Innermost Core of the Earth Confirmed

Researchers have observed a newly discovered innermost core of the earth. Seismic station see up-to-fivefold reverberating waves from selected earthquakes along the Earth’s diameter. Differential travel times of these exotic arrival pairs complement and improve currently available information. There is ~650-km thick innermost ball.

Dr. Tkalcic and Thanh-Son Pham, a postdoctoral researcher, estimate that the innermost inner core is about 800 miles wide; the entire inner core is about 1,500 miles wide. The innermost inner core is a solid ‘metallic ball’ that sits within the centre of the inner core.

Two Harvard seismologists, Miaki Ishii and Adam Dziewonski, first proposed the idea of the innermost inner core in 2002 based on peculiarities in the speed of seismic waves passing through the inner core. The data available then were too sparse to convince everyone.

Professor Hrvoje Tkalčić, also from ANU, said studying the deep interior of Earth’s inner core can tell us more about our planet’s past and evolution. “This inner core is like a time capsule of Earth’s evolutionary history – it’s a fossilised record that serves as a gateway into the events of our planet’s past. Events that happened on Earth hundreds of millions to billions of years ago,” he said.

7 thoughts on “Innermost Core of the Earth Confirmed”

    • It depends on the metal AND the pressure… the same metal can undergo several different phase changes as temperature increases, including becoming a superconductor and then becoming non conductive again, etc. The experiments are difficult and thus we have glimpses at specific pressures of specific metals.
      They found that it pulls off the trick of changing its electrical properties without any shifting of shape – it can be an insulator or conductor depending just on temperature and pressure.

      Combined with computer simulations of just what was going on with the material’s electrons, the group claim that the results show a new type of metallisation.

      “At high temperatures, the atoms in iron oxide crystals are arranged with the same structure as common table salt,” said Ronald Cohen, a co-author of the study. “Just like table salt, iron oxide at ambient conditions is a good insulator—it does not conduct electricity.”

      “Our new results show, instead, that iron oxide metallises without any change in structure and that combined temperature and pressure are required. Furthermore, our theory shows that the way the electrons behave to make it metallic is different from other materials that become metallic.”
      “Under extreme pressure, the iron undergoes twinning, which helps the iron become even more durable. Half of the prism rotates 90°, so the iron ends up as two crystals connected at a right angle. Twinning of the iron crystals was also observed even after the pressure decreased.

      While researchers couldn’t achieve the same pressure found in the inner core, they got pretty close. No one has studied how iron reacts to these extreme pressures or temperatures, so the researchers didn’t have any evidence to suggest how the iron would respond.”

      in this other article, from 2009, a metal became transparent at high pressure

      in this other, the melting point kept increasing with pressure, and then it seems above a certain point, the melting point started decreasing again,than%20its%20normal%20solid%20phase.

    • There are 23 known phases of water ice; there may be many others but those are the ones we’ve discovered. Even pure elements often have allotropes; iron has at least 4. Some of those like austenite can be stabilized at room temperature by additions of small quantities of carbon. At high pressure maybe more can form.

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