Posted on 11/25/2008 5:18:38 PM PST by nickcarraway
Jupiter Core is as Big as Uranus or Neptune By
Jupiter has a rocky core that is more than twice as large as previously thought, according to computer calculations by UC Berkeley and University of Arizona scientists.
Burkhard Militzer, an assistant professor of astronomy and earth and planetary science at Cal, simulated conditions inside the planet on the scale of individual hydrogen and helium atoms.
The simulation predicted the properties of hydrogen and helium for temperature, density and pressure at the surface, all the way to the planet's center. The technique is often used to study semi-conductors, according to a UC Berkeley statement on the discovery.
Militzer's partner, William B. Hubbard, from the University of Arizona, used the data to build the new model for Jupiter's interior.
A comparison of the model with the planet's current known mass, radius, surface temperature, gravity and equatorial bulge implies that Jupiter's core is an Earth-like rock 14 to 18 times the mass of Earth, or about one-twentieth of Jupiter's total mass, Militzer said.
Previous models predicted a much smaller core of only 7 Earth masses, or no core at all.
Jupiter, like many planets its size already discovered throughout the galaxy, is believed to be a failed star. Most of the planet's mass is made up of gas.
The results were published Nov. 20 in Astrophysical Journal Letters.
The simulation suggests that the core is made of layers of metals, rocks and ices of methane, ammonia and water, while above it is an atmosphere of mostly hydrogen and helium.
At the center of the rocky core is probably a metallic ball of iron and nickel, just like Earth's core, scientists said.
"Our simulations show there is a big rocky object in the center surrounded by an ice layer and hardly any ice elsewhere in the planet," Militzer said. "This is a very different result for the interior structure of Jupiter than other recent models, which predict a relatively small or hardly any core and a mixture of ices throughout the atmosphere."
"Basically, Jupiter's interior resembles that of Saturn, with a Neptune or Uranus at the center," he said.
Neptune and Uranus have been called "ice giants" because they also appear to have a rocky core surrounded by icy hydrogen and helium, but without the gas envelope of Jupiter and Saturn.
"This new calculation by Burkhard removes a lot of the old uncertainties of the 19-year-old model we have had until now," Hubbard said. "The new thermodynamic model is a more precise physical description of what's going on inside Jupiter."
Scientists said the large, rocky core implies that as Jupiter and other giant gas planets formed 4.5 billion years ago, they grew through the collision of small rocks. The rocks formed cores that captured a huge atmosphere of hydrogen and helium.
"According to the core accretion model, as the original planetary nebula cooled, planetesimals collided and stuck together in a runaway effect that formed planet cores," Militzer said. "If true, this implies that the planets have large cores, which is what the simulation predicts. It is more difficult to make a planet with a small core."
In order to match the observed gravity of Jupiter, Militzer's simulation also predicts that different parts of Jupiter's interior rotate at different rates.
Jupiter can be thought of as a series of concentric cylinders rotating around the planet's spin axis, with the outer cylinders - the equatorial regions - rotating faster than the inner cylinders. This is identical to the sun's rotation, Militzer said.
How They Did It …
Militzer modeled Jupiter's interior as a collection of 110 hydrogen and nine helium atoms in a tiny cube that is replicated throughout the planet, a common approximation in "density functional theory."
The ratio of hydrogen to helium atoms approximates the ratio measured on the surface of Jupiter.
Each simulation took from one to seven days on parallel computing clusters.
Based on this simulation, under the high pressure and temperature deep within the planet, hydrogen changes from a molecular to a metallic state, which provides good electrical conductivity and gives rise to Jupiter's magnetic field.
This transition happens gradually, contrary to earlier models that predict a sharp transition.
The new model of Jupiter predicts that most of the ices are concentrated in the outer layer of the core, while only a small amount is mixed in the hydrogen-helium gas envelope that contains 95 percent of the planet's mass.
The "planetary ices" in the envelope amount to about four Earth masses, or 1 percent of Jupiter's mass, Militzer said.
"The simulation was in pretty good agreement with what the Galileo probe measured" when the NASA spacecraft descended through Jupiter's atmosphere in 1995, Hubbard said.
Militzer plans to use the new model to simulate other planets' interiors, and to investigate the implications for the formation of planets outside our solar system.
Future data from NASA's Juno mission, to be launched in 2011, orbit Jupiter by 2016 and measure the planet's magnetic field and gravity, will provide a check on Militzer's predictions. Hubbard is one of the mission's co-investigators.
The National Aeronautics and Space Administration and the National Science Foundation supported the research.
cool
Wow we can find that out but we can’t determine Obamas place of Birth
I guess I’m okay with this.
Well, to each his/her own but ‘’big as Your anus’’? Yuck, who’d want to see that!?!(sorry, just a little joke there).
Right now Jupiter is in the evening sky a few degrees from Venus—Venus is much brighter. On Dec. 1 the four-day-old moon will be near both of them which should be worth seeing.
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Jupiter and Saturn full of liquid metal helium
UC Berkeley | Aug 6, 2008 | Rachel Tompa
Posted on 08/06/2008 3:51:07 PM PDT by decimon
http://www.freerepublic.com/focus/f-chat/2057677/posts
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
So how deep would the piers have to be if we build an outpost there? ;o)
Nevermind the piers, what about the PILES for those piers? They'd have to be HUGH!
“I built that pier with me own bare hands, but do they call me Angus the piledriver? NAE”!
... one blasted goat....
I don't know about that, but her butt gets pretty darn cold.
I can tell this is gonna be a fun thread.
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