What order are the planets in? Planets of the solar system in order, starting from the sun. Outer planets or giant planets
All planets are located in a certain sequence, the distances between their orbits increase as the planets move away from the Sun.
Composition of the solar system
Sun
Concentrated in itself 99.9% of the total mass of the system. A star is made up primarily of hydrogen and helium. In fact, this is a giant fusion reactor. The temperature is about 6000 °C. But on the other hand, the luminaries go off scale for 10,000,000 ° C.
At a speed of 250 km / s, our star rushes through space around the center, which is “only” 26,000 light years away. And one revolution takes about 180 million years.
Planets and their satellites
Earth group.
The closest to the Sun, but also the smallest of the planets. It revolves around itself very slowly, making only one and a half turns around its axis for a complete revolution around the star. The planet has neither an atmosphere nor satellites, during the day it heats up to +430 °С, and at night it cools down to -180 °С.
The most romantic and closest planet to Earth is also uninhabitable. She is wrapped tightly in a thick blanket of clouds from carbon dioxide, and at temperatures up to + 475 ° C has a pressure near the surface, dotted with craters, over 90 atmospheres. Venus is very close to Earth in size and mass.
Similar to our planet in its structure. Its radius is half that of the earth, and its mass is an order of magnitude less. It would be possible to live here, but the lack of water and atmosphere prevent this from being done. The Martian year is twice as long as the Earth, but the day is almost the same duration. Mars is richer than the first two planets, having two satellites: Phobos and Deimos, translated from Greek as "fear" and "horror". These are small boulders, very similar to asteroids.
Giant planets.
The largest gas giant planet. If its mass were several tens of times greater, it could really become a star. A day on the planet lasts about 10 hours, and a year passes for 12 Earth hours. Jupiter, like Saturn and Uranus, has a ring system. He has four of them, but they are not very pronounced, from afar you can not notice. But the planet has more than 60 satellites.
It is the most ringed planet in the solar system. Saturn also has a feature that other planets do not have. This is its density. It is less than one, and it turns out that if you find a huge ocean somewhere and throw this planet into it, then it will not sink. To date, more than 60 satellites of this giant have been discovered. The main ones are Titan, Dione, Tethys. Saturn is similar to Jupiter in the structure of the atmosphere.
The peculiarity of this planet, which appears to the observer in blue-green tones, is in its rotation. The axis of rotation of the planet is almost parallel to the plane of the ecliptic. In everyday language, Uranus lies on its side. But this did not prevent him from acquiring 13 rings and 27 satellites, the most famous of which are Oberon, Titania, Ariel, Umbriel.
Just like Uranus, Neptune is made up of gas, including water, ammonia, and methane. The latter, concentrating in the atmosphere, gives the planet a blue color. The planet has 5 rings and 13 satellites. Main:, Proteus, Larissa, Nereid.
The largest of the dwarf planets. It consists of a rocky core covered with a layer of ice. Only in 2015 did a spacecraft fly to Pluto and take detailed pictures. His main companion is Charon.
Small objects
Kuiper Belt. Part of our planetary system from 30 to 50 AU. e. A mass of small bodies, ice, is concentrated here. They are composed of methane, ammonia and water, but there are objects that include rocks and metals.
The orbits of these stone or metal blocks are mainly located near the plane of the ecliptic. The paths of some asteroids intersect with the earth's orbit. And, although the probability of an unwanted meeting is negligible, but ... 65 million years ago, it probably still took place.
According to legend, a certain planet Phaethon, peacefully revolving around the star, was torn to shreds by Jupiter's gravity. And it turned out to be a beautiful asteroid belt. In fact, science does not confirm this.
If you translate this word from Greek, you get "long-haired." And it is. When the ice wanderer approaches the Sun, it spreads a long tail of evaporating gases for hundreds of millions of kilometers. A comet also has a head, consisting of a nucleus and a coma. The core is an ice block of frozen gases with the addition of silicates and metal particles. It is possible that some organic matter is also present. A coma is the gas and dust environment of a comet.
Jan Oort, back in 1950, suggested the existence of a cloud filled with objects from icy ammonia, methane and water. It has not yet been proven, but it is possible that the cloud starts from 2 - 5 thousand AU, extending to 50 thousand AU. e. Most comets come from the Oort cloud.
Earth's place in the solar system
It is impossible to think of a more successful position than what it occupies. Part of our galaxy is pretty quiet. The sun provides a constant, uniform glow. It emits exactly as much heat, radiation and energy as is required for the origin and development of life. The very same Earth as if thought out in advance. The ideal composition of the atmosphere, and the geological structure. Desired radiation background and temperature regime. The presence of water from amazing properties. Presence, just such a mass and at such a distance as required. There are many more coincidences that are crucial for a favorable life on the planet. And the violation of almost any of them would make the emergence and existence of life unlikely.
System stability
The revolution of the planets around the Sun occurs in one (direct) direction. The orbits of the planets are almost circular, and their planes are close to the Laplace plane. This is the main plane of the solar system. Our life is subject to the laws of mechanics, and the solar system is no exception. The planets are related to each other by law. gravity. Based on the absence of friction in interstellar space, we can confidently assume that the motion of the planets relative to each other will not change. In any case, in the next million years. Many scientists have tried to calculate the future of the planets in our system. But everyone - and even Einstein - got one thing: the planets solar system will always be stable.
Some interesting facts
- The temperature of the solar corona. The temperature near the Sun is greater than on its surface. This riddle has yet to be solved. Perhaps the magnetic forces of the star's atmosphere are at work.
- Atmosphere of Titan. It is the only satellite of the planets that has an atmosphere. And it consists mainly of nitrogen. Almost like earth.
- It remains a mystery why the activity of the Sun with a certain frequency and time.
Our planetary system has been successfully explored for a long time. The Moon, Venus, Mars, Mercury, Jupiter and Saturn are under constant surveillance. There are traces of people and all-terrain vehicles left on our satellite. Autonomous rovers travel around Mars, transmitting valuable information. The legendary Voyager has already flown through the entire solar system, stepping over its borders. Even to a comet. And a manned trip to Mars is already being prepared.
We are incredibly lucky to have settled in such a place in the universe. Although, whether there are other worlds, no one has yet proven. But we still know so little about our system of beautiful planets. And now we are calm, businesslike. And, perhaps, a pebble has already been released from the Oort cloud and flies exactly to Jupiter. Or, nevertheless, this time to us?
Planets of the solar system - a bit of history
Previously, a planet was considered to be any body that revolves around a star, glows with light reflected from it, and has a size larger than that of asteroids.
Also in Ancient Greece mentioned seven luminous bodies that move across the sky against the background of fixed stars. These cosmic bodies were: Sun, Mercury, Venus, Moon, Mars, Jupiter and Saturn. 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 the Revolution of the Celestial Spheres,” came to the conclusion that not the Earth, but the Sun, should be in the center of the planetary system. Therefore, the Sun and the 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 next definition of a planet.
A planet is a celestial body that must satisfy four conditions:
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
The solar system is a planetary system that consists of a central star - the Sun - and all natural space objects revolving 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.
outer planets are Jupiter, Saturn, Uranus and Neptune. The composition of gas giants consists mainly of hydrogen and helium.
The sizes of the planets in the solar system vary both within groups and between groups. So, the gas giants are much larger and more massive than the terrestrial planets.
Closest to the Sun is Mercury, then as far as the distance: 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 a 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 over 5,000 degrees Kelvin, and the core temperature is over 13 million K.
The Sun is one of the largest and brightest stars in our galaxy, which is called the Milky Way Galaxy. The Sun is located at a distance of about 26 thousand light years from the center of the Galaxy and makes a complete revolution around it in about 230-250 million years! For comparison, the Earth makes a complete revolution around the Sun in 1 year.
Mercury planet
Mercury is the smallest planet in the system and 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 as a result of massive bombardments by meteorites. The diameter of the craters can range from a few meters to more than 1000 km.
The atmosphere of Mercury is highly rarefied, consists mainly of helium and is blown by the solar wind. Since the planet is located very close to the Sun and does not have an atmosphere that would keep warm at night, the temperature on the surface ranges from -180 to +440 degrees Celsius.
By earthly standards, Mercury makes a complete revolution around the Sun in 88 days. On the other hand, a Mercury day is equal to 176 Earth days.
Venus planet
Venus is the second closest planet to the Sun in the solar system. Venus is only slightly smaller than Earth, which is why it is sometimes referred to as "Earth's sister". Has no satellites.
The atmosphere consists of carbon dioxide mixed with nitrogen and oxygen. The air pressure on the planet is more than 90 atmospheres, which is 35 times more than the earth.
Carbon dioxide and, as a result, the greenhouse effect, a dense atmosphere, as well as proximity to the Sun, allow Venus to carry 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 known planet in the universe today that has life on it. The Earth has the largest size, mass and density among the so-called inner planets of the 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 atmosphere of the Earth is fundamentally different from the atmospheres of other planets due to the presence of life. Most of the atmosphere is nitrogen, but it also contains oxygen, argon, carbon dioxide and water vapor. The ozone layer and the Earth's magnetic field, in turn, weaken the life-threatening effects of solar and cosmic radiation.
Due to the carbon dioxide contained in the atmosphere, the greenhouse effect also takes place on Earth. It does not appear as strongly as on Venus, but without it, the air temperature would be approximately 40 ° C lower. Without the 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 oceans, the remaining 29% are continents and islands.
mars planet
Mars is the seventh largest planet in the solar system. The "Red Planet", as it is also called due to the presence of a large amount of iron oxide in the soil. Mars has two moons: Deimos and Phobos.
The atmosphere of Mars is highly rarefied, and the distance to the Sun is almost one and a half times greater than that of the Earth. Therefore, the average annual temperature on the planet is -60 ° C, and temperature drops in some places reach 40 degrees during the day.
Distinctive features of the surface of Mars are impact craters and volcanoes, valleys and deserts, ice polar caps like those on Earth. On Mars is the most high mountain in the solar system: the extinct volcano Olympus, whose height is 27 km! As well as the largest canyon: the Valley of the Mariner, the depth of which reaches 11 km, and the length is 4500 km. 
Jupiter planet
Jupiter is the largest planet in the 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 radiates a huge amount of heat, equal to 4 * 1017 watts. However, in order to become a star like the Sun, Jupiter must be another 70-80 times heavier.
Jupiter has as many as 63 satellites, of which it makes sense to list only the largest ones - Callisto, Ganymede, Io and Europa. Ganymede is the largest moon in the solar system, larger than even Mercury.
Due to certain processes in the inner atmosphere of Jupiter, many vortex structures appear in its outer atmosphere, for example, stripes of clouds of 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. The hallmark of Saturn is, of course, its ring system, which consists mainly of ice particles of various 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 outer atmosphere of the planet looks calm and homogeneous, which is explained by a very dense layer of fog. However, the wind speed in some places can reach 1800 km/h.
Uranus planet
Uranus is the first planet to be discovered with a telescope, and also the only planet in the solar system that wraps around the sun, "lying on its side."
Uranus has 27 moons named after Shakespearean heroes. The largest of them are Oberon, Titania and Umbriel.
The composition of the planet differs from the gas giants in the presence of a large number of high-temperature modifications of ice. Therefore, along with Neptune, scientists have identified Uranus in the category of "ice giants". And if Venus has the title of "hottest planet" in the solar system, then Uranus is the coldest planet with a minimum temperature of about -224 ° C.
Neptune planet
Neptune is the most distant planet from the center of the solar system. The history of its discovery is interesting: before observing the planet through a telescope, scientists calculated its position in the sky using mathematical calculations. This happened after the discovery of inexplicable changes in the movement of Uranus in its own orbit.
To date, 13 satellites of Neptune are known to science. The largest of them - Triton - is the only satellite that moves in the opposite direction 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.
The composition of Neptune is very similar to Uranus, therefore it is the second "ice giant". However, like Jupiter and Saturn, Neptune has an internal source of heat and radiates 2.5 times more energy than it receives from the Sun.
The planet's blue color comes from traces of methane in the outer atmosphere.
Conclusion
Pluto, unfortunately, did not have time to get into our parade of planets in the solar system. But it is absolutely not worth worrying about this, because all the planets remain in their places, despite changes in scientific views and concepts.
So, we answered the question of how many planets are there in the solar system. There are only 8 of them.
solar system- these are 8 planets and more than 63 of their satellites, which are being discovered more often, several dozen comets and a large number of asteroids. All cosmic bodies move along their clear directed trajectories around the Sun, which is 1000 times heavier than all the bodies in the solar system combined. The center of the solar system is the Sun - a star around which planets revolve in orbits. They do not emit heat and do not glow, but only reflect the light of the Sun. There are currently 8 officially recognized planets in the solar system. Briefly, in order of distance from the sun, we list them all. And now some definitions.
Planet- this is a celestial body that must satisfy four conditions:
1. the body must revolve around a star (for example, around the Sun);
2. the body must have sufficient gravity to have a spherical or close to it shape;
3. the body should not have other large bodies near its orbit;
4. the body should not be a star
Planet satellites. The solar system also includes the Moon and the natural satellites of other planets, which all of them have, except for Mercury and Venus. More than 60 satellites are known. Most of the satellites of the outer planets were discovered when they received photographs taken by robotic spacecraft. Jupiter's smallest moon, Leda, is only 10 km across.
is a star, without which life on Earth could not exist. It gives us energy and warmth. According to the classification of stars, the Sun is a yellow dwarf. The age is about 5 billion years. It has a diameter at the equator equal to 1,392,000 km, 109 times larger than the earth. The rotation period at the equator is 25.4 days and 34 days at the poles. The mass of the Sun is 2x10 to the 27th power of tons, approximately 332950 times the mass of the Earth. The temperature inside the core is about 15 million degrees Celsius. The surface temperature is about 5500 degrees Celsius. According to the chemical composition, the Sun consists of 75% hydrogen, and of the other 25% of the elements, most of all helium. Now let's figure out in order how many planets revolve around the sun, in the solar system and the characteristics of the planets.
The four inner planets (nearest to the Sun) - Mercury, Venus, Earth and Mars - have a solid surface. They are smaller than four giant planets. Mercury moves faster than other planets, being burned by the sun's rays during the day and freezing at night.
Period of revolution around the Sun: 87.97 days. Diameter at the equator: 4878 km.
Rotation period (turn around the axis): 58 days.
Surface temperature: 350 during the day and -170 at night.
Atmosphere: very rarefied, helium.
How many satellites: 0.
The main satellites of the planet: 0.
More like the Earth in size and brightness. Observation of it is difficult because of the clouds enveloping it. The surface is a hot rocky desert. 
Period of revolution around the Sun: 224.7 days.
Diameter at the equator: 12104 km.
Rotation period (turn around the axis): 243 days.
Surface temperature: 480 degrees (average).
Atmosphere: dense, mostly carbon dioxide.
How many satellites: 0.
The main satellites of the planet: 0.
Apparently, the Earth was formed from a gas and dust cloud, like other planets. Particles of gas and dust, colliding, gradually "raised" the planet. The temperature on the surface reached 5000 degrees Celsius. Then the Earth cooled down and became covered with a hard stone crust. But the temperature in the depths is still quite high - 4500 degrees. Rocks in the bowels are molten and pour out to the surface during volcanic eruptions. Only on earth there is water. That's why life exists here. It is located relatively close to the Sun to receive the necessary heat and light, but far enough away so as not to burn out.
Period of revolution around the Sun: 365.3 days. Diameter at the equator: 12756 km.
The period of rotation of the planet (rotation around the axis): 23 hours 56 minutes.
Surface temperature: 22 degrees (average).
Atmosphere: mostly nitrogen and oxygen.
Number of satellites: 1.
The main satellites of the planet: the Moon.
Due to the similarity with the Earth, it was believed that life exists here. But the spacecraft that landed on the surface of Mars found no signs of life. This is the fourth planet in order. 
Period of revolution around the Sun: 687 days.
Diameter of the planet at the equator: 6794 km.
Rotation period (rotation around the axis): 24 hours 37 minutes.
Surface temperature: -23 degrees (average).
Atmosphere of the planet: rarefied, mostly carbon dioxide.
How many satellites: 2.
Main moons in order: Phobos, Deimos.
Jupiter, Saturn, Uranus and Neptune are made up of hydrogen and other gases. Jupiter is more than 10 times larger than Earth in diameter, 300 times in mass and 1300 times in volume. It is more than twice as massive as all the planets in the solar system combined. How much planet Jupiter does it take to become a star? It is necessary to increase its mass by 75 times!
The period of revolution around the Sun: 11 years 314 days. Diameter of the planet at the equator: 143884 km.
Rotation period (turn around the axis): 9 hours 55 minutes.
Surface temperature of the planet: -150 degrees (average).
Number of satellites: 16 (+ rings).
The main satellites of the planets in order: Io, Europa, Ganymede, Callisto.
This is the number 2 largest of the planets in the solar system. Saturn draws attention to itself thanks to a system of rings formed from ice, rocks and dust that orbit the planet. There are three main rings with an outer diameter of 270,000 km, but their thickness is about 30 meters. 
The period of revolution around the Sun: 29 years 168 days.
Diameter of the planet at the equator: 120536 km.
Rotation period (turn around the axis): 10 hours 14 minutes.
Surface temperature: -180 degrees (average).
Atmosphere: mostly hydrogen and helium.
Number of satellites: 18 (+ rings).
Main satellites: Titan.
Unique planet in the solar system. Its peculiarity is that it revolves around the Sun not like everyone else, but "lying on its side." Uranus also has rings, although they are harder to see. In 1986, Voyager 2 flew 64,000 km and had six hours of photography, which it successfully completed.
Orbital period: 84 years 4 days. Diameter at the equator: 51118 km.
The period of rotation of the planet (rotation around the axis): 17 hours 14 minutes.
Surface temperature: -214 degrees (average).
Atmosphere: mostly hydrogen and helium.
How many satellites: 15 (+ rings).
Main satellites: Titania, Oberon.
At the moment, Neptune is considered the last planet in the solar system. Its discovery took place by the method of mathematical calculations, and then they saw it through a telescope. In 1989, Voyager 2 flew by. He took amazing photographs of the blue surface of Neptune and its largest moon, Triton. 
The period of revolution around the Sun: 164 years 292 days.
Diameter at the equator: 50538 km.
Rotation period (turn around the axis): 16 hours 7 minutes.
Surface temperature: -220 degrees (average).
Atmosphere: mostly hydrogen and helium.
Number of satellites: 8.
Main moons: Triton.
On August 24, 2006, Pluto lost planetary status. The International Astronomical Union has decided which celestial body should be considered a planet. Pluto does not meet the requirements of the new formulation and loses its "planetary status", at the same time, Pluto passes into a new quality and becomes the prototype of a separate class of dwarf planets.
How did the planets appear? Approximately 5-6 billion years ago, one of the gas and dust clouds of our large Galaxy (the Milky Way), which has the shape of a disk, began to shrink towards the center, gradually forming the current Sun. Further, according to one of the theories, under the influence of powerful forces of attraction, a large number of dust and gas particles rotating around the Sun began to stick together into balls - forming future planets. According to another theory, the gas and dust cloud immediately broke up into separate clusters of particles, which compressed and condensed, forming the current planets. Now 8 planets revolve around the sun constantly.
solar system- a typical planetary system that includes a central star - Sun- and all natural space objects revolving around the sun. It was formed by gravitational compression of a gas and dust cloud about 4.57 billion years ago.
The solar system is part of the galaxy Milky Way, whose structure resembles a disk with a diameter of 100,000-120,000 light years and a thickness of 1000 light years. There are about 400 billion stars here. The solar system supposedly originated 13 billion years ago, and in the process of evolution acquired a structure peculiar only to it, not repeated in the vastness of the Universe.
The place of the solar system in the galaxy
It is located in the inner sleeve constellation Orion. The system, together with its cosmic bodies, rotates around the nucleus of the Galaxy at a speed of 250 km/sec. It takes 1 galactic year with a duration of 225 million years to complete a revolution.
Almost the entire mass of the solar system (99.87%) is concentrated in the Sun. The size of the Sun also greatly exceeds any planet in its system: even Jupiter, which is 11 times larger than the Earth, has a radius 10 times smaller than the sun. The sun is an ordinary star that shines on its own due to high temperature surfaces. The planets, on the other hand, shine by reflected sunlight (albedo) because they themselves are quite cold.
The sizes of the planets of the solar system
They are in the following order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and a dwarf planet Pluto.
Most large objects revolving around the Sun move in almost the same plane, called plane of the ecliptic. At the same time, comets and Kuiper belt objects often have large tilt angles to this plane.
Scientists also divide the planets of the solar system into two types:
- terrestrial planets;
- giant planets.
The structure of the solar system has a significant impact not only on the planets, but also on their satellites, asteroids, comets and countless meteor elements that are also part of it.
Composition of the solar system
Sun
This is a star, without which life on Earth could not exist. It gives us energy and warmth. According to the classification of stars, the Sun is a yellow dwarf. The age is about 5 billion years. It has a diameter at the equator equal to 1,392,000 km, 109 times larger than the earth. At a speed of 250 km / s, our star rushes through space around the center of the galaxy, which is “only” 26,000 light-years away. And one revolution takes about 180 million years.
The rotation period at the equator is 25.4 days and 34 days at the poles. .The temperature inside the core is approximately 15 million degrees Celsius. The surface temperature is about 5500 degrees Celsius.
A star is chemically composed mainly of hydrogen and helium. In fact, this is a giant fusion reactor. The position of the Sun on the main sequence shows that it has not yet exhausted its supply of hydrogen for nuclear fusion and is approximately in the middle of its evolution.
Now the Sun is gradually becoming brighter, in the earlier stages of its development, its brightness was only 70% of today.
Now let's figure out in order how many planets revolve around the sun, in the solar system and the characteristics of the planets.
interplanetary space
In addition to bright light, the yellow star emits a continuous stream of charged particles. It is called the “solar wind”, it propagates at a speed of 1.5 million km / h, forming a near-solar region - heliosphere. Particle flows are capable of disrupting the atmosphere of cosmic bodies that are not protected by magnetic fields, which happened to Venus and Mars.
cosmic rays come from outside the solar system.
Both the density of cosmic rays in the interstellar medium and the force magnetic field The suns change over time, so the level of cosmic radiation in the solar system is not constant, although the magnitude of the deviations is not reliably known.
The interplanetary medium is the site of the formation of at least two disk-like regions space dust.
Planets and their satellites
Earth group
Mercury
The closest to the Sun, but also the smallest of the planets (0.055 Earth masses). It revolves around itself very slowly, making only one and a half turns around its axis for a complete revolution around the star. The planet has neither an atmosphere nor satellites, during the day it heats up to +430 °С, and at night it cools down to -180 °С.
Characteristic details of the relief of its surface, in addition to impact craters, are numerous lobed ledges extending for hundreds of kilometers. It is believed that they arose as a result of tidal deformations at an early stage in the history of the planet.
Mercury has an extremely rarefied atmosphere, it consists of atoms "knocked out" from the surface of the planet by the solar wind. The relatively large iron core of Mercury and its thin crust have not yet been satisfactorily explained.
There is a hypothesis suggesting that the outer layers of the planet, consisting of light elements, were torn off as a result of a giant collision, as a result of which the size of the planet decreased.
Venus
The most romantic and closest planet to Earth is also uninhabitable. It is tightly wrapped in a thick blanket of clouds of carbon dioxide, and at a temperature up to + 475 °С has a pressure near the surface, dotted with craters, over 90 atmospheres. Venus is very close to Earth in size and mass.
It also has a thick silicate shell around an iron core and an atmosphere ( Because of this, Venus is often called the "sister" of the Earth.). There is also evidence of its internal geological activity. However, the amount of water on Venus is much less than on Earth, and its atmosphere is denser.
Venus has no satellites.
There are no clear signs of modern geological activity on Venus, but since it does not have a magnetic field that would prevent the depletion of its dense atmosphere, this allows us to assume that its atmosphere is regularly replenished by volcanic eruptions.
Earth
The Earth is the largest and densest of the terrestrial planets. The Earth has plate tectonics. The question of the presence of life anywhere other than the Earth remains open. Among the terrestrial planets, the Earth is unique (primarily due to hydrosphere). Earth's atmosphere is radically different from the atmospheres of other planets - it contains free oxygen. The Earth has one natural satellite - Moon, the only large satellite of the terrestrial planets of the solar system.
Mars
Mars is smaller than Earth and Venus (0.107 Earth masses). Similar to our planet in its structure. Its radius is half that of the earth, and its mass is an order of magnitude less. It has an atmosphere composed mainly of carbon dioxide with a surface pressure of 6.1 mbar (0.6% of Earth's).
On its surface there are volcanoes, the largest of which, Olympus, exceeds the size of all terrestrial volcanoes, reaching a height 21.2 km. Rift depressions (Mariner valleys), along with volcanoes, testify to former geological activity, which, according to some sources, continued even during the last 2 million years. The red color of the surface of Mars is caused by a large amount of iron oxide in its soil.
The Martian year is twice as long as the Earth, but the day is almost the same duration. Mars is richer than the first two planets, having two satellites: Phobos And Deimos, translated from Greek as "fear" and "horror". These are small boulders, very similar to asteroids.
Today (after the Earth) Mars is the most studied planet in the solar system.
giant planets
Jupiter
The largest gas giant planet. If its mass were several tens of times greater, it could really become a star.
Jupiter has a mass of 318 times that of the earth, and 2.5 times more massive than all the other planets combined.
It consists mainly of hydrogen And helium. high internal temperature Jupiter causes many semi-permanent vortex structures in its atmosphere, such as cloud bands and big red spot.
A day on the planet lasts about 10 hours, and a year passes for 12 Earth hours. Jupiter, like Saturn and Uranus, has a ring system. He has four of them, but they are not very pronounced, from afar you can not notice.
Jupiter has 79 satellites. The four largest Ganymede, Callisto, And about And Europe- are similar to the terrestrial planets in such phenomena as volcanic activity and internal heating.
Ganymede, the largest moon in the solar system, is larger than Mercury.
Saturn
Saturn, known for its extensive ring system, has a somewhat similar structure to Jupiter's atmosphere and magnetosphere. Although the volume of Saturn is 60% of Jupiter's, the mass (95 Earth masses) is less than a third of Jupiter's; thus, Saturn is the least dense planet in the solar system (its average density is less than that of water).
Saturn has 82 confirmed moons; two of them - Titanium And Enceladus- show signs of geological activity. This activity, however, is not similar to the Earth's, since it is largely due to the activity of ice.
Titanium, larger than Mercury, is the only satellite in the solar system with a substantial atmosphere.
Uranus
With a mass 14 times that of Earth, Uranus is the lightest of the giant planets. The peculiarity of this planet, which appears to the observer in blue-green tones, is in its rotation. The axis of rotation of the planet is almost parallel to the plane of the ecliptic. In everyday language, Uranus lies on its side. If other planets can be compared to spinning tops, then Uranus is more like a rolling ball.
But this did not stop him from acquiring 13 rings and 27 satellites, the most famous of which Oberon, Titania, Ariel, Umbriel.
It has a much colder core than other gas giants and radiates very little heat into space.
Neptune
Externally, Neptune is similar to Uranus; its spectrum is also dominated by methane and hydrogen bands. The flow of heat from Neptune significantly exceeds the power of the solar heat incident on it, which indicates the existence of an internal source of energy. It is possible that a significant part of the internal heat is released as a result of tides caused by a massive satellite. Triton, which rotates in the opposite direction at a distance of 14.5 planetary radii. Voyager 2, flying in 1989 at a distance of 5000 km from the cloud layer, discovered 6 more satellites and 5 rings near Neptune.
In the atmosphere were open Great Dark Spot and a complex system of vortex flows. The pinkish surface of Triton revealed amazing geological details, including powerful geysers. Satellite discovered by Voyager Proteus turned out to be larger than the Nereid discovered from Earth back in 1949.
Ninth planet
On January 20, 2016, astronomers announced a possible ninth planet on the outskirts of the solar system, outside the orbit of Pluto. The planet is about ten times more massive than the Earth, about 20 times farther from the Sun than Neptune (90 billion kilometers), and orbits the Sun in 10,000-20,000 years. According to scientists, the probability that this planet really exists is "perhaps 90%". For now, this hypothetical planet is simply referred to as "Planet Nine".
dwarf planets
Dwarf planets are those that have a diameter of about 1000 km. This Pluto, which received this status in 2006, is the brightest representative of the main asteroid ring - Ceres and distant Eris.
Small objects
Kuiper Belt
The Kuiper Belt, a region of relics from the formation of the solar system, is a large belt of debris, similar to the asteroid belt, but composed mostly of ice. Extends between 30 and 55 AU. e. from the Sun. Composed primarily of small Solar System bodies, but many of the largest Kuiper Belt objects, such as Quaoar, Varuna And Orc, can be reclassified to dwarf planets after specifying their parameters. A mass of small bodies, ice, is concentrated here.
They are composed of methane, ammonia and water, but there are objects that include rocks and metals.
asteroids
asteroids- the most common small bodies of the solar system.
asteroid belt occupies an orbit between Mars and Jupiter. According to modern views, asteroids are the remnants of the formation of the solar system, which were not able to combine into a large body due to the gravitational perturbations of Jupiter.
Asteroids vary in size from a few meters to hundreds of kilometers. Among them there are both very small and large ones, for example, Vesta And Hygiea They may even be reclassified as dwarf planets if they can be shown to maintain hydrostatic equilibrium.
The belt contains tens of thousands, perhaps millions, of objects larger than one kilometer in diameter. Despite this, the total mass of the belt's asteroids is hardly more than one-thousandth the mass of the Earth.
Meteors and meteorites
Space objects of small size, periodically breaking into the atmospheric layer of the Earth, until the moment of falling are called meteorites. At the moment they enter the earth's atmosphere, they are reclassified as meteors. They burn in the air before falling, a small part falls to the surface.
Comets
If you translate this word from Greek, you get "long-haired." And it is. When the ice wanderer approaches the Sun, it spreads a long tail of evaporating gases for hundreds of millions of kilometers.
A comet also has a head, consisting of a nucleus and a coma. The core is an ice block of frozen gases with the addition of silicates and metal particles. It is possible that some organic matter is also present. A coma is the gas and dust environment of a comet.
outlying areas
The question of exactly where the solar system ends and interstellar space begins is ambiguous.
Two factors are taken as key in their determination: the solar wind and solar gravitation. Outer boundary of the solar wind - heliopause, behind it the solar wind and interstellar matter mix, mutually dissolving.
The heliopause is about four times farther than Pluto and is considered the beginning of interstellar medium .
However, it is assumed that the region in which the gravity of the Sun prevails over the galactic - hill sphere extends a thousand times further.
Much of our solar system is still unknown. It is estimated that the gravitational field of the Sun dominates the gravitational forces of the surrounding stars at a distance of approximately two light years (125,000 AU).
Oort cloud
The hypothetical Oort cloud is a spherical cloud of icy objects (up to a trillion) that serves as a source of long-period comets. The estimated distance to the outer boundaries of the Oort cloud from the Sun is from 50 000 a. e. (approximately 1 light year) to 100 000 a. e. (1.87 light years).
The objects that make up the cloud are believed to have formed near the Sun and were scattered far into space by the gravitational effects of the giant planets early in the evolution of the solar system.
Earth's place in the solar system
A better position than what occupies Earth, impossible to imagine. The part of our Galaxy is quite calm. The sun provides a constant, uniform glow. It emits exactly as much heat, radiation and energy as is required for the origin and development of life.
The Earth itself seemed to have been thought out in advance:
- The ideal composition of the atmosphere, and the geological structure.
- Desired radiation background and temperature regime.
- The presence of water with its amazing properties.
Presence Moon, of just such a mass and at such a distance as required. There are many more coincidences that are crucial for a favorable life on the planet. And the violation of almost any of them would make the emergence and existence of life unlikely.
System stability
The revolution of the planets around the Sun occurs in one (direct) direction. The orbits of the planets are almost circular, and their planes are close to the Laplace plane. This is the main plane of the solar system. Our life is subject to the laws of mechanics, and the solar system is no exception.
The planets are connected to each other law of gravity. Based on the absence of friction in interstellar space, we can confidently assume that the motion of the planets relative to each other will not change. In any case, in the next million years. Many scientists have tried to calculate the future of the planets in our system.
But everyone - and even Einstein - got one thing: the planets of the solar system will always be stable.
Chemical composition
In the solar system, there is a strong gradient (difference) in chemical composition: planets and satellites close to the Sun consist of refractory materials, and in the composition of distant bodies there are many volatile elements. This means that during the formation of the solar system there was a large temperature gradient. Modern astrophysical models of chemical condensation suggest that the initial composition of the protoplanetary cloud was close to the composition of the interstellar medium and the Sun: by mass up to 75% hydrogen, up to 25% helium and less than 1% of all other elements.
These models successfully explain the observed variations in chemical composition in the solar system.
ABOUT chemical composition distant objects can be judged based on the meaning of their medium density, as well as by spectra of their surface and atmosphere. This could be done much more accurately by analyzing samples of planetary matter, but so far we have only samples from the Moon and meteorites.
By studying meteorites, we begin to understand the chemical processes in the primordial nebula. However, the process of agglomeration of large planets from small particles is still unclear.
Life in the solar system
It has been suggested that life in the solar system once existed beyond the Earth, and perhaps exists now. The advent of space technology made it possible to begin direct testing of this hypothesis. Mercury turned out to be too hot and devoid of atmosphere and water. On Venus it is also very hot - lead melts on its surface. The possibility of life in the upper cloud layer of Venus, where conditions are much milder, is nothing more than a fantasy. Moon and the asteroids look completely sterile.
Great hopes were placed on Mars. Seen through a telescope 100 years ago, systems of thin straight lines - "channels" - then gave reason to talk about artificial irrigation facilities on the surface of Mars. But now we know that the conditions on Mars are unfavorable for life: cold, dry, very rarefied air and, as a result, strong ultraviolet radiation from the Sun, sterilizing the surface of the planet.
Instruments of the Viking landing blocks did not detect organic matter in the soil of Mars.
True, there are signs that the climate of Mars has changed significantly and may once have been more favorable for life. It is known that in the distant past there was water on the surface of Mars, since detailed images of the planet show traces of water erosion, reminiscent of ravines and dry riverbeds.
Illustration on the theme "Is there life on Mars?"
Although in atmospheres giant planets a lot of organic molecules, it's hard to believe that in the absence of a solid surface, life could exist there. In this sense, the satellite of Saturn is much more interesting. Titanium, which has not only an atmosphere with organic components, but also a solid surface where synthesis products can accumulate. True, the temperature of this surface (90 K) is more suitable for oxygen liquefaction. Therefore, the attention of biologists is more attracted by the satellite of Jupiter Europe, although devoid of an atmosphere, but, apparently, having an ocean of liquid water under its icy surface.
It should be noted that interplanetary probes are able to detect signs of active life on the surface of planets. But if life is hidden under Europa's ice shell, then a vehicle flying by is unlikely to detect it.
Some comets almost certainly contain complex organic molecules dating back to the formation of the solar system. But it's hard to imagine life on a comet. So while we have there is no evidence that life in the solar system exists anywhere beyond Earth.
- About 99.86% of the total mass of the solar system is the Sun itself.
- Between the Earth and the Moon, all the other planets of the solar system would fit.
- Among all the planets of the solar system, Uranus and Neptune are the least studied, and Mars is the most studied.
- Of all the planets in the solar system, only Venus rotates clockwise. All others are counter-clockwise, except for Uranus. Due to the 90 degree tilt angle, Uranus rotates as if lying on its side.
- Only three celestial bodies in the solar system, not counting the gas giants, have a dense atmosphere - Earth, Venus and Titan, a satellite of Saturn.
- Mercury's core occupies a larger percentage of the total volume than any other planet. Scientists believe that the once monstrous collision literally ripped off the planetary crust from it.
- Europa, one of Jupiter's moons, has more water than Earth.
- Not only Saturn has rings, but all the other giant planets - Jupiter, Uranus and Neptune.
- The temperature near the Sun is greater than on its surface. This riddle has yet to be solved. Perhaps the magnetic forces of the star's atmosphere are at work.
- Atmosphere of Titan. It is the only satellite of the planets that has an atmosphere. And it consists mainly of nitrogen. Almost like earth.
- It remains a mystery why the activity of the Sun changes with a certain frequency and time.
- Pluto for all the time that has passed since its discovery until the deprivation of its status as a planet, has not made a single complete revolution around the Sun.
- Jupiter protects our Earth from asteroids and meteorites - its powerful gravity attracts them, and they burn up in its atmosphere without reaching our planet.
- The radiation emitted by the Sun is deadly, and only the atmosphere and the Earth's magnetic field protect us from it.
- The largest space object in the solar system is the International Space Station. And at the same time the most expensive, and in the entire history of mankind at once.
- Our solar system has a tail that resembles a four-leaf clover.
- A huge number of planetary satellites of the solar system are dead.
- If we compare the solar system and space, then it is just a grain of sand in it.
- Some researchers claim that the solar system was created artificially.
- Launched in 1977, Voyager 1 was the first spacecraft to travel outside the solar system.
Our home in space is the solar system, a star system made up of eight planets and part of the Milky Way galaxy. In the center is a star called the Sun. The solar system is four and a half billion years old. We live on the third planet from the sun. Do you know about other planets in the solar system? Now we will tell you a little about them.
Mercury is the smallest planet in the solar system. Its radius is 2440 km. The period of revolution around the Sun is 88 Earth days. During this time, Mercury has time to complete a revolution around its own axis only one and a half times. A day on Mercury lasts approximately 59 Earth days. The orbit of Mercury is one of the most unstable: not only the speed of movement and its distance from the Sun change there, but also the position itself. There are no satellites.
Neptune is the eighth planet in the solar system. It is close enough to Uranus. The radius of the planet is 24547 km. A year on Neptune is equal to 60190 days, that is, somewhere around 164 Earth years. Has 14 satellites. It has an atmosphere in which the strongest wind is recorded - up to 260 m / s.
By the way, Neptune was discovered not with the help of observations, but through mathematical calculations.
Uranus is the seventh planet in the solar system. Radius - 25267 km. The coldest planet is a surface temperature of -224 degrees. A year on Uranus is equal to 30,685 Earth days, that is, approximately 84 years. Day - 17 hours. Has 27 satellites.
Saturn is the sixth planet in the solar system. The radius of the planet is 57350 km. It is the second largest after Jupiter. A year on Saturn is equal to 10759 days, which is almost 30 Earth years. A day on Saturn is almost equal to a day on Jupiter - 10.5 Earth hours. Most similar to the Sun in the composition of chemical elements.
Has 62 satellites.
The main feature of Saturn is its rings. Their origin has not yet been established.
Jupiter is the fifth planet from the Sun. It is the largest planet in the solar system. The radius of Jupiter is 69912 km. This is already 19 times larger than the Earth. A year there lasts as much as 4333 Earth days, that is, almost incomplete 12 years. A day has a duration of about 10 Earth hours.
Jupiter has 67 moons. The largest of them are Callisto, Ganymede, Io and Europa. At the same time, Ganymede is 8% larger than Mercury, the smallest planet in our system, and has an atmosphere.
Mars is the fourth planet in the solar system. Its radius is 3390 km, which is almost half the size of the Earth. A year on Mars is 687 Earth days. It has 2 satellites - Phobos and Deimos.
The atmosphere of the planet is rarefied. The water found on some parts of the surface suggests that some kind of primitive life on Mars was once before or even exists now.
Venus is the second planet in the solar system. It is similar in mass and radius to the Earth. There are no satellites.
The atmosphere of Venus is almost entirely composed of carbon dioxide. The percentage of carbon dioxide in the atmosphere is 96%, nitrogen is approximately 4%. Water vapor and oxygen are also present, but in very small quantities. Due to the fact that such an atmosphere creates a greenhouse effect, the temperature on the surface of the planet reaches 475 ° C. A day on Venus is equal to 243 Earth days. A year on Venus is 255 days.
Pluto is a dwarf planet at the edges of the solar system, which is the dominant object in a distant system of 6 small cosmic bodies. The radius of the planet is 1195 km. The period of revolution of Pluto around the Sun is approximately 248 Earth years. A day on Pluto is 152 hours. The mass of the planet is approximately 0.0025 of the mass of the Earth.
It is noteworthy that Pluto was excluded from the category of planets in 2006 due to the fact that in the Kuiper belt there are objects that are larger or equal in size to Pluto, which is why, even if it is taken as a full-fledged planet, then in this case it is necessary add Eris to this category - it has almost the same size as Pluto.
