Featured Research

from universities, journals, and other organizations

Rubik's Cube In Center Of Earth? Computer Simulations Support New Model Of Earth's Core

Date:
February 11, 2008
Source:
Uppsala University
Summary:
Swedish researchers have presented evidence in Science to support their new theory about the structure of the earth's core. The findings may be of significance for our understanding of the cooling down of the earth, and of the stability of the earth's magnetic field. It has long been known that the inner core of the earth, a sphere consisting of a solid mass with a radius of about 1,200 km, is mainly made up of iron. However, seismic observations have shown that elastic waves pass more rapidly through this core in directions that are parallel to the earth's axis of rotation than in directions parallel to the equator­-a phenomenon that has not been previously explained.

Swedish researchers have presented evidence to support their new theory about the structure of the earth's core. "We found that the body-centered cubic structure of iron is the only structure that could correspond to the experimental observations," says Börje Johansson, professor of condensed-matter theory at Uppsala University.
Credit: Image courtesy of Uppsala University

Swedish researchers have presented evidence to support their new theory about the structure of the earth's core. The findings may be of significance for our understanding of the cooling down of the earth, and of the stability of the earth’s magnetic field.

Related Articles


It has long been known that the inner core of the earth, a sphere consisting of a solid mass with a radius of about 1,200 km, is mainly made up of iron. However, seismic observations have shown that elastic waves pass more rapidly through this core in directions that are parallel to the earth’s axis of rotation than in directions parallel to the equator­-a phenomenon that has not been previously explained. At the high temperatures that prevail in the core of the earth, these waves should pass at the same speed regardless of their direction.

In the present study, scientists from Uppsala University and KTH present an explanation for this puzzling characteristic. The new publication in Science is part of a series of articles published by the same research team in Nature and Science.

Initially, in 2003, they published strong theoretical proof that the earth’s core assumes the so-called body-centered cubic crystal structure at high temperatures­-a structure that despite its high degree of symmetry evinces a surprisingly high level of elastic anisotropy, that is, its elastic properties are contingent on direction. This theory about the crystal structure directly contradicted the then prevailing view, but since then the theory has found both experimental and theoretical support.

In this new study the researchers present simulations of how seismic waves are reproduced in iron under the conditions that prevail in the core of the earth, showing a difference of about 12 percent depending on their direction-­which suffices as an explanation for the puzzling observations. First the trajectories of movement were calculated for several million atoms in strong interaction with each other. On this basis, the scientists were then able to determine that the progress of the sound waves was actually accurately described in the computer-generated model for iron under the conditions prevailing in the core of the earth.

“We found that the body-centered cubic structure of iron is the only structure that could correspond to the experimental observations,” says Börje Johansson, professor of condensed-matter theory at Uppsala University.

The earth’s heat balance, like its magnetic field, is dependent on the amount of heat that is stored in the inner core of the earth. These conditions, in turn, are dependent on the crystal structure of the iron in the inner core. Previously these estimates were based on models deriving from the hexagonal structure of iron in the inner core. The Swedish scientists’ discovery will now entail a critical revaluation of the cooling off of the earth and of the stability of its magnetic field.

“This study opens new perspectives for our understanding of the earth’s past, present, and future,” says Natalia Skorodumova, a researcher at the Department of Physics and Materials Science.

In their studies these researchers have used models based on the so-called density-functional theory for which Walter Kohn was awarded the 1999 Nobel Prize. The calculations were carried out using the most powerful parallel supercomputers in existence, in Stockholm and Linköping.

The body-centered cubic crystal structure forms a cube with atoms in each corner and a further atom in the middle of this cube. It is oriented in such a way that its great diagonal is directed along the earth’s axis of rotation, which makes it possible for the iron to evince sound propagations with the velocities observed.

Journal reference: Anatoly B. Belonoshko, Natalia V. Skorodumova, Anders Rosengren, Börje Johansson. Elastic Anisotropy of Earth's Inner Core. Science 8 February 2008: Vol. 319. no. 5864, pp. 797 - 800 DOI: 10.1126/science.1150302


Story Source:

The above story is based on materials provided by Uppsala University. Note: Materials may be edited for content and length.


Cite This Page:

Uppsala University. "Rubik's Cube In Center Of Earth? Computer Simulations Support New Model Of Earth's Core." ScienceDaily. ScienceDaily, 11 February 2008. <www.sciencedaily.com/releases/2008/02/080208091314.htm>.
Uppsala University. (2008, February 11). Rubik's Cube In Center Of Earth? Computer Simulations Support New Model Of Earth's Core. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/2008/02/080208091314.htm
Uppsala University. "Rubik's Cube In Center Of Earth? Computer Simulations Support New Model Of Earth's Core." ScienceDaily. www.sciencedaily.com/releases/2008/02/080208091314.htm (accessed October 30, 2014).

Share This



More Earth & Climate News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Mudslide in Sri Lanka Buries Houses

Deadly Mudslide in Sri Lanka Buries Houses

AP (Oct. 29, 2014) — A mudslide triggered by monsoon rains buried scores of workers' houses at a tea plantation in central Sri Lanka on Wednesday, killing at least 10 people and leaving more than 250 missing, an official said. (Oct. 29) Video provided by AP
Powered by NewsLook.com
Galapagos Tortoises Bounce Back, But Ecosystem Lags

Galapagos Tortoises Bounce Back, But Ecosystem Lags

Newsy (Oct. 29, 2014) — The Galapagos tortoise has made a stupendous recovery from the brink of extinction to a population of more than 1,000. But it still faces threats. Video provided by Newsy
Powered by NewsLook.com
Saharan Solar Project to Power Europe

Saharan Solar Project to Power Europe

Reuters - Business Video Online (Oct. 29, 2014) — A solar energy project in the Tunisian Sahara aims to generate enough clean energy by 2018 to power two million European homes. Matt Stock reports. Video provided by Reuters
Powered by NewsLook.com
Obama: The US Will Not 'run and Hide' From Ebola

Obama: The US Will Not 'run and Hide' From Ebola

AP (Oct. 29, 2014) — Surrounded by health care workers in the White House East Room, President Barack Obama said the U.S. will likely see additional Ebola cases in the weeks ahead. But he said the nation can't seal itself off in the fight against the disease. (Oct. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins