Planets of the solar system: photos. What the planets look like: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. The structure of the solar system Jupiter is the largest giant planet
If you are interested in seeing the photo, what do all the planets look like solar system, the material in this article is just for you. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune in the photo look extremely diverse and this is not surprising, because each planet is a perfect and unique “organism” in the universe.
So, see below for a brief description of the planets, as well as photos.
What Mercury looks like in the photo
Mercury
Venus is more similar in size and emitted brightness to Earth. Observing it is extremely difficult due to the densely enveloping clouds. The surface is a rocky, hot desert.
Characteristics of the planet Venus:
Diameter at the equator: 12104 km.
Average surface temperature: 480 degrees.
Orbit around the Sun: 224.7 days.
Rotation period (rotation around an axis): 243 days.
Atmosphere: dense, mostly carbon dioxide.
Number of satellites: no.
The main satellites of the planet: none.
What does the Earth look like in the photo?
Earth
Mars is the 4th planet from the sun. For some time, due to its similarities to Earth, it was assumed that life existed on Mars. But the spacecraft launched onto the surface of the planet did not detect any signs of life.
Characteristics of the planet Mars:
Diameter of the planet at the equator: 6794 km.
Average surface temperature: -23 degrees.
Orbit around the Sun: 687 days.
Rotation period (rotation around an axis): 24 hours 37 minutes.
The planet's atmosphere: thin, mostly carbon dioxide.
Number of satellites: 2 pcs.
The main satellites in order: Phobos, Deimos.
What Jupiter looks like in the photo
Jupiter
Planets: Jupiter, Saturn, Uranus and Neptune are composed of hydrogen and other gases. Jupiter is 10 times larger than Earth in diameter, 1300 times in volume and 300 times in mass.
Characteristics of the planet Jupiter:
Diameter of the planet at the equator: 143884 km.
Average surface temperature of the planet: -150 degrees (average).
Orbit around the Sun: 11 years 314 days.
Rotation period (rotation around an axis): 9 hours 55 minutes.
Number of satellites: 16 (+ rings).
The main satellites of the planets in order: Io, Europa, Ganymede, Callisto.
What Saturn looks like in the photo
Saturn
Saturn is considered the second largest planet in the solar system. A system of rings formed from ice, rocks and dust rotates around the planet. Among all the rings, there are 3 main rings with a thickness of about 30 meters and an outer diameter of 270 thousand km.
Characteristics of the planet Saturn:
Diameter of the planet at the equator: 120536 km.
Average surface temperature: -180 degrees.
Orbit around the Sun: 29 years 168 days.
Rotation period (rotation around an axis): 10 hours 14 minutes.
Atmosphere: Mainly hydrogen and helium.
Number of satellites: 18 (+ rings).
Main satellites: Titan.
What does Uranus look like in the photo?
UranusNeptune
Currently, Neptune is considered the last planet of the solar system. Pluto has been removed from the list of planets since 2006. In 1989, unique photographs of the blue surface of Neptune were obtained.
Characteristics of the planet Neptune:
Diameter at the equator: 50538 km.
Average surface temperature: -220 degrees.
Orbit around the Sun: 164 years 292 days.
Rotation period (rotation around an axis): 16 hours 7 minutes.
Atmosphere: Mainly hydrogen and helium.
Number of satellites: 8.
Main satellites: Triton.
We hope you saw what the planets look like: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and found out
how great they all are. Their view, even from space, is simply mesmerizing.
Also see "Planets of the solar system in order (in pictures)"
The most important (and most massive!) member of the Solar System is the Sun itself. Therefore, it is no coincidence that the great luminary occupies a central position in the solar system. It is surrounded by numerous satellites. The most significant of them are the large planets.
The planets are spherical "celestial lands". Like the Earth and the Moon, they do not have their own light - they are illuminated exclusively by the sun's rays. Nine large planets are known, distant from the central luminary in the following order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. Five planets - Mercury, Venus, Mars, Jupiter and Saturn - have been known to people since time immemorial due to their bright brilliance. Nicolaus Copernicus included our Earth among the planets. And the most distant planets - Uranus, Neptune and Pluto - were discovered using telescopes.
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Solar system, a system of cosmic bodies, including, in addition to the central body - Sun- nine large planets, their satellites, many small planets, comets, small meteoroids and cosmic dust moving in the region of the prevailing gravitational action of the Sun. The Solar system was formed about 4.6 billion years ago from a cold cloud of gas and dust. Currently, using modern telescopes (in particular the Hubble Space Telescope), astronomers have discovered several stars with similar protoplanetary nebulae, which confirms this cosmogonic hypothesis. |
Our Earth is in third place from the Sun. Its average distance from it is 149,600,000 km. It is taken as one astronomical unit (1 AU) and serves as a standard in measuring interplanetary distances. Light travels 1 a. i.e. in 8 minutes and 19 seconds, or in 499 seconds.
The average distance of Mercury from the Sun is 0.387 AU. That is, it is 2.5 times closer to the central luminary than our Earth, and the average distance of distant Pluto is almost 40 such units. A radio signal sent from Earth towards Pluto would take almost 5.5 hours to travel. The further a planet is from the Sun, the less radiant energy it receives. Therefore, the average temperature of the planets decreases rapidly with increasing distance from the radiant star.
According to their physical characteristics, the planets are clearly divided into two groups. The four closest to the Sun - Mercury, Venus, Earth and Mars - are called terrestrial planets. They are relatively small, but their average density is high: about 5 times the density of water. After the Moon, the planets Venus and Mars are our closest cosmic neighbors. Far from the Sun, Jupiter, Saturn, Uranus and Neptune are much more massive than the terrestrial planets and are even larger in volume. In the interiors of these planets, the matter is highly compressed, however, their average density is low, and Saturn has even less than the density of water. Hence, giant planets consist of lighter (volatile) substances than terrestrial planets.
At one time, astronomers considered Pluto to be a planet like Earth. However, recent research has forced scientists to abandon this view. Frozen methane was detected on its surface using spectroscopy. This discovery indicates the similarity of Pluto with the large satellites of the giant planets. Some researchers are inclined to think that Pluto is a “runaway” satellite of Neptune.
Even Galileo, who discovered the four largest satellites of Jupiter (they are called Galilean satellites), imagined the remarkable Jupiterian family as a miniature Solar System. Today natural satellites are known from almost all major planets (with the exception of Mercury and Venus), and their total number has increased to 137. The giant planets have especially many moon satellites.
If we had the opportunity to look at the solar system from its north pole, we would be able to observe a picture of the orderly movement of the planets. They all move around the Sun in almost circular orbits in the same direction - opposite to the clockwise rotation. This direction of movement in astronomy is usually called straight movement. But the revolution of the planets does not occur around the geometric center of the Sun, but around the general center of mass of the entire Solar System, in relation to which the Sun itself describes a complex curve. And very often this center of mass ends up outside the solar globe.
The solar system is far from being limited to the central luminary - the Sun and nine large planets with their satellites. There are no words, the major planets are the most important representatives of the Sun family. However, our great luminary still has many other “relatives”.
The German scientist Johannes Kepler spent almost his entire life searching for the harmony of planetary movements. He was the first to draw attention to the fact that between the orbits of Mars and Jupiter there is an empty space. And Kepler was right. Two centuries later, in this interval, a planet was actually discovered, only not a large one, but a small one. In terms of its diameter, it turned out to be 3.4 times smaller, and in terms of volume, 40 times smaller than our Moon. The new planet was named after the ancient Roman goddess Ceres, the patroness of agriculture.
Over time, it became clear that Ceres has thousands of celestial “sisters” and most of them move just between the orbits of Mars and Jupiter. There they form a kind of belt of minor planets. Mostly these are tiny planets with a diameter of about 1 km. Second belt of minor planets recently discovered on the outskirts of our planetary system - beyond the orbit of Uranus. It is possible that the total number of these celestial bodies in the Solar System reaches several million.
But the family of the Sun is not limited to just the planets (large and small). Sometimes tailed “stars” are visible in the sky - comets. They come to us from afar and usually appear suddenly. According to scientists, on the outskirts of the solar system there is a “cloud” consisting of 100 billion potential, that is, not manifested, cometary nuclei. This is what serves as a constant source of the comets we observe.
Occasionally we are “visited” by giant comets. The bright tails of such comets stretch almost across the entire sky. Thus, the comet of September 1882 had a tail reaching a length of 900 million km! When the nucleus of this comet flew near the Sun, its tail went far beyond the orbit of Jupiter...
As you can see, our Sun turned out to have a very large family. In addition to the nine large planets with their satellites, under the leadership of the great luminary there are at least 1 million small planets, about 100 billion comets, as well as countless meteor bodies: from blocks several tens of meters in size to microscopic dust grains.
The planets are located at enormous distances from each other. Even Venus, which is adjacent to the Earth, is never closer to us than 39 million km, which is 3000 times the diameter of the globe...
You can’t help but wonder: what is our solar system? A space desert with individual worlds lost in it? Emptiness? No, the solar system is not empty. An incalculable number of particles of solid matter of the most varied sizes, but mostly very small, with a mass of thousandths and millionths of a gram, are moving in interplanetary space. This meteor dust. It is formed by the evaporation and destruction of cometary nuclei. As a result of the fragmentation of colliding small planets, fragments of various sizes arise, the so-called meteoroids. Under the pressure of solar rays, the smallest particles of meteoric dust are swept to the outskirts of the solar system, and larger ones spiral towards the Sun and, before reaching it, evaporate in the vicinity of the central star. Some meteoroids fall to Earth as meteorites.
The circumsolar space is penetrated by all types of electromagnetic radiation and corpuscular flows.
Their very powerful source is the Sun itself. But on the outskirts of the Solar system, radiation emanating from the depths of our Galaxy predominates. By the way: how to establish the boundaries of the solar system? Where do they go?
It may seem to some that the boundaries of the solar domain are delineated by the orbit of Pluto. After all, there seem to be no large planets beyond Pluto. This is where it’s time to “dig in” the boundary pillars... But we must not forget that many comets go far beyond the orbit of Pluto. Aphelia- the farthest points of their orbits lie in a cloud of primordial ice cores. This hypothetical (alleged) cometary cloud is apparently 100 thousand AU away from the Sun. e., that is, 2.5 thousand times further than Pluto. So the power of the great luminary extends here too. The solar system is here too!
Obviously, the Solar System reaches those places in interstellar space where the gravitational force of the Sun is commensurate with the gravitational force of the nearest stars. The closest star to us, Alpha Centauri, is 270 thousand AU away from us. e. and its mass is approximately equal to the Sun. Consequently, the point at which the gravitational forces of the Sun and Alpha Centauri are balanced is located approximately in the middle of the distance separating them. This means that the boundaries of the solar domain are at least 135 thousand AU away from the great luminary. e., or 20 trillion kilometers!
The planets of the Jupiter group include giant fluid planets (,), which have a powerful thermal reserve in their depths. Based on the composition of the fluid shells, the planets of the Jupiter group are divided into peripheral planets with shells of mostly water composition (Uranus, Neptune) and hydrogen planets occupying an internal position in the solar system (Jupiter, Saturn), with a composition not significantly different from the solar one.
Jupiter
Jupiter is the fifth largest planet from the Sun and the largest planet in the Solar System. Jupiter looks like a golden ball, barely flattened perpendicular to the poles. This planet is 5.2 times farther from the Sun than , and spends almost 12 years on one orbital revolution. Jupiter's equatorial diameter is 142,600 km (11 times the diameter of Earth). The period of Jupiter's revolution around its axis in the equatorial region is 9 hours 50 minutes, near the poles - 9 hours 55 minutes.
Photo of Jupiter (taken by NASA's Juno spacecraft).
Thus, Jupiter, like , does not rotate like a rigid body, since its rotation speed is not the same at different latitudes. Due to its rapid rotation, this planet is strongly compressed at the poles. Jupiter's mass is equal to 318 Earth masses. The average density of its substance is close to the density of the Sun - 1.33 g/cm 3 .
Jupiter's rotation axis is almost perpendicular to the plane of its orbit (inclination 87°). Jupiter's fluid envelope consists mainly of helium (74%) and helium (26%), as well as methane (0.1%) and small amounts of ethane, acetylene, phosphene and water vapor. The atmospheric layer is about 1000 km thick.
The planet is shrouded in a layer of clouds, but all the details on the surface of Jupiter constantly change their appearance, since violent movements occur in this layer associated with the transfer of large amounts of energy. Jupiter consists of crystals and drops of ammonia.
The most revealing feature of the planet is the Great Red Spot, which has been observed for more than 300 years. This is a huge oval formation, measuring about 35,000 x 14,000 km, located between the southern tropical and southern temperate zones. Its color is red, but undergoes changes. Probably, the Great Red Spot is supported by convective cells, through which its substance and internal heat are carried from the depths to the visible surface of Jupiter.
In 1956, radio emission from Jupiter was discovered at a wavelength of 3 cm, which corresponds to thermal radiation with a temperature of 145 K. According to measurements in the infrared range of the outer clouds of Jupiter, it was 130 K. It has already been reliably established that Jupiter emits heat, the amount of which is more than twice that thermal energy it receives from the Sun. Perhaps heat is released due to the fact that the giant planet is constantly shrinking (1 mm per year).
In the center of the planet is a huge iron-stone core that generates a powerful magnetic field. The planet’s magnetic field turned out to be complex and consists of two fields: a dipole (similar to Earth’s), extending up to 1,500,000 km from Jupiter, and a non-dipole, occupying another part of the magnetosphere. The surface magnetic field strength is 20 times greater than on Earth. In addition, Jupiter is also a source of radio bursts (sharp jumps in radiation power) at wavelengths from 4 to 85 m; they occur with a period from a fraction of a second to several minutes or even hours. Long bursts include a whole series of disturbances consisting of peculiar noise storms and thunderstorms. According to modern hypotheses, these bursts are explained by plasma oscillations in the planet’s ionosphere.
Jupiter has 15 satellites. The first 4 satellites were discovered by Galileo (Io, Europa, Ganymede, Callisto). They, as well as the inner, closest satellite Amalthea, move almost in the plane of the planet’s equator. In size, Io and Europa can be compared with the Moon, and Ganymede and Callisto are larger than Mercury, but are significantly inferior to it in mass.
The outer satellites rotate around the planet along highly elongated orbits with large inclination angles to the equator (up to 30°). These are small bodies (from 10 to 120 km), obviously of irregular shape. Jupiter's four outer satellites orbit the planet in the opposite direction. In the equatorial region, Jupiter is surrounded by a system of rings. The rings are located at a distance of 50,000 km from the surface of the planet, the width of the rings is about 1000 km.
Saturn
Saturn is the second largest, but rather light (with an average density of 0.69 g/cm 3) planet in the Solar System. The low density is explained by the fact that giant planets consist primarily of hydrogen and helium. At the same time, in the depths of Saturn the pressure does not reach such high values as on Jupiter, so the density of matter there is less. Like Jupiter, it rotates very quickly on its axis (with an orbital period of about 10 hours) and is therefore noticeably oblate.
Saturn. Photo taken by the Cassini spacecraft (NASA) Spectroscopic studies have made it possible to find some molecules in the atmosphere of Saturn. The planet's interior contains powerful heat, which it emits (2.5 times more than it receives from the Sun). The surface temperature of clouds on Saturn is close to the melting point of methane (-184 ° C), the solid particles of which are most likely contained in the cloud layer of the planet.
Saturn is surrounded by rings (about 3 km thick), which are clearly visible through a telescope in the form of “ears” on both sides of the planet’s disk. They were noticed back in 1610 by Galileo. The plane of the rings practically coincides with the plane of the planet's equator and has a constant inclination to the orbital plane of approximately 27°.
Photo of Saturn's rings taken by Cassini in 2008. The rings of Saturn are one of the most amazing and interesting formations in the solar system. A flat system of rings encircles the planet around the equator and does not touch the surface anywhere. The rings are divided into three main concentric zones, delimited by narrow gaps: the outer ring A (with a diameter of about 275 thousand km), the middle B (the brightest) and the inner ring C, which is relatively transparent. The barely visible parts of the inner ring closest to the planet are designated by the symbol D. The existence of another, almost transparent outer ring has also been discovered. The rings rotate around Saturn and the speed of movement of their inner layers is greater than the outer ones.
The rings of Saturn are a flat system of many small satellites of the planet. Saturn has 17 known moons. The largest satellite is Titan, which is also one of the largest satellites in the solar system in terms of size and mass. The Janus satellite is the closest to Saturn, located almost close to the planet. One of the satellites, Phoebe, moves in orbit with a fairly large eccentricity in the opposite direction.
Uranus
Uranus is the seventh planet from the Sun, with a diameter (with a radius of 25,650 km) almost four times larger than the Earth. Uranus is very far from the Sun and is relatively dimly illuminated. The average density of Uranus (1.58 g/cm3) is slightly greater than the density of Saturn and Jupiter, although the matter in the depths of these giants is much more compressed than on Uranus. According to spectroscopic observations, hydrogen and a small amount of methane were found in the composition of the atmosphere of Uranus; there is also, according to indirect evidence, a relatively large amount of helium. Like other giant planets, Uranus has this composition, probably almost all the way to the center.
Uranus Uranus is still poorly studied, as it is extremely difficult to examine due to its small angular dimensions in the field of view of a telescope. For the same reason, it is impossible to study the patterns of rotation of the planet. It is obvious that Uranus (unlike other planets) rotates around its axis, as if lying on its side. This tilt of the equator creates unusual lighting conditions: at the poles in a certain season, the sun's rays fall almost vertically, and the polar day and night cover (alternately) the entire surface of the planet, except for a narrow strip along the equator.
Since Uranus completes its orbit around the Sun in 84 years, the polar day at its poles lasts 42 years, then gives way to a polar night of the same duration. Only in the equatorial belt of Uranus the Sun regularly rises and sets with a periodicity equal to the axial rotation of the planet. Even in those areas where the Sun is at its zenith, the temperature on the visible surface of the clouds is about -215 ° C. Under such temperature conditions, some gases freeze.
The iron-stony core of Uranus is larger in size (about 8000 km) compared to the terrestrial planets. The generated magnetic field of Uranus is also greater than that of Earth.
An unusual feature of Uranus is a system of rings, the distance of which from the planet is from 1.6 to 1.85 of the radius of Uranus. Narrow rings that look like “thread-like” formations, consisting of many individual opaque and, apparently, very dark particles. In the region of the rings there is a whole system of radiation belts filled with high-energy particles, which are similar to the earth's radiation belts, but are distinguished by high levels of radiation.
Uranus has 6 satellites rotating in orbits whose planes practically coincide with each other. The entire system as a whole is distinguished by an extraordinary tilt - its plane is almost perpendicular to the average plane of all planetary orbits.
Neptune
Neptune is the eighth planet in the solar system and a close analogue of Uranus, but has a slightly larger mass and a slightly smaller radius. The average distance of Neptune from the Sun is 4500000000 km, its orbital period is 164 years and 288 days. Neptune's equatorial diameter is 50,200 km; average density - 2.30 g/cm3.
Neptune The characteristics of Neptune are typical of giant planets, which consist mainly of hydrogen and helium with an admixture of other chemical compounds. Neptune has a heavy core containing silicates and other terrestrial elements. The fluid (mostly water) shell of the atmosphere consists of hydrogen, helium and methane.
Neptune has a strong magnetic field, the axis of which, like that of Uranus, is inclined by about 50° to the axis of rotation and is offset from the center of the planet by about 10,000 km. Unlike the calm, freezing surface of Uranus, strong winds dominate on the surface of Neptune, causing storms from powerful jets of gases that rise from the bowels of the planet. Features on Neptune's surface are very difficult to discern.
Neptune has only two satellites. The first - Triton - is larger in size and mass than the Moon, and has the opposite direction of orbital motion. The second satellite, Nereid, unlike the first, is very small and has a highly elongated orbit. The distance from the satellite to the planet varies from 1,500,000 to 9,600,000 km. The direction of orbital motion is direct.
Pluto It is very difficult to study Pluto due to its considerable distance from the Sun and low illumination. The diameter of Pluto is approximately 3 thousand km. The surface of Pluto, heated by the Sun to -220 ° C, even in the coldest midday areas is apparently covered with snow from frozen methane.
The planet's atmosphere is rarefied and consists of methane gas with a possible admixture of inert gases. The brightness of Pluto varies with a rotation period of 6 days 9 hours. Relatively recently, it became clear that this same periodicity corresponds to the orbital motion of Pluto’s satellite, Charon. The satellite is relatively bright, but is located so close to the planet that its images in photographs merge with the image of Pluto and it looks like the “hump” of the planet. Charon, like Pluto, is an accumulation of cometary matter, that is, a mixture of ice and dust.
It was possible to calculate the mass of the Pluto-Charon system: 1.7% of the mass of the Earth. Almost all of it is concentrated in Pluto, because the diameter of the satellite, judging by its brightness, is small compared to the diameter of the planet. The average density of Pluto is approximately 0.7-1.12 g/cm 3 . Such a low density means that Pluto consists predominantly of light chemical elements and compounds, that is, its composition is similar to that of the giant planets and their satellites.
The solar system includes the central star and all the natural space objects orbiting it. It was formed by gravitational compression of a gas and dust cloud approximately 4.57 billion years ago. The Solar System includes 8* planets, half of which belong to the terrestrial group: Mercury, Venus, Earth and Mars. They are also called the inner planets in contrast to the outer planets - the giant planets Jupiter, Saturn, Uranus and Neptune, located outside the ring of minor planets.
1. Mercury
The planet closest to the Sun in the Solar System is named after the ancient Roman god of commerce, the fleet-footed Mercury, because it moves across the celestial sphere faster than other planets.
2. Venus
The second planet of the solar system was named in honor of the ancient Roman goddess of love Venus. It is the brightest object in the earth's sky after the Sun and Moon and the only planet in the solar system named after a female deity.
3. Earth
The third planet from the Sun and the fifth largest among all the planets in the Solar System has had its current name since 1400, but who exactly named it that is unknown. The English word Earth comes from an 8th century Anglo-Saxon word meaning earth or ground. This is the only planet in the solar system with a name that is not related to Roman mythology.
4. Mars
The seventh largest planet in the solar system has a reddish tint to its surface due to iron oxide. With such a “bloody” association, the object was named after the ancient Roman god of war, Mars.
5. Jupiter
The largest planet in the solar system is named after the ancient Roman supreme god of thunder. 6. Saturn Saturn is the slowest planet in the solar system, which is symbolically reflected in its first name: it was given in honor of the ancient Greek god of time, Kronos. In Roman mythology, the god of agriculture Saturn turned out to be the analogue of Kronos, and as a result, this name was assigned to the planet.
7. Uranus
The third largest planet in diameter and fourth largest planet in the solar system was discovered in 1781 by the English astronomer William Herschel. The tradition of naming planets was continued, and the international community named the new celestial body in honor of the father of Kronos, the Greek god of the sky, Uranus.
8. Neptune
Discovered on September 23, 1846, Neptune became the first planet discovered through mathematical calculations rather than through regular observations. The large blue giant (this color is due to the hue of the atmosphere) is named after the Roman god of the seas.
Pluto in 2006, it lost its status as a solar system planet and was classified as a dwarf planet and the largest object in the Kuiper belt. It has been the ninth planet of the solar system since its discovery in 1930. The name "Pluto" was first suggested by an eleven-year-old schoolgirl from Oxford, Venetia Bernie. She was interested not only in astronomy, but also in classical mythology, and decided that this name - an ancient Roman version of the name of the Greek god of the underworld - was best suited for a dark, distant and cold world. By voting, astronomers chose this option.
Look at the model of the solar system created in the American desert.
*Recently scientists. Since it does not yet have a full name, and research is still ongoing, we did not include it in the above list.
The sun holds the planets and other bodies belonging to the solar system with its gravity.
Other bodies are planets and their satellites, dwarf planets and their satellites, asteroids, meteoroids, comets and cosmic dust. But in this article we will only talk about the planets of the solar system. They make up most of the mass of objects associated with the Sun by gravity (attraction). There are only eight of them: Mercury, Venus, Earth Mars, Jupiter, Saturn, Uranus and Neptune . The planets are named in order of their distance from the Sun. Until recently, the planets of the solar system also included Pluto, the smallest planet, but in 2006 Pluto was deprived of planet status because Many objects more massive than Pluto have been discovered in the outer solar system. Following the reclassification, Pluto was added to the list of minor planets and received catalog number 134340 from the Minor Planet Center. But some scientists disagree with this and continue to believe that Pluto should be reclassified back to a planet.
Four planets - Mercury, Venus, Earth and Mars - are called terrestrial planets. They are also called inner planets, because their orbits lie inside the Earth's orbit. What the terrestrial planets have in common is that they consist of silicates (minerals) and metals.
Four other planets - Jupiter, Saturn, Uranus and Neptune - they call gas giants, because they are mainly composed of hydrogen and helium and are much more massive than the terrestrial planets. They are also called outer planets.
Look at the picture of the terrestrial planets scaled by their sizes in relation to each other: Earth and Venus are about the same size, and Mercury is the smallest planet among the terrestrial planets (from left to right: Mercury, Venus, Earth, Mars).
What unites the terrestrial planets, as we have already said, is their composition, as well as the fact that they have a small number of satellites and that they do not have rings. The three inner planets (Venus, Earth and Mars) have an atmosphere (a shell of gas around a celestial body held in place by gravity); all have impact craters, rift basins and volcanoes.
Let us now consider each of the terrestrial planets.
Mercury
It is located closest to the Sun and is the smallest planet in the solar system, its mass is 3.3 × 10 23 kg, which is 0.055 the mass of the Earth. The radius of Mercury is only 2439.7 ± 1.0 km. The average density of Mercury is quite high - 5.43 g/cm³, which is slightly less than the density of Earth. Considering that the Earth is larger in size, the density value of Mercury indicates an increased content of metals in its depths.
The planet got its name in honor of the ancient Roman god of trade, Mercury: he was fleet-footed, and the planet moves across the sky faster than other planets. Mercury has no satellites. Its only known geological features, other than impact craters, are numerous jagged escarpments extending for hundreds of kilometers. Mercury has an extremely thin atmosphere, a relatively large iron core and a thin crust, the origin of which is currently a mystery. Although there is a hypothesis: the outer layers of the planet, consisting of light elements, were torn off as a result of a giant collision, which reduced the size of the planet and also prevented the complete absorption of Mercury by the young Sun. The hypothesis is very interesting, but requires confirmation.
Mercury revolves around the Sun in 88 Earth days.
Mercury has not yet been sufficiently studied; only in 2009 was its complete map compiled based on images from the Mariner 10 and Messenger spacecraft. The planet’s natural satellites have not yet been discovered, and it is not easy to see in the sky due to its small angular distance from the Sun.
Venus
It is the second inner planet of the solar system. It orbits the Sun in 224.7 Earth days. The planet is close in size to Earth, its mass is 4.8685ˑ10 24 kg, which is 0.815 Earth's mass. Like Earth, it has a thick silicate shell around an iron core and an atmosphere. Venus is the third brightest object in the Earth's sky after the Sun and Moon. It is believed that internal geological activity occurs within the planet. The amount of water on Venus is much less than on Earth, and its atmosphere is ninety times denser. Venus has no satellites. This is the hottest planet, its surface temperature exceeds 400 °C. Astronomers consider the most likely reason for such a high temperature to be the greenhouse effect, which occurs due to a dense atmosphere rich in carbon dioxide, which is approximately 96.5%. The atmosphere on Venus was discovered by M. V. Lomonosov in 1761.
There is no evidence of geological activity on Venus, but since it has no magnetic field to prevent the depletion of its substantial atmosphere, it is assumed that its atmosphere is regularly replenished by volcanic eruptions. Venus is sometimes called " sister of the earth“- they really have a lot in common: similar sizes, gravity and composition. But there are still more differences. The surface of Venus is covered by a thick cloud of highly reflective sulfuric acid clouds, making its surface impossible to see in visible light. But radio waves were able to penetrate its atmosphere, and with their help its relief was explored. Scientists have debated for a long time about what lies under the thick clouds of Venus. And only in the 20th century, the science of planetology established that the atmosphere of Venus, consisting mainly of carbon dioxide, is explained by the fact that on Venus there is no carbon cycle and no life that could process it into biomass. Scientists believe that once upon a time, a very long time ago, oceans similar to those on Earth existed on Venus, but they completely evaporated due to the intense heating of the planet.
The atmospheric pressure on the surface of Venus is 92 times greater than on Earth. Some astronomers believe that volcanic activity on Venus continues today, but no clear evidence of this has been found. Not found yet... It is believed that Venus is a relatively young planet, by astronomical standards, of course. She is approximately only... 500 million years old.
The temperature on Venus has been calculated to be approximately +477 °C, but scientists believe that Venus is gradually losing its internal high temperature. Observations from automatic space stations have detected thunderstorms in the planet's atmosphere.
The planet got its name in honor of the ancient Roman goddess of love Venus.
Venus has been actively studied using spacecraft. The first spacecraft was the Soviet Venera 1. Then there were the Soviet Vega, the American Mariner, Pioneer Venus 1, Pioneer Venus 2, Magellan, the European Venus Express, and the Japanese Akatsuki. In 1975, the Venera 9 and Venera 10 spacecraft transmitted the first photographs of the surface of Venus to Earth, but conditions on the surface of Venus are such that none of the spacecraft worked on the planet for more than two hours. But research on Venus continues.
Earth
Our Earth is the largest and densest of the inner planets in the solar system. Among the terrestrial planets, the Earth is unique due to its hydrosphere (water shell). The Earth's atmosphere differs from the atmospheres of other planets in that it contains free oxygen. The Earth has one natural satellite - the Moon, the only large satellite of the terrestrial planets of the Solar System.
But we will have a more detailed conversation about planet Earth in a separate article. Therefore, we will continue the story about the planets of the solar system.
Mars
This planet is smaller than Earth and Venus, its mass is 0.64185·10 24 kg, which is 10.7% of the Earth's mass. Mars is also called " red planet" - due to iron oxide on its surface. Its rarefied atmosphere consists mainly of carbon dioxide (95.32%, the rest is nitrogen, argon, oxygen, carbon monoxide, water vapor, nitrogen oxide), and the pressure on the surface is 160 times less than that on Earth. Impact craters like those on the Moon, as well as volcanoes, valleys, deserts and polar ice caps like those on Earth - all this makes it possible to classify Mars as a terrestrial planet.
The planet got its name in honor of Mars, the ancient Roman god of war (which corresponds to the ancient Greek Ares). Mars has two natural, relatively small satellites - Phobos and Deimos (translated from ancient Greek - “fear” and “horror” - that was the name of the two sons of Ares, who accompanied him in battle).
Mars was studied by the USSR, the USA and the European Space Agency (ESA). The USSR/Russia, USA, ESA and Japan sent an Automatic Interplanetary Station (AIS) to Mars to study it; there were several programs to study this planet: “Mars”, “Phobos”, “Mariner”, “Viking”, “Mars Global Surveyor” and others.
It has been established that due to low pressure, water cannot exist in a liquid state on the surface of Mars, but scientists suggest that in the past conditions on the planet were different, so they do not exclude the presence of primitive life on the planet. In 2008, water in the form of ice was discovered on Mars by NASA's Phoenix spacecraft. The surface of Mars is explored by rovers. The geological data they collected suggests that most of the surface of Mars was once covered with water. On Mars, they even discovered something like geysers - sources of hot water and steam.
Mars can be seen from Earth with the naked eye.
The minimum distance from Mars to the Earth is 55.76 million km (when the Earth is exactly between the Sun and Mars), the maximum is about 401 million km (when the Sun is exactly between the Earth and Mars).
The average temperature on Mars is −50 °C. The climate, like on Earth, is seasonal.
Asteroid belt
Between Mars and Jupiter there is a belt of asteroids - small bodies of the solar system. Scientists suggest that these are remnants of the formation of the Solar System, which were unable to unite into a large body due to gravitational disturbances of Jupiter. The sizes of asteroids vary: from several meters to hundreds of kilometers.
Outer Solar System
In the outer region of the Solar System there are gas giants ( Jupiter, Saturn, Uranus and Neptune ) and their companions. The orbits of many short-period comets are also located here. Because of their greater distance from the Sun, and therefore much lower temperature, the solid objects in this region contain ices of water, ammonia and methane. In the photo you can compare their sizes (from left to right: Jupiter, Saturn, Uranus, Neptune).
Jupiter
This is a huge planet with a mass of 318 Earth masses, which is 2.5 times more massive than all other planets combined, and its equatorial radius is 71,492 ± 4 km. It consists mainly of hydrogen and helium. Jupiter is the most powerful (after the Sun) radio source in the Solar System. The average distance between Jupiter and the Sun is 778.57 million km. The presence of life on Jupiter seems unlikely due to the low concentration of water in the atmosphere, the absence of a solid surface, etc. Although scientists do not exclude the possibility of the existence of water-hydrocarbon life on Jupiter in the form of some unidentified organisms.
Jupiter has been known to people since ancient times, which is reflected in the mythology of different countries, and its name comes from the ancient Roman thunder god Jupiter.
There are 67 known moons of Jupiter, the largest of which were discovered by Galileo Galilei in 1610.
Jupiter is explored using ground-based and orbital telescopes; Since the 1970s, 8 interplanetary NASA probes have been sent to the planet: Pioneers, Voyagers, Galileo and others. Powerful storms, lightning, and aurorae, many times greater than those on Earth, have been observed on the planet.
Saturn
A planet known for its ring system. In reality, these romantic rings are just flat, concentric formations of ice and dust that lie in Saturn's equatorial plane. Saturn has a structure of atmosphere and magnetosphere somewhat similar to Jupiter, but is much smaller: 60% of the mass of Jupiter (5.6846 10 26 kg). Equatorial radius - 60,268 ± 4 km.
The planet received its name in honor of the Roman god of agriculture, Saturn, so its symbol is a sickle.
The main component of Saturn is hydrogen with admixtures of helium and traces of water, methane, ammonia and heavy elements.
Saturn has 62 satellites. Of these, the largest is Titan. It is interesting because it is larger than the planet Mercury and has the only dense atmosphere among the satellites of the Solar System.
Observations of Saturn have been going on for a long time: Galileo Galilei noted in 1610 that Saturn has “two companions” (satellites). And Huygens in 1659, using a more powerful telescope, saw the rings of Saturn and discovered its largest satellite, Titan. Then, gradually, astronomers discovered other satellites of the planet.
The modern study of Saturn began in 1979, when the US automatic interplanetary station Pioneer 11 flew near Saturn and then finally approached it. Then the American spacecraft Voyager 1 and Voyager 2, as well as Cassini-Huygens, followed to Saturn, which, after 7 years of flight, reached the Saturn system on July 1, 2004 and entered orbit around the planet. The main objectives were to study the structure and dynamics of the rings and satellites, as well as to study the dynamics of the atmosphere and magnetosphere of Saturn and a detailed study of the planet's largest satellite, Titan. In 2009, a joint American-European project between NASA and ESA appeared to launch the Titan Saturn System Mission to study Saturn and its satellites Titan and Enceladus. During it, the station will fly to the Saturn system for 7-8 years, and then become a satellite of Titan for two years. It will also launch a probe balloon into Titan's atmosphere and a landing module.
The lightest of the outer planets is 14 Earth masses (8.6832·10 25 kg). Uranus was discovered in 1781 by the English astronomer William Herschel using a telescope and named after the Greek god of the sky, Uranus. It turns out that Uranus is visible in the sky with the naked eye, but those who saw it before did not realize that it was a planet, because the light from it was very dim, and the movement was very slow.
Uranus, as well as Neptune, which is similar to it, are classified as “ ice giants", since there are many modifications of ice in their depths.
The atmosphere of Uranus is mainly hydrogen and helium, but traces of methane and solid ammonia are also present. Its atmosphere is the coldest (−224 °C).
Uranus also has a ring system, a magnetosphere, and 27 moons. The axis of rotation of Uranus lies, as it were, “on its side” relative to the plane of rotation of this planet around the Sun. As a result, the planet faces the Sun alternately with the north pole, the south, the equator, and the middle latitudes.
In 1986, the American spacecraft Voyager 2 transmitted close-range images of Uranus to Earth. The images do not show images of such storms as on Jupiter, but, according to observations from Earth, seasonal changes are occurring there, and weather activity has been noticed.
Neptune
Neptune is smaller than Uranus (equatorial radius 24,764 ± 15 km), but its mass is 1.0243·10 26 kg greater than the mass of Uranus and is 17 Earth masses.
It is the farthest planet in the solar system. Its name is associated with the name of Neptune, the Roman god of the seas, so the astronomical symbol is Neptune's trident.
Neptune is the first planet discovered through mathematical calculations rather than observations (Neptune is not visible to the naked eye), and this happened in 1846. This was done by a French mathematician who studied celestial mechanics and worked most of his life at the Paris Observatory - Urbain Jean Joseph Le Verrier.
Although Galileo Galilei observed Neptune in 1612 and 1613, he mistook the planet for a fixed star in conjunction with Jupiter in the night sky. Therefore, the discovery of Neptune is not attributed to Galileo.
Soon its satellite Triton was discovered, but the remaining 12 satellites of the planet were discovered in the 20th century.
Neptune, like Saturn and Pluto, has a ring system.
Neptune's atmosphere, like that of Jupiter and Saturn, is composed primarily of hydrogen and helium, with traces of hydrocarbons and possibly nitrogen, but contains a lot of ice. Neptune's core, like Uranus, consists mainly of ice and rock. The planet appears blue - this is due to traces of methane in the outer layers of the atmosphere.
Neptune's atmosphere has the strongest winds among the planets in the solar system.
Neptune has only been visited by one spacecraft, Voyager 2, which flew close to the planet on August 25, 1989.
This planet, like all the others, holds many mysteries. For example, for unknown reasons, the planet’s thermosphere has an abnormally high temperature. But it is too far from the Sun for it to heat up the thermosphere with ultraviolet radiation. Here's a problem for you, future astronomers. And the Universe sets a lot of such tasks, enough for everyone...
The weather on Neptune is characterized by strong storms and winds reaching almost supersonic speeds (about 600 m/s).
Other bodies of the Solar System
This comets- small bodies of the Solar System, usually only a few kilometers in size, consisting mainly of volatile substances (ices), centaurs- icy comet-like objects, trans-Neptunian objects, located in space beyond Neptune, Kuiper belt- fragments similar to the asteroid belt, but consisting mainly of ice, scattered disk…
There is no exact answer yet to the question of where exactly the solar system ends and interstellar space begins...
