Unlike Jupiter or Saturn, which are made primarily of basic materials hydrogen and helium, Neptune is made mostly of icy material, the solid form of complex molecules such as methane, ethane, and water. The reason for this is because the nebula itself influenced the kind of material which formed near Neptune.

Most of the original air of the giant planets remains in place. (The earth-like planets lost most of their atmospheres very soon after they formed because the atmosphere drifted away).

Unlike Jupiter or Saturn, which are made of the simple materials hydrogen and helium, Neptune is made mostly of icy material and other complex molecules such as methane. The reason for this is because the cloud from which the planets formed told what kind of material was to form near Neptune.

Most of the original air of the giant planets remains in place. (The earth-like planets lost most of their atmospheres very soon after they formed because the atmosphere drifted away).

Unlike Jupiter or Saturn, which are made of simple molecules, Neptune is made mostly of icy material and complex molecules. The reason for this is because the cloud from which the planets formed told what kind of material was to form near Neptune.