URANUS NEPTUNE PLUTO
is the largest gas giant and has an atmosphere similar to that of Uranus, rich in hydrogen, helium and methane, but is more turbulent, with a blue-green instead of blue, because it has higher concentrations of methane in the layers higher.
In 1989 the Voyager 2 spacecraft revealed the presence of a dark spot, similar to the red spot of Jupiter, in the southern hemisphere. When
five years after the space telescope Hubble (HST) observed it, the stain was gone, but they had formed a similar one in the northern hemisphere.
It is subject, therefore, the formation of these dark spots short-lived, surrounded by methane ice clouds clear. Both
instruments to detect the existence of bands of clouds at high altitude in the composition is not yet clear, but this is mostly Solfrid acid.
The interior should be similar to that of Uranus, which is a rocky core surrounded by water, ammonia and methane.
Neptune rotates on its axis in 16 hours and 7 minutes and orbit around the Sun in 165 years.
It has a faint system of four rings, are not easily observed through a telescope. What
largest, called Adams presents blocks of denser matter, the so-called ring arcs.
eight satellites of Neptune are known, but Triton is the most characteristic, which extends 2700 km, resulting, therefore, larger those of Pluto.
And for this reason we think that in the past it was a planet to himself and then he was captured by the gravitational field of Neptune.
Triton has a surface covered in frozen nitrogen and methane, has a temperature of -235 ° C making it the coldest place in the Solar System.
jets rise from its surface oxide, forming geysers and draw dark streaks around it.
It has a retrograde orbit with respect to Neptune, it moves in the opposite direction.
Neptune has a large magnitude, it reaches' s 8 and, therefore, is not visible to the naked eye, but faintly visible with binoculars.
The planet was discovered in 1846 by Johann Gottfried Galle, ma la sua posizione era stata già intuita, in base alle perturbazioni sul moto di Urano, causate dal suo campo gravitazionale.
Origine foto: http://puntadellest.blogspot.com/2010/12/nettuno-in-pesci.html