BASIC DATA ABOUT NEPTUNE
Neptune is primarily a giant of gas and ice.
Neptune is the eighth planet of the solar system.
Neptune is the farthest planet from the Sun since Pluto was demoted to the rank of dwarf planet.
Scientists don't know how clouds can move so fast on a cold, icy planet like Neptune. They suggest that cold temperatures and the flow of liquid gases in the planet's atmosphere may reduce friction enough to allow winds to pick up significant speeds.
Of all the planets in our system, Neptune is the coldest.
The upper layers of the planet's atmosphere have a temperature of -223 degrees Celsius.
Neptune produces more heat than it receives from the Sun.
Neptune's atmosphere is dominated by chemical elements such as hydrogen, methane and helium.
Neptune's atmosphere gradually transitions into a liquid ocean, which then transitions into a frozen mantle. This planet has no surface as such.
Presumably, Neptune has a rocky core whose mass is approximately equal to the mass of the Earth. Neptune's core is composed of silicate magnesium and iron.
Neptune's magnetic field is 27 times more powerful than Earth's.
Neptune's gravity is only 17% stronger than that of Earth.
Neptune is an icy planet made of ammonia, water and methane.
An interesting fact is that the planet itself rotates in the opposite direction from the rotation of the clouds.
A Great Dark Spot was discovered on the planet's surface in 1989.
SATELLITES OF NEPTUNE
Neptune has an officially registered number of 14 satellites. Neptune's moons are named after Greek gods and heroes: Proteus, Talas, Naiad, Galatea, Triton and others.
Neptune's largest satellite is Triton.
Triton moves around Neptune in a retrograde orbit. This means that its orbit around the planet is backwards compared to Neptune's other moons.
Most likely, Neptune once captured Triton - that is, the moon did not form on the spot, like the other moons of Neptune. Triton is locked in synchronous rotation with Neptune and slowly spirals towards the planet.
Triton, in about three and a half billion years, will be torn apart by its gravity, after which its debris will form another ring around the planet. This ring may be more powerful than the rings of Saturn.
Triton's mass is more than 99.5% of the total mass of all other Neptune satellites
Triton was most likely once a dwarf planet in the Kuiper Belt.
RINGS OF NEPTUNE
Neptune has six rings, but they are much smaller than Saturn's and are not easy to see.
Neptune's rings are made mostly of frozen water.
It is believed that the planet's rings are the remains of a once torn apart satellite.
VISITING NEPTUNE
In order for the ship to reach Neptune, it needs to travel a path that will take approximately 14 years.
The only spacecraft to visit Neptune is.
In 1989, Voyager 2 passed within 3,000 kilometers of Neptune's north pole. He circled the celestial body once.
During its flyby, Voyager 2 studied Neptune's atmosphere, its rings, magnetosphere and met Triton. Voyager 2 also took a look at Neptune's Great Dark Spot, a rotating storm system that has disappeared, according to Hubble Space Telescope observations.
Voyager 2's beautiful photographs of Neptune will long remain the only thing we have
Unfortunately, no one plans to explore the planet Neptune again in the coming years.
The second planet (after Uranus) discovered in the “Modern Era” - Neptune - is the fourth largest and eighth planet in distance from the Sun. He was named after the Roman sea god, similar to Poseidon among the Greeks. After the discovery of Uranus, scientists around the world began to argue, because... the trajectory of its orbit did not quite correspond to the universal law of gravity discovered by Newton.
This gave them the idea of the existence of another planet, not yet known, which influenced the orbit of the seventh planet with its gravitational field. 65 years after the discovery of Uranus, the planet Neptune was discovered on September 23, 1846. She was the first planet to be discovered using mathematical calculations rather than through long observations. The Englishman John Adams began calculations back in 1845, but they were not entirely correct. They were continued by Urbain Le Verrier, an astronomer and mathematician originally from France. He calculated the position of the planet with such accuracy that it was found on the very first evening of observations, so Le Verrier began to be considered the discoverer of the planet. The British protested and after much debate, everyone recognized Adams's considerable contribution, and he is also considered the discoverer of Neptune. It was a breakthrough in computational astronomy! Until 1930, Neptune was considered the most distant and last planet. The discovery of Pluto made it the second to last. But in 2006, the IAU, the International Astronomical Union, adopted a more precise formulation of the definition of “planet”, and Pluto began to be considered a “dwarf planet”, and Neptune again became the last planet of our solar system.
Structure of Neptune
The characteristics of Neptune were obtained using only one spacecraft, Voyager 2. All photographs were taken from him. In 1989, he passed 4.5 thousand km from the planet, discovering several new satellites and recording a “Great Dark Spot”, similar to the “Red Spot” on Jupiter.
The structure of Neptune in its composition is very close to Uranus. It is also a gaseous planet with a solid core, approximately the same mass as the Earth and a temperature similar to the surface of the Sun - up to 7000 K. Moreover, the total mass of Neptune is approximately 17 times the mass of the Earth. The core of the eighth planet is enveloped in a mantle of water, methane ice and ammonia. Next comes the atmosphere, it includes 80% hydrogen, 19% helium and about 1% methane. The upper clouds of the planet also consist of methane, which absorb the red spectrum of the sun's rays, so blue dominates the color of the planet. The temperature of the upper layers is – 200 °C. Neptune's atmosphere has the strongest winds of any known planet. Their speed can reach 2100 km/h! Located at a distance of 30 a. That is, a full revolution around the Sun takes Neptune almost 165 Earth years, therefore, since its discovery, it will make its first full revolution only in 2011.
Moons of Neptune
William Lassell discovered the largest moon, Triton, just a couple of weeks after the discovery of Neptune itself. Its density is 2 g/cm³, therefore, in mass it exceeds by 99% all the satellites of the planet. Although its size is slightly larger than the Moon.
It has a retrograde orbit and most likely, a very long time ago, was captured by Neptune's field from the nearby Kuiper belt. This field constantly pulls the satellite closer and closer to the planet. Therefore, in the near future, by cosmic standards (in 100 million years), it will collide with Neptune, as a result of which rings may form that are more powerful and noticeable than those currently observed around Saturn. Triton has an atmosphere, which may indicate the presence of a liquid ocean beneath the icy crust at the edge of the surface. Because Neptune in Roman mythology was a sea god, all of his moons are named after Roman sea gods of lesser rank. Among them are Nereid, Proteus, Despina, Talasa and Galatea. The mass of all these satellites is less than 1% of the mass of Triton!
Characteristics of Neptune
Mass: 1.025 * 1026 kg (17 times more than Earth)
Diameter at equator: 49,528 km (3.9 times larger than Earth)
Diameter at the pole: 48680 km
Axle tilt: 28.3°
Density: 1.64 g/cm³
Temperature of the upper layers: about – 200 °C
Period of revolution around the axis (days): 15 hours 58 minutes
Distance from the Sun (average): 30 a. e. or 4.5 billion km
Orbital period around the Sun (year): 165 years
Orbital speed: 5.4 km/s
Orbital eccentricity: e = 0.011
Orbital inclination to the ecliptic: i = 1.77°
Gravity acceleration: 11 m/s²
Satellites: there are 13 pieces.
When astronomer Johann Gottfried Halle actually found the planet in 1846, both mathematicians took credit for the discovery. And then they fought for a long time, finding out who was the first to make the discovery, and they still haven’t decided (for them). Astronomers decided to equally share the credit of the discoverers between Le Verrier and Adams.
- The strongest winds in the solar system are on Neptune
Do you think a hurricane is scary? Imagine a hurricane with winds that reach 2100 km/h. As you can probably imagine, scientists are perplexed by how clouds can move so quickly on a cold, icy planet like Neptune. It is believed that cold temperatures and the flow of liquid gases in the planet's atmosphere can reduce friction so much that the winds gain significant speed.
- Neptune is the coldest planet in the solar system
In the cloud tops, temperatures on Neptune can drop to -221.45 degrees Celsius. This is more than twice below the freezing point of water, and an unprotected person will become ice in the blink of an eye. Pluto is, of course, even colder (temperatures drop to -240 degrees Celsius). But Pluto is no longer a planet, remember?
- Neptune has rings
When people think of ring systems, Saturn often helpfully comes to mind. It may surprise you, but Neptune also has a ring system. True, it is not worth comparing it with the bright and wide rings of Saturn. Neptune has five rings, each named after astronomers who made important discoveries about Neptune: Galle, Le Verrier, Lascelles, Arago and Adams.
These rings consist of at least 20% dust (in some its content reaches 70%) micron-sized, similar to the particles that make up the rings of Jupiter. The remaining materials of the ring are represented by small stones. The planet's rings are difficult to see because they are dark (likely due to the presence of organic components that have been altered by cosmic radiation. They are similar to the rings of Uranus, but very different from the icy rings around Saturn.
Neptune's rings are believed to be relatively young - much younger than the Solar System and much younger than the rings of Uranus. The theory that Triton was a Kuiper Belt object captured by Neptune's gravity suggests that the rings were the result of a collision between the planet's original moons.
- Neptune may have caught its older moon Triton
Neptune's largest moon, Triton, moves around Neptune in a retrograde orbit. This means that its orbit around the planet is backwards compared to Neptune's other moons. This is considered a sign that Neptune appears to have captured Triton - meaning the moon did not form on the spot like Neptune's other moons. Triton is locked in synchronous rotation with Neptune and slowly spirals towards the planet.
At some point, billions of years from now, Triton will likely be torn apart by Neptune's gravitational forces and become a perfect ring around the planet. This ring will be attracted and fall onto the planet. It’s a pity that this won’t happen soon, because the spectacle will certainly be beautiful.
- Neptune has only been seen close once
The only spacecraft to ever visit Neptune was NASA's Voyager 2, which visited the planet during its . Voyager 2 flew past Neptune on August 25, 1989, passing less than 3,000 kilometers from the planet's north pole. This was the closest approach to the object that Voyager 2 had made since launch from Earth.
During its flyby, Voyager 2 studied Neptune's atmosphere, its rings, magnetosphere and met Triton. Voyager 2 also took a look at Neptune's Great Dark Spot, a rotating storm system that has disappeared, according to Hubble Space Telescope observations. It was initially thought to be a large cloud, but information collected by Voyager shed light on the true nature of this phenomenon.
- There are no plans to visit Neptune again
Voyager 2's beautiful photographs of Neptune will remain the only thing we have for a long time, since no one plans to fly to the Neptune system again. However, NASA was considering a possible Flagship mission, which was supposed to take place in the late 2020s - early 2030s.
Another NASA proposal was Argo, a spacecraft that was planned to be launched in 2019 with the goal of visiting Jupiter, Saturn, Neptune and a Kuiper belt object. Argo's focus would be on Neptune and its moon Triton, which it would begin exploring sometime in 2029. But I haven't had to yet.
Summing up and remembering all of the above, it is surprising to note that Neptune may well be one of the most interesting planets (in terms of the number of awards), not counting, of course, the Earth. Perhaps future missions to the outer reaches of the solar system will reveal even more interesting things.
Neptune is the eighth and outermost planet in the solar system. Neptune is also the fourth largest planet in diameter and third largest in mass. The mass of Neptune is 17.2 times, and the diameter of the equator is 3.9 times greater than that of the Earth. The planet was named after the Roman god of the seas.
Discovered on September 23, 1846, Neptune became the first planet discovered through mathematical calculations rather than through regular observations. The discovery of unforeseen changes in the orbit of Uranus gave rise to the hypothesis of an unknown planet, the gravitational disturbing influence of which caused them. Neptune was found within its predicted position. Soon its satellite Triton was discovered, but the remaining 13 satellites known today were unknown until the 20th century. Neptune has only been visited by one spacecraft, Voyager 2, which flew close to the planet on August 25, 1989.
Neptune is similar in composition to Uranus, and both planets differ in composition from the larger giant planets Jupiter and Saturn. Sometimes Uranus and Neptune are placed in a separate category of "ice giants." Neptune's atmosphere, like that of Jupiter and Saturn, consists mainly of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, but contains a higher proportion of ices: water, ammonia, and methane. Neptune's core, like Uranus, consists mainly of ice and rock. Traces of methane in the outer layers of the atmosphere are, in part, responsible for the planet's blue color.
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| Planet Discovery: | |
| Discoverer | Urbain Le Verrier, Johann Halle, Heinrich d'Arre |
| Opening place | Berlin |
| opening date | September 23, 1846 |
| Detection method | calculation |
| Orbital characteristics: | |
| Perihelion | 4,452,940,833 km (29.76607095 AU) |
| Aphelion | 4,553,946,490 km (30.44125206 AU) |
| Major axle shaft | 4,503,443,661 km (30.10366151 AU) |
| Orbital eccentricity | 0,011214269 |
| Sidereal period of revolution | 60,190.03 days (164.79 years) |
| Synodic period of revolution | 367.49 days |
| Orbital speed | 5.4349 km/s |
| Average anomaly | 267.767281° |
| Mood | 1.767975° (6.43° relative to the solar equator) |
| Longitude of the ascending node | 131.794310° |
| Periapsis argument | 265.646853° |
| Satellites | 14 |
| Physical characteristics: | |
| Polar compression | 0.0171 ± 0.0013 |
| Equatorial radius | 24,764 ± 15 km |
| Polar radius | 24,341 ± 30 km |
| Surface area | 7.6408 10 9 km 2 |
| Volume | 6.254 10 13 km 3 |
| Weight | 1.0243 10 26 kg |
| Average density | 1.638 g/cm 3 |
| Acceleration of free fall at the equator | 11.15 m/s 2 (1.14 g) |
| Second escape velocity | 23.5 km/s |
| Equatorial rotation speed | 2.68 km/s (9648 km/h) |
| Rotation period | 0.6653 days (15 hours 57 minutes 59 seconds) |
| Axis tilt | 28.32° |
| Right ascension of the north pole | 19h 57m 20s |
| North pole declination | 42.950° |
| Albedo | 0.29 (Bond), 0.41 (geom.) |
| Apparent magnitude | 8.0-7.78m |
| Angular diameter | 2,2"-2,4" |
| Temperature: | |
| level 1 bar | 72 K (about -200 °C) |
| 0.1 bar (tropopause) | 55 K |
| Atmosphere: | |
| Compound: | 80±3.2% hydrogen (H 2) 19±3.2% helium 1.5±0.5% methane approximately 0.019% hydrogen deuteride (HD) approximately 0.00015% ethane |
| Ice: | ammonia, aqueous, ammonium hydrosulfide (NH 4 SH), methane |
| PLANET NEPTUNE | |
Neptune's atmosphere is home to the strongest winds of any planet in the solar system; according to some estimates, their speeds can reach 2,100 km/h. During the flyby of Voyager 2 in 1989, the so-called Great Dark Spot, similar to the Great Red Spot on Jupiter, was discovered in the southern hemisphere of Neptune. The temperature of Neptune in the upper atmosphere is close to -220 °C. At the center of Neptune, the temperature ranges, according to various estimates, from 5400 K to 7000-7100 °C, which is comparable to the temperature on the surface of the Sun and comparable to the internal temperature of most known planets. Neptune has a faint and fragmented ring system, possibly discovered as early as the 1960s, but only reliably confirmed by Voyager 2 in 1989.
July 12, 2011 marks exactly one Neptunian year - or 164.79 Earth years - since the discovery of Neptune on September 23, 1846.
Physical characteristics:
With a mass of 1.0243·10 26 kg, Neptune is an intermediate link between the Earth and the large gas giants. Its mass is 17 times that of Earth, but is only 1/19 of the mass of Jupiter. Neptune's equatorial radius is 24,764 km, which is almost 4 times that of Earth. Neptune and Uranus are often considered a subclass of gas giants called "ice giants" due to their smaller size and lower concentrations of volatiles.
The average distance between Neptune and the Sun is 4.55 billion km (about 30.1 average distance between the Sun and Earth, or 30.1 AU), and it takes 164.79 years to complete a revolution around the Sun. The distance between Neptune and Earth is between 4.3 and 4.6 billion km. On July 12, 2011, Neptune completed its first full orbit since the discovery of the planet in 1846. From Earth it was visible differently than on the day of discovery, as a result of the fact that the period of the Earth's revolution around the Sun (365.25 days) is not a multiple of the period of Neptune's revolution. The planet's elliptical orbit is inclined 1.77° relative to Earth's orbit. Due to the presence of an eccentricity of 0.011, the distance between Neptune and the Sun changes by 101 million km - the difference between perihelion and aphelion, that is, the closest and most distant points of the planet’s position along the orbital path. Neptune's axial tilt is 28.32°, which is similar to the axial tilt of Earth and Mars. As a result, the planet experiences similar seasonal changes. However, due to Neptune's long orbital period, the seasons last about forty years each.
The sidereal rotation period for Neptune is 16.11 hours. Due to an axial tilt similar to Earth's (23°), changes in the sidereal rotation period during its long year are not significant. Because Neptune does not have a solid surface, its atmosphere is subject to differential rotation. The broad equatorial zone rotates with a period of approximately 18 hours, which is slower than the 16.1-hour rotation of the planet's magnetic field. In contrast to the equator, the polar regions rotate every 12 hours. Among all the planets of the Solar System, this type of rotation is most pronounced in Neptune. This leads to a strong latitudinal wind shift.
Neptune has a great influence on the Kuiper Belt, which is very distant from it. The Kuiper Belt is a ring of icy small planets, similar to the asteroid belt between Mars and Jupiter, but much longer. It ranges from the orbit of Neptune (30 AU) to 55 astronomical units from the Sun. The gravitational force of Neptune has the most significant effect on the Kuiper belt (including in terms of the formation of its structure), comparable in proportion to the influence of Jupiter’s gravity on the asteroid belt. During the existence of the Solar System, some regions of the Kuiper Belt were destabilized by Neptune's gravity, and gaps appeared in the structure of the belt. An example is the area between 40 and 42 a. e.
The orbits of objects that can be held in this belt for a sufficiently long time are determined by the so-called. age-old resonances with Neptune. For some orbits, this time is comparable to the time of the entire existence of the Solar System. These resonances appear when an object's orbital period around the Sun is related to Neptune's orbital period as small natural numbers, such as 1:2 or 3:4. In this way, the objects mutually stabilize their orbits. If, for example, an object orbits the Sun twice as fast as Neptune, it will travel exactly halfway, while Neptune will return to its original position.
The most densely populated part of the Kuiper belt, which includes more than 200 known objects, is in a 2:3 resonance with Neptune. These objects orbit once every 1 1/2 revolutions of Neptune and are known as "plutinos" because among them is one of the largest Kuiper Belt objects, Pluto. Although the orbits of Neptune and Pluto are very close to each other, the 2:3 resonance will prevent them from colliding. In other, less populated areas, there are resonances of 3:4, 3:5, 4:7 and 2:5.
At its Lagrange points (L4 and L5) - zones of gravitational stability - Neptune holds many Trojan asteroids, as if dragging them along in orbit. Neptune's Trojans are in a 1:1 resonance with him. The Trojans are very stable in their orbits, and therefore the hypothesis of their capture by Neptune's gravitational field is doubtful. Most likely, they formed with him.
Internal structure
The internal structure of Neptune resembles the internal structure of Uranus. The atmosphere makes up approximately 10-20% of the planet's total mass, and the distance from the surface to the end of the atmosphere is 10-20% of the distance from the surface to the core. Near the core, the pressure can reach 10 GPa. Volumetric concentrations of methane, ammonia and water found in the lower layers of the atmosphere
Gradually, this darker and hotter region compacts into a superheated liquid mantle, where temperatures reach 2000-5000 K. The mass of Neptune's mantle is 10-15 times greater than that of Earth, according to various estimates, and is rich in water, ammonia, methane and other compounds. According to the generally accepted terminology in planetary science, this matter is called icy, even though it is a hot, very dense liquid. This highly conductive liquid is sometimes called an ocean of aqueous ammonia. At a depth of 7,000 km, conditions are such that methane decomposes into diamond crystals, which “fall” onto the core. According to one hypothesis, there is an entire ocean of “diamond liquid.” Neptune's core is composed of iron, nickel and silicates and is believed to have a mass 1.2 times that of Earth. The pressure in the center reaches 7 megabars, that is, about 7 million times more than on the surface of the Earth. The temperature in the center may reach 5400 K.
Atmosphere and climate
Hydrogen and helium were found in the upper layers of the atmosphere, which account for 80 and 19%, respectively, at a given altitude. Traces of methane are also observed. Noticeable absorption bands of methane occur at wavelengths above 600 nm in the red and infrared parts of the spectrum. As with Uranus, the absorption of red light by methane is a major factor in giving Neptune's atmosphere its blue tint, although Neptune's bright azure is different from the more moderate aquamarine color of Uranus. Since the methane content of Neptune's atmosphere is not very different from that of Uranus, it is assumed that there is also some, as yet unknown, component of the atmosphere that contributes to the formation of the blue color. Neptune's atmosphere is divided into 2 main regions: the lower troposphere, where the temperature decreases with altitude, and the stratosphere, where the temperature, on the contrary, increases with altitude. The boundary between them, the tropopause, is at a pressure level of 0.1 bar. The stratosphere gives way to the thermosphere at a pressure level lower than 10 -4 - 10 -5 microbars. The thermosphere gradually turns into the exosphere. Models of Neptune's troposphere suggest that, depending on altitude, it consists of clouds of varying compositions. Upper-level clouds are in a zone of pressure below one bar, where temperatures favor methane condensation.
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Methane on Neptune
The false-color image was taken by the Voyager 2 spacecraft using three filters: blue, green and a filter that shows the absorption of light by methane. Thus, regions in the image that are bright white or red contain a higher concentration of methane. All of Neptune is covered in a ubiquitous methane haze in a translucent layer of the planet's atmosphere. At the center of the planet's disk, light passes through the haze and goes deeper into the planet's atmosphere, causing the center to appear less red, and at the edges, methane haze scatters sunlight at high altitudes, resulting in a bright red halo. |
| PLANET NEPTUNE |
At pressures between one and five bars, clouds of ammonia and hydrogen sulfide form. At pressures greater than 5 bar, clouds may consist of ammonia, ammonium sulfide, hydrogen sulfide and water. Deeper down, at a pressure of approximately 50 bar, clouds of water ice can exist at temperatures as low as 0 °C. It is also possible that clouds of ammonia and hydrogen sulfide may be found in this area. Neptune's high-altitude clouds were observed by the shadows they cast on the opaque cloud layer below. Prominent among them are cloud bands that “wrap” around the planet at a constant latitude. These peripheral groups have a width of 50-150 km, and they themselves are 50-110 km above the main cloud layer. Study of Neptune's spectrum suggests that its lower stratosphere is hazy due to the condensation of ultraviolet photolysis products of methane, such as ethane and acetylene. Traces of hydrogen cyanide and carbon monoxide were also found in the stratosphere.
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High-altitude cloud bands on Neptune
The image was taken by the Voyager 2 spacecraft two hours before its closest approach to Neptune. The vertical bright streaks of Neptune's clouds are clearly visible. These clouds were observed at a latitude of 29 degrees north near Neptune's eastern terminator. Clouds cast shadows, meaning they are higher than the underlying opaque cloud layer. Image resolution is 11 km per pixel. The width of the cloud bands is from 50 to 200 km, and the shadows they cast extend for 30-50 km. The height of the clouds is approximately 50 km. |
| PLANET NEPTUNE |
Neptune's stratosphere is warmer than Uranus' stratosphere due to its higher concentration of hydrocarbons. For unknown reasons, the planet's thermosphere has an anomalously high temperature of about 750 K. For such a high temperature, the planet is too far from the Sun for it to heat up the thermosphere with ultraviolet radiation. Perhaps this phenomenon is a consequence of atmospheric interaction with ions in the planet’s magnetic field. According to another theory, the basis of the heating mechanism is gravity waves from the inner regions of the planet, which are dissipated in the atmosphere. The thermosphere contains traces of carbon monoxide and water that entered it, possibly from external sources such as meteorites and dust.
One of the differences between Neptune and Uranus is the level of meteorological activity. Voyager 2, which flew near Uranus in 1986, recorded extremely weak atmospheric activity. In contrast to Uranus, Neptune experienced noticeable weather changes during Voyager 2's 1989 survey.
The weather on Neptune is characterized by an extremely dynamic storm system, with winds reaching near supersonic speeds (about 600 m/s). While tracking the movement of permanent clouds, a change in wind speed was recorded from 20 m/s in the east to 325 m/s in the west. In the upper cloud layer, wind speeds vary from 400 m/s along the equator to 250 m/s at the poles. Most winds on Neptune blow in the direction opposite to the planet's rotation on its axis. The general pattern of winds shows that at high latitudes the direction of the winds coincides with the direction of rotation of the planet, and at low latitudes it is opposite to it. Differences in the direction of air currents are believed to be a consequence of the "skin effect" rather than any underlying atmospheric processes. The content of methane, ethane and acetylene in the atmosphere in the equator region is tens and hundreds of times higher than the content of these substances in the pole region. This observation can be considered evidence in favor of the existence of upwelling at Neptune's equator and its decrease closer to the poles.
In 2006, it was observed that the upper troposphere of Neptune's south pole was 10 °C warmer than the rest of Neptune, where temperatures average -200 °C. This difference in temperature is enough to allow methane, which is frozen in other areas of Neptune's upper atmosphere, to leak into space at the south pole. This “hot spot” is a consequence of the axial tilt of Neptune, whose south pole has been facing the Sun for a quarter of a Neptunian year, that is, about 40 Earth years. As Neptune slowly moves along its orbit to the opposite side of the Sun, the south pole will gradually go into shadow, and Neptune will substitute the north pole for the Sun. Thus, the release of methane into space will move from the south pole to the north. Due to seasonal changes, cloud bands in Neptune's southern hemisphere have been observed to increase in size and albedo. This trend was noticed back in 1980, and is expected to continue until 2020 with the arrival of a new season on Neptune. The seasons change every 40 years.
In 1989, NASA's Voyager 2 discovered the Great Dark Spot, a persistent anticyclone storm measuring 13,000 x 6,600 km. This atmospheric storm resembled Jupiter's Great Red Spot, but on November 2, 1994, the Hubble Space Telescope did not find it in its original location. Instead, a new similar formation was discovered in the northern hemisphere of the planet. Scooter is another storm found south of the Great Dark Spot. Its name is a consequence of the fact that several months before Voyager 2's approach to Neptune, it was clear that this group of clouds was moving much faster than the Great Dark Spot. Subsequent images revealed groups of clouds even faster than the scooter.
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Big dark spot
The photo on the left was taken with Voyager 2's narrow-angle camera using a green and orange filter, from a distance of 4.4 million miles from Neptune, 4 days and 20 hours before closest approach to the planet. The Great Dark Spot and its smaller companion to the west, the Lesser Dark Spot, are clearly visible. The series of images on the right shows changes in the Great Dark Spot over 4.5 days during the approach of the Voyager 2 spacecraft, the shooting interval was 18 hours. The large dark spot is located at a latitude of 20 degrees south and extends up to 30 degrees in longitude. The top image in the series was taken at a distance of 17 million km from the planet, the bottom - 10 million km. A series of images showed that the storm was changing over time. In particular, in the west, at the beginning of the survey, a dark plume stretched behind the BTP, which then was drawn into the main area of the storm, leaving behind a series of small dark spots - “beads”. The large bright cloud at the southern border of the BTP is a more or less constant companion to the formation. The apparent movement of small clouds at the periphery suggests counterclockwise rotation of the FTP. |
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| PLANET NEPTUNE | |
The Minor Dark Spot, the second most intense storm observed during Voyager 2's approach to the planet in 1989, is located even further south. Initially it appeared completely dark, but as it got closer, the bright center of the Lesser Dark Spot became more visible, as can be seen in most clear, high-resolution photographs. Neptune's "dark spots" are thought to originate in the troposphere at lower altitudes than the brighter, more visible clouds. Thus, they appear to be holes in the cloud tops, as they open up gaps that allow one to see through darker, deeper cloud layers.
Because these storms are persistent and can persist for months, they are thought to have a vortex structure. Often associated with dark spots are brighter, persistent clouds of methane that form at the tropopause. The persistence of the accompanying clouds shows that some former "dark spots" may continue to exist as a cyclone, even though they lose their dark color. Dark spots can dissipate if they move too close to the equator or through some other as-yet-unknown mechanism
The more varied weather on Neptune, compared to Uranus, is believed to be a consequence of higher internal temperatures. At the same time, Neptune is one and a half times farther from the Sun than Uranus, and receives only 40% of the amount of sunlight that Uranus receives. The surface temperatures of these two planets are approximately equal. The upper troposphere of Neptune reaches a very low temperature of -221.4 °C. At a depth where the pressure is 1 bar, the temperature reaches -201.15 °C. The gases go deeper, but the temperature steadily rises. As with Uranus, the heating mechanism is unknown, but the discrepancy is large: Uranus emits 1.1 times more energy than it receives from the Sun. Neptune emits 2.61 times more than it receives, its internal heat source adding 161% to the energy it receives from the Sun. Although Neptune is the farthest planet from the Sun, its internal energy is sufficient to generate the fastest winds in the solar system.
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New dark spot
The Hubble Space Telescope has discovered a new large dark spot located in Neptune's northern hemisphere. Neptune's tilt and its current position make it almost impossible to see more details now; as a result, the spot in the image is located near the planet's limb. The new spot replicates a similar storm in the southern hemisphere that was discovered by Voyager 2 in 1989. In 1994, images from the Hubble telescope showed that the sunspot in the southern hemisphere had disappeared. Like its predecessor, the new storm is surrounded by clouds at the edge. These clouds form when gas from lower regions rises and then cools to form methane ice crystals. |
| PLANET NEPTUNE |
Several possible explanations have been proposed, including radiogenic heating by the planet's core (similar to the heating of the Earth by radioactive potassium-40), the dissociation of methane into other chain hydrocarbons in Neptune's atmosphere, and convection in the lower atmosphere, which leads to the braking of gravitational waves above the tropopause.
On March 13, 1781, William Herschel (1738-1822), using a homemade telescope, accidentally discovered a new planet. Herschel was a musician who lived in Bath, England, where he worked as an organist. Astronomy was his favorite hobby. He made a telescope himself and compiled a list of double stars that, when observed, seemed to be located very close to each other. One night he noticed a new object, which he mistook for a comet as it slowly moved relative to the stars. However, after a few weeks it became clear that this was not a comet, but a new planet in our solar system.
Herschel's discovery made him famous throughout the world, and King George III awarded him a royal pension. At first, astronomers could not choose a name for the new planet, but in the end they named it Uranus. According to classical mythology, Uranus is the grandfather of Jupiter.
Another new planet, Neptune, was discovered in 1846 as a result of careful, systematic searches. For years, astronomers have been puzzled by Uranus's constant deviation from its path. Based on Newton's law of universal gravitation, they calculated where Uranus should be, but each time they discovered that its true position in the sky did not coincide with the theoretical one. Scientists understood that this could happen if Uranus was exposed to powerful gravitational forces from some unknown planet.
Two mathematicians set to work to calculate the location of the mysterious planet. In 1845, in Cambridge (England), John Couch Adams (1819-1892) joined forces with James Challis (1803-1862). They worked together at the Cambridge University Observatory. Although Challis actually recorded this new planet, he himself did not realize that he had found it! Almost at the same time, the French astronomer Urban Le Verrier (1811-1877) tried to convince scientists at the Paris Observatory in France to begin searching for an invisible planet. For the same purpose, he wrote a letter to the Berlin Observatory in Germany. On the very night that Johann Halle received this letter (September 23, 1846), he discovered the predicted planet in the very place that Le Verrier had determined by calculation. The planet was named Neptune in honor of the ancient Roman sea god.
Uranus is a topsy-turvy planet
Uranium is composed primarily of hydrogen and helium, but one-seventh of its atmosphere is methane. Methane makes Uranus appear bluish, a fact first noted by Herschel. The Voyager 2 space probe discovered only a few stripes of clouds in the upper atmosphere of Uranus. The temperature of this planet is approximately -220°C. At the center of Uranus is a large core made of rock and iron.
Uranus's own axis of rotation is inclined more than at a right angle, which means that its north pole is below the plane of its orbit. This is a unique phenomenon in the entire solar system. Uranus completes its orbit around the Sun in 84 years. The seasons on this planet appear to be very unusual. For about 20 years, the north pole is more or less facing the sun, while the south pole is constantly in darkness.
Astronomers suggest that shortly after the formation of the solar system, Uranus collided with another large planet. It is possible that as a result of this collision, Uranus was overturned on its side.
Rings around Uranus
The rings of Uranus were discovered by chance. Astronomers wanted to know more about the atmosphere of this planet. As Uranus passed in front of one faint star, they noticed that the star blinked several times before and after Uranus completely obscured it. No one foresaw this phenomenon, and the reason for it was that Uranus has at least nine faint rings orbiting this planet. The rings of Uranus are made up of large and small rocks, as well as fine dust.
Miranda
Uranus is orbited by five large moons and ten small ones. The most amazing of them is Miranda, about 500 km across. Its surface amazes with the variety of valleys, gorges and steep cliffs. This moon appears to be fused together from three or four huge rock fragments. Perhaps they represent the remains of a former moon that once collided with an asteroid, and has now managed to put its debris back together.
Neptune from Voyager 2
Voyager 2 zoomed past Neptune on August 24, 1989, after a 12-year journey to that planet, and its findings revealed many surprises. Because Neptune is 30 times farther from the Sun than Earth, sunlight reaching its surface is extremely weak, and the temperature on Neptune is -213°C. However, it is slightly warmer here than on Uranus, although Uranus is closer to the Sun. This is explained by the fact that Neptune has an internal source of thermal energy, which provides three times more heat than the planet receives from the Sun.
A variety of weather phenomena occur in Neptune's atmosphere. Voyager 2 observed a Great Dark Spot there, apparently similar to Jupiter's Great Red Spot. There are also thin cirrus clouds there. Some of them consist of frozen methane.
Voyager 2 is now hurtling toward the edge of the solar system. It will not approach Pluto, the last planet, but astronomers will be able to maintain radio contact with the ship until at least 2020. During this time, Voyager 2 will send information to Earth about gas and dust in distant regions of the solar system.
Triton
Neptune has a satellite larger than Earth's Moon: Triton. Like Earth, Triton has a nitrogen atmosphere and is composed of seven-tenths solid rock and three-tenths water. Near Triton's south pole, Voyage 2 captured images of red ice, and at the equator it captured blue ice made from frozen methane.
Triton has huge rocks cut by water ice, as well as countless craters. Neptune changes the direction of movement of comets entering the Solar System from outside. Perhaps some of them collided with Triton, and as a result of these collisions its craters appeared. Triton has dark streaks of volcanic origin. Scientists believe that LSD, composed of frozen water, methane and nitrogen, was erupted from the depths of Triton through volcanoes.
- 1690 Uranus was first described, but as a star.
- 1781 Uranus is discovered as a planet by William Herschel.
- 1787 William Herschel discovers two moons of Uranus.
- 1846 Discovery of Neptune. 1977 The rings of Uranus are discovered.
- 1986 Voyager 2's approach to Uranus. New moons of Uranus have been discovered.
- 1989 Voyager 2 passes near Neptune, discovers rings.
