There are four giant planets solar system- Uranus, Neptune, Saturn, Jupiter. They are distinguished from the rest of the terrestrial planets not only by their huge size, but also chemical composition. Interesting Facts read about the giant planets in our article.
According to the structure of the giant planets, they are gaseous, they contain a lot of hydrogen and helium, they are rarefied and they are distinguished by large sizes. the only exception to the four planets mentioned above is Pluto, since chemical elements its shells are close to the terrestrial planets. But among the defining difference between these planets, of course, is the size - even the smallest Uranus is fifteen times larger than the Earth.
All giant planets have a large number of satellites, which are called moons. For comparison with the only satellite Earth, Jupiter has over 60 small satellites.
Everyone remembers that Saturn is famous for its rings, but not everyone knows about the presence of the same rings in the other four planets, they have a slightly different chemical composition and are less distinguishable, however, when observing giants using astronomical technology, it allows them to be seen .
Like the Earth, the giant planets rotate around their axis and around the solar system, but their rotation has a slightly different character, which is due to the gaseous structure, so the rotation zone is represented by layers, the most fast speed turnover is characterized by the zone of the equator, or the middle, the slowest movement occurs in the zones of the poles.
The largest of the giant planets is Jupiter, named after the famous Roman god. The attraction on this planet is much greater than on our Earth, and the weight of Jupiter exceeds the masses of other planets by 70 percent. It is also characterized by high rotation speeds, if we compare the duration of the day with the Earth, then on Jupiter it is equal to ten hours.
Jupiter- the largest planet in the solar system, it has the largest radius and mass. Therefore, the acceleration of free fall on Jupiter is 2.67 times greater than on Earth. The composition of Jupiter is similar to the composition of stars: hydrogen in it is about 80%, helium - about 17%. The huge speed of rotation of Jupiter leads to the fact that it is strongly flattened at the poles. Jupiter has a powerful magnetic field, the origin of which is due to the fact that in the bowels of Jupiter there is a huge pressure at which hydrogen passes into a metallic state.
Jupiter has 64 moons, the largest are Io, Europa, Ganymede and Calisto, their sizes are comparable to the size of the Moon. These satellites are visible from Earth through strong binoculars.
Saturn(Fig. 52) - a planet famous for its rings. Saturn's rings are a thin layer of debris of varying sizes orbiting around it. The first ring was discovered in 1656 by a Dutch astronomer and physicist X. Huygens(1629-1695). Images transmitted to Earth from the Voyager spacecraft showed that there are almost 1000 such rings. Their width is from 25 to 90 km.
62 satellites revolve around Saturn, the largest being Titan, which has a diameter 1.5 times the diameter of the Moon.
Uranus just like Saturn and Jupiter, it is a gaseous sphere consisting of hydrogen, helium, methane and ammonia. He also has rings, only relatively thin ones. Uranus has 27 moons of various sizes, many of which are over 1,000 km in diameter.
Neptune very similar in physical properties to Uranus. Its size and mass are close to the size and mass of Uranus, the atmosphere has the same composition. It is surrounded by a system of rings thinner than Uranus, and 13 satellites revolve around it with a diameter of 54 to 400 km. material from the site
The history of the discovery of Neptune is very interesting, it confirms not only the validity physical laws, but also their predictive role in scientific knowledge. Neptune is the most distant planet in the solar system, and scientists could not detect it during observations. Studying in the middle of the XIX century. movement of Uranus, English astronomer J.-K. Adams(1819-1892) and French astronomer W.-J. Le Verrier(1811-1877) discovered that Uranus moves with some deviations from the orbit that they calculated for it, using Newton's laws of motion. They suggested that there is another planet behind Uranus, the attraction to which distorts the calculated trajectory of its movement. Using the law of universal gravitation, they calculated the coordinates of the proposed planet. Later, Neptune was discovered exactly in the place whose coordinates they had calculated.
In 1930, in the same way, Pluto, for a long time considered the ninth planet of the solar system (has 4 satellites). However, in 2006, it was hypothesized that Pluto was a satellite of Neptune that had descended from orbit.
There are currently eight planets in our solar system. The four planets Jupiter, Saturn, Uranus and Neptune are classified by scientists as a separate group of "gas giants", together they make up 99% of the mass of matter that is in orbits of rotation belonging to the Sun. The article presents the most interesting facts about the giant planets.
- The hallmark of Jupiter are the stripes on its surface., there are several theories about their origin. One theory claims that the stripes appeared as a result of convection, this process involves heating and raising some layers of the atmosphere, cooling and falling off others.
- The Great Red Spot located on Jupiter, an atmospheric phenomenon similar to a storm, was discovered back in the 17th century. Lightning discharges have been detected on the planet, which are three times the power of the earth. The speed of wind gusts exceeds 600 km / h, and their formation is due to the release of heat from the bowels of the gas giant.
- Astronomers now know about the existence of 67 satellites of the planet Jupiter.. The largest - Io, Europa, Ganymede and Callisto were discovered in the 17th century by Galileo Galilei.
- If the name of the moon of Jupiter ends with "e", for example, Karma, Pasipha, this means that neither rotate in the opposite direction relative to the axial rotation of the gas giant.
- Jupiter has the highest rotational speed on its axis in the solar system, the planet makes a complete rotation in 9 hours 50 minutes. There is no change of seasons on Jupiter, this is due to a slight tilt of the axis around which the "giant" rotates, a little more than 3 degrees, for comparison, the Earth has 23.5.
- At the north pole of Saturn there is a hexagon formed by clouds, and its shape tends to be correct, the reasons for its occurrence are unknown. At both poles, scientists have discovered oval and spiral aurora borealis.
- To make a complete revolution around the Sun, Saturn needs almost 30 Earth years, but the change of day and night during this time occurs only ~ 10 times. Different parts of this gas giant rotate at different speeds, "zone 1" has a rotation interval of 10 hours 14 minutes, "zone 2" - 10 hours, 34 minutes, "zone 3" - 10 hours 39 minutes.
- Of the entire group of giant planets, Saturn has the most noticeable rings, they consist of particles of ice.. The rings of Saturn are very thin, less than 1 kilometer, in 1921 the whole world decided that the rings had disappeared, this happened due to the fact that the rings became at a certain angle and the instruments of that time did not allow them to be seen.
- Uranus was discovered in 1781 by astronomer William Herschel and was the first planet to be discovered in modern world. Initially, this Gas giant was mistaken for a star, later for a comet. The first name of the planet was "George", in honor of George III, who ruled in England at the time of its discovery.
- The atmosphere is 98% hydrogen and helium, but unlike the other two giant planets, Uranus and Neptune contain a large amount of ice in their depths. Atmospheric phenomena on Uranus are extremely insignificant, this is due to the low temperatures on the planet, it is the coldest planet in our solar system.
- Uranus' axis of rotation is offset at an angle of almost 98 degrees relative to its rotation around the Sun, as a result of which different parts alternately face the Sun. Day and night alternate at the poles every 42 Earth years.
- Uranus is the second planet to have a ring system. Scientists are inclined to believe that the rings were not formed together with Uranus, but later, during the destruction of some of its satellites. There are 13 rings, the inner rings are gray, the middle ones are red, and the two outer ones are blue.
- In terms of the composition of the atmosphere and body, Neptune is most similar to Uranus, but the blue color gives it a significant content of methane in the atmosphere. Scientists suggest that this planet has the fastest winds in the entire solar system, up to 2100 km/h. The estimated temperature on the surface is -220 degrees, and in the bowels of the planet 7000-7100.
- From Earth, Neptune can only be observed once a year.(on opening day 26 September 1846, later in 2011). In 2011, exactly one year has passed on Neptune since its discovery, it was 164.79 Earth years.
- Neptune's largest moon, Triton, orbits the planet in the opposite direction of its rotation. Triton moves in a spiral and about 10 million years later will be destroyed after overcoming the Roche limit.
The solar system consists of eight planets, among which four belong to the terrestrial group and four to the category of gas giants. The difference between these two categories can be traced literally in everything. This is the size, and composition, and movement, and atmosphere. Below we have collected the most which for many will be a real discovery. Well, those who already know a lot about astronomy will be able to replenish their stock of knowledge.
What objects are included in this group
To begin with, let's consider the system and where exactly our gas giants are located within it. In the center is the Sun, four planets of the terrestrial group revolve around it. These are Mercury, Venus, Earth and Mars. They are followed by the asteroid belt, which seems to separate these two categories. The next four planets are Jupiter, Saturn, Uranus and Neptune. Below will be presented numerous facts about the giant planets that will help us distinguish them from the celestial bodies of the terrestrial group. Most astronomers also attribute Pluto, the most distant SS, to the category of planets. However, it is more reminiscent of Mercury than Jupiter or Neptune, both in its structure and parameters.
Size is the most important criterion for evaluating a planet
Based on the fact that we are listing facts about giant planets here, it is easy to guess that the parameters of these celestial bodies are really very large. by the most big object of this group is Jupiter, followed by Saturn, Uranus and after Neptune. In a word, they seemed to be located in a decreasing order relative to the Sun. So, what are the exact parameters equal to 142,800 km, while in the equatorial region the planet is constantly “growing” due to the fact that it rotates very quickly around its axis. Saturn has a diameter of 120,000 km. The same figures for Uranus and Neptune - 51,800 km and 48,600 km, respectively. For comparison, we propose to consider the diameter of the Earth - the largest planet of the terrestrial group. It is equal to 12,756 km, which is ten times less than that of the giants.
Chemical composition and mass
It would seem that 2 facts about the giant planets, which should not be related, are actually one. So, four pieces as a selection consist of hydrogen and helium. It should be borne in mind that these gases are the basis of each planet. They have no surface, no solid rock, meteorite craters, glaciers or water. Therefore, the giant planets are called gas, as they represent a cluster of this physical element due to gravitational forces. Its density there is higher than in outer space, and due to this, the gas is transformed into a planet, acquiring rounded outlines. Of course, helium and hydrogen are not the only gases present on giants. But they are the basis to which all other chemical elements adjoin. For example, on Jupiter, molecules of methane, hydrogen sulfide, nitrogen and even oxygen are found in the upper ones. In the structure of Saturn, you can find ammonia, ethane, phosphine. Uranus looks greenish due to a large number methane, which is present in upper layers atmosphere. And Neptune is supplemented with ammonia and hydrogen sulfide, which, mixed with the same methane, makes it blue. Now about the mass. The most amazing facts about giant planets are that they don't weigh that much. On average, the mass of Uranus is about 3 Earth masses. The low weight of the planets provides their composition, because if they had a solid surface, water and rocks, they would weigh incredibly much.
The splendor of the rings
The very first facts in the world about giant planets, which were discovered back in the 17th and 18th centuries, testified to the presence of so-called rings that surround each such heavenly body. Such rings are formed due to the fact that many moons revolve around the planet. In this zone, a special type of gravity is formed, the chemical composition changes slightly (compared to the general environment of space). Due to this, the rings become visible to us, earthly observers. The brightest owner of this astronomical splendor is Saturn. Its rings are visible through an amateur telescope. The second in the ranking of the visibility of the rings is Neptune. Jupiter and Uranus are also surrounded by similar "fields", but they can already be seen only with the help of very powerful equipment.
Satellites that can't be counted
Now consider some interesting facts about the planets of the solar system, which are still incomprehensible to astronomers. We are talking about the satellites that surround the planets, and their number. The fact is that all objects of the terrestrial group have a very small number of moons or do not have any at all. Mercury and Venus have no satellites. The Earth is equipped with only one - the Moon, and Mars with two - Demos and Phobos. But the gas giants just abound with moons. Jupiter wins everyone in number - it has as many as 67 satellites (perhaps there are more of them, they just haven't been discovered yet). It is important to note that some of them are analogues of the Earth. There is water, oxygen, therefore the origin of life is likely. Saturn has a total of 62 satellites that spin in the sphere of its magnificent rings. Uranus is surrounded by 27 moons, and Neptune - 14. But Pluto's environment is comparable to the terrestrial planets. He has only one satellite - Charon, who is the same as himself, hard, cold and very mysterious.
Other Planet Facts
List amazing facts is coming to an end, so we decided to summarize with brief data that relate to the entire SS. So:
- The mass of the Sun makes up 99.86% of the total weight of the solar system. The rest is on the planets.
- Jupiter is the most powerful. Its radiations constantly enrich the Earth with electricity.
- On some planets, a day lasts longer than a year.
- There is a hypothesis that the core of Neptune consists of rocks. If its icy clouds ever melt, it could gain an atmosphere and become a habitable planet.
The group of giant planets is made up of four planets in the solar system - Neptune, Saturn, Uranus and Jupiter. Since these huge planets are much farther away from the Sun than the smaller planets, they have another name - the outer planets.
You can distribute interesting facts about the giant planets into several categories. The first takes into account their structure and rotation. The second is devoted to the phenomena observed in their atmospheres. In the third, the presence of rings in the planets is noted. The fourth describes the presence of their satellites.
The structure of the giant planets and their rotation
Basically, the giant planets are formed from a complex mixture of gases - ammonia, hydrogen, methane and helium. According to scientists, these planets have small stone or metal cores.
Due to the huge mass of the object, the pressure in the bowels of the gas planet reaches millions of atmospheres. Its compression by the force of gravity releases significant energy. As a result of this factor, the giant planets release more heat than is absorbed from solar radiation.
Having dimensions much larger than the earth, such gas planets make a daily revolution in 9-17 hours. as for the average density of the giant planets, it is close to 1.4 g/cu. see - approximately equal to the solar.
Jupiter, the largest planet in the solar system, has a mass greater than the total mass of all other planets. Probably, it was for this that he was named after the main god of the Roman Pantheon. Scientists believe that it is the rapid rotation of Jupiter that explains the location of clouds in its atmosphere - we observe them in the form of extended bands.
atmospheric phenomena
Among the interesting facts about giant planets is the presence of powerful atmospheric shells, where extraordinary earthly concepts processes.
In the atmospheres of such planets, strong winds are not uncommon, with speeds of over a thousand kilometers per hour.
Long-lived hurricane vortices are also observed there, for example, on Jupiter - a three-hundred-year-old Great Red Spot. The Great Dark Spot existed on Neptune for a long period, and spots of anticyclones are noted on Saturn.
Rings and satellites of the giant planets
The inconspicuousness of the “rim” of Jupiter is explained by its narrowness and the small size of dust particles in its composition.
The ring of Saturn is the most impressive in size - its diameter is 400 thousand kilometers, but the width of the ring is only a few tens of meters. The ring consists of pieces of ice and small stones rotating around the planet. These parts are separated by several gaps, which form several different rings encircling the planet.
Uranus's ring system is the second largest, and its "rim" is red, gray, and blue. It contains pieces of water ice and very dark debris no larger than a meter in diameter.
Neptune's ring contains five sub-rings, which are thought to be ice particles.
Jupiter's satellite system includes almost 70 objects. One of them - Ganymede, is considered the largest satellite in the solar system.
Researchers have discovered more than 60 moons of Saturn, Neptune has 27 moons, Neptune has 14, including Triton. The latter is notable for its retrograde orbit - the only one of all the large satellites of the solar system.
This satellite, as well as two other satellites of the gas planets - Titan and Io, have atmospheres.
Jupiter
Jupiter, the fifth largest planet from the Sun in the solar system, is the largest of the giant planets.
Movement, dimensions, shape
Jupiter moves around the Sun in a close to circular elliptical orbit, the plane of which is inclined to the plane of the ecliptic at an angle of 1 ° 18.3 ". The minimum distance of Jupiter from the Sun is 4.95 AU, the maximum is 5.45 AU, the average - 5.2 AU (1 AU = 149.6 million km).
The equator is inclined to the plane of the orbit at an angle of 3 ° 5 "; due to the smallness of this angle, seasonal changes on Jupiter are very weak. Jupiter, moving around the Sun at an average speed of 13.06 km / s, makes one revolution in 11, 862 Earth years The distance of Jupiter from the Earth varies from 188 to 967 million km At opposition, Jupiter is visible as a slightly yellowish star of -2.6 magnitude, of all the planets second in brilliance only to Venus and Mars during the great opposition of the latter.
Jupiter does not have a solid surface, therefore, speaking of its size, they indicate the radius of the upper boundary of the clouds, where the pressure is about 10 kPa; The radius of Jupiter at the equator is 71400 km. In the atmosphere of Jupiter, layers, or zones parallel to the plane of its equator, are clearly visible, rotating around the axis of the planet with different angular velocities. The equatorial zone rotates the fastest - its rotation period is 9 h 50 min 30 s, which is 5 min 11 s less than the rotation period of the polar zones. No other planet in the solar system rotates so fast.
The mass of Jupiter is 1.899 * 10 27 kg, which is 317.8 times the mass of the Earth, but the average density is 1.33 g / cm 3, that is, 4 times less than that of the Earth. The free fall acceleration at the equator is 23.5 m/s 2 .
In the temperate southern latitudes of Jupiter, the oval Great Red Spot slowly moves, the transverse dimensions of which are 30-40 thousand km. In a hundred years, it makes about 3 revolutions. The nature of this phenomenon is not entirely clear.
The structure and composition of Jupiter
Like other giant planets, Jupiter differs significantly in chemical composition from the terrestrial planets. Absolutely dominant here are hydrogen and helium in a "solar" ratio of 3.4: 1, but in the center of the planet, according to existing models, there is a liquid core of molten metals and silicates, surrounded by a water-ammonia liquid shell. The radius of this core is about 1/10 of the radius of the planet, the mass is ~ 0.3-0.4 of its mass, the temperature is about 2500 K at a pressure of ~ 8000 GPa.
The flow of heat from the bowels of Jupiter is twice the energy it receives from the Sun. Due to the absence of a solid surface, Jupiter does not have an atmosphere as such. Its gas envelope consists mainly of hydrogen and helium, but there is also a small admixture of methane, water molecules, ammonia, etc.
Physical and chemical parameters
Thunderstorms in Jupiter's atmosphere. The presence of an ionosphere was also established, the length of which in height is about 3000 km.
Jupiter has a magnetic field. Its magnetic dipole moment is almost 12,000 times greater than the dipole moment of the Earth, but since the magnetic field strength is inversely proportional to the cube of the radius, and Jupiter has it by two orders of magnitude greater than that of the Earth, the strength near the surface of Jupiter is higher, compared to the Earth, only 5-6 times. The magnetic axis is inclined to the rotation axis by (10.2 ± 0.6)°. The dipole structure of the magnetic field dominates up to distances of the order of 15 planetary radii. Jupiter has a vast magnetosphere that is similar to Earth's, but magnified by about 100 times. There are radiation belts.
Moons of Jupiter
The first of the Galilean satellites, Io, is larger than the Moon. It has an atmosphere and ionosphere, consisting mainly of sulfur and sodium ions. Its volcanic activity is very active (more than on Earth). The dimensions of volcanic craters reach hundreds of kilometers, exceeding the earth's by tens and even hundreds of times, although the height of the volcanoes is relatively small. Only in the polar regions of Io there are volcanoes about 10 km high. Emissions of sulfur from volcanoes rise to a height of up to 250 km. According to a number of researchers, under the thin hard surface crust of the satellite, covered with a layer of sulfur and its dioxide, there may be liquid sulfur. The temperature near the surface of Io is about -120 ° C at the equator (except for volcanic regions) and another 50 ° lower at the poles. The relative scarcity of impact craters larger than 1-2 km allows us to consider the surface of Io relatively young (less than 1 million years).
However, not all of Jupiter's moons have smooth surfaces. Thus, the density of craters in some areas of Callisto, inferior in size to Ganymede, is close to the limit. In some areas, the edges of the craters are closed. One of the reasons for such a distribution of craters may be the fusibility of surface rocks (in particular, ice).
Jupiter Ring
Jupiter has established the existence of a huge flat ring of dust and small stones, which, with a width of 6 km and a thickness of 1 km, extends up to tens of thousands of km from the top of the clouds.
The study of Jupiter and its satellites, which has already yielded many essentially new results, has also led to the formulation of a number of new problems. In particular, studies on the physical nature of intense electric fields near the satellites closest to Jupiter are still in the process of formation.
Saturn
Saturn, the sixth from the Sun, the second largest planet in the solar system after Jupiter; refers to the giant planets.
Movement, dimensions, shape
Saturn's elliptical orbit has an eccentricity of 0.0556 and a mean radius of 9.539 AU. e. (1427 million km). The maximum and minimum distances from the Sun are approximately 10 and 9 AU. e. Distances from the Earth vary from 1.2 to 1.6 billion km. The inclination of the planet's orbit to the plane of the ecliptic is 2°29.4". The angle between the planes of the equator and the orbit reaches 26°44". Saturn moves in its orbit at an average speed of 2.64 km/s; The period of revolution around the Sun is 29.46 Earth years.
The planet does not have a solid surface, optical observations are hampered by the opacity of the atmosphere. For the equatorial and polar radii, the values of 60 thousand km and 53.5 thousand km are accepted. The average radius of Saturn is 9.1 times that of the Earth. In the earth's sky, Saturn looks like a yellowish star, the brightness of which varies from zero to the first magnitude. The mass of Saturn is 5.68 × 10 26 kg, which is 95.1 times the mass of the Earth; while the average density of Saturn, equal to 0.68 g/cm3, is almost an order of magnitude less than the density of the Earth. The free fall acceleration near the surface of Saturn at the equator is 9.06 m/s 2 . The surface of Saturn (cloud layer), like Jupiter, does not rotate as a whole. Tropical regions in the atmosphere of Saturn rotate with a period of 10 hours 14 minutes of Earth time, and at temperate latitudes this period is 26 minutes longer.
Structure and composition
The temperature in the middle layers of the atmosphere (mainly hydrogen, although the presence of a small amount of helium, ammonia and methane) is about 100 K.
In terms of internal structure and composition, Saturn strongly resembles Jupiter. In particular, on Saturn in the equatorial region there is a formation similar to the Great Red Spot, although it is smaller than on Jupiter.
Two-thirds of Saturn is made up of hydrogen. At a depth approximately equal to R / 2, that is, half the radius of the planet, hydrogen at a pressure of about 300 GPa passes into the metallic phase. As the depth increases further, starting from R/3, the proportion of hydrogen and oxide compounds increases. In the center of the planet (in the core region) the temperature is about 20,000 K.
Satellites of Saturn
All satellites, except for the huge Titan, which is larger than Mercury and has an atmosphere, are composed mainly of ice (with some admixture of rocks at Mimas, Dione and Rhea). Enceladus is unique in brightness - it reflects light, almost like freshly fallen snow. The darkest surface of Phoebe, which is therefore almost invisible. The surface of Iapetus is unusual: its front (in the direction of travel) hemisphere is very different in reflectivity from the back.
Of all the large moons of Saturn, only Hyperion has an irregular shape, possibly due to a collision with a massive body, such as a giant icy meteorite. The surface of Hyperion is heavily polluted. The surfaces of many moons are heavily cratered. So, on the surface of Dione, the largest ten-kilometer crater was discovered; on the surface of Mimas lies a crater whose shaft is so high that it is clearly visible even in photographs. In addition to craters, there are faults, furrows, and depressions on the surfaces of a number of satellites. The greatest tectonic and volcanic activity was found at Enceladus.
Ring of Saturn
Uranus
URANUS (astronomical sign I), planet, average distance from the Sun - 19.18 AU. e. (2871 million km), circulation period 84 years, rotation period approx. 17 hours, equatorial diameter 51,200 km, mass 8.7·10 25 kg, atmospheric composition: H 2 , He, CH 4 . The axis of rotation of Uranus is tilted at an angle of 98°. Uranus has 15 satellites (5 discovered from Earth - Miranda, Ariel, Umbriel, Titania, Oberon, and 10 discovered by the Voyager 2 spacecraft - Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Pack ) and a system of rings.
Movement, dimensions, mass
Uranus moves around the Sun in an elliptical orbit, the semi-major axis of which (mean heliocentric distance) is 19.182 more than that of the Earth, and is 2871 million km. The eccentricity of the orbit is 0.047, that is, the orbit is quite close to circular. The plane of the orbit is inclined to the ecliptic at an angle of 0.8°. Uranus completes one revolution around the Sun in 84.01 Earth years. The rotation period of Uranus is approximately 17 hours. The existing scatter in determining the values of this period is due to several reasons, of which two are the main ones: the gaseous surface of the planet does not rotate as a whole and, moreover, no noticeable local inhomogeneities have been found on the surface of Uranus, which would help to clarify the duration of the day on the planet.
Composition and internal structure
Like other giant planets, Uranus's atmosphere is primarily composed of hydrogen, helium and methane, although their relative contributions are somewhat lower compared to Jupiter and Saturn.
The theoretical model of the structure of Uranus is as follows: its surface layer is a gas-liquid shell, under which there is an icy (mixture of water and ammonia ice) mantle, and even deeper - a core of solid rocks. The mass of the mantle and core is approximately 85-90% of the total mass of Uranus. The zone of solid matter extends up to 3/4 of the radius of the planet
The temperature in the center of Uranus is close to 10,000 K at a pressure of 7-8 million atmospheres (one atmosphere corresponds approximately to one bar). At the core boundary, the pressure is approximately two orders of magnitude lower (about 100 kilobars). The effective temperature, determined by thermal radiation from the surface of the planet, is approx. 55 K.
Moons of Uranus
History of the discovery of Uranus
For many centuries, Earth astronomers knew only five "wandering stars" - planets. 1781 was marked by the discovery of another planet, named Uranus. This happened when the English astronomer W. Herschel embarked on a grandiose program: compiling a complete systematic survey of the starry sky. On March 13, near one of the stars in the constellation Gemini, Herschel noticed a curious object that was clearly not a star: its apparent size changed depending on the magnification of the telescope, and most importantly, its position in the sky changed. Herschel initially decided that he had discovered a new comet (his report at a meeting of the Royal Society on April 26, 1781 was called “Comet Report”), but the comet hypothesis soon had to be abandoned. In gratitude to George III, who appointed Herschel as Royal Astronomer, the latter proposed to name the planet "George's Star", however, in order not to violate the traditional connection with mythology, the name "Uranus" was adopted. The first few observations did not yet allow us to accurately determine the parameters of the orbit of the new planet, but, firstly, the number of these observations (in particular, in Russia, France and Germany) increased rapidly, and secondly, a careful study of the catalogs of past observations made it possible to verify that that the planet was repeatedly fixed before, but taken for a star, which also noticeably increased the number of data.
During the 30 years after the discovery of Uranus, the severity of interest in him periodically fell, but only for a while. The fact is that the increase in the accuracy of observations revealed mysterious anomalies in the motion of the planet: it either "lagged behind" the calculated one, then began to "ahead" it. The theoretical explanation of these anomalies led to new discoveries - the discovery of transuranium planets.
Neptune
NEPTUNE (astrological sign J), planet, average distance from the Sun 30.06 AU. e. (4500 million km), circulation period 164.8 years, rotation period 17.8 hours, equatorial diameter 49,500 km, mass 1.03.10 26 kg, atmospheric composition: CH 4, H 2, He. Neptune has 6 satellites. It was discovered in 1846 by I. Galle according to the theoretical predictions of W. J. Le Verrier and J. C. Adams. The remoteness of Neptune from the Earth significantly limits the possibilities of its study.Neptune, the eighth largest planet from the Sun, is one of the giant planets.
Movement and parameters of the planet
Neptune moves around the Sun in an elliptical, close to circular (eccentricity - 0.009) orbit; its average distance from the Sun is 30.058 times greater than that of the Earth, which is approximately 4500 million km. This means that the light from the Sun reaches Neptune in a little over 4 hours. The duration of the year, that is, the time of one complete revolution around the Sun, is 164.8 Earth years. The equatorial radius of the planet is 24750 km, which is almost four times the radius of the Earth, moreover, its own rotation is so fast that a day on Neptune lasts only 17.8 hours. Although the average density of Neptune, equal to 1.67 g / cm 3, is almost three times less than that of the earth, its mass is 17.2 times greater than that of the Earth due to the large size of the planet. Neptune appears in the sky as a star of magnitude 7.8 (inaccessible to the naked eye); at high magnification, it looks like a greenish disk, devoid of any details. Neptune has a magnetic field that is about twice as strong at the poles as it is on Earth.
Composition and internal structure
Of all the elements on Neptune, hydrogen and helium predominate in approximately the same ratio as on the Sun: there are about 20 hydrogen atoms per helium atom. In the unbound state, there is much less hydrogen on Neptune than on Jupiter and Saturn. There are other elements, mostly light ones. On Neptune, as well as on other giant planets, a multilayer differentiation of matter occurred, during which an extended ice shell was formed, as on Uranus. According to theoretical estimates, there is both a mantle and a core. The mass of the core together with the ice shell, according to computational models, can reach 90% of the entire mass of the planet.
Moons of Neptune
Discovery history
After W. Herschel discovered Uranus in 1781 and calculated the parameters of its orbit, rather soon mysterious anomalies were discovered in the motion of this planet - it either “lagged behind” the calculated one, or was ahead of it.
In 1832, in a report from the British Association for the Advancement of Science, J. Erie, who later became Astronomer Royal, noted that in 11 years the error in the position of Uranus had reached almost half a minute of an arc. Shortly after the report was published, Airy received a letter from the British amateur astronomer, the Rev. Dr. Hassey, suggesting that these anomalies were due to the influence of an as yet undiscovered "transuranium" planet. Apparently, this was the first proposal to look for a "disturbing" planet. Erie did not approve of Hassei's idea, and the search was not launched.
And a year before, a talented young student, J. K. Adams, noted in his notes: “At the beginning of this week, the idea arose to engage immediately after graduation in the study of anomalies in the motion of Uranus, which have not yet been explained. We must find whether they can be due to the influence of an undiscovered planet behind it and, if possible, determine at least approximately the elements of its orbit, which can lead to its discovery.
Adams got the opportunity to start solving this problem only two years later, and by October 1843 the preliminary calculations were completed. Adams decided to show them to Erie, but he was unable to meet with the Astronomer Royal. Adams had only to return to Cambridge, leaving for Erie the results of the calculations. For unknown reasons, Erie reacted negatively to Adams' work, at the price of which England lost priority in the discovery of a new planet.
Independently of Adams, W. J. Le Verrier worked on the problem of a transuranium planet in France. On November 10, 1845, he presented the results of his theoretical analysis of the motion of Uranus to the French Academy of Sciences, noting in conclusion about the discrepancy between observational and calculated data: “This can be explained by the influence of an external factor, which I will evaluate in the second treatise.”
Such estimates were made in the first half of 1846. The success of the case was helped by the assumption that the desired planet moves, in accordance with the empirical rule of Titius Bode, along an orbit whose radius is equal to three times the radius of the orbit of Uranus, and that the orbit has a very small inclination to the plane of the ecliptic. Le Verrier gave instructions on where to look for a new planet. Upon receiving Le Verrier's second treatise, Airy drew attention to the very close agreement between the results of Adams and Le Verrier's research regarding the motion of the supposed planet perturbing the motion of Uranus, and even emphasized this at a special meeting of the Greenwich Board of Inspectors. But he, as before, was in no hurry to start searching and began to bother about them only in July 1846, realizing what indignation his passivity could subsequently cause.
Meanwhile, on August 31, 1846, Le Verrier completed another study, in which the final system of elements of the orbit of the desired planet was obtained and its place in the sky was indicated. But in France, as in England, astronomers did not start searching, and on September 18, Le Verrier turned to I. Galle, an assistant at the Berlin Observatory, who, having received permission from the director of the observatory, on September 23, together with student D "Arre, began searching. In the first the same evening the planet was discovered, it was only 52" from the supposed place.
The news of the discovery of the planet "at the tip of the pen", which was one of the brightest triumphs of celestial mechanics, soon spread throughout scientific world. According to established tradition, the planet was named Neptune in honor of the ancient god.
For about a year, there was a struggle between France and England for the priority of discovery, to which, as often happens, the heroes themselves had no direct relationship. In particular, a complete understanding was established between Adams and Le Verrier, and they remained friends until the end of their lives.