Neptune is the eighth planet from the Sun. In some places, its orbit intersects with the orbit of Pluto. What planet is Neptune? She belongs to the category of giants. Astrological sign - J.
Parameters
The giant planet Neptune moves around the Sun in an elliptical orbit close to circular. The length of 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 duration of the day here is 17.8 hours.
The planet Neptune is approximately 4,500 million kilometers away from the Sun, so light reaches the object in question in just over four hours.
Although the average density of Neptune is almost three times less 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 that are based on solidified gases with a fifteen percent hydrogen content and a small amount of helium. As scientists suggest, the blue giant does not have a clear internal structure. Mostit seems probable that inside Neptune there is a dense core of small sizes.
The planet's atmosphere is made up of helium and hydrogen with minor admixtures of methane. Large storms often occur on Neptune, in addition, vortices and strong winds are characteristic of it. The latter blow in a westerly direction, their speed can reach up to 2200 km/h.
It was noticed that the speed of currents and streams of the giant planets increases with distance from the Sun. An explanation for this pattern has not yet been found. Thanks to the pictures taken by special equipment in the atmosphere of Neptune, it became possible to examine the clouds in detail. Just like Saturn or Jupiter, this planet has an internal source of heat. It is capable of emitting up to three times more energy than it receives from the Sun.
Giant step forward
According to historical documents, Galileo saw Neptune on 1612-28-12. 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, Galileo is not credited with the discovery of Neptune.
It was established that during the observation period of 1612 the planet was at the point of standing, and just on the day when Galileo first saw it, it moved to backward movement. This process is observed when the Earth overtakes the outer planet in its orbit. Since Neptune was not far from the station, its movement was too weak to be able tonotice Galileo's insufficiently strong telescope.
In 1781, Herschel managed to discover Uranus. Then the scientist calculated the parameters of its orbit. Based on the data obtained, Herschel concluded that there were mysterious anomalies in the process of movement of this space object: it was either ahead of the calculated one, or lagged behind it. This fact allowed us to assume that there is another planet behind Uranus, which distorts the trajectory of its movement by gravitational attraction.
In 1843, Adams was able to calculate the orbit of the mysterious eighth planet in order to explain the changes in the orbit of Uranus. The scientist sent data about his work to the king's astronomer - J. Airey. Soon he received a response letter asking for clarification on some issues. Adams began to make the required sketches, but for some reason he never sent the 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. On September 23, 1846, having at their disposal data on the system of elements of the orbit of the object they were looking for, they set to work to determine the exact location of the mysterious object. On the first evening, their efforts were crowned with success. The discovery of the planet Neptune was called a triumph of celestial mechanics at the time.
Choose name
After the discovery of the giant, they began to think about what name to give it. The very first option was proposed by Johann Galle. He wanted to christen a distant space object Janus in honor of the god symbolizingthe beginning and the end in ancient Roman mythology, but this name was not to the liking of many. The proposal of Struve, the director of the Pulkovo Observatory, was received much warmer. His version - Neptune - became the final one. The assignment of an official name to the giant planet put an end to numerous disputes and disagreements.
How ideas about Neptune have changed
Sixty years ago, information about the blue giant was different from today. Despite the fact that the sidereal and synodic periods of rotation around the Sun were relatively accurately known, the inclination of the equator to the plane of the orbit, there were data that were established less accurately. So, the mass was estimated at 17.26 Earth instead of the real 17.15, and the equatorial radius - at 3.89, and not 3.88 from our planet. As for the sidereal period of revolution around the axis, it was believed that it was 15 hours 8 minutes, which is fifty minutes less than the real one.
There were inaccuracies in some other parameters too. For example, before Voyager 2 got as close to Neptune as possible, it was assumed that the planet's magnetic field was similar in configuration to Earth's. In fact, it resembles in appearance the so-called inclined rotator.
A little 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 minor icy planets, similar to the asteroid belt between Jupiter and Mars, but with a much greater extent. The Kuiper Belt is heavily influenced by the gravitational pull of Neptune,resulting in even gaps in its structure.
The orbits of those objects that are kept in the indicated belt 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 existence of the solar system.
Zones of Neptune's gravitational stability are called Lagrange points. In them, the planet holds a large number of Trojan asteroids, as if dragging them along the entire orbit.
Features of the internal structure
In this respect, 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 value is about 10 GPa. The lower atmosphere contains concentrations of water, ammonia and methane.
Elements of the internal structure of Neptune:
- Upper clouds and atmosphere.
- Atmosphere formed by hydrogen, helium and methane.
- Mantle (methane ice, ammonia, water).
- Stone-ice core.
Climatic characteristics
One of the differences between Neptune and Uranus is the degree of meteorological activity. According to data received from the Voyager 2 spacecraft, the weather on the blue giant changes frequently and significantly.
We have identified an extremely dynamic system of storms with winds that reach speeds of even 600 m / s - almost supersonic (most of them blow in the opposite direction of Neptune's rotation around its ownaxis).
In 2007, it was revealed that the upper troposphere of the planet's south pole is ten degrees Celsius warmer than the rest of the world, where the temperature is about -200 ºС. Such a difference is quite enough for methane from other zones of the upper atmosphere to seep into space in the region of the south pole. The resulting "hot spot" is a consequence of the axial tilt of the blue giant, the south pole of which 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 go into shadow. Thus, Neptune will expose its north pole to the Sun. Consequently, the zone of methane release into space will move to this part of the planet.
Giant's Escorts
Neptune is a planet that, according to today's data, has eight satellites. Among them, one large, three medium and four small. Let's take a closer look at the three largest.
Triton
This is the largest satellite that the giant planet Neptune has. It was discovered by W. Lassell in 1846. Triton is 394,700 km from Neptune and has a radius of 1,600 km. It is supposed to have an atmosphere. The object is close in size 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 under consideration. On average, it is 6.2 million kilometers away from Neptune. The radius of the Nereid is 100 kilometers, and the diameter is twice that. In order toto make one revolution around Neptune, this satellite takes 360 days, that is, almost a whole earth year. The discovery of Nereid occurred in 1949.
Proteus
This planet ranks third not only in size, but also in distance from Neptune. This is not to say that Proteus has any special characteristics, but it was his scientists who chose to create a three-dimensional interactive model based on images from the Voyager 2 apparatus.
The rest of the satellites are small planets, of which there are a great many in the solar system.
Study Features
Neptune - which planet is from the Sun? Eighth. If you know exactly where this giant is, you can see it even with powerful binoculars. Neptune is a rather difficult cosmic body to study. This is partly due to the fact that its brightness is slightly more than eighth magnitude. For example, one of the above satellites - Triton - has a brightness equal to fourteen magnitudes. High magnifications are required to locate the disk of Neptune.
The Voyager 2 spacecraft managed to reach an object like 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 isthe most famous detail about the object, obtained as a result of the work of the spacecraft. In diameter, this Spot was almost equal to the Earth. The winds of Neptune carried him at a tremendous speed of 300 m / s in a westerly direction.
According to the observations of the HST (Hubble Space Telescope) in 1994, the Great Dark Spot has disappeared. It is assumed that it either dissipated or was covered by other parts of the atmosphere. A few months later, thanks to the Hubble telescope, it was possible to discover a new Spot, which is already in the northern hemisphere of the planet. Based on this, we can conclude 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 has been 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 faint arcs were visible. Once again, Voyager 2 came to the rescue. In 1989, the apparatus took detailed pictures of the rings. One of them has an interesting curved structure.
What is known about the magnetosphere
Neptune is a planet with a strangely oriented magnetic field. The magnetic axis is 47 degrees inclined to the axis of rotation. On Earth, this would be reflected in the unusual behavior of the compass needle. Thus, the North Pole would be located south of Moscow. Another unusual fact is that for Neptune, the axis of symmetry of the magnetic field does not passthrough its center.
Unanswered questions
- Why does Neptune have such strong winds when it is very far from the Sun? To carry out such processes, the internal heat source located in the depths of 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 explore Uranus and Neptune as fully as possible using spacecraft?
- Due to what processes is the unusual magnetic field of the planet formed?
Modern Research
Creating accurate models of Neptune and Uranus in order to visually describe the process of formation of ice giants proved to be a difficult task. To explain the evolution of these two planets put forward a considerable number of hypotheses. According to one of them, both giants appeared due to instability within the basic 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 their current orbits. This hypothesis has become the most common, since it can explain the existing resonances in the Kuiper belt.
Observations
Neptune - which planet is from the Sun? Eighth. And it is not possible to see it with the naked eye. The magnitude of the giant is between +7.7 and +8.0. So he's dimmer than manycelestial 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 times magnification and a diameter of 200-250 millimeters is required. With 7x50 binoculars, the blue giant will be visible as a faint star.
Change in the angular diameter of the considered space object is within 2.2-2.4 arc seconds. This is due to the fact that the planet Neptune is located at a very large distance from the Earth. It was extremely difficult to extract 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 made it possible 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 zone of the spectrum, disturbances in the depths of the planet's atmosphere, the so-called storms, are clearly visible. They are generated by the heat emanating from the contracting core. Thanks to observations, you can determine their size and shape as accurately as possible, as well as track their movements.
The mysterious planet Neptune. Interesting Facts
- For almost a century, this blue giant was considered the most distant in the entire solar system. And even the discovery of Pluto did not change this belief. Neptune - what planet is it? eighth, notlast, ninth. However, it sometimes turns out to be the 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 most distant planet. And all thanks to the fact that Pluto was transferred to the category of dwarf objects.
- Neptune is the smallest of the four known gas giants. Its equatorial radius is smaller than that of Uranus, Saturn and Jupiter.
- As with all gas planets, Neptune does not have a solid surface. Even if the spacecraft had managed to get to him, he would not have been able to land. Instead, a dive deep into the planet would occur.
- Neptune's gravity is slightly more than Earth's (by 17%). This means that the force of gravity acts on both planets in almost the same way.
- Neptune takes 165 Earth years to revolve around the Sun.
- The blue saturated color of the planet is explained by the most powerful lines of such gas as methane, prevailing in the reflected light of the 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 is now known to mankind about the Universe is only a small part of the real picture. Space is a great mystery, and it will take more than one century to unravel it.
