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Supercritical C02Scientists have known for more than a century that at 75 times atmospheric pressure and 31 °C, carbon dioxide goes into an odd state that chemists call "supercritical." In this state, the liquid and the gas forms of carbon dioxide become indistinguishable: they merge into one fluid with unusual properties. Among the strangest, the viscosity of the fluid drops to almost nothing and its surface tension goes to zero. The low viscosity means it flows unusually well with low resistance, and the zero surface tension means the fluid's surface doesn't curl up at the edges and stick to the sides of its container. The net result: supercritical carbon dioxide can flow into crevices and nooks so tiny that other liquid solvents would gum up.
by David Voss
January 2002
Technology ReviewLos Alamos Computers Probe How Giant Planets FormedWorking with a French colleague, Didier Saumon of Los Alamos' Applied Physics Division created models establishing that heavy elements are concentrated in Saturn's massive core, while those same elements are mixed throughout Jupiter, with very little or no central core at all. The study, published in this week's Astrophysical Journal, showed that refractory elements such as iron, silicon, carbon, nitrogen and oxygen are concentrated in Saturn's core, but are diffused in Jupiter, leading to a hypothesis that they were formed through different processes. Saumon collected data from several recent shock compression experiments that have showed how hydrogen behaves at pressures a million times greater than atmospheric pressure, approaching those present in the gas giants. These experiments - performed over the past several years at U.S. national labs and in Russia - have for the first time permitted accurate measurements of the so-called equation of state of simple fluids, such as hydrogen, within the high-pressure and high-density realm where ionization occurs for deuterium, the isotope made of a hydrogen atom with an additional neutron. Working with T. Guillot of the Observatoire de la Cote d'Azur, France, Saumon developed about 50,000 different models of the internal structures of the two giant gaseous planets that included every possible variation permitted by astrophysical observations and laboratory experiments.
Science News
July 22, 2004
New insights into composition of giant planets
Spaceflight Now | October 18, 2006 | Division For Planetary Sciences
Posted on 10/18/2006 11:22:12 PM PDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1722070/posts
Radio Storms on Jupiter
NASA | 02/20/2004 | NASA
Posted on 02/20/2004 8:01:32 PM PST by kenth
http://www.freerepublic.com/focus/f-news/1082495/posts
Remnants of 1994 Comet Impact Leave Puzzle at JupiterFrom July 16 through July 22, 1994, more than 20 fragments of Comet P/Shoemaker-Levy 9 collided with the gaseous planet, all coming in at about the same latitude, 45 degrees south. Fragments up to 1.2 miles (2 kilometers) sent plumes of hot gas into the Jovian atmosphere. Dark scars lasted for weeks. Shocks created by the impacts led to high-temperature chemical reactions that produced hydrogen cyanide, which remains in the air but has been spread around a bit in the years since. The comet also delivered carbon monoxide and water, which through an interaction with sunlight, scientists suspect, was converted to carbon dioxide... The hydrogen cyanide has diffused some both north and south, mixed by wave activity... Jupiter's cloud bands carry material around the planet swiftly, but the bands do not mix easily. Not surprisingly, hydrogen cyanide is most abundant in a belt at the latitude where the comet was absorbed. At five degrees of latitude change in both directions, its presence drops off sharply. The highest concentration of carbon dioxide, however, has shifted away from the latitude of the impact. It is most prevalent poleward of 60 degrees south and decreases abruptly, toward the equator, north of 50 degrees south. Another smaller spike in its presence occurs at high northern latitudes, around 70 to 90 degrees north... The work also uncovered two new compounds, diacetylene and a so-called methyl radical, which are products of the breakup of methane by ultraviolet radiation from the Sun. These were expected but had not been observed at Jupiter before.
by Robert Roy Britt
August 23 2004