Evidence Indicates the Presence of a Fifth Layer Within Earth’s Structure

Evidence Indicates the Presence of a Fifth Layer Within Earth’s Structure

Geologists and scientists in general previously believed that there are only four layers in Earth’s structure, but new research made by a group from Australian National University claims something different. Except for the crust, mantle, the liquid outer core, and the inner core, scientists found a hint for another layer, as the article from Salon.com reveals.

The solid inner core that is made of iron and nickel could actually have two distinct layers. The unexpected conclusion came after analyzing thousands of models of Earth’s inner core while using a special search algorithm. As it happens many times in science, the researchers were after something else: to study how long it took for some seismic waves to travel across the planet.

A change in the structure of iron

The slower seismic waves changed at a 54-degree angle, while faster waves ran parallel to the rotational axis of the Earth. This was unexpected, considering that there is not too much variation regarding the depth of the inner core.

PhD researcher Joanne Stephenson, who’s the study’s lead author, declared:

We found evidence that may indicate a change in the structure of iron, which suggests perhaps two separate cooling events in Earth’s history.

Stephenson added:

The details of this big event are still a bit of a mystery, but we’ve added another piece of the puzzle when it comes to our knowledge of the Earths’ inner core.

The scientist explained for Salon.com that the study confirms the existence of a change at 650 km in the Earth’s inner core. While it’s extremely difficult to know for sure what dwells inside our planet’s core, the study’s results hint at the possible change from one form of iron to another inside the inner core. The possible cause could be some dramatic event that might have happened long ago when our Earth started to cool down. Until about 4 billion years ago, our planet was like a living Hell covered in lava.


Even since he was a child, Cristian was staring curiously at the stars, wondering about the Universe and our place in it. Today he's seeing his dream come true by writing about the latest news in astronomy. Cristian is also glad to be covering health and other science topics, having significant experience in writing about such fields.

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