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Earth Core File
Madrid. (Europa Press). – Scientists have determined that the temperature near the center of the Earth is 6,000 degrees Celsius , ie 1,000 degrees hotter than in a previous experiment 20 years ago.
geophysical models These measurements confirm that the temperature difference between the solid core and upper mantle must have at least 1,500 degrees to explain why Earth has a magnetic field.
The research team, led by Agnès Dewaele of the French national research organization CEA technology, along with members of the French National Center for Scientific Research (CNRS, its acronym in French) and the European Synchrotron Radiation Facility ( ESRF, its acronym in English) in Grenoble (France), whose findings were published Friday in the journal Science , was even able to establish why in the previous experiment had produced a number of minor temperature.
Earth core consists mainly of a sphere of molten iron at temperatures above 4,000 degrees and pressures over 1.3 million atmospheres. Under these conditions iron is so fluid as water in the oceans and only in the center of the Earth is where the pressure and temperature increase is even greater, so that the molten iron solidifies.
analysis earthquake causing seismic waves passing through the Earth tells us the thickness of the solid and liquid core, and even how the earth pressure increases with depth. However, these waves do not provide information on temperature, which has an important influence on the movement of material within the liquid core and the solid mantle above. In fact, the temperature difference between the mantle and the core is the main driver of the large-scale thermal movements, which together with the rotation of the Earth, acting as a dynamo generates the magnetic field of the Earth.
The temperature profile through the Earth’s interior also underpins geophysical models that explain the creation and intense volcanic activity hot as the Hawaiian Islands (USA) or La Réunion (France). To generate an accurate picture of the temperature profile in the center of the Earth, scientists can observe the melting point of iron to different pressures in the laboratory, using a diamond anvil cell samples to compress the size of a speck pressures several million atmospheres and laser beams to heat reaching 4,000 or even 5,000 degrees Celsius.
“In practice, many experimental challenges have to be met – CEA explains Agnès Dewaele – like iron sample must be thermally insulated and not be allowed to chemically react with their environment. Even if a sample reaches extreme temperatures and pressures of the Earth’s center, only do it for a matter of seconds.
In this short period of time, it is extremely difficult to determine if it has begun to melt or solid remains. “This is where the X-rays come into play.” We have developed a new technique in which an intense beam synchrotron X can probe a sample and deduce whether solid, liquid or partially melted in just one second, using a process known as diffraction, “says Mohamed Mezouar from the ESRF, for whom this is” short enough “to keep temperature and constant pressure, and while avoiding any chemical reaction.
Scientists
experimentally determined melting point of iron to 4800 degrees Celsius and 2.2 million atmospheres of pressure, and then used a method of extrapolation to determine that 3.3 million atmospheres pressure in the boundary between liquid and solid core, the temperature would be 6000 + / – 500 degrees. This extrapolated value might change slightly if the iron is subjected to an unknown phase transition between the measure and the extrapolated values.
When scientistsscanned across the area of ??pressures and temperatures observed why Reinhard Boehler, then at the MPI for Chemistry in Mainz (Germany) in 1993 gave values ??of about 1,000 degrees below. From 2,400 degrees recrystallization effects appear on the surface of iron samples, which leads to the dynamic changes of the crystal structure of solid iron.
twenty years experiment uses an optical technique for determining whether the samples were solid or molten, and it is highly likely that the recrystallization observation surface was interpreted as fusion.
“Of course, we are very pleased that our experiment validates best current theories about the transfer of heat from the Earth’s core and the generation of Earth’s magnetic field. Hopefully in the not too distant future we can play in our laboratories, and research with synchrotron X-rays, all states of matter in the Earth’s interior, “says Agnès Dewaele.
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