The planets of the solar system in order. Planet Earth, Jupiter, Mars

Many of you, hearing the word "planet", imagine a massive spherical object such as Jupiter or Saturn. However, this term has a much deeper definition, which has changed more than once over time. Its latest revision, and to this day remains controversial, was adopted in 2006 at a meeting of the International Astronomical Union (IAU) after the discovery of several worlds on the outskirts of the solar system.

It sounds like this: a planet is an object that revolves around the Sun, has sufficient mass to be round or almost round, is not a satellite of any other object, and has cleared its orbit from similar cosmic bodies.

The eight planets of the solar system and Pluto. Credit: NASA

At the same time, the IAU approved a new classification of celestial bodies - "". Such objects meet all the criteria of the planet with the exception of one, they were unable to clear the vicinity of their orbit from "debris". The introduction of new definitions meant that Pluto, then considered the ninth planet in the solar system, was demoted and reclassified as a dwarf planet.

Pluto. Credit: NASA / JHUAPL / SwRI / Seán Doran

But not all scientists agreed with the demotion of Pluto, especially after NASA's New Horizons spacecraft visited its system in 2015. The mission revealed that it is a complex world, full of geological features, including mountains reaching 3500 meters in height, a methane "heart" and a strange icy one. Since then, members of the New Horizons team have claimed that Pluto is a planet, trying to convince the public of this and return it to "solid" status.

History of the planets

The term "planet" comes from the Greek word for "wanderer". Many ancient cultures observed these "moving stars", but it wasn't until the advent of telescopes in the 1600s that astronomers were able to see them in detail. Then people first learned about the moons of Jupiter, the rings of Saturn, etc.

Telescopes have also revealed the existence of objects that were unknown in antiquity because they are too distant or too small to be seen with the naked eye. Uranus was discovered on March 13, 1781 by the English astronomer William Herschel, and on January 1, 1801, the Italian astronomer Giuseppe Piazzi first observed Ceres, which was originally assigned to the planets, but later migrated to the asteroid camp. Then, in 1846, Neptune was discovered.

It was with this instrument that Giuseppe Piazzi first saw Ceres. Credits: NASA / JPL-Caltech / Palermo Observatory

Astronomers continued to "plow" the outer edges of the solar system, which they believed was affecting the orbits of Uranus and Neptune. And although these fluctuations were later dispelled by further observations, in 1930 they led to the discovery by the American astronomer Clyde Tombaugh of an object later named Pluto and assigned to the planets.

Discovering more worlds

There was a lull and for a long time not a single celestial body close in size to Pluto was found, but everything changed in the 2000s when Michael Brown, a young astronomer from the California Institute of Technology (USA), began searching for objects as part of his research project in the outer solar system.

In a short time, he and his team discovered several large ice bodies outside the orbit of Neptune. By that time, their discovery had not come as a surprise, since the existence of the Oort Cloud, which is home to trillions of comets, had already been proposed. However, the size of the "trans-Neptunian objects" found by Michael Brown made other astronomers pay attention to them.

The dwarf planet Eris with the satellite Dysnomia as seen by the artist. Credit: ESO.

Among the most famous discoveries of the American astronomer: Kwavar, Sedna, Haumea, Eris and her satellite Dysnomia as well. All of them were discovered in a relatively short period from 2001 to 2005. Eris, which was originally nicknamed "Xena", turned out to be large enough, and many publications then rushed to call it the 10th planet of the solar system.

Voting and consequences

For two years after a series of discoveries, the IAU studied the evidence and in 2006 organized the XXVI Assembly in Prague (Czech Republic), which voted for a new definition of the planet. As a result, the representatives of the delegations lowered Pluto, Eris and other objects close to them in size.

The dwarf planet Ceres (the largest and most massive body in the Main Asteroid Belt) through the eyes of NASA's Dawn spacecraft. Credit: NASA, JPL-Caltech, UCLA, MPS, DLR, IDA

According to a newer definition, a dwarf planet is an object that revolves around the sun, is round or roughly circular, but smaller than Mercury. Today, only five worlds are officially recognized as dwarf planets: Pluto, Eris, Makemake and Haumea.

There are many other celestial bodies that may one day add to this list. Among them are Kwavar, Sedna, Orcus and Salazia. But this requires additional observations to clarify their dimensions. In addition, according to some astronomers, up to 200 dwarf planets can exist in the Kuiper belt.

A ring around the dwarf planet Haumea as seen by the artist. Credit: IAA-CSIC

However, years after the vote, there are still scientists who attribute Pluto to the planets. For example, in early 2014, NASA published a video in which several speakers at the Science Conference dedicated to it repeatedly referred to it as a "planet." NASA's Alan Stern regularly makes his case for why Pluto should be promoted, citing inaccuracies in the IAU's definition and that some planets will never be able to clear their orbit.

Planet Neptune used to be a hypothetical planet - its existence was predicted, but no one saw it. In fact, at various times, scientists have proposed other hypothetical planets. Some of them have been excluded, while others may have actually existed in the past. Perhaps they still exist.

In the early 1800s, astronomers knew every major planet in our solar system except Neptune. They also knew Newton's laws of motion and gravity, which could be used to predict the motion of planets. These predictions were compared with their actual recorded movement. But bad luck - Uranus did not go on the predicted course. French astronomer Alexis Bouvard suggested that Uranus was being knocked off course by an invisible planet with gravity.

After Neptune was found in 1846, many astronomers decided to test whether its gravity was sufficient to explain the observed motion of Uranus. But it wasn't enough. Well, there was another invisible planet? The ninth planet was proposed by a lot of astronomers. The most persistent seeker of this very ninth planet was the American astronomer Percival Lowell, who called it "Planet X".

Lowell built an observatory to find planet X, but never found it. Fourteen years after Lowell's death, an astronomer at his observatory discovered Pluto, but it was not enough to explain the movement of Uranus, so people continued to search for planet X. They did not stop after the Voyager 2 probe passed Neptune in 1989 year. Then astronomers learned that they incorrectly measure the mass of Neptune. And the updated formula for calculating the mass of Neptune explained the motion of Uranus.

Planet between Mars and Jupiter

In the 16th century, Johannes Kepler noticed a large gap between the orbits of Mars and Jupiter. He suggested that there might be a planet, but he did not particularly look for it. After Kepler, many astronomers noticed a pattern in the orbits of the planets. The relative sizes of the orbits, from Mercury to Saturn, are approximately 4, 7, 10, 16, 52 and 100. If you subtract 4 from each number, you get 0, 3, 6, 12, 48, 96. Note that 6 is two times 3, 12 is twice 6, and 96 is twice 48. But there is a strange factor between 12 and 48.

Astronomers began to wonder if the planet had disappeared between 12 and 48, somewhere around 24 - that is, between Mars and Jupiter. As the German astronomer Johann Elert Bode wrote, “beyond Mars there is empty space at 4 + 24 \u003d 28 segments, where the planet was not yet visible. Would anyone believe that the creator of the universe left this space empty? Of course not". When Uranus was discovered in 1781, its orbit matched the pattern described above. It fit into the law of nature, called Boldé's law or Titius-Bode's law, but the gap between Mars and Jupiter remained.

Hungarian astronomer Baron Franz von Zak was also convinced that Bode's law worked and that there should be a planet between Mars and Jupiter. For several years he searched for her and did not find her. In 1800, he organized several astronomers to conduct a systematic search. One of those astronomers was the Italian Catholic priest Giuseppe Piazzi, who spotted the object in the correct orbit in 1801.

The object, which was named Ceres, was too small for a planet. Ceres was considered an asteroid for a long time, although it was the largest of them in the main asteroid belt. For about half a century it was considered a planet. Today it is classified as a dwarf planet like Pluto. By the way, Bode's law was nevertheless dropped when it was discovered that the orbit of Neptune did not match the pattern.

Thea

Thea is the name of a hypothetical Mars-sized planet that may have collided with Earth 4.4 billion years ago, breaking apart on impact to form the Moon. English geochemist Alex Holliday is credited with proposing the name of Thea, one of the Titanid sisters from ancient Greek mythology who gave birth to the moon goddess Selena.

It should be noted that the origin and formation of the Moon is still the subject of active scientific research. While Thea's model, known as the giant collision hypothesis, leads the way, it is far from the only one. Perhaps the moon was captured by the gravitational pull of the earth. Perhaps the Earth and the Moon formed at the same time as a couple. Maybe something else. It is also worth noting that the young Earth suffered from many large bodies, and Thea is just one such body that could have led to the formation of the moon.

Volcano

Uranus was not the only planet whose observed motion was at odds with forecasts. Another planet with this problem was Mercury. The discrepancy was first noticed by the French mathematician Urbain le Verrier, who noted that at the lowest point of the elliptical orbit of Mercury (at perihelion), the planet moves around the Sun faster than calculations show. The discrepancy was small, but additional observations of Mercury confirmed the fact of its existence. He hypothesized that the divergence was caused by an undiscovered planet orbiting within the orbit of Mercury, which he named Vulcan.

And the observations and searches of Vulcan began. Some sunspots were mistaken for a new planet, other observations by better-known astronomers seemed more plausible. When le Verrier died in 1877, he believed that the existence of Vulcan was or would be confirmed. But in 1915 Einstein's general theory of relativity emerged, which accurately predicted the motion of Mercury. The planet Vulcan was no longer needed, but people continued to search for it. Of course, there is nothing the size of a planet inside the orbit of Mercury, but there could be asteroid-like objects, the so-called "volcanoids".

Phaeton

German astronomer and physicist Heinrich Olbers discovered the second known asteroid Pallas in 1802. He suggested that the two asteroids could be fragments of an ancient medium-sized planet that was destroyed by internal forces or as a result of a collision with a comet. It was suggested that in addition to Ceres and Pallas, there must have been other objects, and two more were soon discovered - Juno in 1804 and Vesta in 1807.

The planet that allegedly disintegrated and formed the main asteroid belt became known as Phaethon after a character in Greek mythology. Phaethon's hypothesis also had problems. For example, the sum of the masses of all asteroids in the main belt is much less than the mass of the planet. Also, asteroids are very different from each other, so how could they have descended from the same ancestor? Today, most planetary scientists believe that asteroids were formed by the gradual clumping of smaller fragments.

Planet V is the name of another hypothetical planet between Mars and Jupiter, but the reasons it might have existed are somewhat different. The story began with apollo missions to the moon... Apollo brought many moon rocks to Earth, some of which were formed by melting rocks. This process occurs when an asteroid hits the moon and generates enough heat to melt the rock. Scientists used radiometric dating to estimate when these stones cooled down, and were quite surprised - they were between 3.8 and 4 billion years old.

Apparently, during this time, many asteroids or comets fell on the Moon, especially during the so-called "late heavy bombardment". It was "late" because it happened later than the rest of the bombings. Major collisions have occurred throughout the early solar system, but those times are long gone. Hence the question: what happened that temporarily increased the number of asteroids falling on the moon?

About 10 years ago, John Chambers and Jack J. Lissot suggested that a long-lost planet, the so-called planet V. Scientists hypothesized that the orbit of planet V lay between the orbits of Mars and the main asteroid belt until the gravity of the inner planets brought planet V too close to the asteroid belt and they simply did not attack it. The planet, in turn, sent them to the moon. She herself went to the Sun and fell on it. The hypothesis met with a wave of criticism - not everyone agreed that there was a big late bombardment, and if there was, there are other explanations without the need for the existence of planet V.

The fifth gas giant

One of the other explanations for the late heavy bombing is the so-called Nice model, named after the French city in which it was developed. According to Nice's model, Saturn, Uranus, and Neptune - the outer gas giants - began in small orbits surrounded by a cloud of asteroid-like objects. Over time, some of these small objects passed close to the gas giants. These close encounters led to the expansion of the orbits of the gas giants, albeit very slowly. Jupiter's orbit has become slightly smaller in general. At some point, the orbits of Jupiter and Saturn entered into resonance, as a result of which Jupiter began to circle the Sun twice, while Saturn orbits it once. This caused chaos.

It all happened very quickly, within the solar system. The nearly circular orbits of Jupiter and Saturn have tensed, and Saturn, Uranus and Neptune have had several "close encounters." The cloud of small objects quivered and a late heavy bombardment began. Once she calmed down, the orbits of Jupiter, Saturn, Uranus and Neptune were almost the same as they are now.

Nice's model also predicted other features of the current solar system, such as Jupiter's Trojan asteroids, but it did not explain everything. She needed improvement. It was proposed to add a fifth gas giant. Simulations showed that the event that triggered the late heavy bombardment also pushed the gas giant out of the solar system. And this kind of modeling leads to the current appearance of the solar system, so the idea is far from stupid.

The cause of the Kuiper belt

The Kuiper Belt is a donut-shaped cloud of small icy objects orbiting beyond Neptune. Pluto and its moons were the only known Kuiper belt objects for a long time, until in 1992 David Jewitt and Jane Lu announced the discovery of another object in the Kuiper belt.

Since then, astronomers have identified over 1,000 other objects, and the list is constantly growing. Almost all of them are within 48 astronomical units (a.u. is the distance from the Sun to the Earth), which surprised astronomers, who expected to find more objects outside this circle. The fact is that the gravity of Neptune should have cleaned out a number of such objects that were previously closer, but distant objects should have remained independent of Neptune from the early days of the solar system.

An unexpected scattering of objects within 48 AU. That is, it became known as the "Kuiper belt", and no one knows why this happened. Various groups of scientists have suggested that the Kuiper belt was generated by an invisible planet. Patrick Lykavka and Tadashi Mukai revised all these theories and developed their own. Their planet could have spawned the Kuiper belt and many other observable features of the Kuiper belt. Unfortunately, it should be within 100 amu. That is, and this is very far away, so we will not find it soon,.

Cause of Sedna-type orbits

Mike Brown, Chad Trujillo, and David Rabinowitz identified Sedna in 2003. It is a distant object with a very strange orbit around the sun when compared to other objects in the solar system. The closest point to the Sun, in which Sedna was, is at a distance of 76 AU. That is, much further than the Kuiper belt. The orbit of Sedna is completed in 11,400 years.

How did Sedna get into such an orbit? It never approaches the Sun enough to be affected by any of the eight planets. Brown and his colleagues wrote that the orbit of Sedna "could be the result of embarrassment by a planet that has not yet been discovered, the disturbance of an abnormally close encounter with a star, or the formation of the solar system in a cluster of stars." To everyone's surprise, in March 2014, astronomers discovered a second object in a similar orbit, now known as 2012 VP113. This find revived gossip about the possibility of the existence of an invisible planet.

Tyche

A comet's period is the time it takes a comet to go around the sun once. Comets with a long period make it at least 200 years, and possibly longer. Long-period comets come from distant clouds of icy bodies known as Oort clouds, which lie well beyond the Kuiper belt.

In theory, long-period comets should come in equal numbers from all directions. In reality, comets come from one side more often than the other. Why? In 1999, John Matese, Patrick Whitman, and Daniel Whitmire suggested that a large, distant object called Tyche might be the cause. Tyche's mass, according to scientists, should be three masses of Jupiter. The distance to the Sun is about 25,000 AU. e.

However, the WISE space telescope recently surveyed the entire sky and provided Matese with disappointing results. On March 7, 2014, NASA reported that WISE “is larger than Jupiter at around 26,000 AU. e. " Apparently, the planet Tyche does not exist.

Space has attracted people's attention for a long time. Astronomers began to study the planets of the solar system in the Middle Ages, examining them in primitive telescopes. But a thorough classification, description of the structural features and movement of celestial bodies became possible only in the 20th century. With the advent of powerful equipment, observatories and spacecraft equipped with the latest technology, several previously unknown objects were discovered. Now each student can list all the planets of the solar system in order. Almost all of them were descended by a space probe, and so far man has only been to the moon.

What is the Solar System

The universe is huge and includes many galaxies. Our solar system is part of a galaxy with over 100 billion stars. But there are very few of them that look like the Sun. Basically, they are all red dwarfs, which are smaller in size than him and shine less brightly. Scientists have suggested that the solar system was formed after the emergence of the sun. Its huge gravitational field was captured by a gas-dust cloud, from which, as a result of gradual cooling, particles of solid matter were formed. Over time, heavenly bodies were formed from them. It is believed that the Sun is now in the middle of its life path, so it will exist, as well as all the celestial bodies dependent on it, for several more billion years. Astronomers have studied the near space for a long time, and anyone knows what planets in the solar system exist. Photos of them taken from space satellites can be found on the pages of all kinds of information resources dedicated to this topic. All celestial bodies are held by the strong gravitational field of the Sun, which makes up more than 99% of the volume of the solar system. Large celestial bodies rotate around the star and around its axis in one direction and in one plane, which is called the plane of the ecliptic.

The planets of the solar system in order

In modern astronomy, it is customary to consider celestial bodies starting from the Sun. In the 20th century, a classification was created, which includes 9 planets of the solar system. But the latest space exploration and the latest discoveries have pushed scientists to revise many positions in astronomy. And in 2006 at the international congress, due to its small size (a dwarf not exceeding three thousand km in diameter), Pluto was excluded from the number of classical planets, and there were eight of them. Now the structure of our solar system has taken on a symmetrical, slender appearance. It includes four terrestrial planets: Mercury, Venus, Earth and Mars, then comes the asteroid belt, followed by four giant planets: Jupiter, Saturn, Uranus and Neptune. On the outskirts of the solar system also passes which scientists called the Kuiper belt. It is in it that Pluto is located. These places are still poorly understood due to their remoteness from the Sun.

Features of the terrestrial planets

What allows these celestial bodies to be attributed to one group? Let's list the main characteristics of the inner planets:

• relatively small size;
• hard surface, high density and similar composition (oxygen, silicon, aluminum, iron, magnesium and other heavy elements);
• presence of atmosphere;
• the same structure: a core of iron with nickel impurities, a mantle consisting of silicates, and a crust of silicate rocks (except for Mercury, it has no crust);
• a small number of satellites - only 3 for four planets;
• rather weak magnetic field.

Features of the giant planets

As for the outer planets, or gas giants, they have the following similar characteristics:

• large sizes and masses;
• they do not have a solid surface and consist of gases, mainly helium and hydrogen (therefore they are also called gas giants);
• liquid core, consisting of metallic hydrogen;
• high rotation speed;
• a strong magnetic field, which explains the unusualness of many processes taking place on them;
• there are 98 satellites in this group, most of which belong to Jupiter;
• the most characteristic feature of gas giants is the presence of rings. All four planets have them, however, they are not always noticeable.

The first planet in a row - Mercury

It is located closest to the Sun. Therefore, from its surface, the star looks three times larger than from the Earth. This also explains the strong temperature drops: from -180 to +430 degrees. Mercury orbits very quickly. Maybe that's why he got such a name, because in Greek mythology, Mercury is the messenger of the gods. There is practically no atmosphere here, and the sky is always black, but the Sun shines very brightly. However, at the poles there are places where its rays never fall. This phenomenon can be explained by the tilt of the rotation axis. No water was found on the surface. This circumstance, as well as the abnormally high daytime temperature (as well as low nighttime), fully explain the fact that there is no life on the planet.

Venus

If you study the planets of the solar system in order, then Venus is the second in a row. People could observe it in the sky even in antiquity, but since it was shown only in the morning and in the evening, it was believed that these are 2 different objects. By the way, our Slavic ancestors called her Mertsana. It is the third brightest object in our solar system. Previously, people called it the morning and evening star, because it is best seen before sunrise and sunset. Venus and Earth are very similar in structure, composition, size and gravity. Around its axis, this planet moves very slowly, making a complete revolution in 243.02 Earth days. Of course, conditions on Venus are very different from those on Earth. It is two times closer to the Sun, so it is very hot there. The high temperature is also explained by the fact that thick clouds of sulfuric acid and an atmosphere of carbon dioxide create a greenhouse effect on the planet. In addition, the pressure at the surface is 95 times greater than on Earth. Therefore, the first ship that visited Venus in the 70s of the 20th century lasted no more than an hour there. Another feature of the planet is that it rotates in the opposite direction compared to most planets. More astronomers about this celestial object are not yet known.

The third planet from the Sun

The only place in the solar system, and in the entire universe known to astronomers where life exists, is Earth. In the terrestrial group, it has the largest dimensions. What else are her

1. The largest gravity among the terrestrial planets.
2. Very strong magnetic field.
3. High density.
4. She is the only one among all the planets to have a hydrosphere, which contributed to the formation of life.
5. It has the largest satellite in comparison with its size, which stabilizes its tilt relative to the Sun and affects natural processes.

The planet Mars

It is one of the smallest planets in our Galaxy. If we consider the planets of the solar system in order, then Mars is the fourth from the Sun. Its atmosphere is very rarefied, and the pressure on the surface is almost 200 times less than on Earth. For the same reason, very strong temperature differences are observed. The planet Mars is little studied, although it has long attracted the attention of people. According to scientists, this is the only celestial body on which life could exist. Indeed, in the past, there was water on the surface of the planet. This conclusion can be made on the basis of the fact that there are large ice caps at the poles, and the surface is covered with many furrows that could be dried up river beds. In addition, there are some minerals on Mars that can only form in the presence of water. Another feature of the fourth planet is the presence of two satellites. Their unusualness is that Phobos gradually slows down its rotation and approaches the planet, while Deimos, on the contrary, moves away.

What is Jupiter famous for

The fifth planet is the largest. The volume of Jupiter would fit 1300 Earths, and its mass is 317 times that of the Earth. Like all gas giants, its structure is hydrogen-helium, reminiscent of the composition of stars. Jupiter is the most interesting planet, which has many characteristic features:

• it is the third brightest celestial body after the Moon and Venus;
• jupiter has the strongest magnetic field of all planets;
• it makes a full revolution around the axis in just 10 Earth hours - faster than other planets;
• an interesting feature of Jupiter is a large red spot - this is how the atmospheric vortex rotating counterclockwise is visible from the Earth;
• like all giant planets, it has rings, although not as bright as those of Saturn;
• this planet has the largest number of satellites. He has 63 of them. The most famous are Europa, where water was found, Ganymede - the largest satellite of the planet Jupiter, as well as Io and Calisto;
• another feature of the planet is that in the shade, the surface temperature is higher than in places illuminated by the sun.

Planet saturn

It is the second largest gas giant, also named after an ancient god. It is composed of hydrogen and helium, but traces of methane, ammonia and water have been found on its surface. Scientists have found that Saturn is the most rarefied planet. Its density is less than that of water. This gas giant rotates very quickly - it makes one revolution in 10 Earth hours, as a result of which the planet is flattened from the sides. Huge speeds on Saturn and in the wind - up to 2000 kilometers per hour. This is more than the speed of sound. Saturn has another distinctive feature - it holds 60 satellites in its field of attraction. The largest of them - Titan - is the second largest in the entire solar system. The uniqueness of this object lies in the fact that, while exploring its surface, scientists first discovered a celestial body with conditions similar to those that existed on Earth about 4 billion years ago. But the most important feature of Saturn is the presence of bright rings. They encircle the planet around the equator and reflect more light than itself. Four is the most amazing phenomenon in the solar system. Unusually, the inner rings move faster than the outer rings.

- Uranus

So, we continue to consider the planets of the solar system in order. The seventh planet from the Sun is Uranus. It is the coldest of all - the temperature drops to -224 ° C. In addition, scientists did not find metallic hydrogen in its composition, but found modified ice. Therefore, Uranus belongs to a separate category of ice giants. An amazing feature of this celestial body is that it rotates while lying on its side. The change of seasons on the planet is also unusual: for 42 Earth years, winter reigns there, and the Sun does not appear at all, summer also lasts 42 years, and the Sun does not set at this time. In spring and autumn, the star appears every 9 hours. Like all giant planets, Uranus has rings and many moons. As many as 13 rings revolve around it, but they are not as bright as those of Saturn, and the planet holds only 27 satellites. If we compare Uranus with the Earth, then it is 4 times larger than it, 14 times heavier and is located at a distance from the Sun 19 times the path to the luminary from our planet.

Neptune: the invisible planet

After Pluto was excluded from the number of planets, Neptune became the last from the Sun in the system. It is located 30 times farther from the star than the Earth, and from our planet is not visible even through a telescope. Scientists discovered it, so to speak, by accident: observing the features of the movement of the planets closest to it and their satellites, they concluded that there must be another large celestial body beyond the orbit of Uranus. After discovery and research, interesting features of this planet were revealed:

• due to the presence of a large amount of methane in the atmosphere, the color of the planet from space appears blue-green;
• neptune's orbit is almost perfectly circular;
• the planet rotates very slowly - it makes one circle in 165 years;
• Neptune is 4 times the size of Earth and 17 times heavier, but the force of gravity is almost the same as on our planet;
• the largest of the 13 satellites of this giant is Triton. He is always turned to the planet with one side and slowly approaches it. Based on these signs, scientists suggested that he was captured by the gravity of Neptune.

There are about a hundred billion planets in the entire Milky Way galaxy. So far, scientists cannot study even some of them. But the number of planets in the solar system is known to almost all people on Earth. True, in the 21st century, interest in astronomy has faded a little, but even children know the name of the planets of the solar system.