Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Helium rains inside jovian planets

29.01.2009
Models of how Saturn and Jupiter formed may soon take on a different look.

By determining the properties of hydrogen-helium mixtures at the millions of atmospheres of pressure present in the interior of Saturn and Jupiter, physicists at Lawrence Livermore National Laboratory and the University of Illinois at Urbana-Champaign have determined the temperature at a given pressure when helium becomes insoluble in dense metallic hydrogen. The results are directly relevant to models of the interior structure and evolution of Jovian planets.

Hydrogen and helium are the two lightest and most common elements in the universe. Because of their ubiquitous nature, they are critical in cosmological nucleosynthesis and are essential elements of stars and giant planets. Hydrogen by itself in the observable universe provides clues to the origin and large-scale structures of galaxies.

However, scientists have struggled to determine what conditions are needed for the two elements to mix.

Using first-principle molecular dynamics simulations, Miguel Morales, a DOE Stewardship Science graduate fellow from David Ceperley's group at the University of Illinois worked with LLNL's Eric Schwegler, Sebastien Hamel, Kyle Caspersen and Carlo Pierleoni from the University of L'Aquila in Italy to determine the equation of state of the hydrogen-helium system at extremely high temperatures (4,000-10,000 degrees Kelvin), similar to what would be found in the interior of Saturn and Jupiter.

The team used LLNL's extensive high-performance computing facilities to conduct simulations over a wide range of density, temperature and composition to locate the equation of state of the two elements.

"Our simulation results are consistent with the idea that a large portion of the interior of Saturn has conditions such that hydrogen and helium phase separate," Morales said. "This can account for the apparent discrepancy between the current evolutionary models for Saturn and observational data."

In addition to being made mostly of hydrogen and helium, a characteristic of Jovian planets is that they radiate more energy than they take in from the sun. Various models of their evolution and structure have been developed to describe a relation between the age, volume and mass of the planet and its luminosity.

While this model works for Jupiter by modeling the energy radiation left over from its formation 4.55 billion years ago, it doesn't exactly work for Saturn. Instead, the model seriously underestimates the current luminosity of Saturn.

So the researchers decided to try something different. They determined where helium and hydrogen mix as well as at what temperature they don't mix.

It turned out the temperature where the two elements don't mix is high enough that helium is "partially mixable over a significant fraction of the interior of the Jovian planets with the corresponding region of Saturn being larger than in Jupiter," Schwegler said. "This, in fact, could change the current interior models of Saturn and Jupiter."

The new findings appear in the Jan. 26 online edition of the journal, Proceedings of the National Academy of Sciences.

Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

Anne Stark | EurekAlert!
Further information:
http://www.llnl.gov

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>