Interesting article
Jason McAlexander
However, it is the “ice” in the deep middle layers that really shapes their properties. On Neptune, for example, beneath a hydrogen-helium atmosphere that is 3,000 kilometers thick lies an ice layer that is 17,500 kilometers thick. Simulations suggest that gravity compresses the “ices” in this middle layer to high densities, and the internal heat raises the internal temperatures to several thousand kelvins. Despite the high temperature, pressures more than one million times greater than the atmospheric pressure on Earth compress the so-called ices into a hot, dense fluid.
Under such heat and pressures, ammonia and methane are chemically reactive. Scientists have modeled exotic processes—including diamond formation—taking place between the compounds deep within the ice layers. Marvin Ross of Lawrence Livermore National Laboratory first introduced the diamond-rain idea in a 1981 article in
Nature titled, “The Ice Layer of Uranus and Neptune—Diamonds in the Sky?” He suggested that the carbon and hydrogen atoms of hydrocarbons such as methane separate at the high pressures and high temperatures inside the ice giant planets. Clusters of isolated carbon atoms would then be squeezed into a diamond structure, which is the most stable form of carbon under such conditions.
www.americanscientist.org
