home
Brick
Features of the structure of Neptune's shells. The eighth planet of the solar system, Neptune: interesting facts and discoveries. Atmosphere and temperature of the planet Neptune

Features of the structure of Neptune's shells. The eighth planet of the solar system, Neptune: interesting facts and discoveries. Atmosphere and temperature of the planet Neptune

Although, of course, the word “giant” will be a little strong in relation to Neptune, a planet that, although very large by cosmic standards, is, nevertheless, significantly inferior in size to our other giant planets: Saturn, Saturn, etc. Speaking of Uranus, although this planet is larger in size than Neptune, Neptune is still 18% larger in mass than Uranus. In general, this planet, named because of its blue color in honor of the ancient god of the seas, Neptune can be considered the smallest of the giant planets and at the same time the most massive - Neptune’s density is many times stronger than that of other planets. But compared to Neptune and our Earth, they are tiny, if you imagine that our Sun is the size of a door, then the Earth is the size of a coin, and Neptune is the same in size as a large baseball.

The history of the discovery of the planet Neptune

The history of the discovery of Neptune is unique in its kind, since it is the first planet in our solar system that was discovered purely theoretically, thanks to mathematical calculations, and only then was it noticed through a telescope. It happened like this: back in 1846, French astronomer Alexis Bouvard observed the movement of the planet Uranus through a telescope and noticed strange deviations in its orbit. The anomaly in the movement of the planet, in his opinion, could be caused by the strong gravitational influence of some other large celestial body. Alexis’s German colleague, astronomer Johann Halle, made the necessary mathematical calculations to determine the location of this previously unknown planet, and they turned out to be correct - soon our Neptune was discovered at the site of the supposed location of the unknown “Planet X”.

Although long before this, the planet Neptune was observed in a telescope by the great. True, in his astronomical notes he noted it as a star, not a planet, so the discovery was not credited to him.

Neptune is the most distant planet in the solar system

“But what about?”, you probably ask. In fact, everything here is not as simple as it seems at first glance. Since its discovery in 1846, Neptune has rightfully been considered the farthest planet from the Sun. But in 1930, little Pluto was discovered, which is even further away. There’s just one nuance here: Pluto’s orbit is strongly elongated along an ellipse in such a way that at certain moments of its movement Pluto is closer to the Sun than Neptune. The last time such an astronomical phenomenon occurred was from 1978 to 1999 - for 20 years, Neptune again had the title of the full-fledged “farthest planet from the Sun.”

Some astronomers, in order to get rid of these confusions, even proposed to “demote” Pluto from the title of planet, they say, it is just a small celestial body flying in orbit, or to assign the status of a “dwarf planet”, however, disputes on this matter are still ongoing.

Features of the planet Neptune

Neptune has its bright blue appearance due to the strong density of clouds in the planet’s atmosphere; these clouds conceal chemical compounds that are still completely unknown to our science, which, when absorbed from sunlight, turn blue. One year on Neptune is equal to our 165 years; it is during this time that Neptune completes its full cycle in its orbit around the Sun. But a day on Neptune is not as long as a year; it is even shorter than ours on Earth, since it lasts only 16 hours.

Neptune temperature

Since the sun’s rays reach the distant “blue giant” in very small quantities, it is natural that it is very, very cold on its surface - the average surface temperature there is -221 degrees Celsius, which is two times lower than the freezing point of water. In a word, if you were on Neptune, you would turn into ice in the blink of an eye.

Surface of Neptune

Neptune's surface consists of ammonia and methane ice, but the planet's core may well turn out to be rock, but this is still just a hypothesis. It is curious that the force of gravity on Neptune is very similar to that of Earth, it is only 17% greater than ours, and this despite the fact that Neptune is 17 times larger than Earth. Despite this, we are unlikely to be able to walk around Neptune in the near future; see the previous paragraph about the ice. And besides, strong winds blow on the surface of Neptune, the speed of which can reach up to 2400 kilometers per hour (!), perhaps on no other planet in our solar system there are such strong winds as here.

Neptune size

As mentioned above, it is 17 times larger than our Earth. The picture below shows a comparison of the sizes of our planets.

Neptune's atmosphere

The composition of Neptune's atmosphere is similar to the atmospheres of most similar giant planets: it is mainly dominated by helium atoms, and there is also ammonia, frozen water, methane and other chemical elements in small quantities. But unlike other large planets, Neptune’s atmosphere contains a lot of ice, which is due to its remote position.

Rings of the planet Neptune

Surely when you hear about planetary rings, Saturn immediately comes to mind, but in fact, it is far from the only owner of rings. Our Neptune also has rings, although not as large and beautiful as those of the planet. Neptune has five rings in total, named after the astronomers who discovered them: Halle, Le Verrier, Lascelles, Arago and Adams.

Neptune's rings consist of small pebbles and cosmic dust (many micron-sized particles), their structure is somewhat similar to the rings of Jupiter and they are quite difficult to notice, since they are black. Scientists believe that Neptune's rings are relatively young, at least much younger than the rings of its neighbor Uranus.

Moons of Neptune

Neptune, like any decent giant planet, has its own satellites, not just one, but thirteen, named after the smaller sea gods of the ancient pantheon.

Particularly interesting is the satellite Triton, discovered, in part, thanks to... beer. The fact is that the English astronomer William Lasing, who actually discovered Triton, made a large fortune by brewing and trading beer, which subsequently allowed him to invest a lot of money and time in his favorite hobby - astronomy (especially since it is not cheap to equip a high-quality observatory).

But what is interesting and unique about Triton? The fact is that this is the only known satellite in our solar system that rotates around the planet in the opposite direction relative to the rotation of the planet itself. In scientific terminology, this is called “retrograde orbit.” Scientists suggest that Triton was not previously a satellite at all, but an independent dwarf planet (like Pluto), which, by the will of fate, fell into the sphere of influence of Neptune’s gravity, essentially captured by the “blue giant.” But it doesn't end there: Neptune's gravity pulls Triton closer and closer, and after several million light years, gravitational forces can tear the satellite apart.

How long does it take to fly to Neptune?

For a long time. This is in short, with modern technology, of course. After all, the distance from Neptune to the Sun is 4.5 billion kilometers, and the distance from Earth to Neptune is 4.3 billion kilometers, respectively. The only satellite sent from Earth to Neptune, Voyager 2, launched in 1977, reached its destination only in 1989, where it photographed the “large dark spot” on the surface of Neptune and observed a number of powerful storms in the planet’s atmosphere.

Planet Neptune video

And at the end of our article, we offer you an interesting video about the planet Neptune.

Neptune compared to our planet

To really understand how big Neptune is, in fact, it can be compared to another planet, for convenience, we can take our planet for these purposes.

Comparison of the sizes of Earth and Neptune

First, let's look at the sizes of the planets being compared. The diameter of the gas giant is about 49,500 km. This makes it the fourth largest planet in the solar system. Compared to our planet, it is 3.9 times larger.

Its mass is 1.02 x 10*26 kg. It turns out that it is 17 times larger in mass than our home planet.

What about volume? Its volume is 6.3 x 10 * 13 km 3. We could fit 57 planets like ours inside it and still have room left. Our day lasts 24 hours, and the day on the gas giant lasts 16 hours and 6 minutes. A year accordingly lasts 164.79 years.

Many parameters of our planets vary greatly, with the possible exception of one thing: the force of gravity.

The gravity on Neptune (assuming the planet has a hypothetical surface) is only 14% stronger than the gravity on Earth.

· · · ·
·

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.
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 more extensive. 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.

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.

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.

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.
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.
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.

Since it is one of the planets that cannot be seen with the naked eye, Neptune was discovered relatively recently. Considering the distance to it, it was observed very close once - in 1989 by the Voyager 2 spacecraft. However, what we learned about this gas (and ice) giant at that time revealed many secrets and the history of its formation.

Opening and Naming:

The discovery of Neptune took place in the 19th century, although there is evidence that it occurred long before that. For example, Galileo Galilei's drawings of December 28, 1612 and January 27, 1613 contained plotted points that are now known to correspond to the location of Neptune on those dates. However, in both cases, Galileo mistook the planet for .

In 1821, French astronomer Alexis Bouvard published astronomical tables. Subsequent observations showed significant deviations from the tables that Bouvard provided, suggesting that an unknown celestial body was disturbing the orbit of Uranus through gravitational interaction.

The new Berlin Observatory on Linden Street, where the planet Neptune was experimentally discovered. Courtesy: Leibniz-Institute for Astrophysics Potsdam.

In 1843, English astronomer John Couch Adams began his work to study the orbit of Uranus using the data he had obtained and made several different estimates of the planet's orbit for the coming years. In 1845 - 1846, Urban Le Verrier, independently of Adams, carried out his own calculations, which he shared with Johann Gottfried Halle of the Berlin Observatory. Galle confirmed the presence of the planet using coordinates given by Le Verrier on September 23, 1846.

The announcement of the discovery was met with controversy, since Le Verrier and Adams also claimed to be the discoverers. Ultimately, an international consensus was reached in which Le Verrier and Adams were jointly recognized for their contributions to the discovery. However, a re-evaluation by historians of the relevant historical documents in 1998 led to the conclusion that Le Verrier was directly responsible for the discovery and deserved a larger share of the contribution to the discovery.

Claiming his rights to the discovery, Le Verrier proposed naming the planet after himself, but this met with stiff resistance outside France. He also proposed the name Neptune, which was eventually accepted by the international community. This was largely because it was consistent with the nomenclature of other planets, all of which were named after deities from Greco-Roman mythology.

Size, mass and orbit of Neptune:

With an average radius of 24.622 ± 19 km, Neptune is the fourth largest planet in the Solar System and is in . But with a mass of 1.0243 x 10 26 kg, which is 17 times the mass of Earth, it is the third most massive planet, ahead of Uranus. The planet has a very slight orbital eccentricity of 0.0086 and the orbital radius at perihelion is 29.81 astronomical units (4.459 x 10 9 km), and at aphelion 30.33 astronomical units (4.537 x 10 9 km).


Comparison of the sizes of Neptune and Earth. Credit: NASA

The planet Neptune takes 16 hours 6 minutes 36 seconds (0.6713 Earth days) to complete one revolution on its axis (one sidereal rotation), and 164.8 Earth years to complete one orbit around the Sun. This means that a day on Neptune lasts 67% of an Earth day, while a Neptunian year is equivalent to approximately 60,190 Earth days (or 89,666 Neptunian days).
Since Neptune's axial tilt (28.32°) is similar to the Earth's axial tilt (~23°) and (~25°), the planet experiences seasonal climate changes. Combined with its long orbital period, this means that Neptune's seasons last 40 Earth years. Also due to its axial tilt comparable to Earth's, the fact is that the variation in day length throughout the year is no more extreme than on Earth.

Neptune's orbit also has a strong influence on the region behind its orbit known as the Kuiper Belt (also called the "trans-Neptunian belt"). In much the same way it dominates, shaping its structure, as Neptune's gravity dominates the Kuiper Belt. During the existence of the Solar System, some regions of the Kuiper Belt were destabilized by the gravity of the planet Neptune, creating gaps in the structure of the Kuiper Belt.

Also within these empty regions are orbits containing objects with an age equal to . These resonances occur when Neptune's orbital period is an exact fraction of the object's orbital period, meaning that they complete part of the orbit during Neptune's full orbit. The most populous resonance in the Kuiper Belt, with over 200 objects, is the 2:3 resonance.

Objects in this resonance travel 2 orbits for every 3 orbits of Neptune and are called plutinos because the largest known is among them. Although Pluto regularly crosses Neptune's orbit, they can never collide due to the 2:3 resonance.

The planet Neptune has a number of known Trojan objects occupying the L4 and L5 Lagrange points - regions of gravitational stability in front of and behind Neptune in its orbit. Some Neptune Trojans have remarkably stable orbits, and were likely formed with Neptune rather than captured by it.

Composition of the planet Neptune:

Because of its smaller size and higher concentrations of volatiles compared to Jupiter and Saturn, the planet Neptune (much like Uranus) is often called an ice giant, a subclass of the giant planets. Just like Uranus, Neptune's internal structure can be roughly divided into different layers: a rocky core consisting of silicates and metals, a mantle containing water, ammonia and methane in the form of ice, and an atmosphere consisting of hydrogen, helium and methane gases.

Neptune's core is made of iron, nickel and silicates, and scientists believe it contains 1.2 times the mass of Earth. The pressure at the center of the core, according to scientists, is 7 Mbar (700 GPa), twice as high as at the center of the Earth, and temperatures at the center of the planet Pluto reach 5400 Kelvin. At a depth of 7,000 km, conditions may be such that methane is converted into diamond crystals that fall as rocks.

The mantle contains 10-15 Earth masses and is rich in water, ammonia and methane. This mixture is called ice, although it is actually a hot, dense liquid, and is sometimes called an "ammonia water ocean." Meanwhile, the atmosphere contains 5-10% of the planet's mass and extends 10-20% towards the core, where it reaches a pressure of about 10 GPa - 100,000 times the pressure of Earth's atmosphere.


Internal structure of the planet Neptune. Credit: NASA

Elevated concentrations of methane, ammonia and water were found in the lower atmosphere. Unlike Uranus, the planet Neptune has a larger ocean inside, while Uranus has a smaller mantle.

Atmosphere of the planet Neptune:

At high altitudes, Neptune's atmosphere is 80% hydrogen and 19% helium, with traces of methane. Like Uranus, absorption of red light by atmospheric methane is part of what gives Neptune its blue hue, although Neptune is darker and brighter. Since Neptune is similar to Uranus in terms of methane content in the atmosphere, scientists believe that some unknown atmospheric component contributes to a more intense color of Neptune.

Neptune's atmosphere is divided into two main regions: the lower troposphere, where the temperature decreases with altitude, and the stratosphere, where the pressure reaches 0.1 bar (10 kPa). The stratosphere is then replaced by the thermosphere with a pressure of 10 -5 - 10 -4 bar (1-10 Pa), which gradually turns into the exosphere.

Spectral analysis of Neptune suggests that its lower stratosphere is hazy due to the condensation of products of the interaction of ultraviolet radiation and methane (photolysis), which creates ethane and acetylene compounds. The stratosphere also contains trace amounts of carbon monoxide and cyanide, which are responsible for the fact that the stratosphere of the planet Neptune is warmer than the stratosphere of the planet Uranus.


A contrasting image in altered colors, emphasizing the features of Neptune's atmosphere, including wind speed. Credit: Erich Karkoschka.

For reasons that remain unclear, the planet's thermosphere has an unusually high temperature of about 750 Kelvin (476.85 °C). The planet is too far from the Sun for this heat to be generated by its ultraviolet radiation, which means another heating mechanism is involved, which could be the interaction of the atmosphere with ions in the planet's magnetic field or gravitational waves from inside the planet that dissipate into the atmosphere.

Since Neptune is not a solid body, its atmosphere is subject to differential rotation. The broad equatorial zone rotates with a period of about 18 hours, which is slower than the 16.1-hour rotation of the planet's magnetic field. On the contrary, the opposite trend is observed in the polar regions, where the rotation period is 12 hours.

This differential rotation is the most pronounced of any planet in the Solar System and results in strong latitudinal wind shears and destructive storms. Three of the most spectacular storms were spotted in 1989 by the Voyager 2 space probe and then named based on their appearance.

The first of these was a massive anticyclone measuring 13,000 x 6,600 km and resembling Jupiter's Great Red Spot. Called the Great Dark Spot, this storm was no longer detected 5 years later (November 2, 1994), when the Hubble Space Telescope looked at the planet. Instead, a new storm, very similar to the previous one, was discovered in the planet's northern hemisphere, suggesting that these storms have a shorter lifespan than storms on Jupiter.


Reconstruction of Voyager 2 images showing the Great Dark Spot (top left), Scooter (middle), and the Lesser Dark Spot (lower right). Credit: NASA/JPL.

Scooter is another storm, a group of white clouds located further south of the Great Dark Spot. The nickname first appeared during the months Voyager 2 spent near the planet in 1989, when it observed a group of clouds moving at speeds faster than the Great Dark Spot.

The Lesser Dark Spot, a southern cyclone, was the second most intense Neptune storm observed in 1989. Initially it was completely dark, but as Voyager 2 approached the planet, a bright core developed and could be seen in the highest resolution images.

Moons of the planet Neptune:

Neptune has 14 known natural satellites (moons), all but one are named after Greco-Roman sea deities (S/2004 N 1 is not currently named). These satellites are divided into two groups - regular and irregular satellites - based on their orbit and proximity to Neptune. Neptune's regular satellites are Naiad, Thalassa, Despina, Galatea, Larissa, S/2004 N 1 and Proteus. These satellites are the closest to the planet and move in circular orbits in the direction of motion around their Neptune axis and lie in the equatorial plane of the planet.

They extend from 48,227 km (Niad) to 117,646 km (Proteus) from Neptune, and all but the two outermost ones, S/2004 N 1 and Proteus, move in their orbits slower than the orbital period of 0.6713 Earth days. Based on observational data and estimated densities, these satellites range in size and mass from 96 x 60 x 52 km and 1.9 x 10^17 kg (Naiad) to 436 x 416 x 402 km and 50.35 x 10^ 17 kg (Proteus).


This composite image from the Hubble Space Telescope shows the location of the newly discovered moon, designated S/2004 N 1, in orbit around the giant planet Neptune, 4.8 billion kilometers from Earth. Credit: NASA, ESA, and M. Showalter (SETI Institute).

With the exception of Larissa and Proteus, which are the most round, all of Neptune's inner moons are elongated. Their spectrum indicates that they are composed of water ice contaminated with darker material, likely organic compounds. In this regard, Neptune's inner moons are very similar to the moons of Uranus.

Neptune's remaining moons are irregular moons, including Triton. They mainly move in inclined eccentric and often retrograde orbits (against the planet's rotation on its axis) away from Neptune. The only exception is Triton, which orbits closer to the planet and moves in a circular orbit, albeit retrograde and inclined.

In order of distance from the planet, the irregular satellites are Triton, Nereid, Halimeda, Sao, Laomedea, Neso and Psamapha - a group that includes retrograde and prograde (moving in the same direction as the attracting celestial body) objects. With the exception of Triton and Nereid, Neptune's irregular moons are similar to those of other giant planets and are believed to have been gravitationally captured in the past.

In terms of size and mass, the irregular satellites are similar, ranging from approximately 40 km in diameter and a mass of 4 x 10^16 kg (Psamapha) to 62 km and 16 x 10^16 kg (Halimeda). Triton and Nereid are unusual irregular moons and are therefore treated separately from Neptune's five other irregular moons. Four differences are noted between these two and other irregular satellites.

First of all, they are the two largest irregular satellites in the Solar System. Triton is almost an order of magnitude larger than all other known irregular satellites and contains more than 99.5% of the mass of all known satellites orbiting Neptune, including the planet's rings and 13 other known satellites.


Color mosaic image of Triton taken by Voyager 2 in 1989. Credit: NASA/JPL/USGS.

Secondly, they both have atypically small semi-major axes; Triton has an order of magnitude smaller in magnitude than other known irregular satellites. Third, they both have unusual orbital eccentricities: Nereid has one of the most eccentric orbits of any known irregular satellite, while Triton's orbit is almost circular. Finally, Nereid has the lowest orbital inclination of any known irregular satellite.

With an average diameter of about 2,700 km and a mass of 214,080 ± 520 x 10^17 kg, Triton is Neptune's largest moon, and the only one large enough to achieve hydrostatic equilibrium (that is, a spherical shape). Triton is located at a distance of 354,759 km from Neptune between the inner and outer satellites.

Triton moves in a retrograde quasi-circular orbit and is mainly composed of ices of nitrogen, methane, carbon dioxide and water. With a geometric albedo of over 70% and a Bond albedo of 90%, this satellite is one of the brightest objects in the Solar System. Its surface has a reddish tint, due to the interaction of ultraviolet radiation and methane, resulting in the creation of tholins (organic substances in the spectra of the icy bodies of our Solar System).

Characteristics of Neptune:(Items without links are under development)

  • Interesting facts about N.
  • Density N.
  • Gravity N.
  • Massa N.
  • Rotation axis tilt N.
  • Size N.
  • Radius N.
  • Temperature N.
  • N. compared to Earth
Neptune's orbit and rotation:
  • How long is a day on N.?
  • Distance from Earth to N.
  • Orbit N.
  • How long is a year in N.?
  • How long does it take for Earth to complete one revolution around the Sun?
  • Distance from the Sun to N.
Natural satellites (moons) of N. and rings:
  • How many moons (natural satellites) does N. have?
  • Rings N.
  • Nereid
  • Triton
  • Naiad
Neptune's story:
  • Who discovered N.?
  • How did N. get its name?
  • Symbol N.
Surface and structure of Neptune:
  • Atmosphere N.
  • Tsvet N.
  • Weather on N.
  • Surface N.
  • Collection of photographs N.
  • Life on N.
  • 10 interesting facts about N.
  • Pluto and N.
  • Uranus and N.
Sections