very similar to our Moon, but the sizes of both satellites are not comparable. Ganymede – largest satellite Jupiter, and the entire solar system. He even has his own magnetic poles – unique case for planetary satellites.

If Ganymede revolved around the Sun, it could be considered a full-fledged planet: the Jovian moon is 8% larger than Mercury and is 3/4 the size of Mars.

Ganymede

9. Miranda - the ugly duckling

The moons of Uranus are generally not particularly beautiful, but Miranda is truly an ugly duckling among them. It seems as if the creator of all the moons of the solar system finally molded together the remaining working day garbage and launched it into the orbit of Uranus in a lump.

However, if people ever manage to land on the moon on this satellite, their eyes will see sights unseen in space. Miranda has the most diverse landscape in the solar system: giant ranges alternate with deep plains, and many canyons are 12 times deeper than the famous Grand Canyon.

Miranda

8. Callisto – record holder for craters

Another Jovian moon, Callisto, most closely resembles the face of a pimply teenager. There is no geological activity on Callisto, which in itself makes it unique in the solar system, so craters resulting from meteorite impacts are constantly superimposed on each other.

It is very difficult to find an untouched corner of Callisto; the entire moon is covered in a network of craters, making it a record holder in the solar system.

Callisto (bottom and left), Jupiter (top and right) and Europa (below and left of the Great Red Spot)

7. Dactyl - asteroid satellite

Dactyl is the smallest moon in the solar system, measuring approximately 1.6 km in length. It is also one of the few moons orbiting small planets called asteroids.

IN Greek mythology Ida was the name of a mountain in which tiny creatures called dactyls (fingers) lived. Therefore, it is logical that the satellite of the asteroid Ida received such a name.

Asteroid Ida and its satellite Dactyl

6. Epimetheus and Janus - an eternal race

Epimetheus and Janus are two satellites of Saturn that move in almost identical orbits, probably because in time immemorial they formed a single whole. Moreover, every four years they change places, each time miraculously avoiding a collision.

Epimetheus and Janus

5. Ringbearer Enceladus

Enceladus is one of the large inner moons of Saturn. The surface of Enceladus reflects almost all the sunlight falling on it, so this Saturnian moon is considered the most reflective cosmic body in the solar system.

Enceladus also has geysers that emit water vapor and dust into the open space. Researchers believe that it was thanks to the volcanic activity of its satellite that Saturn acquired the E ring, through which the orbit of Enceladus passes.

E Ring and Enceladus

4. Triton - a satellite with ice volcanoes

Triton is Neptune's largest moon. It is also the only satellite in the solar system that orbits its planet in the opposite direction to its motion around the Sun.

Triton has many volcanoes, but unlike regular volcanoes that spew lava, the volcanoes on this Neptunian moon spew out water and ammonia, which immediately freeze in very cold outside temperatures.

Triton is a very bright celestial body because its icy surface reflects most of the sunlight.

Triton

3. Europe - ocean satellite

Europa is another satellite of Jupiter and has the smoothest surface in the solar system. The fact is that all of Europe is covered by an ocean with a thick crust of ice on the surface.

However, beneath the ice there is a gigantic amount of water, which is heated by the satellite's inner core and constant tidal currents caused by Jupiter's gravitational pull. Suffice it to say that the ocean of Europe contains 2-3 times more water than all the earth's oceans combined.

According to the calculations of some scientists, ocean waters Europe can have so much high temperature, that the appearance of life on this Jovian moon is not at all ruled out. Moreover, we're talking about not about bacteria, but about much more complex and large forms life.

Europe

2. Io is a volcanic hell

The constant tidal gravitational influence of the giant planet Jupiter causes regular heating of the interior of its moon Io, which in turn leads to ongoing volcanic activity.

The entire surface of Io is covered with volcanoes, and there are currently more than 400 active ones. Eruptions occur so frequently that the Voyager spacecraft flying close to the satellite was able to photograph some of them.

At the same time, it is almost impossible to see craters on Io - the erupting lava immediately fills them.

And about

1. Titan is the best candidate for colonization

Titan is perhaps the strangest moon in the solar system. It has long been known that it has an atmosphere, more dense than that of the earth. The titanium atmosphere is dominated by nitrogen, but there are also other gases, such as methane.

For a long time, it remained a mystery what was hidden under the thick titanium clouds. However, images taken from the Cassini-Huygens spacecraft in 2005 proved the presence of methane-ethane lakes and rivers.

Scientists also suggest the existence of underground reservoirs, which, coupled with low gravity, makes Titan the best candidate for terrestrial colonization of all the satellites in the solar system.

Titan's upper atmosphere and South Pole Saturn