Neptune is the eighth planet from the Sun. In some places, its orbit intersects with the orbit of Pluto. What planet is Neptune? It belongs to the category of giants. Astrological Sign - J.
Parameters
The giant planet Neptune is moving around the Sun in an elliptical orbit close to circular. The radius is 24,750 kilometers. This figure is four times greater than that of the Earth. The planet’s own rotation speed is so fast that the day here is 17.8 hours.
The planet Neptune is about 4,500 million kilometers away from the Sun, therefore, light reaches the object in question in just over four hours.
Although the average density of Neptune is almost three times lower than that of the Earth (it is 1.67 g / cm³), its mass is 17.2 times higher. This is due to the large size of the planet.
Features of the composition, physical conditions and structure
Neptune and Uranus are planets based on solidified gases with fifteen percent hydrogen and a small amount of helium. As scientists suggest, the blue giant does not have a clear internal structure. The most likely fact is that inside Neptune there is a dense core of small size.
The atmosphere of the planet is helium and hydrogen with minor impurities of methane. On Neptune, large storms often occur, in addition, it is characterized by whirlwinds and strong winds. The latter blow westward, their speed can reach 2200 km / h.
It has been observed that the velocity of currents and currents in giant planets increases with distance from the Sun. An explanation of this pattern has not yet been found. Thanks to pictures taken by special equipment in the atmosphere of Neptune, it became possible to examine clouds in detail. Just like Saturn or Jupiter, this planet has an internal source of heat. He is able to radiate up to three times more energy than he receives from the Sun.
Giant step forward
According to historical documents, Galileo saw Neptune on 12/28/1612. The second time he managed to observe an unknown cosmic body on January 29, 1613. In both cases, the scientist took the planet for a fixed star, which is in conjunction with Jupiter. For this reason, the discovery of Neptune is not attributed to Galileo.
It was established that during the observation period of 1612 the planet was at a standing point, and just on the day when Galileo first saw her, she moved backward. This process is observed when the Earth in its orbit overtakes the outer planet. Since Neptune was not far from the standing point, its movement was too weak for Galileo’s insufficiently strong telescope to notice.
In 1781, Herschel managed to discover Uranus. Then the scientist calculated the parameters of his orbit. Based on the obtained data, Herschel concluded that there were mysterious anomalies in the process of moving this space object: it was either ahead of the calculated one, or behind it. This fact suggests that beyond the Uranus is another planet, gravitational attraction distorting the trajectory of its motion.
In 1843, Adams was able to calculate the orbit of the mysterious eighth planet to explain the changes in the orbit of Uranus. The scientist sent data about his work to the astronomer of the king - J. Airy. Soon he received a response letter asking for clarifications on some issues. Adams began to make the required sketches, but for some reason he did not send a message and did not subsequently initiate serious work on this issue.
The direct discovery of the planet Neptune was due to the efforts of Le Verrier, Galle and d'Are. 09/23/1846, having at their disposal data on the system of elements of the orbit of the desired object, they set to work on determining the exact location of the mysterious object. On the very first evening their efforts were crowned with success. The discovery of the planet Neptune at that time was called the triumph of celestial mechanics.
Name selection
After the giant was discovered, they began to think about what name to give it. The very first option was proposed by Johann Halle. He wanted to christen the distant cosmic object Janus in honor of the god, symbolizing the beginning and end in ancient Roman mythology, but this name did not appeal to many. The proposal of Struve, director of the Pulkovo Observatory, was much warmer . His version - Neptune - and became final. The official name of the giant planet put an end to numerous disputes and disagreements.
How did ideas about Neptune change?
Sixty years ago, information about the blue giant was different from today. Despite the fact that it was relatively accurately known about the sidereal and synodic periods of rotation around the Sun, about the inclination of the equator to the plane of the orbit, there were data established less accurately. So, the mass was estimated at 17.26 terrestrial instead of the real 17.15, and the equatorial radius was 3.89, not 3.88 from our planet. As for the stellar period of revolution around the axis, it was believed that it is 15 hours and 8 minutes, which is fifty minutes less than the real one.
In some other parameters there were also inaccuracies. For example, before Voyager 2 approached Neptune, as far as possible, it was assumed that the magnetic field of the planet was similar in configuration to the earth. In fact, it resembles in appearance the so-called inclined rotator.
A bit about orbital resonances
Neptune is able to influence the Kuiper belt located at a great distance from it. The latter is represented by a ring of small ice planets, similar to the asteroid belt between Jupiter and Mars, but with a much greater extent. The Kuiper belt is under the significant influence of the gravitational force of attraction of Neptune, as a result of which gaps even formed in its structure.
The orbits of those objects that are held in the specified zone for a long period are established by the so-called secular resonances with Neptune. In certain cases, this time is comparable to the period of the solar system.
Neptune's gravitational stability zones are called Lagrange points. In them, the planet holds a large number of Trojan asteroids, as if dragging them along along the entire orbit.
Features of the internal structure
In this regard, Neptune is similar to Uranus. The atmosphere accounts for about twenty percent of the total mass of the planet in question. The closer to the core, the higher the pressure. The maximum rate is approximately 10 GPa. In the lower atmosphere there are concentrations of water, ammonia and methane.
Elements of the internal structure of Neptune:
- Top clouds and atmosphere.
- The atmosphere formed by hydrogen, helium and methane.
- Mantle (methane ice, ammonia, water).
- Stone-ice core.
Climatic characteristic
One of the differences between Neptune and Uranus is the degree of meteorological activity. According to data obtained from the Voyager 2 device, the weather on the blue giant is changing often and significantly.
It was possible to identify an extremely dynamic system of storms with winds that reach speeds even at 600 m / s - almost supersonic (most of them blow in the direction opposite to the rotation of Neptune around its own axis).
In 2007, it was revealed that in the upper troposphere of the south pole of the planet ten degrees Celsius is warmer than in other parts, where the temperature is approximately -200 º. This difference is quite enough for methane from other zones of the upper atmosphere to seep into space in the area of the south pole. The resulting "hot spot" is a consequence of the axial tilt of the blue giant, whose south pole has been facing the Sun for forty earth years. As Neptune slowly moves in orbit to the opposite side of the indicated celestial body, the south pole will gradually completely disappear into the shadow. Thus, Neptune will expose the sun to its north pole. Consequently, the zone of methane release into space will move to this part of the planet.
The "accompanying" giant
Neptune is a planet with, according to today's data, eight satellites. Among them, one large, three medium and four small. Let's take a closer look at the three largest.
Triton
It is the largest satellite that the giant planet Neptune has. It was discovered by W. Lassel in 1846. Triton is 394,700 km from Neptune; its radius is 1,600 km. It is supposed to have an atmosphere. In size, the object is close to the moon. According to scientists, before the capture of Neptune, Triton was an independent planet.
Nereid
This is the second largest satellite of the planet in question. On average, it is 6.2 million kilometers from Neptune. The radius of the Nereids is 100 kilometers, and the diameter is two times larger. In order to make one revolution around Neptune, this satellite needs 360 days, that is, almost a whole earthly year. The discovery of Nereida occurred in 1949.
Proteus
This planet takes third place not only in size, but also in remoteness from Neptune. It cannot be said that Proteus has some special characteristics, but it was precisely his scientists who chose to create a three-dimensional interactive model based on images of the Voyager-2 apparatus.
The remaining satellites are small planets, of which there are a great many in the solar system.
Study Features
Neptune - what is the planet from the sun? The eighth. If you know exactly where this giant is, you can even see it with powerful binoculars. Neptune is quite difficult to study the cosmic body. This is partly due to the fact that its brightness slightly exceeds the eighth magnitude. For example, one of the aforementioned satellites - Triton - has a brightness equal to fourteen magnitudes. In order to detect the disk of Neptune, large magnifications are required.
The Voyager 2 spacecraft managed to reach such an object as Neptune. The planet (see photo in the article) received a guest from Earth in August 1989. Thanks to the data collected by this ship, scientists have at least some information about this mysterious object.
Data from Voyager
Neptune is a planet that had a Great Dark Spot in the southern hemisphere. This is the most famous detail about the object, obtained as a result of the work of the spacecraft. In terms of diameter, this Spot was almost equal to the Earth. Neptune's winds carried it at a tremendous speed of 300 m / s in a westerly direction.
According to HST (Hubble Space Telescope) observations in 1994, the Great Dark Spot has disappeared. It is assumed that it either dissipated, or turned out to be closed by other parts of the atmosphere. A few months later, thanks to the Hubble telescope, it was possible to detect a new Spot, already in the northern hemisphere of the planet. Based on this, it can be concluded that Neptune is a planet whose atmosphere is changing rapidly - presumably due to slight fluctuations in the temperatures of the lower and upper clouds.
Thanks to Voyager 2, it was established that the described object has rings. Their presence was revealed in 1981, when one of the stars eclipsed Neptune. Observations from the Earth did not bring much result: instead of full rings, only weak arcs were visible. Voyager 2 again came to the rescue. In 1989, the device took detailed pictures of the rings. One of them has an interesting curved structure.
What is known about the magnetosphere
Neptune is a planet whose magnetic field is oriented quite strangely. The magnetic axis is tilted 47 degrees to the axis of rotation. On Earth, this would be reflected in the unusual behavior of the compass needle. So, the North Pole would be located south of Moscow. Another unusual fact is that in Neptune the axis of symmetry of the magnetic field does not pass through its center.
Unanswered questions
- Why are there such strong winds on Neptune, while it is very distant from the Sun? To carry out such processes, the internal heat source located deep in the planet is not strong enough.
- Why is there a lack of hydrogen and helium at the facility?
- How to develop a relatively inexpensive project to study Uranus and Neptune with the help of spacecraft?
- Due to what processes forms an unusual magnetic field of the planet?
Modern research
Creating accurate models of Neptune and Uranus in order to clearly describe the process of formation of ice giants proved to be a daunting task. A considerable number of hypotheses have been put forward to explain the evolution of these two planets. According to one of them, both giants appeared due to instability inside the base protoplanetary disk, and later their atmospheres were literally blown away by the radiation of a large class B or O star.
According to another concept, Neptune and Uranus formed relatively close to the Sun, where the density of matter is higher, and then moved to current orbits. This hypothesis has become the most widespread, because it can explain the resonances in the Kuiper belt.
Observations
Neptune - what planet is from the sun? The eighth. And it is not possible to see with the naked eye. The magnitude of the giant is between +7.7 and +8.0. Thus, it is dimmer than many celestial objects, including the dwarf planet Ceres, the moons of Jupiter, and some asteroids. To organize high-quality observations of the planet, a telescope with at least two-hundred-fold magnification and a diameter of 200-250 millimeters is required. With 7x50 binoculars, the blue giant will be visible as a faint star.
The change in the angular diameter of the space object in question is within 2.2-2.4 arc seconds. This is due to the fact that at a very great distance from the Earth is the planet Neptune. It was extremely difficult to obtain facts about the state of the surface of the blue giant. Much has changed with the advent of the Hubble Space Telescope and the most powerful ground-based instruments equipped with adaptive optics.
Observations of the planet in the radio wave range allowed us to establish that Neptune is a source of flashes of an irregular nature, as well as continuous radiation. Both phenomena are explained by the rotating magnetic field of the blue giant. Against a colder background, in the infrared region of the spectrum, waves in the depths of the planet’s atmosphere, the so-called storms, are clearly visible. They are generated by heat emanating from a contracting core. Thanks to observations, you can determine their size and shape as accurately as possible, as well as track movements.
The mysterious planet Neptune. Interesting Facts
- For almost a century, this blue giant was considered the farthest in the entire solar system. And even the discovery of Pluto did not change this belief. Neptune - what is the planet in a row? The eighth, not the last, ninth. Nevertheless, he sometimes is farthest from our luminary. The fact is that Pluto has an elongated orbit, which is sometimes closer to the Sun than the orbit of Neptune. The blue giant managed to regain the status of the farthest planet. And all thanks to the fact that Pluto was transferred to the category of dwarf objects.
- Neptune has the smallest size among the four famous gas giants. Its equatorial radius is smaller than that of Uranus, Saturn and Jupiter.
“Like all gas planets, Neptune has no solid surface.” Even if the spacecraft could reach him, he could not land. Instead, diving into the depths of the planet would begin.
- The gravity of Neptune is slightly larger than the Earth (by 17%). This means that the force of gravity acts on both planets almost identically.
“Neptune needs 165 Earth years to wrap itself around the Sun.”
- The blue saturated color of the planet is explained by the most powerful lines of a gas such as methane, prevailing in the reflected light of a giant.
Conclusion
In the process of space exploration, the discovery of planets played a huge role. Neptune and Pluto, as well as other objects, were discovered as a result of the painstaking work of many astronomers. Most likely, what humanity now knows about the Universe is only a small part of the real picture. Space is a great mystery, and it will take more than a century to solve it.