What kind of planet is Neptune?

Answer 1

Neptune is a big, blue ball of gas. But there's more to the story. It is mostly really, really, really cold hydrogen and helium with a bit of methane. (But we're not really sure why it's blue. Cool, huh?! Yeah!) It is thought to have a rocky core surrounded by a thick shell of ice (water, amonia and methane ice). The cloud layer is really thick, and the winds are otherworldly! Really! Temperatures in the clouds are a blazing 55 degrees Kelvin (55 Centigrade degrees above absolute zero). It even gets a bit colder from time to time. And wind? How about 2100km/h for ya? That's about 1300 miles per hour! Wow! Hit the link to Wikipedia (where some of this information originated) for some cool pics and more data. Neptune's upper atmosphere (what we see) is a mixture of hydrogen, helium, methane and traces of acetylene (C2H2), carbon dioxide, and other gasses. Only 10% of the planet's mass is in this outermost layer (approximately 3,100 mi or 5,000 km thick). Under the upper atmosphere lies a lower atmosphere of molecular (gaseous) hydrogen and helium, plus some ices (approximately 6,200 mi or 10,000 km thick). Below the atmosphere lies the mantle, a water ice and rock mixture that perhaps contains methane ice and ammonia ice mixed in. A core is at the center of the planet's mass, and it is likely a body with a 6,200-mi radius and represents 45% of the planet's mass that is composed of silicate rock and water ice. Like the other Jovian planets (Jupiter, Saturn, and Uranus), Neptune has a distinctive structure quite different from the terrestrial planets like Earth.

Answer 2

The dwarf planet Pluto has the same structure as most cometary Kuiper Belt objects. It is largely frozen water and CO2, with a smattering of organic molecules, rock and dirt. Comets are essentially dirty snowballs. It probably has a core of denser material.

Eris, which is larger than Pluto, would have much the same structure. It is expected that the composition of Oort Cloud objects, which are much further away than the Kuiper Belt objects is also about the same.

Answer 3

Neptune is considered a gas planet or an ice planet like Uranus.

Answer 4

Water