Neptun with three of its moons taken up to natural colors
|characteristics of the orbit|
|aphelion|| 4.54567 billion km|
|middle radius|| 4.49506 billion km|
|Perihel|| 4.44445 billion km|
|Sideri period||about 165 years|
|Synodi period||367.49 days|
|Ø orbital speed||of 5.43 km/s|
|smallest earth distance||4.3059 billion km|
|largest earth distance||4.6873 billion km|
|diameters at the equator||49,528 km|
|surface contents|| 7.6195 billion km 2|
(14,94-fache of the earth)
|mass|| 1,0243× 10 26 kg|
(17.147 earth masses)
|middle one density||1.638 g/cm 3|
| Ø acceleration due to gravity|
at the surface
| 11.15 m/s ²|
(1,14-fache of the earth)
|rotation period||16 h 6 min 36 s|
|inclination of the axis of rotation||28,32°|
|escape velocity||23.5 km/s|
|characteristics of the atmosphere|
|hydrogen||80% ± 3.2%|
|helium||19% ± 3.2%|
|methane||1.5% ± 0.5%|
|number of satellites||13, and. A. Triton|
Neptun is the respected planet in the solar system. It is designated after Neptun, the Roman God of the sea and flowing waters and among the jupiterähnlichen (iovianischen) planets is ranked.Its indication is a representative Dreizack, the weapon of the Poseidon (Poseidon is Greek correspondence to the Roman Neptun).
Table of contents
Neptunthe extreme of the large gas planets of the solar system is and runs on a nearly circular orbit with an eccentricity of 0,0113 around the sun. Its sun-next point, the Perihel, is with 29,709 AE and its sun-furthest point, the aphelion,with 30,385 AE. Because of the eccentric orbit of Pluto the Neptun is sometimes the planet furthest from the sun. Its orbit is only easily bent against the ecliptic with 1,769°. For a circulation around the sun Neptun needsabout 165 years.
Neptun cannot be observed with the naked eye. In a telescope it appears similar as bluish green disk, as the Uranus. The bluish green color comes from methane in its atmosphere. Its diameter49,248 km amount to. Neptun is thus somewhat smaller than Uranus and the fourth largest planet of the solar system.
Because of its large distance to the sun only little warmth reaches the Neptun. Its surface temperature is with -218 °C (55 K). The planet seemshowever to possess an internal heat source. One assumes that it acts thereby around remainder warmth out of its time of origin. The atmosphere of the Neptuns has the highest wind velocities in the solar system, those with up to 2000 km/h probably by this internal heat sourcecome. Contrary to the otherwise similar brother planet Uranus has Neptun a remarkable structure in the cloud covering: the large dark mark. One recognizes the mark on the Voyager photographs and assumes the structure similar to Jupiters large one red one Mark an eddy tower is. Neptun rotates altogether once in 16 h 6 min 36 s around its axle, whereby its axis of rotation is bent against its orbit around 28,32°.
The internal structure of the Neptun resembles that of the Uranus: RockierCore, covers the thick atmosphere from an ice sheet, over it. As differently is the case for Uranus, but than with Jupiter and Saturn, Neptun has probably clearly distinguishable layers. Due to its rocky core also its density is higher than from Jupiter andSaturn and amounts to 1.638 g/cm 3. As also with Uranus the magnetic field of Neptun is bent opposite the rotation axle, around 47°.
Neptun has a weak ring system of unknown quantities composition. The rings have one peculiar „clotted “structure, thoseA cause for it is still unknown, could have to do however with the gravitation reciprocal effect with neighbouring smaller moons. For it that the rings are not complete, there were the first signs in the middle of the 1980er years, as with coverage of stars by thatNeptun additional flashing took place, briefly forwards or after the planet before the star had by-pulled.1989 clarified Voyager 2 the affair, when one discovered several weak rings on its photographs, by those the extreme, Adam mentioned, from three largeCircular arcs existed, which were baptized liberty , equality and fraternity. The existence of ring elbows is only difficult to explain, because they would have to actually distribute themselves after longer time to a complete ring. Possibly are gravitation forces of Galatea, a moonat the inner edge of the ring, responsible for it that the individual segments do not dissolve. Further rings were discovered by the cameras of Voyager 2. Additionally to narrow Adam - ring with a radius of 63.000 km gives it still that Leverrier - ring at 53.000 km and the broader, but weaker Galle - ring at 42.000 km radius. The outside extensions of the Leverrier ring are called leaving and Arago.
overview of all Neptunmonde: List of the Neptunmonde
Neptun has 13 admittedMoons. The by far largest one is the moon triton discovered by William leaving 17 days after the discovery of Neptun. Contrary to all other large moons of the planets of the solar system it runs retrograd (opposite the rotation of the planet)over Neptun and approaches this slowly on a spiral course. Neptuns of second companions Nereid has one of the exzentrischsten orbits of all moons of the solar system.
From July to September 1989 the space probe Voyager discovered 2 six new Neptunmonde. From these that stingsirregularly formed Proteus thereby that it is evenly still too small straight, in order by its own force of gravity in spherical shape not to be pulled out. The 4 internal Neptunmonde Naiad, Thalassa, Despina and Galatea have orbits within the Neptunringe.From the inside next moon Larissa was originally discovered 1981, when it covered a star. First one thought the fact that it was a part of a Neptunringbogens but as Voyager investigated 2 1989 Neptun turned out that this star coverage by oneMoon was caused.
The discovery of five further irregular moons of the Neptuns 2004 admits given.
the movement of the Uranus around the sun ran not completely in such a way, like it afterthe Kepler laws should have been. Astronomers assumed therefore that there had to be a further planet beyond the Uranus, by his gravitation strength the movement of the Uranus changed. John couch of Adam as well as the French mathematician Urbain Leverrier calculated independentlythe position, at which the unknown planet would have to be, whereby the computation of Leverrier was substantially more exact. The computation of Adam was James Challis from Cambridge a collecting main for its observations to 4. and 12. August 1846. Challisthe planets had found, but, because it had compared the observations of the different evenings with one another not yet, it under the numerous stars yet by his change of location as planet had not recognized. Due to Leverriers computation succeeded it, at an order of Leverrier,Johann Gottfried Galle, the director of the citizens of Berlin observatory, together with its assistant Heinrich Louis d'Arrest to 23. To discover September 1846 Neptun. The actual position deviated only slightly from the calculated position.
Later one found out thatGalileo Galilei the Neptun had already seen. From his recordings it follows that he had regarded it however as a fixed star. If he would have observed Neptun only some days in former times, its movement in the sky would have been many clearer.
With a scan timefrom 165 years Neptun will happen in the year 2011 for the first time again the same place, in which Johann Gottfried Galle had discovered him. One will only then have observed a complete orbit Neptuns actually.
In August 1989 Voyager 2 was the first and so far only space probe, which investigated Neptun from the proximity. It flew over the north pole of Neptun and passed thatPlanet with approximately 4,950 kilometers distance.
At present (2006) one thinks at NASA about a Neptune orbiter (EN) space probe, which is to possibly have a nuclear reactor as energy source and in approximately 15-20 years is startedcan. The probe could throw one or more atmosphere caps off on Neptun as well as set countries off on triton.
the visibility is indicated by Neptunpositionen until 2020.
in the Astrologie stands for Neptun among other thingsfor Spiritualität, craze and illusion. It becomes the element water, the asterisk of fish and that 12. House assigned.
- William Sheehan, Nicholas vest stream, Craig B. Waff: The Neptun affair. Spektrum der Wissenschaft, April 2005, S. 82 -88 (2005), ISSN 170-2971
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