Jupiter's Core Dissolving

Think climate change is bad? Things are rather worse in the outer solar system. Jupiter's rocky central core may well be dissolving into liquid.

The gas giant, which is twice as massive as all of the other planets orbiting the Sun put together, has a central core comprised of iron, rock and ice. It sits in the centre of the planet, submerged in a fluid of hydrogen and helium under intense pressures about 40 million times greater than atmospheric pressure on Earth, and temperatures around 16,000 degrees kelvin -- hotter than the surface of the Sun.

As such, we can't recreate those conditions experimentally on Earth. But that hasn't stopped planetary scientists Hugh Wilson and Burkhard Militzer of the University of California, Berkeley, giving it a go. They've performed quantum mechanical calculations to try and work out how one of the key ingredients of the core -- magnesium oxide -- responds in such an extreme situation.

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They found that under these intense pressures and temperatures, the magnesium oxide has very high solubility, meaning that it's likely to be dissolving into liquid. The exact rate of the erosion isn't known, but the pair had earlier predicted that the ice in the core is also dissolving. That means that Jupiter's core is likely to be smaller now than it was when the planet formed.

The research has been detailed in a paper submitted to Physical Review Letters, in which Wilson and Militzer say that the work has substantial implications for working out how to simulate these types of planets. "For large exoplanets exceeding Jupiter's mass, higher interior temperatures promote both solubility and redistribution, implying that the cores of sufficiently large super-Jupiters are likely to be completely redistributed," it reads. We'll be able to find out more in 2016, when Nasa's Juno spacecraft arrives at the gas giant and begins to measure its gravitational field. Environment Clean Generations

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Posted in: core,environment clean generations,jupiter,space

New Method for Measuring Nanoparticles

Precise measurement of the molecular weight, size and density of a nanoparticle in a single procedure is now possible, thanks to an ultracentrifugation method, dusted off by Swiss scientists at EPFL.

Although nanoparticles are used in a variety of domains – such as medicine, solar energy and photonics – there is still much about them to be discovered. Establishing their full characterization, including mass, size and density, remains an extremely complex exercise, and this acts as a brake on research in the area. However, this knowledge gap will soon be filled, thanks to the work performed by Constellium Professor Francesco Stellacci and his doctoral-student assistant Randy Carney, from the Supramolecular Nanomaterials and Interfaces Laboratory (SUNMIL). 

In a recent article in Nature Communications, they demonstrate that it’s possible to obtain the complete characterization of a core-shell nanoparticle (the core and the external shell) by using a very simple method – analytical ultracentrifugation. 

This 100-year-old procedure has previously been used, in particular, to study the size and mass of proteins. It was in applying the method to their area of research that the EPFL scientists realized the benefits that could be obtained from its use.

The core and the shell

So far, the analysis of all the parameters that characterize the core, as well as those which characterize the shell of the nanoparticle in a single operation has remained a real challenge. The nanoparticles are indeed polydisperse, which means that, in a sample, each of them has different characteristics (size, mass, weight etc.). 

“Currently, scientists have at their disposal reliable techniques for characterizing the core of nanoparticles. But this requires five or six very complex procedures to obtain a complete characterization”, adds Randy Carney. “By looking at analytical ultracentrifugation, we discovered a method that enables us, in a single process, to obtain all the required parameters in a few hours.”

How does it work?

Technically speaking, the concept is as follows: first, you have to dilute the nanoparticles in a solution, and then to put the solution in an analytical ultracentrifuge, equipped with an optical detection system that analyzes their behavior. It’s then possible, using a computing process, to determine what is called the sedimentation coefficient. 

“When we spin them at a rapid speed, the nanoparticles separate from the liquid at different moments, according to their density,” explains Randy Carney. The biggest particles are thus separated more quickly from the liquid. This observation provides an indication of the weight of the particle, as well as its diameter.” In parallel, the scientists are focusing on another indication – usually ignored by most studies – which is called the particle diffusion coefficient, which relates to the way they spread through the liquid. “This phenomenon, which we can compare with a drop of ink in water, occurs even when the solvent is still.” 

Uses in industry

When used together, the sedimentation coefficient and the diffusion coefficient then enable the obtention of a very precise characterization of both the core and the shell of the nanoparticles: that is to say, their size, weight, form and composition. 

This is very important information, when we consider that the properties of the nanoparticles (chemical, electronic, magnetic etc.) are dependent on all these parameters.

For the moment, this method only works with spherical nanoparticles. However, it should still be of interest for researchers active in nanotechnologies, who can also use it for other nanoparticles, with some additional analyses. “Industry and biological applications also need a method for characterizing nanoparticles. This method could be very useful” concludes Professor Stellacci.

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Posted in: core,New Method for Measuring Nanoparticles,solar energy,weight

Geothermal Energy Cooling the Earth’s Core?

Global warming, holes in the ozone layer, and lush golf courses in the desert all reveal mankind’s ability to mess with the planet. But the Earth’s core, protected by an outer core consisting of some 1,000 miles of 8,000˚F liquid metal, appears safe from our meddling. 

            Geothermal energy systems don’t drain heat directly from the core. Instead, they pull radiant heat from the crust—the rocky upper 20 or so miles of the planet’s surface—either by sucking up pockets of heated water or by circulating water through the hot rock. Power plants then use steam from the hot water to spin turbines to make electricity.

            Geothermal energy generates 7 to 10 billion watts worldwide, barely enough to account for 0.05 percent of global energy consumption and far less than the estimated 44 trillion watts the planet produces.

            But drawing energy from the crust won’t send it into a deep freeze: Its heat is constantly renewed by the virtually continuous decay of radioactive elements sprinkled throughout it. “Cooling the Earth’s core by drawing geothermal energy from the crust is like trying to cool the western end of Lake Superior with a few ice cubes,” says Paul Richards, a professor of natural science at Columbia University.

            It’s a good thing that we can’t cool the core. The spinning metal there generates Earth’s magnetic field, which protects us from deadly cosmic radiation. If the outer core cooled, the liquid would solidify, and both it and the solid inner core would grind to a halt, the magnetic field would dissipate, and high-energy cosmic radiation would bombard the planet, essentially turning Earth into a giant microwave and ending life on the surface. 

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Posted in: core,earth,energy,freez