I had to look up "Negril". I didn't know it was part of Jamaica.
Google satellite image of Jamaica:
http://maps.google.com/maps?ll=18.033360,-76.804379&spn=1.696014,3.689484&t=k&hl=en|detailed
Posted on 08/06/2008 3:51:07 PM PDT by decimon
BERKELEY – A strange, metal brew lies buried deep within Jupiter and Saturn, according to a new study by researchers at the University of California, Berkeley, and in London.
The study, published in this week's online edition of the journal Proceedings of the National Academy of Sciences, demonstrates that metallic helium is less rare than was previously thought and is produced under the kinds of conditions present at the centers of giant, gaseous planets, mixing with metal hydrogen and forming a liquid metal alloy.
"This is a breakthrough in terms of our understanding of materials, and that's important because in order to understand the long-term evolution of planets, we need to know more about their properties deep down," said Raymond Jeanloz, professor of astronomy and of earth and planetary science at UC Berkeley and one of the authors of the study. "The finding is also interesting from the point of view of understanding why materials are the way they are, and what determines their stability and their physical and chemical properties."
Jeanloz studies pressures tens of millions of times greater than Earth's atmospheric pressure - the kinds of forces felt inside Jupiter and Saturn, so called "gas giants" that lack a solid surface. The core of the Earth, which is small and dense compared to the cores of these gas giants, contains pressures of about 3.5 million times atmospheric pressure. Pressures at Jupiter's core, for example, reach 70 million times Earth's atmospheric pressure, the planet's massive size more than offsetting its low density. The cores of Jupiter and Saturn are a balmy 10,000 to 20,000 degrees Celsius, two to four times hotter than the surface of the sun.
In this study, Jeanloz and Lars Stixrude, earth sciences professor at University College London, took a closer look at what happens to helium under such extreme conditions.
Most studies of materials in gaseous planets have focused on hydrogen, Jeanloz said, because it is the predominant element of both these planets and the universe. But even though hydrogen is the lightest element, its behavior is fairly complicated due to its tendency to form molecules of two bonded hydrogen atoms, Jeanloz said. Jeanloz and Stixrude wanted to study a simpler element, to more easily understand the effects of extreme temperatures and pressure.
So, they picked helium, the second most abundant element, which comprises five to 10 percent of the universe. They used theories based on quantum mechanics to calculate the behavior of helium under different pressures and temperatures. Although these equations are only approximations, Stixrude said, the researchers' predictions closely matched experimental results for lower pressures.
Under Earthly conditions, helium is a colorless, see-through, electrically insulating gas. But under the kinds of pressure and temperature found at the centers of Jupiter and Saturn, the researchers found that helium turns into a liquid metal, like mercury.
"You can imagine this liquid looking like mercury, only less reflective," Jeanloz said.
The finding was a surprise, as scientists had assumed that high pressures and high temperatures would make metallization of elements such as helium more difficult, not easier, Jeanloz said. He and his colleagues had previously found that helium starts to have some metal-like qualities in experiments at extremely high pressure, but they have not yet been able to experiment with helium under the conditions found inside giant planets.
A metal's key characteristic is its ability to conduct electricity, meaning electrons can flow through it like water flowing unimpeded down a riverbed.
"High temperatures make the atoms jiggle around, and so people thought that raising the heat would deflect the electrons, like putting enough rocks in a stream to block the flow of water," Jeanloz said. "The scattering caused by atoms was thought to make it harder for the electrons to flow down the stream."
But it turns out that the atoms' jostling also creates new ways for the electrons to move, almost as if new crevices had opened in the ground for the river's flow, Jeanloz said.
Scientists recently discovered that hydrogen metalizes under lower temperatures and pressures than was previously appreciated. The dogma in the field was that the characteristics of hydrogen and helium were different enough that the two wouldn't mix inside giant gaseous planets, Jeanloz said. The researchers' findings, however, indicate that the two elements probably do mix, forming a metal alloy like brass, but liquid.
This finding also speaks to one of the many mysteries of these large planets, Stixrude said. More energy is emitted from Jupiter and Saturn than they absorb from the sun, and scientists don't understand where it comes from. One of the prevailing theories is that droplets of helium condense out of the planets' outer atmospheres and fall to their centers as "helium rain," releasing gravitational energy. But Jeanloz and Stixrude's findings show that helium and hydrogen are probably a more homogenous mix than was previously suspected, meaning that helium rain is unlikely.
"Now, we have to look elsewhere for this energy source," Stixrude said.
Of course, due to the spinning of Earth on its axis, all object appear to 'rise' in the east and set in the west.
In that domain of physics, things get very wierd indeed. . wierder than you can imagine. . .
Chocolate planet...life would abound...
You should see it when Jupiter demands. . . The Cone of Silence. . . it’s REALLY something to see (evil grin)
bump
Ping
There must be something catastrophic in this.
Jupiter, Florida, that is.
If Jupiter is rising at "about" 6:15 PM Eastern Time in the East, then it's rising about 6:15 PM Central Time in the Midwest, 6:15 Mountain Time in the Rockies and 6:15 Pacific Time in the West.
Funny how that works out.
You're right! I didn't really think that part through. Thanks for the clarification, and I'm glad you appreciated the info.
I thought that's what I was seeing but I wasn't sure.
You need to buy (and use) a planisphere.
If you have a pair of modest binoculars (8x at least) and can hold them steady enough, you may be able to see a few of Jupiter’s 4 largest moons (the planet is now thought to have over 50 moons, but just 4 are big enough to see with amateur equipment). The moons will appear, more or less, in a straight line. This is because we are viewing the planet from the side and all of these moons orbit around Jupiter in a flat plane, much like a tiny solar system. The moons are not too far away from the planet, and the other ‘star-like’ objects you may see in its vicinity, are just that, stars. Jupiter is currently in the constellation Sagittarius.
It was pretty amazing, standing there on a beautiful tropical beach gazing up at a planet and it's moons hundreds of millions of miles away.
L
Sounds great to me!
It's currently darn near exactly 400 million miles away, btw, if that adds any extra meaning to it. :)
I had to look up "Negril". I didn't know it was part of Jamaica.
Google satellite image of Jamaica:
http://maps.google.com/maps?ll=18.033360,-76.804379&spn=1.696014,3.689484&t=k&hl=en|detailed
All I know is that it was an incredible coincidence for Mrs L and I to run into a no kidding certified astronomer with a fancy schmancy telescope at an adults only resort on a beach in Negril.
I forgot to ask him which four moons we were looking at, but there were two above and two below the planet, so it looked like Jupiter was a jewel in some sort of cosmic necklace.
It was fairly late IIRC, but there were people standing in line to look through his telescope. The man was kind enough to give Mrs L a 'tour' of the moon, including the landing site of one of the Apollo missions.
We were both mightily impressed.
Perhaps we'll run in to that gentleman again next year.
L
It's truly a lovely spot in the Caribbean. If you ever get the opportunity, I highly recommend you visit it.
L
another oldie (probably requires registration):Los 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
The Centers of PlanetsBack in 1935, Eugene Wigner, one of the founding fathers of quantum mechanics and at the time a professor at Princeton University, suggested that hydrogen, an inert molecular gas at ambient conditions, could turn into a metallic solid, similar to lithium or sodium, at sufficiently high pressure. Wigner's proposal implied a remarkable complexity for "element one," the simplest chemical entity, one electron bound to one proton... Jupiter's magnetic field, first measured by Voyager spacecraft, is ten times stronger than Earth's, and its pattern is considerably more complex. Part of this complexity could be accounted for if the source of the field lay much farther from the center, in relative terms, than does Earth's. Wigner's prediction of metallic hydrogen was based on a simplified analysis of the electronic ground state, but the pressure he calculated for the transition to the metallic state, about 250,000 atmospheres, corresponded to a depth of less than one-twentieth of the planetary radius of Jupiter. In other words, most of the solar system's largest gas giant had to be in a metallic state -- although the metallic hydrogen would have to be a fluid rather than a solid to provide dynamo action... The fact is that the Earth's core is not pure iron but contains about 10 percent (by weight) of other constituents. If you compare the density of the outer core that is derived from seismological data with that of pure iron shocked to comparable pressures and temperatures, the core's density turns out to be about 10 percent lower. Even when the melting temperature of pure iron is accurately known at 2 million to 4 million atmospheres of pressure, we will still have to make a correction for the effect of contaminants. Alloying often decreases the freezing temperature of a material; this is why ice can be melted by putting salt on top of it. The actual freezing temperature at the inner–outer core boundary may therefore be 1,000 kelvins or so lower than that of pure iron.
by Sandro Scandolo
and Raymond Jeanloz
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You were looking at Ganymede, Callisto, Europa, and Io. Those are the large moons of Jupiter easily seen through telescopes. They are called “Galilean moons” because they were first seen by Galileo through his crude telescope.
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