In the solar system, gas giants include Jupiter, Saturn, Uranus and Neptune. According to the origin hypothesis solar system, giant planets formed later than the terrestrial planets. By this time, most of the refractory substances (oxides, silicates, metals) had already fallen out of the gas phase, and the inner planets (from Mercury to Mars) were formed from them. There is a hypothesis about a fifth gas giant, pushed during the formation of the modern appearance of the Solar System to its distant outskirts (which became the hypothetical planet Tyukhe or another “Planet X”) or beyond its borders (which became an orphan planet). The latest such hypothesis is the hypothesis about the ninth planet by Brown and Batygin.

Gas giants are planets consisting largely of hydrogen, helium, ammonia, methane and other gases. Planets of this type have low density, a short period of daily rotation and, therefore, significant compression at the poles; their visible surfaces reflect well, or, in other words, scatter the sun's rays.

The period of very rapid rotation of gas giants around their axis is 9-17 hours.

Models internal structure gas planets suggest the presence of several layers. At a certain depth, the pressure in the atmospheres of gas planets reaches high values, sufficient for hydrogen to transform into a liquid state. If the planet is large enough, then even lower there may be a layer of metallic hydrogen (resembling liquid metal, where protons and electrons exist separately), electric currents in which they generate a powerful magnetic field of the planet. It is assumed that gas planets They also have a relatively small stone or metal core.

As measurements by the Galileo lander have shown, pressure and temperature are growing rapidly already in the upper layers of gas planets. At a depth of 130 km in the atmosphere of Jupiter, the temperature was about 420 kelvin (145 degrees Celsius), the pressure was 24 atmospheres. All gas planets of the Solar System emit noticeably more heat than they receive from the Sun, due to the release of gravitational energy during compression. Models have been proposed that allow for the release of extremely small amounts of heat inside Jupiter during thermonuclear fusion reactions, but these models do not have observational confirmation.

In the atmospheres of gas planets, powerful winds blow at speeds of up to several thousand kilometers per hour (the wind speed at Saturn’s equator is 1800 km/h). There are permanent atmospheric formations that are giant vortices. For example, the Great Red Spot (several times the size of Earth) on Jupiter has been observed for more than 300 years. There is a Great Dark Spot on Neptune and smaller spots on Saturn.

For all gas planets in the Solar System, the ratio of the total mass of their satellites to the mass of the planet is about 0.01% (1 in 10,000). To explain this fact, models have been developed for the formation of satellites from gas-dust disks with a large amount of gas (in this case, a mechanism that limits the growth of satellites operates).

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Gas giants are planets whose main part consists of gases. various types. These gases are predominantly hydrogen and helium. To a lesser extent, the presence of ammonia and methane, and sometimes nitrogen, is possible. Such planets are usually characterized by low temperatures and high pressure in the atmosphere.

Main features of gas giants:

1. They have low density. Thus, they do not have a hard surface in the usual sense.
2. They have an extremely short daily rotation period. It ranges from approximately 9 to 17 hours, which by earthly standards is very little.
3. Due to rapid rotation, they are usually compressed or flattened at the poles.
4. They scatter the sun's rays well.

Structure of gas giants

The structure of gas planets consists of several layers:

• gaseous (represented as clouds);
• liquid gas arising due to high pressure;
• metal gas (an electromagnetic field arises here);
• a small core, which may be metal or stone.

Gas planets are characterized by the presence of strong winds in their atmospheres, reaching thousands of kilometers. And also stable giant vortices that have existed for hundreds of years.

According to modern data, most of the planets outside our solar system, that is, exoplanets, are gaseous. There are now about one hundred billion of them in our galaxy.

Gas giants of the solar system

All planets of our solar system are usually divided into two parts: external and internal. Gas giants are represented by a group that science calls the “outer planets.” It includes Neptune, Uranus, Saturn and Jupiter. They are further from the Sun than the other inner planets and are separated from them by an asteroid belt.

The outer planets have a set of common distinctive features:

1. Considerable distance from the Sun.
2. The presence of strong magnetic fields.
3. Large in size and weight.
4. The presence of many satellites around the planet.
5. Low temperatures.
6. The presence of ring systems encircling the planet.

The largest of the outer planets is Jupiter. It is the fifth in distance from the Sun. It has an atmosphere consisting primarily of hydrogen and eleven percent helium. The presence of sulfur and phosphorus in it gives a beautiful orange the external appearance of the planet. In the lower layers there is an ocean filled with liquid hydrogen.

The classic signs of gas planets are present here: strong winds and long-lasting (up to three hundred years of existence) vortices. The most gigantic of the latter is the Great Red Spot. Its dimensions are several times larger than those on Earth.

The planet has the most powerful magnetic field 650 million kilometers. Twenty-eight satellites orbit in its zone.

The next gas giant in the outer system is Saturn. The planet is the second largest in our solar system. Its rotation time is very short - just over 10 hours. In size it is slightly inferior to Jupiter. But by weight - three times.

The composition of Saturn consists mainly of hydrogen, with a small amount of helium, ammonia, methane and residual water.

The famous ring of Saturn surrounding it at the equator is not a single whole. Its outer layers rotate around the planet at a much lower speed than the inner layers. Their structure consists of tiny particles of ice with the addition of silicate dust. They can reach eighty thousand kilometers in width. The thickness of the rings is much smaller - no more than one kilometer.

The length of the year on Saturn is 29.5 times longer than on Earth. During the annual cycle, the appearance of the rings of a celestial body from Earth varies greatly.

The equinox period is characterized by the cessation of the possibility of their observation. That is, they practically cease to be visible from our planet, with the exception of a small line. After this, over a period of seven years, the rings become increasingly visible in width and reach their maximum visual size when the solstice occurs. Then the cycle repeats.

Saturn has sixty-two satellites. Their composition is represented by rocks and ice, and their sizes are usually small. One of its satellites, Titan, which received its name for its maximum size compared to others, has a dense atmosphere consisting mainly of nitrogen with the addition of methane. Scientists suggest that similar conditions could have existed on Earth during the period when life appeared on it.

The planet next to Saturn is Uranus. Discovered in the 17th century, it is the fourth largest in the solar system.

A year on Uranus is 84 times longer than on Earth, and it rotates around its axis in just seventeen hours. In the composition of Uranus, unlike most other planets except Neptune, scientists have not discovered metallic hydrogen. However, a large percentage of ice was detected there. Therefore, the planet, like Neptune, was classified as an ice giant.

In its hydrogen-helium atmosphere, impurities of methane, ammonia and hydrogen were found.

Uranus is the coldest planet in the solar system. With a temperature of 224 degrees Celsius, it is completely unsuitable for life.

The presence of faint rings on Uranus is undoubted. In this case, the outer ring formations have a brighter color.

A special feature of Uranus is its ability to rotate in a horizontal position, as if lying on its “side.” Twenty-seven satellites of the planet are named after heroes of the works of W. Shakespeare and A. Pope.

The last and smallest of the outer gas giants is Neptune. Not visible from Earth, it has a unique discovery history, as it was first discovered not visually, but using mathematical calculations. The reason for this was changes in the orbit of Uranus and the assumption that they were caused by the influence of gravity of an unknown planet.

Neptune's composition is similar to Uranus. This led scientists to classify it as an ice giant. The surface of the planet is an ocean of water and liquefied gases. One year on the planet corresponds to approximately 165 Earth years. A day lasts about 16 hours.

Due to Neptune's internal energy source, the strongest winds in the solar system arise on it. They can reach 2100 kilometers per hour. The planet's atmosphere is characterized by persistent storms that last for several months.

Faint rings with a reddish tint were discovered on Neptune. It is assumed that it is due to the presence of carbon in their composition, people with ice and silicate.

Neptune has the strongest magnetic field, extending 650 thousand kilometers. But, unlike the Earth, its orbit is deviated from the axis of rotation of the planet itself by 47 degrees.

Of Neptune's fourteen moons, Triton is the largest.

Currently, there is also a theory among scientists that there was another planet in our solar system, which was a gas giant. But under the influence of Jupiter's gravity, she had to leave the area of ​​gravity of the Sun.

Largest gas giant

At the beginning of the 21st century, the largest planet in the Universe was discovered, which is also a gas giant. It was given the name TrES-4. It is located in the constellation Hercules, at a distance of 1600 light years from our planet. The celestial body is twenty times larger than the Earth. It is 1.7 times larger in diameter than Jupiter, but only three times in mass. A day on TrES-4 is equal to three and a half days on Earth.

Due to its proximity to the parent star, the temperature on the planet is extremely high, reaching approximately 1260 degrees. Therefore, and also due to its small mass, it is constantly expanding. TrES-4 cannot retain the atmosphere. Part of it constantly evaporates, transforming into a tail, like those that accompany a comet.

Planets in the solar system are divided into two types - earth and gas. The gas planets of the Solar System are celestial bodies that do not have a specific shell. That is, the combination “gas planets” directly implies its condition. They are also called gas giants and there are four of them in the solar system:

1. Jupiter
2. Saturn
3. Neptune.

Distinctive features of gas planets

The most interesting thing is that with gas giants it is difficult to say where the outline of the ball begins and the atmosphere ends. Scientists suggest that inside such a planet, still following the example of the earth, there is a solid core.

If you believe the most common hypothesis of the origin of our system, then the giants appeared much later than earthly celestial bodies, that is, such as our Earth.

The gas giant planets of the solar system not only have a small solid core. It is also assumed that after the atmosphere the pressure only increases, and therefore hydrogen takes, instead of the gaseous appearance, the one we are familiar with, that is, in the form of water.

Celestial bodies consisting of gas have a short period of rotation in time. Of considerable importance are one interesting fact, which consists in the fact that the largest giants emit noticeably more heat than they themselves receive from the sun. This happens due to gravitational energy.

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At high pressure, which acquires large units already in the atmosphere, compression occurs. Due to compression, even more gravitational energy is released. Now let's look at the individual planets, ordered by size.

• Jupiter. The largest planet in the Solar System, it is the fifth most distant planet from the Sun. 11 times - so much the radius of Jupiter exceeds the radius of the Earth. Mainly composed of hydrogen and helium. Jupiter also has the well-known Great Red Spot, which is a long-lived giant anticyclone.
• Saturn. It is located after Jupiter both from the sun and in size. Saturn is famous for the fact that it has more than sixty satellites and is surrounded by a ring, by which it can be immediately recognized. Moreover, Saturn is the most rarefied celestial body in our system.
• Uranus. This giant is also the third in size and seventh in distance from the Sun.
• Neptune is the eighth in size and distance. Similar to Jupiter, Neptune has a large dark spot.

Modern scientists believe that previously there were about six giants and all of them were much closer to the Sun.

Do not think that they have always been of a gaseous form, which does not have the outline of a figure. Everything is completely wrong. On Uranus and Neptune, all gases (ammonia, methane, etc.) can only be in solid form.

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Any large planet can be classified as giant. Such planets are mostly composed of substances with low boiling points, such as ice and gases, although giant planets like Earth exist. The giant planets of the solar system, also called the outer planets, include Jupiter, Neptune, Uranus and Saturn. The phrase gas giant was first used in 1952 by James Blish, a science fiction writer.

The four largest planets in the solar system:

Jupiter

The mass of Jupiter is 2.5 times heavier than the total mass of the others and is one thousandth the mass of the Sun. Jupiter is a gas giant composed primarily of hydrogen and also a quarter of its mass made of helium. The rapid rotation affected the shape of the planet, making it oblate-spheroidal. The diameter of Jupiter at the equator is 142,984 km. Jupiter has interested the minds of astronomers since ancient times, and the Romans even gave it a name in honor of their main deity, Jupiter. The planet has at least 69 moons (satellites), and the largest of them, Ganymede, is considered the largest in the solar system and is larger in diameter than Mercury.

Saturn

Saturn, like Jupiter, is a gas giant that is also formed from helium and hydrogen. It is distinguished by its ring system, which includes 9 continuous primary rings in addition to three breaking arcs. The planet has at least 62 moons, 53 of which are officially named. This figure excludes hundreds of lunar zones that make up the rings. The largest of Saturn's moons is Titan, which is the second largest moon in our system. Saturn is about 30% less dense than water. Jupiter and Saturn together make up 92% of the total mass of the planets in the solar system.

Uranus

Uranus is classified as an ice giant, and although its composition is dominated by hydrogen and helium, it has more "ice" including methane, water and ammonia. Uranus was named after greek god sky named Ouranos. The planet has 27 satellites, a magnetosphere and a ring system. Uranus's minimum temperature is estimated at -223 degrees Celsius, making its atmosphere . Uranus makes a complete revolution around the Sun every 84 years, and the average distance to the star is 20 astronomical units. The mass of Uranus is equal to just over fourteen and a half times the mass of the Earth.

Neptune

Neptune's mass is seventeen times that of Earth. Neptune is recognized as the only planet in the solar system discovered through mathematical calculations rather than empirical observations. Johann Halle became the first person to identify the planet through a telescope on September 23, 1846, and he relied on the predictions of Urban Le Verrier. Neptune's largest satellite, Triton, was discovered just two and a half weeks after the planet itself, although the remaining 13 satellites were identified using a telescope only in the 20th century. The significant distance from Earth to Neptune makes it very small, making it difficult to study the planet through a telescope. Advanced modern telescopes with adaptive optics have made it easier to obtain more information from afar. Neptune's atmosphere has visible and active weather conditions, while temperatures at the planet's center are estimated at 5,100 degrees Celsius.