Who discovered uranium. Interesting and fascinating facts about the planet Uranus

URANUS

Vika Vorobieva

Uranus is the seventh planet solar system. It moves around the Sun in a nearly circular orbit at a distance of about 19.2 AU. and makes one revolution in 84 years. The illumination created by the Sun at such a distance is 390 times less than the illumination created by the Sun in Earth's orbit (by eye, this roughly corresponds to early twilight after sunset). The mass of Uranus is 14.37 Earth masses, its diameter is almost 4 times the diameter of our planet, and the average density (1.30 g/cm3) is only 30% greater than the density of water.
Uranus is part of the group of giant planets in the solar system, which also includes Jupiter, Saturn and Neptune. However, unlike Jupiter and Saturn, which are composed mainly of hydrogen and helium, the mass of hydrogen and helium in Uranus and Neptune is no more than 15-20% of their total mass. Uranus and Neptune are also called the small or ice giants of the solar system.
A unique feature of Uranus among the "real" planets of the solar system is an unusually large inclination of the axis of rotation to the plane of its orbit. This slope is almost 98 degrees. Uranus rotates, as they say, "lying on its side."

If we could look at the solar system "from above", from the north pole of the sun, we would see that all the planets revolve around the sun counterclockwise in approximately the same plane. Most planets rotate around their axis in the same direction (counterclockwise). Such a rotation is called prograde, or direct. However, Uranus and Venus rotate in the opposite direction, clockwise. This rotation is called retrograde, or reverse.
All this leads to a very unusual change of seasons on Uranus. Being near its pole, we would see how the Sun rises in a spiral almost to the zenith for 21 years, then it also spirals down below the horizon, and after a 42-year polar summer, a 42-year polar night begins. Almost the entire hemisphere of the planet is beyond the Arctic Circle, except for a narrow strip along the equator. Only in spring and autumn, near the equinoxes, Uranus is illuminated by the Sun "as it should be" - with sunrises, sunsets and a change of day and night. A day on Uranus lasts 17 hours and 14 minutes.

ATMOSPHERE OF URANUS

THE MAGNETIC FIELD OF URANUS

RINGS OF URANUS

SATELLITES OF URANUS

The atmosphere of Uranus consists of hydrogen (about 72%), helium (26%) and methane (about 2%). In addition to these main components, it also contains small impurities of substances resulting from the photolysis of methane: acetylene C2 H2 , diacetylene C4 H2 , ethylene C2 H4 and ethane C2 H6 , as well as more complex hydrocarbons that form a thin overcloud haze. Methane molecules actively absorb red rays, which gives the disk of Uranus a bluish-turquoise color.
Voyager 2, flying past Uranus in 1986, did not find any contrasting details on its disk, the planet's atmosphere was very clean and transparent.

This image of Uranus was taken by Voyager 2 on January 10, 1986 from a distance of 18 million km. At this time, Uranus was turned to the Sun by the southern hemisphere, there was a polar summer. Voyager 2 approached Uranus from the south pole (it is just left of the center of this image)

The effective temperature of Uranus is only about 60K (-213C). At this temperature, at a pressure level of about 1.2 atmospheres, methane could condense, forming bright white clouds like the methane clouds in Neptune's atmosphere. However, at that moment it was polar summer in the southern hemisphere of Uranus, and the pressure of methane vapor in the troposphere ("methane humidity") was only about 50% of that necessary for the formation of methane clouds. More recent images taken by the Space Telescope. Hubble (in 1994 and 1997) showed the presence of isolated bright clouds at low latitudes. Apparently, Voyager 2 was simply "unlucky", and it flew past Uranus at the wrong time for studying atmospheric dynamics.

The main layer of clouds on Uranus is located at a pressure level of 2.4-3.4 atmospheres and consists of frozen hydrogen sulfide H2 S. The temperature in this area is about 100K (-173C).Below the first layer of clouds, at a pressure level of 20-30 atmospheres, there is a second cloud layer of ammonium hydrosulfide NH4 SH. Even deeper (at a pressure level of about 50 atmospheres) are clouds of water ice.
The temperature minimum (tropopause) in the atmosphere of Uranus is 52K (-221C) and is reached at a pressure of 0.1 atmospheres. At such a low temperature, vapors of methane photolysis products (acetylene, diacetylene, etc.) condense, forming a thin overcloud haze. It was previously believed that it is the optically thick haze that hides the various cloud details on the disk of Uranus, however, according to Voyager 2, the optical thickness of the above-cloud air is only 0.3 to 0.9, and the absorption of sunlight is mainly due to absorption in lines of methane and molecular hydrogen, broadened due to frequent mutual collisions of molecules. The overcloud atmosphere of Uranus is clean and transparent.
Above the tropopause lies the stratosphere, a region of the atmosphere where temperature rises with height. At a pressure level of 10-8 atmospheres, the temperature is about 800K, and then it does not change with height.

Temperature profiles of the atmosphere of Uranus. The upper graph shows the temperature profile of the upper atmosphere of Uranus: the stratosphere, the mesopause region and the thermosphere. The lower graph shows the deeper layers of Uranus' atmosphere: the troposphere and stratosphere. The tropopause is visible at the level of 0.1 atmosphere and a steady increase in temperature with depth. At a level of about 1 atm. clouds of frozen methane can condense. The main cloud layer is located at a level of about 3 atmospheres and consists of frozen hydrogen sulfide. These data were obtained by radio translucence of the atmosphere of Uranus by Voyager 2, when the spacecraft, from the point of view of an earthly observer, passed behind the planet. The graph marked with the word "entry" reflects the temperature profile when Voyager 2 entered Uranus, the graph marked with the word "exit" reflects the data when the device exited from behind Uranus.

The atmosphere of Uranus rotates in the same direction as the planet as a whole. In the middle latitudes, the wind blows in the direction of the planet's motion at a speed of about 150 m/s; in the equatorial zone, the wind blows in the opposite direction at a speed of about 100 m/s. Atmospheric temperature is maximum near the equator, decreases by several degrees towards middle latitudes and rises again towards the pole.

Uranus is the only giant planet in the solar system that does not have a powerful internal source heat and radiates almost as much as it receives from the sun. The reason for this is not yet known.

The magnetic field of Neptune and Uranus differs markedly from magnetic field Earth, Jupiter and Saturn. If the magnetic field of the Earth and the nearest giant planets is caused by convection in the liquid core of the planet and is dipole in structure (has one north and one south pole), then the magnetic field of Uranus is caused by convection in the water-ammonia mantle of the planet. If we describe the real magnetic field of Uranus as a dipole, then it turns out that the magnetic axis of the dipole is shifted from the center of the planet by a third of the radius and is inclined by 60 degrees to the axis of rotation.
Even better, Uranus' magnetic field is described as quadrupole (ie, having two south and two north poles).
The magnetic field strength on the surface of the planet is approximately 0.25 Gauss.

Like all gas giants in the solar system, Uranus has a ring system. They were discovered in 1977 during Uranus' occultation of a distant star (i.e. when Uranus passed exactly between the star and Earth observers). First, 5 rings were discovered, then 4 more. During the Voyager 2 flyby in 1986, 2 more rings were discovered. And, finally, quite recently, in 2003, according to images from the Space Telescope. Hubble discovered 2 new rings of Uranus.
The rings of Uranus are very dark and narrow. The albedo of the particles that make up the rings is only about 1.5%, they are blacker hard coal! In this they are strikingly different from the rings of Saturn, which are composed mainly of water ice and are therefore very bright.
In total, 13 rings of Uranus are known. Their properties are shown in this table.

ring name	distance from the center of Uranus, km	eccentricity	inclination to the equator of Uranus, * 0.001 degrees	width, km	thickness, km	average optical depth	albedo
1986U2R	38 000			2,5	0,1	0,001-0,0001	0,015
	41 840	0,0010		1-3	0,1	0,2-0,3	0,015
	42 230	0,0019		2-3	0,1	0,5-0,6	0,015
	42 580	0,0010		2-3	0,1	0,3	0,015
alpha	44 720	0,0008		7-12	0,1	0,3-0,4	0,015
beta	45 670	0,0004		7-12	0,1	0,2	0,015
this	47 190			0-2	0,1	0,1-0,4	0,015
gamma	47 630	0,0001		1-4	0,1	1,3-2,3	0,015
delta	48 290			3-9	0,1	0,3-0,4	0,015
1986U1R	50 020			1-2	0,1	0,1	0,015
epsilon	51 140	0,0079		20-100	0,5-2,1	0,5-2,3	0,018
R/2003 U2	66 100
R/2003 U1	97 730

Judging by the noticeable eccentricity and non-zero inclination of several rings (the maximum height of rings 4, 5, 6 above the plane of Uranus's equator reaches 24-46 km), the rings of Uranus are young formations. They are closely related to inner satellites and are rapidly evolving. Perhaps in the relatively near future (millions and tens of millions of years) some of the inner satellites will be destroyed by mutual collisions, and the rings of Uranus will become denser, wider and more massive.
Unlike the rings of Neptune, which are composed of small dust particles, the rings of Uranus consist of large blocks ranging in size from approximately 10 cm to 10 m.

There are currently 27 known moons of Uranus. Like the moons of Neptune, they can be divided into three distinct groups. The first are the inner satellites: Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Cupid, Belinda, Perdita, Puck and Mab. The second is the relatively large satellites of Uranus: Miranda, Ariel, Umbriel, Titania and Oberon. Finally, the third group includes the outer satellites: Francisco, Caliban, Stefano, Trinculo, Sycorax, Margarita, Prospero, Setebos, and Ferdinand.
All the inner satellites of Uranus are dark (albedo about 7%) blocks of irregular shape 50-150 km in size, rotating in the forward direction (i.e. in the direction of rotation of Uranus) in circular orbits almost in the plane of the planet's equator. Some of them (perhaps all) are associated with the rings of Uranus and are the source of the ring material. Each of the inner satellites circles the planet in just a few hours.
Recent observations of Uranus not only led to the discovery of two new moons (Cupid and Mab) and two new rings, but also revealed significant changes in the parameters of the orbits of the inner satellites since the first observations of Uranus with the space telescope. Hubble in 1994. Apparently, the system of inner satellites of Uranus is young and dynamic, their orbits are rapidly evolving. In the next few tens of millions of years, some of them will collide with each other, crumble into many fragments and give rise to new rings, some will fall on Uranus or its large satellites, and some may leave the Uranian system and go to heliocentric orbits.

None of the main moons of Uranus reaches the size of Pluto. None of them have an atmosphere. The largest moon of Uranus - Titania - has a diameter of 1578 km, which is about half the diameter of the moon. Oberon is only slightly smaller than Titania, with a diameter of 1522 km. Ariel and Umbriel, respectively, measure 1158 km and 1170 km. At the same time, it is Ariel who demonstrates the youngest surface. Its images show numerous faults, reminiscent of faults on the surface of Saturn's moon Dione, and there are relatively few craters. Some details of its surface resemble solidified cryovolcanic lava flows. Its albedo is 0.39 and it is the brightest moon of Uranus.
Umbriel, on the other hand, has the darkest surface of large satellites Uranus, its albedo is 0.21. On a dark surface covered with numerous craters, a bright White spot near the limb - apparently, a large young crater with bright ice walls.
Titania is covered with numerous craters, its surface is noticeably older than the surface of Ariel. At the same time, it also contains clear traces of geological activity, for example, a large fault near the terminator.
Miranda is the most unusual moon of Uranus. Being only 472 km in diameter, it exhibits a complex young surface. Perhaps it is an analogue of Enceladus, a satellite of Saturn, which is also small sizes shows a young surface and modern volcanism.
The average density of the main satellites of Uranus is close and amounts to 1.52-1.70 g/cm3. This suggests that in their composition, in addition to ice, there is a significant amount of rock.

Nine outer satellites orbit at the very edge of the Uranian system at a distance of millions and tens of millions of kilometers from the planet. Judging by the eccentric orbits, the strong inclination to the plane of the equator of Uranus and the backward movement, these small, very dark blocks are captured objects, similar to the outer satellites of Neptune.

Uranus is the seventh planet in the solar system, the third in diameter and the fourth in mass. It was discovered in 1781 by the English astronomer William Herschel and named after the Greek god of the sky Uranus, the father of Kronos (in Roman mythology, Saturn) and, accordingly, the grandfather of Zeus (among the Romans, Jupiter).
Unlike the gas giants Saturn and Jupiter, which consist mainly of hydrogen and helium, there is no metallic hydrogen in the bowels of Uranus and Neptune similar to it, but there is a lot of ice in its high-temperature modifications. For this reason, experts have identified these two planets in a separate category of "ice giants". The basis of the atmosphere of Uranus is hydrogen and helium. In addition, traces of methane and other hydrocarbons were found in it, as well as clouds of ice, solid ammonia and hydrogen. It is the coldest planetary atmosphere in the solar system, with a minimum temperature of 49 K (-224 °C). Uranus is thought to have a complex layered cloud structure, with water at the bottom and methane at the top. Unlike Neptune, the interior of Uranus consists mainly of ice and rocks.

PLANET URANUS
Discoverer	William Herschel
Location of discovery	Bath, UK
opening date	March 13, 1781
Detection method	direct observation
Orbital characteristics:
Perihelion	2,748,938,461 km (18.375 AU)
Aphelion	3,004,419,704 km (20.083 AU)
Major axis	2,876,679,082 km (19.229 AU)
Orbital eccentricity	0,044 405 586
sidereal period	30,685.4 days (84.01 years)
Synodic period of circulation	369.66 days
Orbital speed	6.81 km/s
Mean anomaly (Mo)	142.955717°
Mood	0.772556° (6.48° relative to the solar equator)
Ascending node longitude	73.989821°
periapsis argument	96.541318°
Physical characteristics:
polar contraction	0,02293
Equatorial radius	25,559 km
Polar radius	24,973 km
Volume	6.833*10 13 km 3
Weight	8.6832 * 10 25 kg (14.6 earth)
Average density	1.27 g/cm3
Acceleration of free fall at the equator	8.87 m/s 2
Second space velocity	21.3 km/s
Equatorial rotation speed	2.59 km/s (9,324 km/h)
Rotation period	0.71833 days (17 h 14 min 24 s)
Axis Tilt	97.77°
Right ascension north pole	17 h 9 min 15 s (257.311°)
declination of the north pole	-15.175°
Visible magnitude	5,9 - 5,32
Angular diameter	3,3" - 4,1"
Temperature:
level 1 bar	76K
0.1 bar (tropopause)	min. 49 K (-224°C) avg. 53 K (-220 °C), max. 57 K (-216 °C)
Atmosphere:
Compound:	83±3% Hydrogen 15±3% Helium 2.3% Methane Ice: - ammonia, - water, - hydrosulfide-ammonia, - methane
PLANET URANUS

Just like other gas giants of the solar system, Uranus has a system of rings, a magnetosphere and 27 satellites. The orientation of Uranus in space differs from the rest of the planets of the solar system - its axis of rotation lies, as it were, "on its side" relative to the plane of revolution of this planet around the Sun. As a result, the planet is turned to the Sun alternately with the north pole, then the south, then the equator, then the middle latitudes.
In 1986, the American spacecraft Voyager 2 transmitted close-up images of Uranus to Earth. They show an "inexpressive" planet in the visible spectrum without cloud bands and atmospheric storms characteristic of other giant planets. However, at present, ground-based observations have been able to discern signs of seasonal changes and an increase in weather activity on the planet, caused by the approach of Uranus to its equinox. Wind speeds on Uranus can reach 250 m/s (900 km/h).

Orbit and rotation:

The average distance of the planet from the Sun is 19.1914 AU. e. (2.8 billion km). The period of complete revolution of Uranus around the Sun is 84 Earth years. The distance between Uranus and Earth varies from 2.7 to 2.85 billion km. The semi-major axis of the orbit is 19.229 AU. e., or about 3 billion km. The intensity of solar radiation at such a distance is 1/400 of the value in Earth's orbit. For the first time, the elements of the orbit of Uranus were calculated in 1783 by the French astronomer Pierre-Simon Laplace, but over time, inconsistencies in the calculated and observed positions of the planet were revealed. In 1841, Briton John Couch Adams was the first to suggest that errors in calculations were caused by the gravitational influence of an undiscovered planet. In 1845 the French mathematician Urbain Le Verrier began independent work to calculate the elements of the orbit of Uranus, and on September 23, 1846, Johann Gottfried Galle discovered a new planet, later named Neptune, almost in the same place that Le Verrier had predicted. The period of rotation of Uranus around its axis is 17 hours 14 minutes. However, as with other giant planets, upper layers atmospheres of Uranus blow very strong winds in the direction of rotation, reaching speeds of 240 m/s. Thus, near 60 degrees south latitude, some visible atmospheric features make an orbit around the planet in just 14 hours.
The equatorial plane of Uranus is inclined to the plane of its orbit at an angle of 97.86 ° - that is, the planet rotates retrograde, "lying on its side slightly upside down." This leads to the fact that the change of seasons occurs in a completely different way than on other planets of the solar system. If other planets can be compared to spinning tops, then Uranus is more like a rolling ball. Such an anomalous rotation is usually explained by the collision of Uranus with a large planetesimal on early stage its formation. At the moments of the solstices, one of the poles of the planet turns out to be directed towards the Sun. Only a narrow strip near the equator experiences a rapid change of day and night; at the same time, the Sun is located there very low above the horizon - as in the earth's polar latitudes. After half a year (Uranian) the situation changes to the opposite: the "polar day" comes in the other hemisphere. Each pole of 42 Earth years is in darkness - and another 42 years under the light of the Sun. At the moments of the equinox, the Sun stands "in front" of the equator of Uranus, which gives the same change of day and night as on other planets. The next equinox on Uranus occurred on December 7, 2007.

PLANET URANUS
North hemisphere	Year	Southern Hemisphere
Winter solstice	1902, 1986	Summer solstice
The vernal equinox	1923, 2007	autumnal equinox
Summer solstice	1944, 2028	Winter solstice
autumnal equinox	1965, 2049	The vernal equinox
PLANET URANUS

Due to this axial tilt, the polar regions of Uranus receive during the year more energy from the Sun than equatorial. However, Uranus is warmer in the equatorial regions than in the polar regions. The mechanism that causes such a redistribution of energy remains unknown.
Explanations for the unusual position of Uranus' axis of rotation are also still in the realm of hypotheses, although it is generally believed that during the formation of the solar system, a protoplanet roughly the size of the Earth crashed into Uranus and changed its axis of rotation. Many scientists do not agree with this hypothesis, since it cannot explain why none of the moons of Uranus has the same inclined orbit. A hypothesis was proposed that the axis of rotation of the planet for millions of years was shaken by a large satellite, which was subsequently lost.

Axis of rotation of Uranus The most unusual feature of Uranus is its strange position. Mercury and Jupiter revolve around the Sun strictly vertically, the Earth and Mars have a moderate tilt relative to their axis by about 20-30 °, and Uranus, as it turned out, is tilted by 98 ° - in other words, its North Pole located slightly lower relative to the orbit of the planet. If other planets rotate like a top, Uranus, apparently, spins in its orbit like a ball. The strangest system of seasons of the year has formed on the planet: in the polar regions, winter lasts for 40 years with eternal night, followed by a summer of endless sunlight, which also lasts 40 years, and in the equatorial regions, the change of day and night occurs in accordance with the daily rotation of Uranus (the planet completes a revolution around its axis in 17 hours 14 minutes). Throughout the year, the ice giant appears to have a relatively uniform temperature over its entire surface, a factor thought to be related to the planet's weather.

PLANET URANUS

During the first visit to Uranus by Voyager 2 in 1986, the south pole of Uranus was facing the Sun. This pole is called "south". According to the definition approved by the International Astronomical Union, the south pole is the one that is located on a certain side of the plane of the solar system (regardless of the direction of rotation of the planet). Sometimes another convention is used, according to which the north direction is determined based on the direction of rotation according to the rule right hand. By this definition, the pole, which was illuminated in 1986, is not south, but north. Astronomer Patrick Moore commented on this problem in the following succinct way: "Pick any."

physical characteristics

Internal structure

Uranus is 14.5 times heavier than Earth, making it the least massive of the giant planets in the solar system. The density of Uranus, equal to 1.270 g / cm 3, puts it in second place after Saturn among the least dense planets in the solar system. Although the radius of Uranus is slightly larger than that of Neptune, its mass is slightly less, which supports the hypothesis that it consists mainly of various ice- water, ammonia and methane. Their mass, according to various estimates, ranges from 9.3 to 13.5 Earth masses. Hydrogen and helium make up only a small part of the total mass (between 0.5 and 1.5 Earth masses); the remaining fraction (0.5 - 3.7 Earth masses) is rock (which is believed to be the core of the planet).
The Standard Model for Uranus suggests that Uranus is made up of three parts: in the center - a stone core, in the middle - an ice shell, outside - a hydrogen-helium atmosphere. The core is relatively small, with a mass of approximately 0.55 to 3.7 Earth masses and with a radius of 20% of that of the entire planet. The mantle (ice) makes up most of the planet (60% of the total radius, up to 13.5 Earth masses). The atmosphere, with a mass of only 0.5 Earth masses (or, according to other estimates, 1.5 Earth masses), extends over 20% of the radius of Uranus. At the center of Uranus, the density should increase to 9 g/cm 3 , the pressure should reach 8 million bar (800 GPa) at a temperature of 5000 K. The ice shell is actually not ice in the conventional sense of the word, as it consists of a hot and dense liquid, which is a mixture of water, ammonia and methane. This highly electrically conductive liquid is sometimes referred to as the "aquatic ammonia ocean". The composition of Uranus and Neptune is very different from that of Jupiter and Saturn due to the "ices" prevailing over the gases, justifying the placement of Uranus and Neptune in the category of ice giants.

Structure of Uranus Its cold upper atmosphere is dominated by hydrogen and helium, which is also mixed with about 2.3% methane. Weak gravity allows Uranus to form a huge corona of hydrogen that extends for a distance twice the radius of the planet itself. Above the surface lie layers of clouds made up of various chemical elements, including water. About 5000 km below the visible surface is a layer of "squishy" mantle rich in water and ammonia. Although these layers are called "ices", they are more like liquid slush mixed with an unknown amount of hydrogen and helium. The rocky core of Uranus is probably the size of the Earth.

PLANET URANUS

Although the model described above is the most common, it is not the only one. Based on observations, other models can also be built - for example, if a significant amount of hydrogen and rock material is mixed in the ice mantle, then the total mass of ice will be lower, and, accordingly, the total mass of hydrogen and rock material will be higher. At present, the available data do not allow us to determine which model is correct. The liquid internal structure means that Uranus does not have any solid surface, as the gaseous atmosphere smoothly transitions into liquid layers. However, for the sake of convenience, it was decided to conditionally take an oblate spheroid of revolution, where the pressure is equal to 1 bar, for the “surface”. The equatorial and polar radii of this oblate spheroid are 25559 ± 4 and 24973 ± 20 km. Further in the article, this value will be taken as the zero reading for the Uranus height scale.
internal warmth Uranus is much smaller than other giant planets in the solar system. The planet's heat flux is very low, and the reason for this is currently unknown. Neptune, similar in size and composition to Uranus, radiates 2.61 times more thermal energy into space than it receives from the Sun. Uranus, on the other hand, has very little, if any, excess thermal radiation. The heat flow from Uranus is 0.042 - 0.047 W / m 2, and this value is less than that of the Earth (approximately 0.075 W / m 2). Far infrared measurements have shown that Uranus emits only 1.06 ± 0.08% of the energy it receives from the Sun. The coldest temperature recorded at Uranus' tropopause is 49 K, making the planet the coldest of all planets in the solar system - even colder than Neptune.
There are two hypotheses trying to explain this phenomenon. The first of these states that the alleged collision of a protoplanet with Uranus during the formation of the solar system, which caused a large tilt of its axis of rotation, led to the dissipation of the initially available heat. The second hypothesis says that in the upper layers of Uranus there is a certain layer that prevents the heat from the core from reaching the upper layers. For example, if adjacent layers have different composition, convective heat transfer from the core upwards can be difficult.

The absence of excess thermal radiation of the planet makes it much more difficult to determine the temperature of its interior, however, if we assume that the temperature conditions inside Uranus are close to those characteristic of other giant planets, then the existence of liquid water is possible there and, therefore, Uranus can be among the planets of the solar system, where the existence of life is possible.

The seventh planet of the solar system - Uranus - was discovered only in 1781 and was named after the ancient Greek god who was the father of Kronos. This planet is classified as one of the gaseous giant planets, along with Jupiter, Saturn and Neptune.
William Herschel, who discovered Uranus, first mistook it for a comet. He watched the constellation of Taurus, and drew attention to the celestial body, located in a place that should have been empty, judging by the star maps of that time. The object was quite clear and moved slowly relative to the stars.

He told his fellow astronomers, mathematicians and other scientists about his observation. European astronomers began to study the object, its distance, mass, orbit and other characteristics. Russian scientist Andrey Leksel, determined the distance between the Sun and Uranus, it was as much as 18 AU. e. (2.8 billion km). So, after 2 months, after many hours of daily observations, scientists were convinced that Herschel had discovered not a comet, but a distant seventh planet. For his discovery, he was awarded a lifetime cash royalties of £200 and was awarded an order. This was the first planet discovered in modern times. Uranus has expanded the boundaries of the solar system in the eyes of man since Antiquity.

Structure of Uranus

As observations from satellites show, an iron-stony core with a temperature of about 7000 K is present on Uranus, but rivers and oceans cannot be observed. The absence of metallic hydrogen reduces the amount of heat generated by the planet by up to 30%, so Uranus receives 70% of its thermal energy from the Sun. Behind the core, a dense, very dense atmosphere immediately begins, with a thickness of about 8 thousand km. The chemical composition of the atmosphere of Uranus is as follows: 83% hydrogen (H2), 15% helium (He) and about 2% methane (CH4). Methane, as well as hydrogen, take an active part in the absorption of solar radiation, and, consequently, infrared and red spectra. This explains the blue-green color of the planet. Winds in the middle layers move at a speed of 250m/s.

Axis tilt of Uranus

Uranus is a unique planet in the solar system. The tilt of the axis of rotation is about 98 °, which means that the planet is practically littered on its side. For clarity: if all the planets are like a spinning top, then Uranus is more like a rolling bowling ball. Due to such an unusual situation, the change of day and night and the seasons on the planet proceed, to put it mildly, non-standard. It turns out that 42 years, one pole is in darkness, the Sun shines on the other, and then they change. Scientists explain such a strange position of the planet, a collision with another celestial body(possibly with another planet) that happened millions of years ago.

Moons of Uranus

At the beginning of the third millennium, 27 satellites of the planet Uranus were discovered and explored. The main ones are the 5 largest satellites. The largest satellite - Titania - has a diameter of only 1570 km, which is very small compared to the satellites of other planets. Oberon is the second largest moon of Uranus. He and Titania were discovered by the same Herschel, who discovered the planet itself. Next come even smaller satellites: Umbriel, Ariel and Miranda. An interesting fact is that the names of all the satellites of Uranus were given in honor of the heroes of the immortal works of William Shakespeare.

Characteristics of Uranus

Mass: 8.69 * 1025 kg (14 times the Earth)
Diameter at equator: 51,118 km (4 times Earth's)
Pole diameter: 49946 km
Axis Tilt: 98°
Density: 1.27 g/cm³
Temperature upper layers: approx. -220 °C
Period of revolution around the axis (day): 17 hours 15 minutes
Distance from the Sun (average): 19 AU e. or 2.87 billion km
Orbital period around the Sun (year): 84.5 years
Orbital speed: 6.8 km/s
Orbital eccentricity: e = 0.044
Orbital inclination to the ecliptic: i = 0.773°
Free fall acceleration: approx. 9 m/s²
Satellites: there are 27 pcs.

1. If the Sun were the size of an ordinary front door, then the Earth would be the size of a keyhole, and Uranus would be no bigger than a soccer ball.
2. Uranus is the seventh planet from the Sun, the distance of Uranus from the Sun is 2.9 billion km, or 19.19 astronomical units (1 AU is equal to the average distance of the Earth from the Sun, 149,597,870.7 km).
3. Uranus rotates around its axis in about 17 hours (a uranian day), and a complete revolution around the Sun (Uranic year) lasts about 84 Earth years.
4. Uranus rotates around its axis "lying on its side slightly upside down." If other planets of the solar system can be compared with spinning tops, then Uranus is like a rolling ball.
5. Uranus was the first planet to be discovered with a telescope.
6. Uranus is the coldest planet in the solar system. The bowels of Uranus are composed of ice rocks formed by water, methane and ammonia. The atmosphere of Uranus consists of hydrogen and helium, the minimum temperature is 224°C. Science does not know why the planet's heat flux is much less than that of other giant planets.
7. There are 27 moons revolving around Uranus. named after the works of William Shakespeare and Alexander Pope.
8. Uranus has thin rings that are made up of very dark and small particles. 13 rings of different transparency are known. The inner rings are narrow and dark, while the outer rings are brightly colored.
9. Voyager 2 is the only spaceship who visited Uranus.
10. There is no life on Uranus as we know it.

Unlike other giant planets, the axis of rotation of Uranus is almost in the plane of the orbit, i.e., the inclination of the equator to the orbit is 82 °. Uranus, as it were, "lies on its side", therefore the duration of the polar day and night in latitude, which are 42 years at the poles, at a latitude of 60 ° - 28 years, at a latitude of 30 ° - 14 years.

Uranus has a small solid iron-stone core, over which a dense powerful atmosphere at least 8000 km thick immediately begins. It consists of 83% hydrogen, 15% helium and 2% methane (Fig. 1).

General characteristics of the planet Uranus

Methane, acetylene and other hydrocarbons in the atmosphere of Uranus are found in much greater quantities than on Jupiter and Saturn. It is the methane haze that absorbs red rays well, which is why Uranus appears blue. Like other gas planets, it has cloud bands that move very quickly.

The average temperature on the planet's surface is 200°C. Winter and summer on Uranus are very different: the whole hemisphere hides from the Sun for several years in winter. In summer, it also does not get hot there, since Uranus receives 370 times less heat from the Sun than the Earth. Mid-latitude winds on Uranus will move the clouds in the same directions as on Earth. They blow at a speed of 40 to 160 m/s (on Earth - about 50 m/s).

Rice. 1. The composition of the atmosphere of Uranus

Uranus was discovered on March 13, 1791 by an English astronomer of German origin by William Ger walked(1738-1822) (Fig. 55). In 1787, he also discovered the first two satellites and gave them the names Oberon and Titania in honor of the king and queen of the fairies from W. Shakespeare's play A Midsummer Night's Dream. This marked the beginning of the tradition of naming new satellites after the characters in W. Shakespeare's plays: Desdemona, Cordelia, Ophelia, Juliet, Rosalind, Belinda, Caliban, etc. The largest of them is Titania, with a diameter of 1580 km. In total, Uranus has more than 20 satellites.

In 1977, rings were discovered from the Earth near Uranus, then this discovery was confirmed by photographs from the Voyager 2 probe, which flew by on January 24, 1986 near Uranus.