what is the atmosphere like in Neptune's? and what are the gases present and their percentages?

Answer 1

Neptune has a diameter of 49,500 km and a mass 17.22 times that of Earth, making the planet slightly smaller and heavier than Uranus. It has an average density of 1.67/cm3. Like Uranus, Neptune is believed to have a rocky core surrounded by a liquid water mantle, which is surrounded in turn by liquid hydrogen and helium. The atmosphere consists mainly of hydrogen and helium, with about 2.5 to 3 percent by weight of methane. The cirruslike clouds in Neptune's atmosphere are composed of crystals of methane. Methane's strong absorption band dominates the planet's spectrum, giving Neptune its deep blue color. Ammonia is probably also present.

Temperatures on Neptune rise with increasing depth, as on Uranus. Scientists had expected Neptune's temperature to be about -228°C, but measurements made by Voyager 2 indicated a higher temperature of at least -218°C. Thus Neptune, like Jupiter and Saturn but unlike Uranus, appears to have an internal heat source.

Voyager 2 discovered that the magnetic field of Neptune is tilted more than 50 degrees from the rotation axis and is offset from the center of the planet. This means that the magnetic field strength varies across the surface. This unexpected orientation resembles that of Uranus's magnetic field. The orientation of Uranus's magnetic field had been thought to be linked to that planet's unusual orientation, with a rotation axis nearly parallel to the plane of the ecliptic. Now scientists must find some other explanation for this shared characteristic.

Answer 2

Atmosphere? What atmosphere? It's mostly all frozen gasses laying on the surface with a very litle bit of hydrogen, helium, and maybe some methane floating around.

Doug