2 planets of the solar system. The origin and evolutionary process of the solar system

On March 13, 1781, English astronomer William Herschel discovered the seventh planet in the solar system - Uranus. And on March 13, 1930, the American astronomer Clyde Tombaugh discovered the ninth planet in 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 have been discovered using spacecraft. Most satellites are made up of rocks and ice. The largest satellite, Titan, discovered in 1655 by Christian 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 the size of Earth's, and consisting mostly of 90% nitrogen, with a moderate amount of methane.

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 the mass of Pluto is almost 500 times less than the Earth's, even less than the mass of the Moon. The mass of Pluto is 1.2 times 1022 kg (0.22 Earth masses). The average distance of Pluto from the Sun is 39.44 AU. (5.9 by 10 to the 12th degree km), the 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. The composition of Pluto supposedly includes rock and ice; the planet has a thin atmosphere composed of nitrogen, methane and carbon monoxide. Pluto has three moons: Charon, Hydra and Nyx.

In the late 20th and early 21st centuries, many objects were discovered in the outer solar system. It has become clear that Pluto is only one of the largest Kuiper belt objects known to date. Moreover, at least one of the objects of the belt - Eris - is a larger body than Pluto and 27% heavier than it. In this regard, the idea arose to no longer consider Pluto as a planet. On August 24, 2006, at the XXVI General Assembly of the International Astronomical Union (IAU), it was decided to henceforth call Pluto not a "planet", but a "dwarf planet".

At the conference, a new definition of the planet was developed, according to which planets are considered to be bodies revolving around a star (and not being a star themselves), having a hydrostatically equilibrium shape and "clearing" the area in the region of their orbit from other, smaller, objects. Dwarf planets will be considered objects that revolve around 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 of solar system objects. All other objects revolving around the Sun and not being 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. Five dwarf planets are officially recognized by the International Astronomical Union: 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 plutoids celestial bodies that revolve around the Sun in an orbit whose radius is greater than the radius of Neptune's orbit, whose mass is sufficient for gravitational forces to give 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 relation to the class of dwarf planets for such distant objects as plutoids, scientists recommended temporarily assigning to plutoids all objects whose absolute asteroid magnitude (brilliance from a distance of one astronomical unit) is brighter than +1. If later it turns out that the object assigned to the plutoids is not a dwarf planet, it will be deprived of this status, although the assigned name will be left. 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 on the basis of information from open sources

The solar system is the central star the Sun and all the cosmic bodies that revolve around it.

There are 8 largest celestial bodies, or planets, in the solar system. Our Earth is also a planet. In addition to it, 7 more planets make their journey in space around the Sun: Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune. The last two can only be observed with a telescope from Earth. The rest are visible to the naked eye.

More recently, another celestial body, Pluto, was ranked among the planets. It is very far from the Sun, beyond the orbit of Neptune, and was discovered only in 1930. However, in 2006, astronomers introduced a new definition of a classical planet, and Pluto did not fall under it.

The planets have been known to people since ancient times. The nearest neighbors of the Earth are Venus and Mars, the most distant from it are Uranus and Neptune.

Large planets are usually divided into two groups. The first group includes the planets that are closest to the Sun: these are terrestrial planets, or inner planets, - Mercury, Venus, Earth and Mars. All these planets have a high density and a solid surface (although there is a liquid core under it). The largest planet in this group is Earth. However, the planets farthest from the Sun - Jupiter, Saturn, Uranus and Neptune are much larger than the Earth in size. That's why they got the name giant planets. They are also called outer planets. Thus, the mass of Jupiter exceeds the mass of the Earth by more than 300 times. The giant planets differ significantly from the terrestrial planets in their structure: they do not consist of heavy elements, but of gas, mainly hydrogen and helium, like the Sun and other stars. The giant planets do not have a solid surface - they are just balls of gas. Therefore they are also called gas planets.

There is a belt between Mars and Jupiter asteroids, or minor planets. An asteroid is a small planet-like body in the solar system, ranging in size from a few meters to a thousand kilometers. The largest asteroids in this belt are Ceres, Pallas and Juno.

Beyond the orbit of Neptune is another belt of small celestial bodies, which is called the Kuiper belt. It is 20 times wider than the asteroid belt. Pluto, which lost its planet status and was relegated to dwarf planets, just located in this belt. There are other dwarf planets in the Kuiper belt, similar to Pluto, in 2008 they were named like that - plutoids. These are Makemake and Haumea. By the way, Ceres from the asteroid belt is also classified as a dwarf planet (but not plutoid!).

Another plutoid - Eris - is comparable in size to Pluto, but is located much further from the Sun - beyond the Kuiper belt. Interestingly, Eris was at one time even a candidate for the role of the 10th planet in the solar system. But as a result, it was the discovery of Eris that caused the revision of the status of Pluto in 2006, when the International Astronomical Union (IAU) introduced a new classification of the celestial bodies of the solar system. According to this classification, Eris and Pluto did not fall under the concept of a classical planet, but "deserved" only the title of dwarf planets - celestial bodies that revolve around the Sun, are not satellites of the planets and have a large enough mass to maintain an almost rounded shape, but, unlike the planets, they are not able to clear their orbit from other space objects.

The composition of the solar system, in addition to the planets, includes their satellites that revolve around them. In total, there are now 415 satellites. The Moon is the constant companion of the Earth. Mars has 2 moons - Phobos and Deimos. Jupiter has 67 moons and Saturn has 62. Uranus has 27 moons. And only Venus and Mercury have no satellites. But the "dwarfs" of Pluto and Eris have satellites: Pluto has Charon, and Eris has Dysnomia. However, astronomers have not yet come to the final conclusion whether Charon is a satellite of Pluto or the Pluto-Charon system is the so-called double planet. Even some asteroids have moons. The champion in size among satellites is Ganymede, a satellite of Jupiter, not far behind Saturn's satellite Titan. Both Ganymede and Titan are larger than Mercury.

In addition to planets and satellites, dozens, if not hundreds of thousands of different small bodies: tailed celestial bodies - comets, a huge number of meteorites, particles of gas and dust matter, scattered atoms of various chemical elements, streams of atomic particles and others.

All objects of the solar system are held in it due to the force of gravity of the sun, and they all revolve around it, and in the same direction with the rotation of the sun itself and practically in the same plane, which is called plane of the ecliptic. The exception is some comets and Kuiper belt objects. In addition, almost all objects of the solar system also rotate around their axis, and in the same direction as around the sun (the exception is Venus and Uranus; the latter rotates completely "lying on its side").

Pluto's orbit is strongly inclined relative to the ecliptic (by 17°) and highly elongated

Almost the entire mass of the solar system is concentrated in the Sun - 99.8%. The four largest objects - gas giants - make up 99% of the remaining mass (with most of it - about 90% - falling on Jupiter and Saturn). As for the size of the solar system, astronomers have not yet come to a consensus on this issue. According to modern estimates, the size of the solar system is at least 60 billion kilometers. In order to at least roughly imagine the scale of the solar system, let's give a more illustrative example. Within the solar system, an astronomical unit (AU) is taken as a unit of distance - the average distance from the Earth to the Sun. It is approximately 150 million km (light travels this distance in 8 min 19 s). The outer boundary of the Kuiper belt is located at a distance of 55 AU. e. from the Sun.

Another way to imagine the actual dimensions of the solar system is to imagine a model in which all dimensions and distances are reduced to a billion times . In this case, the Earth will be about 1.3 cm in diameter (the size of a grape). The moon will rotate at a distance of about 30 cm from it. The sun will be 1.5 meters in diameter (about the height of a person) and 150 meters from Earth (about a city block). Jupiter is 15 cm in diameter (the size of a large grapefruit) and 5 city blocks from the Sun. Saturn (the size of an orange) is 10 blocks away. Uranus and Neptune (lemons) - 20 and 30 quarters. A person on this scale would be the size of an atom; and the nearest star is at a distance of 40,000 km.

Our solar system consists of the sun, the planets orbiting it, and smaller celestial bodies. All of these are mysterious and amazing, because they are still not fully understood. Below will be indicated the sizes of the planets of the solar system in ascending order, and briefly talk about the planets themselves.

There is a well-known list of planets, in which they are listed in order of their distance from the Sun:

Pluto used to be in last place, but in 2006 it lost its status as a planet, as larger celestial bodies were found farther away. These planets are divided into stone (inner) and giant planets.

Brief information about the stone planets

The inner (stone) planets include those bodies that are located inside the asteroid belt that separates Mars and Jupiter. They got their name "stone" because they consist of various hard rocks, minerals and metals. They are united by a small number or even the absence of satellites and rings (like Saturn). On the surface of the stone planets there are volcanoes, depressions and craters formed as a result of the fall of other cosmic bodies.

But if we compare their sizes and arrange them in ascending order, the list will look like this:

Brief information about the giant planets

The giant planets are located beyond the asteroid belt and therefore they are also called outer. They consist of very light gases - hydrogen and helium. These include:

But if you make a list by the size of the planets in the solar system in ascending order, then the order changes:

A little information about the planets

In modern scientific understanding, a planet means a celestial body that revolves around the Sun and has enough mass for its own gravity. Thus, there are 8 planets in our system, and, importantly, these bodies are not similar to each other: each has its own unique differences, both in appearance and in the very components of the planet.

- This is the closest planet to the Sun and the smallest among the rest. It weighs 20 times less than the Earth! But, despite this, it has a sufficiently high density, which allows us to conclude that there are a lot of metals in its depths. Due to its close proximity to the Sun, Mercury is subject to sharp temperature changes: at night it is very cold, during the day the temperature rises sharply.

- This is the next planet close to the Sun, in many ways similar to the Earth. It has a more powerful atmosphere than the Earth, and is considered a very hot planet (its temperature is above 500 C).

is a unique planet due to its hydrosphere, and the presence of life on it led to the appearance of oxygen in its atmosphere. Most of the surface is covered with water, and the rest is occupied by the continents. A unique feature is the tectonic plates, which move, albeit very slowly, which leads to a change in the landscape. The Earth has one satellite - the Moon.

Also known as the "Red Planet". It gets its fiery red color due to the large amount of iron oxides. Mars has a very rarefied atmosphere and much lower atmospheric pressure than Earth. Mars has two satellites - Deimos and Phobos.

- this is a real giant among the planets of the solar system. Its weight is 2.5 times the weight of all the planets combined. The surface of the planet is made up of helium and hydrogen and is similar in many ways to the sun. Therefore, it is not surprising that there is no life on this planet - no water and no solid surface. But Jupiter has a large number of satellites: 67 are known at the moment.

- this planet is famous for the presence of rings, consisting of ice and dust, revolving around the planet. With its atmosphere, it resembles that of Jupiter, and is slightly smaller in size than this giant planet. In terms of the number of satellites, Saturn is also slightly behind - it knows 62 of them. The largest satellite, Titan, is larger than Mercury.

- the lightest planet among the outer ones. Its atmosphere is the coldest in the entire system (minus 224 degrees), it has a magnetosphere and 27 satellites. Uranus is made up of hydrogen and helium, and ammonia ice and methane have also been noted. Due to the fact that Uranus has a large axial tilt, it seems that the planet is rolling rather than rotating.

- despite being smaller than y, it is heavier than it and exceeds the mass of the Earth. This is the only planet that was found through mathematical calculations, and not through astronomical observations. On this planet, the strongest winds in the solar system were recorded. Neptune has 14 moons, one of which, Triton, is the only one that rotates backwards.

It is very difficult to imagine all the scales of the solar system within the studied planets. It seems to people that the Earth is a huge planet, and, in comparison with other celestial bodies, it is. But if you put giant planets next to it, then the Earth already takes on tiny sizes. Of course, next to the Sun, all celestial bodies seem small, so representing all the planets at their full scale is a difficult task.

The most famous classification of the planets is their distance from the Sun. But a listing that takes into account the sizes of the planets of the solar system in ascending order will also be correct. The list will be presented as follows:

As you can see, the order has not changed much: the first lines are the inner planets, and the first place is occupied by Mercury, and the other positions are the outer planets. In fact, it doesn’t matter at all in what order the planets are located, from this they will not become less mysterious and beautiful.

The solar system is our space region, and the planets in it are at home. Agree, each house should have its own number.

In this article, you will learn about the correct location of the planets, as well as why they are called that way and not otherwise.

Let's start with the sun.

In the literal sense, the star of today's article is the Sun. They named him so, according to some sources, in honor of the Roman god Sol, he was the god of the heavenly body. The root “sol” is present in almost all languages ​​of the world and in one way or another gives an association with the modern concept of the Sun.

From this luminary begins the correct order of objects, each of which is unique in its own way.

Mercury

The very first object of our attention is Mercury., named after the divine messenger of Mercury, distinguished by its phenomenal speed. And Mercury itself is by no means slow - due to its location, it orbits the Sun faster than all the planets of our system, being, moreover, the smallest “house” revolving around our star.

Interesting Facts:

• Mercury revolves around the Sun in an ellipsoidal orbit, not round like other planets, and this orbit is constantly shifting.
• Mercury has an iron core, which makes up 40% of its mass and 83% of its volume.
• Mercury can be seen in the sky with the naked eye.

Venus

“House” is number two in our system. Venus was named after the goddess- the beautiful patroness of love. Venus is only slightly smaller than our Earth in size. Its atmosphere consists almost entirely of carbon dioxide. There is oxygen in its atmosphere, but in very small quantities.

Interesting Facts:

Earth

The only space object on which life has been discovered is the third planet in our system. For a comfortable stay of living organisms on Earth, there is everything: a suitable temperature, oxygen and water. The name of our planet comes from the Proto-Slavic root “-zem”, meaning “low”. Probably, it was called so in ancient times because it was considered flat, in other words, “low”.

Interesting Facts:

• The Earth's satellite, the Moon, is the largest satellite among the satellites of the terrestrial planets - dwarf planets.
• It is the densest planet among the terrestrial group.
• Earth and Venus are sometimes called sisters due to the fact that they both have an atmosphere.

Mars

The fourth planet from the Sun. Mars is named after the ancient Roman god of war for its blood-red color, which is not bloody at all, but, in fact, iron. It is the high iron content that gives the surface of Mars its red color. Mars is smaller than Earth but has two moons: Phobos and Deimos.

Interesting Facts:

asteroid belt

The asteroid belt is located between Mars and Jupiter.. It acts as a boundary between the terrestrial planets and the giant planets. Some scientists believe that the asteroid belt is nothing more than a planet shattered into fragments. But so far the whole world is more inclined to the theory that the asteroid belt is a consequence of the Big Bang that gave birth to the galaxy.

Jupiter

Jupiter is the fifth house from the Sun. It is two and a half times heavier than all the planets in the galaxy combined. Jupiter is named after the ancient Roman king of the gods, most likely because of its impressive size.

Interesting Facts:

Saturn

Saturn is named after the Roman god of agriculture. The sickle is the symbol of Saturn. The sixth planet is widely known for its rings. Saturn has the lowest density of all natural satellites orbiting the Sun. Its density is even lower than that of water.

Interesting Facts:

• Saturn has 62 moons. The most famous of them: Titan, Enceladus, Iapetus, Dione, Tethys, Rhea and Mimas.
• Saturn's moon Titan has the most substantial atmosphere of any moon in the system, and Rhea has rings like Saturn itself.
• The composition of the chemical elements of the Sun and Saturn is the most similar than that of the Sun and other objects of the solar system.

Uranus

The seventh "house" in the solar system. Sometimes Uranus is called the “lazy planet”, because during the rotation it lies on its side - the tilt of its axis is 98 degrees. Uranus is also the lightest planet in our system and its moons are named after characters from William Shakespeare and Alexander Pope. Uranus itself is named after the Greek god of the sky.

Interesting Facts:

• Uranus has 27 moons, the most famous being Titania, Ariel, Umbriel and Miranda.
• The temperature on Uranus is -224 degrees Celsius.
• One year on Uranus is equal to 84 years on Earth.

Neptune

The eighth, last planet of the solar system is quite close to its neighbor Uranus. Neptune got its name in honor of the god of the seas and oceans. Apparently, it was given to this space object after the researchers saw the deep blue color of Neptune.

Interesting Facts:

About Pluto

Pluto has officially ceased to be considered a planet since August 2006. It was considered too small and declared an asteroid. The name of the former planet of the galaxy is not the name of any god at all. The discoverer of this now asteroid named this space object in honor of his daughter's favorite cartoon character, the dog Pluto.

In this article, we briefly reviewed the location of the planets. We hope you found this article useful and informative.