Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Iron 'snow' helps maintain Mercury's magnetic field

09.05.2008
New scientific evidence suggests that deep inside the planet Mercury, iron “snow” forms and falls toward the center of the planet, much like snowflakes form in Earth’s atmosphere and fall to the ground.

The movement of this iron snow could be responsible for Mercury’s mysterious magnetic field, say researchers from the University of Illinois and Case Western Reserve University. In a paper published in the April issue of the journal Geophysical Research Letters, the scientists describe laboratory measurements and models that mimic conditions believed to exist within Mercury’s core.

“Mercury’s snowing core opens up new scenarios where convection may originate and generate global magnetic fields,” said U. of I. geology professor Jie (Jackie) Li. “Our findings have direct implications for understanding the nature and evolution of Mercury’s core, and those of other planets and moons.”

Mercury is the innermost planet in our solar system and, other than Earth, the only terrestrial planet that possesses a global magnetic field. Discovered in the 1970s by NASA’s Mariner 10 spacecraft, Mercury’s magnetic field is about 100 times weaker than Earth’s. Most models cannot account for such a weak magnetic field.

Made mostly of iron, Mercury’s core is also thought to contain sulfur, which lowers the melting point of iron and plays an important role in producing the planet’s magnetic field.

“Recent Earth-based radar measurements of Mercury’s rotation revealed a slight rocking motion that implied the planet’s core is at least partially molten,” said Illinois graduate student Bin Chen, the paper’s lead author. “But, in the absence of seismological data from the planet, we know very little about its core.”

To better understand the physical state of Mercury’s core, the researchers used a multi-anvil apparatus to study the melting behavior of an iron-sulfur mixture at high pressures and high temperatures.

In each experiment, an iron-sulfur sample was compressed to a specific pressure and heated to a specific temperature. The sample was then quenched, cut in two, and analyzed with a scanning electron microscope and an electron probe microanalyzer.

“Rapid quenching preserves the sample’s texture, which reveals the separation of the solid and liquid phases, and the sulfur content in each phase,” Chen said. “Based on our experimental results, we can infer what is going on in Mercury’s core.”

As the molten, iron-sulfur mixture in the outer core slowly cools, iron atoms condense into cubic “flakes” that fall toward the planet’s center, Chen said. As the iron snow sinks and the lighter, sulfur-rich liquid rises, convection currents are created that power the dynamo and produce the planet’s weak magnetic field.

Mercury’s core is most likely precipitating iron snow in two distinct zones, the researchers report. This double-snow state may be unique among the terrestrial planets and terrestrial-like moons in our solar system.

“Our findings provide a new context into which forthcoming observational data from NASA’s MESSENGER spacecraft can be placed,” Li said. “We can now connect the physical state of our innermost planet with the formation and evolution of terrestrial planets in general.”

James E. Kloeppel | EurekAlert!
Further information:
http://www.uiuc.edu

More articles from Earth Sciences:

nachricht Colorado River's connection with the ocean was a punctuated affair
16.11.2017 | University of Oregon

nachricht Researchers create largest, longest multiphysics earthquake simulation to date
14.11.2017 | Gauss Centre for Supercomputing

All articles from Earth Sciences >>>

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 >>>