In the hustle and bustle of days, the world for an ordinary person is sometimes reduced to the size of work and home. Meanwhile, if you look at the sky, you can see how insignificant it is on the scale of the universe. Maybe that's why young romantics dream of devoting themselves to the conquest of space and the study of the stars. Scientists-astronomers do not forget for a second that, in addition to the Earth with its problems and joys, there are many other distant and mysterious objects. One of them is the planet Neptune, the eighth in terms of distance from the Sun, inaccessible to direct observation and therefore doubly attractive to researchers.
How it all began
Even in the middle of the 19th century, the solar system, according to scientists, contained only seven planets. Earth's neighbors, near and far, have been studied using all available advances in technology and computing. Many characteristics were first described theoretically, and only then found practical confirmation. With the calculation of the orbit of Uranus, the situation was somewhat different. Thomas John Hussey, astronomer andthe priest, discovered a discrepancy between the real trajectory of the planet's supposed movement. There could be only one conclusion: there is an object that affects the orbit of Uranus. In fact, this was the first report of the planet Neptune.
After almost ten years (in 1843), two researchers simultaneously calculated in what orbit the planet could move, forcing the gas giant to make room. They were the Englishman John Adams and the Frenchman Urbain Jean Joseph Le Verrier. Independently of each other, but with different accuracy, they determined the path of the body.
Detection and designation
Neptune was found in the night sky by astronomer Johann Gottfried Galle, to whom Le Verrier came with his calculations. The French scientist, who later shared the glory of the discoverer with Galle and Adams, made a mistake in the calculations by only a degree. Neptune officially appeared in scientific papers on September 23, 1846.
Initially, the planet was proposed to be named after the two-faced Janus, but this designation did not take root. Astronomers were more inspired by the comparison of the new object with the king of the seas and oceans, as alien to the earth's firmament as, apparently, the open planet. The name of Neptune was proposed by Le Verrier and supported by V. Ya. Struve, who headed the Pulkovo Observatory. The name was given, it only remained to understand what the composition of the atmosphere of Neptune is, whether it exists at all, what is hidden in its depths, and so on.
Compared to Earth
A lot of time has passed since the opening. Today is about the eighthplanet of the solar system we know much more. Neptune is much larger than the Earth: its diameter is almost 4 times greater, and its mass is 17 times. A considerable distance from the Sun leaves no doubt that the weather on the planet Neptune is also significantly different from the earth. There is no and cannot be life here. It's not even about the wind or some unusual phenomena. The atmosphere and surface of Neptune are almost the same structure. This is a characteristic feature of all gas giants, including this planet.
Imaginary surface
The planet is significantly inferior in density to the Earth (1.64 g/cm³), making it difficult to step on its surface. Yes, and as such it is not. The level of the surface was agreed to be identified by the magnitude of the pressure: a pliable and rather liquid-like "solid" is located in the lower layers of the atmosphere, where the pressure is equal to one bar, and, in fact, is part of it. Any report of the planet Neptune as a cosmic object of a specific size is based on this definition of the imaginary surface of a giant.
The parameters obtained with this feature in mind are as follows:
- diameter near the equator is 49.5 thousand km;
- its size in the plane of the poles is almost 48.7 thousand km.
The ratio of these characteristics makes Neptune far from a circle in shape. It, like the Blue Planet, is somewhat flattened at the poles.
Composition of Neptune's atmosphere
The mixture of gases enveloping the planet,content is very different from the earth. The overwhelming majority is hydrogen (80%), the second position is occupied by helium. This inert gas makes a significant contribution to the composition of the atmosphere of Neptune - 19%. Methane is less than a percent, ammonia is also found here, but in small quantities.
Oddly enough, one percent of methane in the composition greatly affects what kind of atmosphere Neptune has and what the entire gas giant looks like from the point of view of an external observer. This chemical compound makes up the planet's clouds and does not reflect light waves corresponding to red. As a result, Neptune turns out to be a deep blue for passing spacecraft. This color is one of the mysteries of the planet. Scientists do not yet fully understand what exactly leads to the absorption of the red part of the spectrum.
All gas giants have an atmosphere. It is the color that distinguishes Neptune among them. Due to these characteristics, it is called an ice planet. Frozen methane, which by its existence adds weight to the comparison of Neptune with an iceberg, is also part of the mantle surrounding the core of the planet.
Internal structure
The core of the space object contains iron, nickel, magnesium and silicon compounds. In terms of mass, the core is approximately equal to the entire Earth. At the same time, unlike other elements of the internal structure, it has a density that is twice as high as that of the Blue Planet.
The core is covered, as already mentioned, by the mantle. Its composition is in many ways similar to atmospheric: hereammonia, methane, water are present. The mass of the layer is equal to fifteen Earth's, while it is strongly heated (up to 5000 K). The mantle does not have a clear boundary, and the atmosphere of the planet Neptune smoothly flows into it. A mixture of helium and hydrogen makes up the upper part in the structure. The smooth transformation of one element into another and the blurred boundaries between them are properties that are characteristic of all gas giants.
Research difficulties
Conclusions about the atmosphere of Neptune, which is typical for its structure, are largely based on the already obtained data on Uranus, Jupiter and Saturn. The remoteness of the planet from the Earth makes it much more difficult to study it.
In 1989, the Voyager 2 spacecraft flew near Neptune. This was the only meeting of the ice giant with the earthly messenger. Its fruitfulness, however, is obvious: it was this ship that provided most of the information about Neptune to science. In particular, Voyager 2 discovered the Large and Small dark spots. Both blackened areas were clearly visible against the background of the blue atmosphere. To date, it is not clear what the nature of these formations is, but it is assumed that these are eddy currents or cyclones. They appear in the upper atmosphere and sweep around the planet at great speed.
Perpetual motion
Many parameters determine the presence of the atmosphere. Neptune is characterized not only by its unusual color, but also by the constant movement created by the wind. The speed at which clouds circle the planet around the equator exceeds a thousand kilometers per hour. At the same time, they move in the direction opposite to the rotation of Neptune itself around the axis. At the same time, the planet turns even faster: a complete rotation takes only 16 hours and 7 minutes. For comparison: one revolution around the Sun takes almost 165 years.
Another mystery: the wind speed in the atmosphere of gas giants increases with distance from the Sun and reaches a peak on Neptune. This phenomenon has not yet been substantiated, as well as some of the temperature features of the planet.
Heat distribution
The weather on the planet Neptune is characterized by a gradual change in temperature depending on the altitude. That layer of the atmosphere, where the conditional surface is located, fully corresponds to the second name of the cosmic body (ice planet). The temperature here drops to almost -200 ºC. If you move from the surface higher, then there will be a noticeable increase in heat up to 475º. Scientists have not yet found a worthy explanation for such differences. Neptune is supposed to have an internal heat source. Such a “heater” should produce twice as much energy as it comes to the planet from the Sun. The heat from this source, combined with the energy coming here from our star, is probably the reason for the strong winds.
However, neither the sunlight nor the internal "heater" can raise the temperature on the surface so that the change of seasons is felt here. And although other conditions for this are met, it is impossible to distinguish winter from summer on Neptune.
Magnetosphere
Voyager 2 research has helped scientists learn a lot about Neptune's magnetic field. It is very different from the Earth's: the source is located not in the core, but in the mantle, due to which the planet's magnetic axis is greatly offset from its center.
One of the functions of the field is protection from the solar wind. The shape of Neptune's magnetosphere is highly elongated: the protective lines in that part of the planet that is illuminated are located at a distance of 600 thousand km from the surface, and on the opposite side - more than 2 million km.
Voyager recorded the inconsistency of the field strength and the location of the magnetic lines. Such properties of the planet are also not yet fully explained by science.
Rings
At the end of the 19th century, when scientists were no longer looking for an answer to the question of whether there is an atmosphere on Neptune, another task arose before them. It was necessary to explain why, along the path of the eighth planet, the stars began to fade for the observer a little earlier than Neptune was approaching them.
The problem was solved only after almost a century. In 1984, with the help of a powerful telescope, it was possible to consider the brightest ring of the planet, later named after one of the discoverers of Neptune - John Adams.
Further research revealed several more similar formations. It was they who closed the stars along the path of the planet. Today, astronomers consider Neptune to have six rings. They contain another mystery. The Adams ring consists of several arches located on somedistance from each other. The reason for this placement is unclear. Some researchers are inclined to think that the force of the gravitational field of one of Neptune's satellites, Galatea, keeps them in this position. Others give a weighty counterargument: its size is so small that it would hardly have coped with the task. Perhaps there are several more unknown satellites nearby helping Galatea.
In general, the rings of the planet are a sight inferior in impressiveness and beauty to similar formations of Saturn. Not the last role in the somewhat dull appearance is played by the composition. The rings mainly contain chunks of methane ice coated with silicon compounds that absorb light well.
Satellites
Neptune is the owner (according to the latest data) of 13 satellites. Most of them are small in size. Only Triton has outstanding parameters, which is only slightly inferior in diameter to the Moon. The composition of the atmosphere of Neptune and Triton is different: the satellite has a gas envelope of a mixture of nitrogen and methane. These substances give a very interesting look to the planet: frozen nitrogen with inclusions from methane ice creates a real riot of colors on the surface near the South Pole: overflows of yellow are combined with white and pink.
The fate of the handsome Triton, meanwhile, is not so rosy. Scientists predict it will collide with Neptune and be swallowed up by it. As a result, the eighth planet will become the owner of a new ring, comparable in brightness to the formations of Saturn and even ahead of them. The remaining satellites of Neptune are significantly inferior to Triton, some of themdoesn't even have a name yet.
The eighth planet of the solar system largely corresponds to its name, the choice of which was also affected by the presence of the atmosphere - Neptune. Its composition contributes to the appearance of a characteristic blue color. Neptune rushes through space incomprehensible to us, like the god of the seas. And similarly to the ocean depths, that part of the cosmos that begins beyond Neptune keeps a lot of secrets from man. Scientists of the future have yet to discover them.
