The composition of the "missing" 5% of the earth's core
Japanese scientists believe that identified the "missing element" in the Earth's core. They were looking for this item for decades, believing that it is a significant part of the center of the world after iron and nickel. Now, recreate the conditions of high temperatures and pressures deep in the bowels of the planet, by means of experiments, researchers discovered: the most likely candidate is silicon.
The finding could help us better understand how our world was formed.
Lead researcher Eiji Ohtani Tohoku University said: "We believe that silicon is an essential element - about 5% by weight of silicon can take in the inner core of the Earth dissolved in the iron-nickel alloys."
It is difficult to find a
The innermost part of the earth is believed to be a solid sphere with a radius of 1200 km. It is too deep, so that it can be investigated directly, so instead, scientists are studying how seismic waves travel through the area and reveal the composition of the data.
The inner core for the most part consists of iron, which accounts for 85% by weight, and nickel, which accounts for about 10% of the core. To find the unknown 5% of the core, Eiji Otani and his team created iron-nickel alloys, and mixed them with silicon. Then they subjected them exposed to enormous pressures and temperatures that occur in the inner core.
Scientists have discovered that the mixture corresponds to that shown on the seismic data of the Earth's interior. Professor Otani says that further work is needed, which confirmed the presence of silicon and does not exclude the presence of other elements. Forming the nucleus
Commenting on the study, Professor Simon Redfern from Cambridge University in the UK says: "because it opens a window into the bowels of the earth, as they were immediately after the formation of the core 4, 5 billion years ago these difficult experiments proved to be very interesting when the kernel is just the beginning to separate from the solid parts of the Earth. But other recent works also point to an important role of oxygen in the core. "
He said that the knowledge of what is in the nucleus, will help scientists better understand the conditions that were at the time of formation of the Earth. In particular, it was there then a lot of oxygen, or else he was limited. If the core of a lot of silicon proved to Earth more than four billion years ago, the rest of the world turned out to be relatively rich in oxygen. If not, the oxygen has been sucked into the core and the surrounding solid mantle was poor in this element.
"In a sense, these two options are viable alternatives, depending on the conditions prevailing on the earth during the formation of the core. The new work adds depth to our understanding, but I'm sure it's not the last word in the story. "