Introductory text to the planet Neptune
Neptune is the eighth and outermost planet in the solar system. The gas planet is counted together with Uranus to the ice giants. The planet, which is 4,500,000,000 km from Earth, is named after Neptune, the Roman god of water. He corresponds in Greek mythology Poseidon. 165 years pass on Neptune, before the celestial body once turned around the sun. Longer than any other planet in the solar system.
Neptune is too far away from Earth to be seen without a telescope. The discovery was made by collaboration between the mathematician Urbain Le Verrier, and the astronomer Johann Gottfried Galle. Le Verrier noticed irregularities in the orbit of Uranus, which could not be explained by the already known objects. He suspected another planet whose gravitational field had to interact with Uranus. Since no French astronomer at his request was concerned with the search for this object, Le Verrier wrote to Johann Gottfried Galle. His orbital calculations were so accurate that Galle found the planet a short time later at the calculated position.
The NASA spacecraft Voyager 2 is still the only object that flew past Neptune. Launched in 1977, the probe took 12 years to reach orbit. A landing is only possible on rocky planets. Missions with land vehicles, such as the Rover Curiosity on Mars, therefore, will not be possible in the future. Regardless, no further Neptune missions are planned to the edge of the solar system.
Facts about Neptune
The unmistakable distinguishing feature is the intense blue color of Neptune. This is not water. The atmosphere consists of 80% hydrogen, 19% helium and 1% methane. As with Uranus, the methane in the atmosphere causes the blue color. Why Neptune appears in a more intense blue than the green-blue Uranus, is so far unknown. Presumably, other factors contribute to the coloring of the planet.
The surface temperature is -200 ° C. Because of the great distance between Sun and Neptune, the planet remains very cold. Sunlight needs just over four hours from the sun to Neptune. By comparison, sunlight only needs 8min and 20sec to Earth. Neptune radiates even more heat into space, as the planet receives through the sun. Deep inside there must be a heat source that has not yet been clearly identified.
Like the three other gas planets Saturn, Uranus and Jupiter, Neptune also has its own ring system. With the exception of Saturn, the rings are barely visible. And although Neptune and Uranus are similar in many ways, Neptune has the most extreme wind speeds (up to 2100 km / h) in the solar system, while there is virtually no to no weather on Uranus.
Moons of Neptune
14 moons orbit the Neptune: Despina, Galatea, Halimede, Laomedeia, Larissa, Naiad, Nereid, Neso, Proeus, Psamathe, Sao, Thalassa and Triton. The names are chosen according to the planet according to sea gods. A moon is currently waiting for its official designation.
Triton, by far the largest moon with a diameter of 2700km, is an ice-moon whose surface consists mainly of frozen nitrogen and carbon dioxide. The size is about 3/4 the size of the Earthmoon, although the density of Triton is much lower. Compared to the other 13 moons, Triton surpasses them many times over. Between 20 and 400km are the diameter, with more than half of the moon less than 100km in diameter.
Probably Triton comes from the nearby Kuiper Belt and was captured by the gravity of Neptune. The spacecraft Voyager 2 determined a surface temperature of -237 ° C. This is the lowest, ever measured temperature.