Astronomy
Uranus
Planet
How long did Uranus last?
Is Uranus a dreamy distance from the sun?
What is the average temperature in the atmosphere of Uranus?
How many moons and rings does Uranus have?
What is so unusual about the axis of Uranus?
Uranus, the seventh planet at a distance from the Sun and the four giants of the solar system, or Jupiter, the largest of the planets, including Jupiter, Saturn and Neptune. At its brightest level, Uranus appears as a blue-green dot of light without assistance.
Two views of the southern hemisphere of Uranus, created from images obtained by Voyager 2 on January 17, 1986. In the colors of the human eye without any help, Uranus is a light, almost non-existent sphere (left). Uranus shows a shared band-cloud structure for four large planets (right), in a color-changing scene for low-contrast front-to-front processing. At this point, from Voyager's polar point of view, the bands are centered around the planet's orbital axis, which is almost pointing towards the sun. The small features of the ring shape in the picture on the right are the patterns created by the dust in the spacecraft.
Jet Propulsion Laboratory / National Aeronautics and Space Administration
Uranus is named in Greek mythology for the figure of the sky and the child and husband of Gaia. It was found by a bean in 1781. It was the first planetary epoch. It was not recognized in the prehistoric period. Uranus was seen by many barbinians in the last century, but was rejected as another star. Its average distance from the sun is about 2.9 billion kilometers (1.8 billion miles), which is 19 times longer than the earth, and it never gets closer to 2.7 billion kilometers (1.7 billion miles) from the earth. Its relatively low density (only 1.3 times that of water) and its large size (four times the radius of the Earth) make it a high cement that, like other large crusts, Uranus is mainly composed of hydrogen, helium, water, And other non-authentic compounds. Like its brethren, Uranus has no solid surface. In the uranium atmosphere, methane absorbs red wavelengths of sunlight, giving North Korea its blue-green color.
Britannica Quiz
Space Odyssey
"far off". "Specially". "Out of this world." You've heard the abusive gossip, but do you really know about space ... cad? Join in and start the journey to the planets and the universe.
Planetary data for Uranus
* It takes time for the planet to return to the same position in the solar system as seen from Earth.
** Used for heights for which results count 1 time.
Average distance from the sun 2,870,658,000 km (19.2 AU)
The eccentricity of the orbit is 0.0472
The tilt of the orbit is 0.77 طرف towards the lunar eclipse
Uranium year (by revolution) 84.02 Earth years
Visual Speed Average Update to 5.5
Meaning synodic period * 369.6 Earth days
Meaning orbital speed 6.80 km per second
Equatorial radius ** 25,559 km
Polar radius ** 24,973 km
Mass 8.681 × 1025 kg
Average density 1.27 g / cm3
Gravity ** 887 cm / sec 2
Escape speed ** 21.3 km / s
Duration of rotation (magnetic field) 17 hours 14 minutes (retreat)
Tilt the equator to 97.8
The power of the logical field at the equator is 0.23 gauss
The angle of inclination of the axis is 58.6
The power axis of the radius of Uranus offset 0.31
Number of known moons 27
Planetary ring system 13 known circles
Hubble Space Telescope: Uranus
Hubble Space Telescope, Uranus image taken after 1998. Showing its four large circles and its 10 satellites.
Erich Karkoska, University of Arizona and NASA
Most planets revolve around an axis that is more or less straight in the orbit of the orbit around the sun. But the axis of Uranus is almost parallel to that of the orbital plane, which means that as the planet rotates, its poles turn towards the sun as it travels in its orbit. In addition, the axis of the planet's logical field is significantly tipped over the axis of rotation and offset from the center of the planet. Uranus has more than two dozen moons (natural planets), five of which are relatively large, and a system of narrow circles.
Uranus has only sailed once - 1986 US Voyager 2 probe. Before that, astronomers knew very little about it. . Different values are generated to increase the rotation period of the planets on Earth from 24 to 13 hours to try to use the feature primarily, while Voyager 2 has a rotation period of 17.24 hours for the Uranium inner size. Told Establishment After the Voyager collision, advances in ground-based observation technology increased knowledge of the uranium system.
From the sun to the atmosphere of Uranus, the planet completes one orbit for 84 Earth years, basically during the entire human life. The eccentricity of its orbit is low - that is, its orbit deviates very far from a perfect circle - and the tilt of the orbit is a lunar eclipse - the plane of the Earth's orbit and the approximate plane of the solar system - less than 1. ° Low orbital eccentricity and inclination of the solar system's planets, with Mercury and Pluto notable. Scientists believe that collisions and gaseous drag removed energy from orbits when the planets were forming, thus reducing their eccentricity and inclination toward existing values. Thus, about 4.6 billion years ago, immediately after the Sun's birth, Uranus formed with other planets (see Solar System: Origin of the Solar System).
Uranus and its neighbor Neptune, the next extraterrestrial planet, are almost twin in size. Once there is a boundary of space (equal to Earth's sea level), the equatorial radius of Uranus is 25,559 km (15,882 miles). Is. The difference in their bulk density - 1.285 and 1.64 grams per cubic centimeter, respectively - shows the basic difference in structure and internal structure. Although Uranus and Neptune are significantly larger than the terrestrial planets, their pulses are less than half that of the largest planets and Saturn. For additional orbital and physical data about Uranus, see Table.
For this one pole is above the lunar eclipse and the other below it. (The terms above and below refer to the sides of the eclipse that occur above the Earth's North and South Poles, respectively, regardless of the direction in which the planet is orbiting. By this definition, Uranus is at its North Pole. In the direction of rotation, or retreat, which is the opposite of the progressive spin of most of the Earth and other planets. When Voyager 2 flew from Uranus in 1986, the North Pole was in darkness, and the Sun was almost Right at the South Pole. 42 In North Korea, or in a year and a half a year, the sun will move almost to the top of the pole. One evening after the event you collided with Uranus, which crashed into your country. An alternative theory is that it was a Mars-sized moon, orbiting Uranus in the opposite direction to the planet's danger, eventually colliding with the planet. Went and dropped it on his country.
The orbital period of Uranus was 17.24 hours when Wake 2 detected the emission of waves starting from charged particles trapped in the logical field of the planet. A straight path later in the field shows that it is tilted at an angle of 58.6 شدت to the intensity of the axis of rotation and turns with the same duration of 17.24 hours. These fields are thought to be the planet's electrically ascendant, for which a period of 17.24 hours is assumed to be an internal size. Relatively fast rotation causes the poles of the planet to become thicker, or flatter, as the polar radius is about 2.3% less than the equator radius. Clouds revolve around the planet on the visible surface as it moves through the atmosphere, during which time it can be anywhere from 18 hours near the equator to more than 14 hours at high altitudes.
Space
Molecular hydrogen and atom helium are two important components of the uranium atmosphere. Hydrogen can be detected from the earth in the spectrum of sunlight scattered from the planet's clouds. The balance of helium-hydrogen and the disturbance of the radio signal (Mo) of Voyager 2 in the atmosphere was determined as it passed behind spacecraft C. Helium contains 15% of the total number of hydrogen molecules and helium atoms, which is equivalent to 26% of the total number of hydrogen and helium. These values are higher than the values estimated for the Sun and higher than the values estimated for Jupiter and Saturn. It is assumed that the four major planets had a hydrogen-helium relationship like the Sun during their formation, but in the case of the joint and Saturn, some helium settles towards its center (see joint: ؛ Saturn: ). The processes that lead to this settlement in theoretical studies do not work on large planets such as Uranus and Neptune.
Man is strongly attracted to near and long wavelengths and is exposed to the light of the reflected spectrum as the number of molecules is only 2.3%. Astronomers have estimated that the abundance of methane uses Voyager 2 radio signals that examine the depths of the atmosphere where the hydrogen connection with methane is part of a permanent routine. If this consistency is characteristic of the planet as a whole, then Uranus' carbon-hydrogen ratio is 24 times that of the Sun. (Methane [CH4]] contains one atom of carbon and four hydrogen atoms. As can be seen below. Director Observations on Earth A strange decrease in ammonia molecules appears in the atmosphere, probably due to the high concentration of hydrogen sulfide and all ammonia together to form cloud particles of ammonium hydro sulfide. Ultraviolet spectrometers rarely detect traces of acetylene and ethane, gases of methane, which are separated when the sun's ultraviolet light hits the upper atmosphere.
On average, Uranus releases an amount of energy at 59.1 K (K ؛ 3 353 ° F, 14214 ° C) as an ideal, absorbing surface. This radiation temperature is about 0.4 times the equivalent of ambient temperature. With the compounder the temperature decreases - that is, with increasing altitude - in this observation of the atmosphere this level reaches the level of millibars, where Uranus is about 52 K (−36 ° F, −221 ° C). Cold temperatures in the atmosphere. From this point the temperature rises again until it reaches 750 K (890 ° F, 480 C) in the outer sphere - 1.1 Uranus from the center of the planets. Above - where the point is in order. One trillionth. High temperatures remain to be fixed, but may include ultraviolet absorption, electron bombardment, and failure to emit gas at weapon wavelengths.
Voyager 2 measures the horizontal temperature of the atmosphere in the range of twice the height, measuring 60-200 mm bar and 500-1000 mm bar. The pole-to-pole difference in both ranges is eliminated - less than 1 K (1.8 ° F, 1 ° C) - due to the fact that one pole faces the sun during the fly-by. This reduction in global change is thought to be related to the efficient horizontal temperature transfer and greater capacity to store heat in the home.
Although not particularly significant for comparison to Uranus, the Vail 2 contrasting fine images and recent observations of the Earth show bands of fading clouds parallel to the equator. This type of zonal flow is common and dominates the rotation of Saturn's atmosphere, whose axis of rotation is slightly tilted from the axis of Uranus, as well as those whose climatic changes in solar light are very different. Apparently, the rotation of the planet itself controls the distribution patterns of absorbed sunlight, not the pattern itself. Rotation shows you through your Coriolis force, an effect that causes a rotating object to turn to the right or to the left. In terms of the pattern being, because, Uranus looks like the tip and version of Jupiter or Saturn.
Orbiting planets move. At high altitude over Uranus, this nation-state moves in the direction of the planet's orbit. The movement of women in the equator is in the opposite direction. Uranus is like the earth in his experiments. On Earth, these directions are called East and West, respectively, but the more common terms are development and retreat. Many times more than the land on Uranus. The wind blows at 200 meters per second (720 kilometers [450 miles] per hour) at 55 ° S latitude and 110 meters per second (400 kilometers [250 miles] per hour) at the equator. Neptune's equator also retreats to the equator, but is moving towards the joint and Saturn. There is no satisfactory theory to explain these statements.
Jupiter's long stay in Uranus is not as big a spot as the Great Red Dot or the Great Dark spot (Neptune: see the atmosphere) seen on the Voyager 2 video Neptune in 1989. On Uranus, there were only four small spots around Voyager whose visual contrast was not 2 or 3% higher than in the surrounding environment. There is no solid surface, so the consensus of hurricanes to the spots is not clear because of them, it seems that Uranus also has the lowest number of hurricanes of any major planet.
Destination field and field field
Like the other major planets, Uranus has a dissertation field generated by convection currents in an electrically charged internal structure. Doppol Field, which is centered on a small but time-lapse field, has a force of 0.23 gas in its equatorial plane on a field of uranium equatorial radius from the center. The polarity of the field is based on the same direction as the current field of the earth - that is, the counterclockwise of a general article report will point to the rotating pole, which is the north pole for the earth (see: geographic field and cross field ). The Doppler axis rotates at an angle of 58.6 سے with a glimpse of the planet's orbital axis, which is too much for Earth 11.5 °) Jupiter (9.6 °) and Saturn (less than 1). The nearest center is 31% (approximately 8,000 kilometers [5,000 miles]) of Uranus's radius from the center of the planet. Migration occurs mainly along the axis of rotation towards the North Pole.
The logical field is not only due to its unusual inclination and offset but also due to its large size in terms of small components. This "roughness" indicates that it grows at shallow depths within the field C, as small-scale components rapidly disappear from the electrically conductive area. Thus the common portion of Uranus, electronically closer to Saturn and Earth, is thought to be due to the fact that the internal structure of Uranus is known for its ammonia, which contains more water, methane and more than the average density of C. Methane must be present. Water and ammonia are separated into positive and positive ions at relatively low temperatures - which move electrically. That together, on Saturn and Earth, this field is formed by fluid movements in the convex layers, but the layers on Uranus are not two-sided.
Britannica Quiz
Something in space in a 25 minute quiz
Ever wanted to observe everything in outer space in just 25 minutes? Now you can do it with this quiz, which can take you from planets to black holes to satellites. If you can finish it in less than 15 minutes, then you are the master of the universe!
On the other hand, the path of the planets which have the field of dissertation, the field of Uranus repels the solar, the stream of charged particles which is very far from the sun. Planetary segmentation - a large region of space in which charged particles emerge from the required field - surround the planet and view it from below. Upstairs, the meeting of the Sun, the magnetopias; the airspace between the magnetic sphere and the sun, from the center of the planet to the hotel at 18 Uranine Place (460,000 km [286,000 miles]).
The particles trapped inside the uranium magnetosphere contain protons and electrons, which indicates that the planet's upper atmosphere is providing most of the material. There is no evidence of helium, which originated from the sun, or of heavy ions, which could come from the uranium moons. The largest uranium circulates inside the silver sphere, they make some sense in trapped particles. As they are connected to the dissertation field lines, so that the moon in the orbit that the particles trapped in the exposure lines compared to the neighboring field lines.
Partition that is common to Saturn, particles charged from the uranium magnetosphere collide in the upper atmosphere and form auroras. The high temperatures of the outer sphere of Uranus can hardly be (see atmosphere above). One of the effects of high temperatures is that the atmosphere is outward, which includes rings and limits their life span by increasing the drag. It looks like a sack that encloses with a drawstring.
Inside out
Although Uranus has a slightly lower density than Jupiter, it has a higher proportion of heavier elements than hydrogen and helium. The greater mass of Jupiter (from the element of 22) leads to greater gravity and thus compresses itself against Uranus. This extra compression adds to the bulk density of Jupiter. If Uranus is equal to the common, it is much less.
The various rocks (silicate and metals) recommended for Uranus, ice (water, methane, and ammonia), and gases (mainly hydrogen and helium) have different ratios. At high temperatures and locations within the giant planets, f "actually" in the past "to keep up with the bulk density data and statistics, the chrysanthemum of ice except chit should be about 80% of the total mass. 10% for Jupiter and 2% for the composition of the Sun. All in one liquid planet, in which the gaseous light enters U in a high atmosphere. About five mega bars at the center of the planet.
Scientists have responded to the response of fugal forces arising from the planet's rotation by obtaining information about them, along with the actual planetary response measured by Voyager 2. By combining the force of the flattening force at the poles with the speed of rotation, the distribution of density within the dream planet can be estimated. For two planets of the same mass and bulk density, the mass near the center is less flat than the rotation. Before the Voyager mission, they had to choose between the three components, hard rock, ice and gas, and the ones that got along well with ice and gas. Combining the great altitude and relatively cheap rotation for Uranus on the Voyager scale, it appears that ice and gas are well mixed and that a rocky portion is small or non-existent.
The fact is that those who mix Uranus prefer better observations to information about the formation of the planet. This process is made up of the center of a rock ice in changing the situation after which gas has been extracted from the solar molecule, it seems to have been incorporated into it, in favor of which, a solid budget is continuously a. Was imprisoned on a large planet that already had a large amount. Gas component.
Unlike the other three major planets, Uranus does not emit much heat. The total heat output is determined by the measurement and emission of C, while the heat input absorbs this vacuum of sunlight. ۔ For Uranus, the ratio of the two is between 1.00 and 1.14, which means that it provides more energy to the planet than its internal energy, 14% more energy from the sun. (For other giant planets, the equivalent relationship is greater than 1.7. For example, the heat flow from the inner part of the earth is only one tenth of the heat of the sun.)
It is not clear why Uranus produces less heat than other living organisms. All the planets should be warm, because the energy of gravity has not changed during this time. Over the age of the solar system, Earth and other small companies have lost most of the heat of their formation. Due to the massive investment in cool surfaces, however, the giant planets store heat well and deteriorate. Therefore, the massive heat of its structure must change it, and it must escape today. A small event (such as some planets experiencing collisions with large objects but others have not formed them and suggested a difference between the resulting giant planets) One explanation is that Uranus produces extraordinary heat.
Moon and rings of Uranus
With 27 known moons of Uranus, each of the countless particles forming at least 10 circles can be considered as one moon in its orbit. Generally, all are located close to the circle, some small moons orbiting outside the circle, the largest moon is out of orbit, and other smaller moons are farther away in orbit. The orbits of the outermost group of moons are eccentric (long) and very inclined towards the equator of Uranus. Other moons and rings are mainly along the equator with coplanar.
Video of Uranus' hemisphere, orbital system, and Voyager K2 came out with images of eight of the ten tiny moons, which were shown on July 28, 199, in the 90-minute atmosphere of the Hubble Space Telescope. The movement appears. The rotation of the moon with the equator of Uranus and the clockwise rotation of the cloud in the planetary atmosphere.
Erich Karkoska, University of Arizona, Takin, and NASA
The moon of Uranus
The five largest moons of Uranus are about 240 to 800 kilometers (150 to 500 miles) in radius. People were grounded through binoculars, four of them before the 20th president (see observations from the ground below). The ten smaller moons Voyager 2 highlighted in 1985-86 were estimated to be between about 10 and 80 kilometers (6 and 50 miles) in radius, and they hovered between 49,800 and 86,000 kilometers (31,000 and 53,500 miles). But they revolve around the planet. To reach the innermost moon, Cordelia, the outermost circles, Lambda and Epsilon. The 11th, like the moon, was photographed by Voyager near the orbit of Belanda with a picture of Predata. All 18 of the above people who participated in the Earth observations in 2003 are progressives from planetary divisions, with less inclination, and less eccentric orbits.
The moon of Uranus
Composite image of Uranus with its five large moons, mounted on Voyager 2 at one time. From the smallest to the largest moon, Ariel, Miranda, Titania, Oberon, and Umbrella are here.
Nine outer moons of about the same size met Earth in 1997 that Voyager observed. These are irregular planets with extremely elliptical orbits which are inclined at great angles towards the planet's equator. In the direction of all orbits except one. Their average distance from the planet is between 4 4 and ڈالر 21 kilometers (2.5 2.5 and ڈالر 13 miles), which is 7-36 times more than the outermost powerful moon, Oberon. Immediately after the formation of the planet, the irregular moon was caught in orbit around Uranus. Question: The moon is probably in the orbit of its equator at the same time as the planets. The characteristics of known Uranium moons are summarized in the table. The names and orbital and physical characteristics are listed separately for the mass and the 10 smaller moons that Voyager actually saw the moon.
The moon of Uranus
The name means distance from the center of Uranus (radius of volume 3 km) Orbital distance (cedril period; day of the earth) * Tilt of the orbit of the planet's equator (degrees) ** Radius (km) Mass (1020 kg) Average density (g / cm3)
* Following the amount of R does not lead to a receding orbit.
** Values of tilt in parentheses related to lunar eclipse.
*** Scene rotation and orbital periods such as.
Cordelia 49,800 0.335 0.085 0.0003 20
Ophelia 53,800 0.376 0.104 0.0099 21
Statement 59,200 0.435 0.193 0.0009 26
Cressida 61,800 0.464 0.006 0.0004 40
Desdemona 62,700 0.474 0.113 0.0001 32
Juliet 64,400 0.493 0.065 0.0007 47
$ 66,100 0.513 0.059 0.0001 68
Rosalind 69,900 0.558 0.279 0.0001 36
Cupid 74,392 0.613 0.099 0.0013 5
Belanda 75,300 0.624 0.031 0.0001 40
Perdita 76,417 0.638 0.47 0.0116 10
86,000 0.762 0.319 0.0001 81.
Mab 97,736 0.923 0.134 0.0025 5
Miranda 129,900 1.413 4.338 0.0013 Scenario 235.7 0.66 1.2
Ariel 190,900 2.52 0.041 0.0012 Imagine. 578.9 13.5 1.67
Umbriel 266,000 4.144 0.128 0.0039 sync. 584.7 11.7 1.4
Titania 436,300 8.706 0.079 0.0011 Concept. 788.9 35.2 1.71
O'Brien 583,500 13.46 0.068 0.0014 Map. 761.4 30.1 1.63
Francisco 4,276,000 266.56R (145.22) 0.1459 11
Caliban 7,231,000 579.73R (140.881) 0.1587 36
Stephano 8,004,000 677.36R (144.113) 0.2292 16
Trinculo 8,504,000 749.24R (167.053) 0.22 9
Sycorax 12,179,000 1288.3R (159.404) 0.5224 75
Margaret 14,345,000 1687.01 (56.63) 0.6608 10
Prospero 16,256,000 1978.29R (151.966) 0.4448 25
Setbus 17,418,000 2225.21R (158.202) 0.5914 24
Ferdinand 20,901,000 2887.21R (169.84) 0.3682 10
The density of the four largest Titania, Oberon, Umbrella and Ariel - the equivalent of a reinforced moon - is 1.4–1.7 grams per cubic centimeter. This limit is higher than the density of a hypothetical object which is to cool the solar compound and remove all gaseous substances and run it. All that's left is 60 percent ice and 40 percent rock compared to the four Miranda, the fifth largest moon in Uranium, but only half the size of Ariel or Umbrella. Like Saturn's small moons, Miranda's density (1.2 grams per cubic centimeter) is slightly below the solar system, due to the high ratio of ice to rock.
Moon of Uranus: Ariel
Ariel (White Doctor) and his shadow (Black Doctor) cross the middle of Uranus in a widely patterned image from the Hubble Space Telescope.
Water Snow Show the Spectra of the Surface of the Five Great Moons The surface of the lunar moon is less than that of pure ice, which clearly means that they contain ice water. The composition of the dark component is not known, but at wavelengths other than water, the surface tectonics appears to be darker, which speaks of a non-free gray color and thus rejects materials such as iron ore. Which produces a reddish hue, a fraction of carbon, which emanates from under the moons or from the rings of Uranus, emitting methane gas, which is then bombarded by charged particles and solar ultraviolet light to produce solid carbon. There are flowers for. ۔
Titania, the largest moon of Uranus, in a collection of images taken by Voyager 2 when it formed the closest approach to the uranium system on January 24, 1986. The shape of the upper right side of the lunar disk near the terminator (night range). The non-selective gray color of Titania represents the planet's five largest moons as a whole.
Two observations show that the surface of large moons is insecure and highly insulated. First, when the observer is within 2 سور of the sun being seen from the planet, the reflection is dramatically created. Such so-called opposition surges are characteristic of loose-fitting particles that shadow each other, except for the special geometry in which the observer corresponds to the light source and reflects the light directly from the spaces between the particles. Can see Second, changes in surface temperature appear to follow the sun during the day, with no significant intervals due to thermal inertia. Again, such behavior is characteristic of unsafe surfaces that block the internal flow of heat.
Auburn, the largest of Uranus' five largest moons, as recorded by Voyager 2 on January 24, 1986. This image, taken from the best of the moon, shows several large impact pits surrounded by bright rays of ejaculation. The most notable crater, located just below Oberon's disc, has a bright central peak and a floor partially covered with black material. Rising on the lower left limb against a dark background is a mountain approximately 6 km (4 miles) high.
NASA / Caltech / JPL
Practically all that is known about the specific superficial characters of Uranus's giant moons comes from Voyager 2, which passed through them in a matter of hours and photographed only their sunlit southern hemisphere. O'Brien, and Umbrella in particular, represent the dense population of large-impact citadels, similar to the highlands of the Earth's moon and many of the oldest regions in the solar system. In contrast, Titania and Ariel have very few large craters (50–100 km [30–60 mi] in diameter) but their numbers are comparable in smaller sizes. Larger craters are thought to be four billion years older than the early history of the solar system, when large planets still existed, while smaller craters reflect recent events, including, perhaps, the effects of knocked objects. Are Loose than other moons in the uranium system. Thus, the surfaces of Titania and Ariel should be smaller than the surfaces of Auburn and Umbrella. These differences, which do not follow any clear pattern regarding the distance of the moon from Uranus or their size, are largely obscure.
Umbrella, the third closest and darkest of the five largest moons of Uranus, in an image created by Voyager 2 on January 24, 1986. Umbrella is also the heaviest and evenly crater in the large Uranine moons, indicating that very little work has been done on its surface. Through tectonic activity in the past. This view shows the southern hemisphere in Umbrella sunlight. The bright ring near the moon's equator (at the top of the picture), called Wanda, is a mysterious feature that appears to line the floor of the impacting pit.
NASA / JPL
Volcanic deposits seen on large moons are usually flat, with shoreline and surface waves characteristic of fluid flow. Some deposits are bright, while others are dark. Due to the extremely low temperatures expected for the outer solar system, the erupting fluid was probably a mixture of water and ammonia, the melting point of which is below the ice of pure water. Differences in brightness can indicate differences in the structure or surface history of the erupting fluid.
Ariel, one of the five largest moons of Uranus, in a mosaic of photographs taken on January 24, 1986 by Voyager 2 during a flight through the Uranus system. Small impact pits - close to the resolution limit in this image - most of the moon's surface. The most notable features are the spots and valleys that traverse the rugged terrain. Some valleys are partially filled with material that may have risen from the interior of the moon.
Jet Propulsion Laboratory / National Aeronautics and Space Administration
The raft-like valley visible on the big moons means the expansion and rupture of their surfaces. The Miranda valleys are the most spectacular, some 80 kilometers (50 miles) wide and 15 kilometers (9 miles) deep. The eruption of the crust was caused by an increase in the size of the moon, which is estimated to be in the range of 1-2%, except for Miranda, for which this expansion is considered to be 6%. The spread of Miranda can be explained by the fact that all the water forming its interior is once liquid and then freezes after the formation of crust. By freezing at low pressure, the water would expand and thus spread and disperse the surface. Liquid water is unlikely to be present on the surface at any stage of the moon's history.
Miranda, the innermost of the large moons of Uranus and the most diverse in terms of topography, in a mosaic of images obtained by Voyager 2 on January 24, 1986. In this South Pole landscape, the old, heavily pitted region is connected to the great currents of youth. , Light-pitted areas characterized by parallel bright and deep bands, spots and peaks. The patches, called coronae, are unique to Miranda in all parts of the solar system.
US Geological Survey / NASA / JPL
Miranda has a mess of something made up of separate pieces that didn't fit together completely. The base surface is very deep, but is disturbed by three light-pitted regions, which astronomers have named Coroni (but which are not geologically related to the surface features of Venus of the same name). They are quite square in shape, approximately the length of a Miranda radius on one side, and are surrounded by parallel bands that revolve around the edges. The boundaries where the corona meets the crater are sharp. Corona is the opposite of the features found elsewhere in the solar system. Whether they reflect a different origin for the moon, a larger effect that shattered it, or a unique pattern of eruption from its interior is not known.
Ring system
The orbits of Uranus were the first to be found around a planet other than Saturn. Nine years before the collision of Voyager 2 in 1977, American astronomer James L. Elliott and his colleagues performed a stellar spell by Uranus, meaning that when the planet passed between a star and the Earth, the starlight Stopping, he discovered the color system from the ground. . Unexpectedly, they saw the star fade briefly five times before and after landing on the planet's star at some considerable distance above the atmosphere of Uranus. The decrease in brightness indicates that the planet is surrounded by five narrow circles. Later ground-based observations revealed four additional circles. Voyager 2 detected the 10th ring and found clues from others. Outside of Uranus, 10 is named 6, 5, 4, Alpha, Beta, Eta, Gamma, Delta, Lambda and Epsilon. This cumbersome name arose because new rings were found in places that did not match the original name. The characteristics of the rings are given in the table.
Rings of Uranus
Name distance from the center of the planet (km) Observed width (km) * Equal width (km) **
* Value range reflects real variations in latitude and measurement error.
** Equal width is the product of the observed width and the dimming part of the light and is given for visible light.
6 41,837 1–2 0.66
5 42,235 2–7 1.23
4 42,571 1–6 1.06
Alpha 44,718 4–11 3.86
Beta 45,661 4–13 3.16
Eta 47,176 1–4 0.64
Gamma 47,627 2–8 3.13
Delta 48,300 3–8 2.69
Lambda 50,026 2–3 0.3
Epsilon 51,149 20–95 42.8
Circles are narrow and quite vague. Observed widths are only the radial distances between the beginning and end of individual fading events. Product of equal width radial distance (more precisely, integral) and part of the starlight is blocked. The fact that the equivalent widths are generally less than the observed widths indicates that the circles are not completely obscure. Combining the brightness of the circles seen in the Voyager images with the width equal to the magic shows that the colored particles reflect less than 5% of the sunlight. Their almost flat reflection spectrum means that the particles are mainly gray in color. Ordinary mascara, which is mostly carbon, is the closest ground analogue. It is unknown at this time what he will do after leaving the post.
The scattering effects on Voyager's radio signals were spread through circles on Earth, which are mostly composed of large particles, more than 140 centimeters (4.6 feet) long. The scattering of sunlight when Voyager was far away from the circles and its camera was back towards the sun, also revealed small particles of dust in the micrometer size range. Only a small amount of dust was found in the central circles. Instead, most of the microscope particles were distributed in the spaces between the central circles, indicating that the circles were losing mass as a result of the collision. The life span of dust in orbit around Uranus is limited by the planet's diffuse atmosphere and the radiation pressure of sunlight. Dust particles move to the lower orbit and eventually fall into the uranium atmosphere. Mathematical orbital life is so short - 1,000 years - that dust must be created quickly and continuously. Dragging Uranus into space seems so large that current circles themselves could be short-lived. If so, the rings did not form with Uranus, and their origin and date are unknown.
The collision between the particles of the tightly filled ring will naturally increase the radial width of the circles. Moons larger than rings can stop its spread in a process called shepherding. Specific orbits that occur inside or outside the orbit of a given circle are at a suitable radius for the moon in such an orbit so that a stable dynamic resonance is established with the particles in the circle. The condition for resonance is that the orbital periods of the moon and the particles of the circle are related to each other in the ratio of small whole numbers. In this type of relationship, as the moon and particles pass through each other from time to time, they interact with gravity in a way that maintains the regularity of competition. The moon applies pure torque to the ring, and as the moon and the ring exchange angular momentum, energy is dispersed by collision between the particles in the ring. The result is that the moon and the ring particles repel each other. Every body in the outer orbit moves outwards, while the body in the inner orbit moves inwards. Because the moon is much larger than the ring, it prevents the ring from spreading in the radius at which it resonates. A pair of shepherd's moons, on either side of a ring, can maintain its narrow width.
Voyager 2 found that the innermost two moons, Cordelia and Ophelia, were needed for the shepherd to orbit on the far right in either orbit of the Epsilon ring. Shepherds have not been observed for other circles, perhaps because the moons are too small to be seen in Voyager images. Small moons can also be deposits that leave the color system and provide dust.
The part of the ring system of Uranus that contains the Epsilon ring lit by its two shepherds, Cordelia and Ophelia, in a photograph obtained by Voyager 2 on January 21, 1986, of the spacecraft's Urine. Three days before the closest approach to the system. Many other rings of Uranus can be seen on the inside of the Epsilon ring.
Jet Propulsion Laboratory / National Aeronautics and Space Administration
Observations from the ground
Uranus was discovered by the English astronomer William Herschel, who surveyed all the stars below the eighth magnitude - the stars that are five times weaker than the stars visible to the naked eye. On March 13, 1781, he discovered "a curious star, or perhaps a comet," distinguishing it from a disk clearly visible to the stars. With no trace of its tail and its slow movement, it came to the conclusion within months that the object was a planet, rather than a comet, orbiting Saturn in an almost circular orbit. Observations of the new planet over the next 65 years revealed discrepancies in its orbital motion - evidence of the forces of gravity on Uranus that were not due to any other known planet, which eventually led to the discovery of Neptune in 1846. Made
Herschel suggested the name of his new discovery Georgium Siddus (Latin: "Georgian Star"), but Herschel and others called it the "Georgian Planet" - in honor of their patron, King George III of England, while the French named Herschel's Name supported. The planet was eventually named after the Greek and Roman mythological deities. Uranus is the father of Saturn, who in turn is the father of Jupiter.
The orbit of Uranus seems to fulfill a simple experimental principle, the prediction of Baude's law, which was formulated in 1766 and became popular in 1772 to measure the Earth's orbital distance from the Sun and the five planets known to the ancients. To be explained. In addition, where the law predicted another planet between Mars and Jupiter, the planets appeared to be filling the gap, beginning in 1801 with the discovery of the largest planet, Ceres. For almost three-quarters of a century, these achievements overcame doubts. From the fact that the law had no ideological basis and that it provided only an approximate fit for the orbits of the planets. Neptune did not fit this pattern at all (approximately 21% closer to the Sun as predicted by the law), nor did Pluto, and now Bod's law is only historically significant.
After the discovery of Uranus, Herschel continued to observe it with larger and better telescopes, and finally in 1787 discovered his two largest moons, Titania and Oberon. The absence of these moons was not realized until the middle of the 19th century, despite an almost complete lack of confirmation from other astronomers. Did The Four Moons comes from English literature, taken from the characters of William Shakespeare and Alexander Pope, and was suggested by Herschel's son John. (The names of the children of Uranus, the Titans, have already been assigned to the moons of Saturn.) The works of Shakespeare and the Pope continued to apply to later discoveries.
Search for the spacecraft
In this computer animation of the Voyager 2 space probe, discover Uranus' nightside and ring system as it emerges from the planet's solar system.
This computer animation shows the Voyager 2 space probe with the planet Uranus on January 24, 1986. As the spacecraft moves toward the planet's night shore, Uranus's system of thin circles becomes increasingly visible. Near the end of the sequence, the distant sun passes behind Uranus, while Voyager 2 begins to move away from the solar system at its own speed.
NASA
Watch all the videos for this article
Although the twin Voyager 1 and 2 spacecraft missions originally required only the fly-bikes of Jupiter and Saturn, the launch time of the Voyager 2 allowed it to change its speed to allow Uranus and Neptune to launch an expansion mission. But could be targeted again. Was finally done. After more than eight years in space, Voyager 2 passed through the uranium system on January 24, 1986. His instruments accurately determined the size and radiology of the planet and its large moons, detected the magnetic field of Uranus and determined its strength and direction. , And measured the rate of internal rotation of the planet. Images of the Uranium system, numbering more than 8,000, show for the first time the weather patterns in the planet's atmosphere and the surface features of the moon. In addition to Voyager's discovery of the new moon, a ring, and the dust band between the rings, he provided details of the structure of the ring on a non-ground scale. Yet, despite these successes, Voyager has left many unanswered questions that only one other spacecraft could solve with a major breakthrough in mission or ground-based observation technology. No future missions are planned for Uranus.
