Re: Ice in Neptune?

Thank you for your question Demetrius. Is there water ice in the core of Neptune? The short answer is that we do not really know for sure. However it is unlikely to compose the core, but may be in a layer above the core.

Neptune and Uranus compose the "ice giants", large "gas giant" planets which exist beyond the orbit of Saturn. Ice giants contain more "ices" like water and ammonium than other gas giants like Jupiter and Saturn. Neptune is rich in hydrogen and helium, but also contain various organic compounds like ammonia and methane as well as water. At the extreme distance of the "ice giants", planets such as Neptune are though to be chemically similar to the solar nebula prior at the beginning of our solar system.

As containing the building blocks of our sun and solar system, water is a chief component. The extreme distance from our sun precludes water from being present in the clouds. But pressure and temperature in the correct amounts can form either liquid water or solid water (ice) within Neptune. This is still a matter of scientific discussion. We have no detailed probe data beyond the cloud-tops of Neptune.

The current models for Neptune's interior suggests that it has a liquid rock core, surrounded by an icy mantle and a deep ocean of liquid hydrogen, helium and possibly water which gradually thins out to an atmosphere. Despite the higher temperatures as one descends into Neptune, pressure is also increasing. Under the right pressure, density and temperature conditions, one can form either liquid or solid forms of water. But whether this has in fact happened on Neptune (or might yet happen) is still a matter of discussion. We have no direct measurements.

Below are some links of interest:

http://www.sciencedaily.com/releases/2008/09/080923181112.htm

http://www.nineplanets.org/neptune.html

http://www.nasa.gov/worldbook/neptune_worldbook.html

http://www.space.com/businesstechnology/technology/neptune_orbiter_techwed