Planets of the solar system stars. Planets of our solar system

On March 13, 1781, English astronomer William Herschel discovered the seventh planet in the solar system - Uranus. And on March 13, 1930, 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 satellite 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 hydrostatic 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 it later 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 a system of planets, which includes its center - the Sun, as well as other objects of the Cosmos. They revolve around the sun. More recently, 9 objects of the Cosmos that revolve around the Sun were called “planet”. Now scientists have established that beyond the boundaries of the solar system there are planets that revolve around stars.

In 2006, the Union of Astronomers declared that the planets of the solar system are spherical cosmic objects revolving around the sun. On the scale of the solar system, the Earth appears to be extremely small. In addition to the Earth, eight planets revolve around the Sun in their individual orbits. All of them are larger than the Earth. They rotate in the plane of the ecliptic.

Planets in the solar system: types

Location of the terrestrial group in relation to the Sun

The first planet is Mercury, followed by Venus; next comes our Earth and finally Mars.
The terrestrial planets do not have many satellites or moons. Of these four planets, only Earth and Mars have moons.

The planets that belong to the terrestrial group are highly dense, composed of metal or stone. Basically, they are small and rotate around their own axis. Their rotation speed is also low.

gas giants

These are the four space objects that are at the greatest distance from the Sun: Jupiter is at number 5, followed by Saturn, then Uranus and Neptune.

Jupiter and Saturn are impressive planets, made up of compounds of hydrogen and helium. The density of gas planets is low. They rotate at high speed, have satellites and are surrounded by asteroid rings.
“Ice giants”, which include Uranus and Neptune, are smaller, their atmospheres contain methane, carbon monoxide.

Gas giants have a strong gravitational field, so they can attract many space objects, unlike the terrestrial group.

According to scientists, asteroid rings are the remains of moons altered by the gravitational field of the planets.

dwarf planet

Dwarfs are space objects, the size of which does not reach the planet, but exceeds the dimensions of the asteroid. There are many such objects in the solar system. They are concentrated in the Kuiper belt region. The satellites of the gas giants are dwarf planets that have left their orbit.

Planets of the solar system: the process of emergence

According to the hypothesis of cosmic nebulae, stars are born in clouds of dust and gas, in nebulae.
Due to the force of attraction, substances are combined. Under the influence of the concentrated force of gravity, the center of the nebula is compressed and stars are formed. Dust and gases are transformed into rings. The rings rotate under the influence of gravity, and planetasimals form in whirlpools, which increase and attract cosmetic objects to themselves.

Under the influence of the force of gravity, the planetazimals are compressed and acquire a spherical shape. Spheres can combine and gradually turn into protoplanets.



There are eight planets within the solar system. They revolve around the sun. Their location is:
The nearest “neighbor” of the Sun is Mercury, followed by Venus, then the Earth, then Mars and Jupiter, further from the Sun are Saturn, Uranus and the last one, Neptune.

The solar system is a planetary system that includes the central star - the Sun - and all the natural objects of space revolving around it. It was formed by gravitational compression of a gas and dust cloud about 4.57 billion years ago. We will find out which planets are part of the solar system, how they are located in relation to the Sun and their brief description.

Brief information about the planets of the solar system

The number of planets in the solar system is 8, and they are classified in order of distance from the Sun:

• Inner planets or terrestrial planets- Mercury, Venus, Earth and Mars. They consist mainly of silicates and metals.
• outer planets- Jupiter, Saturn, Uranus and Neptune are the so-called gas giants. They are much more massive than the terrestrial planets. The largest planets in the solar system, Jupiter and Saturn, are composed mainly of hydrogen and helium; smaller gas giants, Uranus and Neptune, in addition to hydrogen and helium, contain methane and carbon monoxide in their atmospheres.

Rice. 1. Planets of the solar system.

The list of planets in the solar system in order from the sun is as follows: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. By listing the planets from largest to smallest, this order changes. The largest planet is Jupiter, followed by Saturn, Uranus, Neptune, Earth, Venus, Mars and finally Mercury.

All planets revolve around the Sun in the same direction as the Sun's rotation (counterclockwise as viewed from the north pole of the Sun).

Mercury has the highest angular velocity - it manages to make a complete revolution around the Sun in just 88 Earth days. And for the most distant planet - Neptune - the period of revolution is 165 Earth years.

Most of the planets rotate around their axis in the same direction as they revolve around the sun. The exceptions are Venus and Uranus, and Uranus rotates almost "lying on its side" (axis tilt is about 90 degrees).

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Table. The sequence of the planets in the solar system and their features.

Planet	Distance from the Sun	Period of circulation	Rotation period	Diameter, km.	Number of satellites	Density g / cu. cm.
Mercury

Terrestrial planets (inner planets)

The four planets closest to the Sun consist mainly of heavy elements, have a small number of satellites, and have no rings. They are largely composed of refractory minerals such as silicates that form their mantle and crust, and metals such as iron and nickel that form their core. Three of these planets - Venus, Earth and Mars - have an atmosphere.

• Mercury- is the closest planet to the Sun and the smallest planet in the system. The planet has no satellites.
• Venus- is close in size to the Earth and, like the Earth, has a thick silicate shell around the iron core and atmosphere (because of this, Venus is often called the "sister" of the Earth). However, the amount of water on Venus is much less than on Earth, and its atmosphere is 90 times denser. Venus has no satellites.

Venus is the hottest planet in our system, with surface temperatures exceeding 400 degrees Celsius. The most likely reason for such a high temperature is the greenhouse effect due to the dense atmosphere rich in carbon dioxide.

Rice. 2. Venus is the hottest planet in the solar system

• Earth- is the largest and densest of the terrestrial planets. The question of whether life exists anywhere other than Earth remains open. Among the terrestrial planets, the Earth is unique (primarily due to the hydrosphere). Earth's atmosphere is radically different from the atmospheres of other planets - it contains free oxygen. The Earth has one natural satellite - the Moon, the only large satellite of the planets of the terrestrial group of the solar system.
• Mars smaller than Earth and Venus. It has an atmosphere composed mainly of carbon dioxide. On its surface there are volcanoes, the largest of which, Olympus, exceeds the size of all terrestrial volcanoes, reaching a height of 21.2 km.

Outer region of the solar system

The outer region of the solar system is the location of the gas giants and their satellites.

• Jupiter- has a mass of 318 times more than the earth, and 2.5 times more massive than all the other planets combined. It consists mainly of hydrogen and helium. Jupiter has 67 moons.
• Saturn- known for its extensive ring system, it is the least dense planet in the solar system (its average density is less than that of water). Saturn has 62 moons.

Rice. 3. Planet Saturn.

• Uranus- the seventh planet from the Sun is the lightest of the giant planets. What makes it unique among other planets is that it rotates "lying on its side": the inclination of its axis of rotation to the plane of the ecliptic is approximately 98 degrees. Uranus has 27 moons.
• Neptune is the last planet in the solar system. Although slightly smaller than Uranus, it is more massive and therefore denser. Neptune has 14 known moons.

What have we learned?

One of the interesting topics of astronomy is the structure of the solar system. We learned what names of the planets of the solar system are, in what order they are located in relation to the Sun, what are their distinctive features and brief characteristics. This information is so interesting and informative that it will be useful even for children in grade 4.

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Previously, a planet was called any cosmic body that revolves around a star, emits light that reflects this star, and has dimensions larger than an asteroid. Even in ancient Greece, they spoke of 7 planets as luminous bodies that move across the sky against the background of stars. These are Mercury, Sun, Venus, Mars, Moon, Jupiter, Saturn. Note that the Sun, which is a star, and the Moon, a satellite of our Earth, are indicated here. The earth is not included in this list because the Greeks considered it to be the center of everything.

In the 15th century, Copernicus figured out that the center of the system was the sun, not the earth. He laid out his statements in the work "On the Revolution of the Celestial Spheres". The moon and the sun were removed from the list, and the planet Earth was included. When telescopes were invented, three more planets were discovered. Uranus in 1781, Neptune in 1846, Pluto in 1930, which, by the way, is no longer considered a planet.

At the moment, researchers are giving a new meaning to the word "planet", namely: it is a celestial body that satisfies 4 conditions:

• The body must revolve around the star.
• Have a spherical or approximate shape, that is, the body must have sufficient gravity.
• It doesn't have to be a star.
• The celestial body should not have other large bodies in the vicinity of the orbit.

A star is a body that emits light and has a powerful source of energy.

Planets in the solar system

The solar system includes the planets and other objects that revolve around the sun. 4.5 billion years ago, clumps of stellar matter clouds began to form in the Galaxy. The gases heated up and radiated heat. As a result of the increase in temperature and density, nuclear reactions began, hydrogen turned into helium. So there was a powerful source of energy - the Sun. This process took tens of millions of years. Planets with satellites were created. The entire formation of the solar system ended about 4 billion years ago.

To date, the solar system includes 8 planets, which are divided into two groups. The first is the terrestrial group, the second is the gas giants. The terrestrial planets - Venus, Mercury, Mars and Earth - are composed of silicates and metals. The gas giants - Saturn, Jupiter, Neptune and Uranus - are made up of hydrogen and helium. The planets have different sizes both in comparison between the two groups and among themselves. Accordingly, the giants are much larger and more massive than the terrestrial planets.

Mercury is closest to the Sun, next is Neptune. Before characterizing the planets of the solar system, you need to talk about its main object - the Sun. This is a star, thanks to which all living and non-living things in the system began to exist. The Sun is a spherical, plasma, hot ball. A large number of space objects revolve around it - satellites, planets, meteorites, asteroids and cosmic dust. This star appeared about 5 billion years ago. Its mass is 300 thousand times greater than the mass of our planet. The temperature of the core is 13 million degrees Kelvin, and on the surface - 5 thousand degrees Kelvin (4727 degrees Celsius). In the Milky Way galaxy, the Sun is one of the largest and brightest stars. The distance from the Sun to the center of the Galaxy is 26,000 light years. The sun makes a complete revolution around the galactic center in 230-250 million years.

Mercury

It is closest to the Sun and is the smallest planet in the solar system. The planet has no satellites. On the surface of Mercury there are many craters that were formed by many meteorites that fell on the planet more than 3 billion years ago. Their diameter is varied - from a couple of meters to 1000 kilometers. The planet's atmosphere is mostly helium and blown by the Sun's wind. The temperature can reach +440 degrees Celsius. The planet makes a revolution around the Sun in 88 Earth days. A day on the planet equals 176 Earth hours.

Venus

Venus is the second planet from the Sun. Its dimensions are close to the dimensions of the Earth. The planet has no satellites. The atmosphere is carbon dioxide mixed with nitrogen and oxygen. Air pressure is 90 atmospheres, which is 35 times greater than on Earth. Venus is called the hottest planet because the dense atmosphere, carbon dioxide, the proximity of the Sun and the greenhouse effect create very high temperatures on the planet's surface. It can reach 460 degrees Celsius. Venus can be seen from the Earth's surface. It is the brightest space object after the Moon and the Sun.

Earth

The only planet adapted for life. Maybe it exists on other planets, but so far no one can say with certainty. In its group, it is the largest in terms of mass, density and size. Its age is over 4 billion years. Life here originated more than 3 billion years ago. The Earth's satellite is the Moon. The atmosphere on the planet is fundamentally different from others. Most of it is made up of nitrogen. It also includes carbon dioxide, oxygen, water vapor and argon. The ozone layer and the magnetic field make the level of solar and cosmic radiation less. Due to the content of carbon dioxide in the Earth's atmosphere, a greenhouse effect is formed on the planet. Without it, the temperature on the Earth's surface would be 40 degrees less. Islands and continents occupy 29% of the planet's surface, and the rest is the oceans.

Mars

It is also called the "red planet" due to the presence of a large amount of iron oxide in the soil. Mars is the seventh largest planet in the solar system. Two satellites fly near the planet - Deimos and Phobos. Due to the too rarefied atmosphere and the far distance from the Sun, the average annual temperature of the planet is minus 60 degrees. At some points during the day, temperature drops can reach 40 degrees. The presence of volcanoes and craters, deserts and valleys, ice polar caps distinguishes Mars from other planets of the solar system. Also here is the highest mountain - the extinct volcano Olympus, which has reached a height of 27 kilometers. The Mariner Valley is the largest canyon among the planets. Its length is 4500 km and the depth is 11 m.

Jupiter

It is the largest planet in the solar system. Jupiter is 318 times heavier than Earth and 2.5 times more massive than other planets. The main constituents of the planet are helium and hydrogen. Jupiter radiates a lot of heat - 4 * 1017 W. To become a star like the Sun, it must reach a mass 70 times greater than the current one. The planet has the largest number of satellites - 63. Europa, Callisto, Ganymede and Io are the largest of them. Ganymede is also the largest moon in the entire solar system and is even larger than Mercury. There are many eddies in Jupiter's atmosphere that have a brown-red color band of clouds, or a giant storm, known as the Great Red Spot since the 17th century.

Saturn

Like Jupiter, it is a large planet that follows Jupiter in size. The ring system, which consists of ice particles of various sizes, rocks and dust, distinguishes this planet from others. It has one fewer satellites than Jupiter. The largest are Enceladus and Titan. In composition, Saturn resembles Jupiter, but in density it is inferior to the simplest water. The atmosphere looks quite uniform and calm, which can be explained by a dense layer of fog. Saturn has a huge wind speed, it can reach 1800 km per hour.

Uranus

This planet was the first to be discovered using a telescope. Uranus is the only planet in the solar system that lies on its side and revolves around the sun. Uranus has 27 satellites, which are named after the heroes of Shakespeare's plays. The largest among them are Titania, Oberon and Umbriel. Uranus contains a large number of high-temperature modifications of ice. It is also the coldest planet. The temperature here is minus 224 degrees Celsius.

Neptune

It is the most distant planet from the Sun, although until 2006 this title belonged to Pluto. This planet was discovered without the help of a telescope, but by mathematical calculations. The existence of Neptune was suggested to scientists by Uranus, on which strange changes were discovered while moving in its own orbit. The planet has 13 satellites. The largest among them is Triton. Its peculiarity is that it moves opposite to the planet. The strongest winds in the solar system blow in the same direction, reaching speeds of up to 2200 km per hour. The compositions of Neptune and Uranus are similar, but it is also similar in composition to Jupiter and Saturn. The planet has an internal heat source, from which it receives 2.5 times more energy than from the Sun. The outer layers of the atmosphere contain methane, which gives the planet a blue tint.

That's how mysterious the world of space is. Many satellites and planets have their own characteristics. Scientists are making changes to this world, for example, excluding Pluto from the list of planets.

Explore the planets on the portal site - it's very interesting.

The rotation of the planets

All planets, in addition to their orbit, also rotate around their axis. The period for which they make a complete revolution is defined as the epoch. Most of the planets in the solar system rotate in the same direction on their axis as they do around the sun, but Uranus and Venus rotate in the opposite direction. Scientists observe a large difference in the length of the day on the planets - Venus takes 243 Earth days to complete one rotation around its axis, while the planets of the gas giant group need only a couple of hours. The rotation period of exoplanets is not known, but their close location to the stars means that eternal day reigns on one side, and eternal night reigns on the other.

Why are all planets so different? Due to the high temperature closer to the star, the ice and gas evaporated very quickly. The giant planets could not form, but there was an accumulation of metal particles. Thus, Mercury was formed, which contains the largest amount of metals. The farther we are from the center, the lower the temperature. Celestial bodies appeared, where a significant percentage was made up of rocks. The four planets closest to the center of the solar system are called the inner planets. With the discovery of new systems, more and more questions arise. New research will help answer them.

Scientists claim that our system is unique. All planets are built in a strict order. The largest is closer to the Sun, respectively, the smallest is farther. Our system has a more complex structure, because the planets are not lined up by their mass. The sun makes up more than 99 percent of all objects in the system.

This is a system of planets, in the center of which is a bright star, the 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 supernovae. 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 orbits. Since the Sun is displaced from the center of the planetary orbits, then 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 are small in size with a rocky surface, they are closer than others to the Sun.

Giant planets: And . These are large planets, consisting mainly of gas, and they are characterized by the presence of rings consisting of ice 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 start 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, unlike other features ...

Rings and moons of Saturn: Titan, Enceladus and more...
Not only the planet Saturn has characteristic rings, but also on 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 of the solar system ...

Rings and moons of Uranus: Titania, Oberon and others...
The planet Uranus has 17 satellites and, like other giant planets, thin rings encircling the planet, which practically do not have the ability to reflect light, therefore they were discovered not so long ago in 1977 quite by accident ...

Rings and moons of Neptune: Triton, Nereid and others...
Initially, before the exploration of Neptune by the Voyager 2 spacecraft, it was known about two satellites of the planet - Triton and Nerida. An interesting fact is that the Triton satellite has a reverse direction of orbital motion, and strange volcanoes were also discovered on the satellite that spewed nitrogen gas like geysers, spreading a dark mass (from liquid to vapor) for many kilometers into the atmosphere. During its mission, Voyager 2 discovered six more satellites of the planet Neptune...