Like onions and ogres, Earth has layers that are arranged in an orderly fashion and that each have unique properties

Mar 25, 2015 16:26 GMT  ·  By

The one thing all scientists with a soft spot for the anatomy of our planet agree on is that, like onions and ogres, Earth has layers. Just how many layers and what each of them looks like is still up for debate.

Last month, a team of researchers argued that, rather than being a single ball of iron, as believed for decades, our planet's inner core has an inner core of its own, i.e. Earth's so-called inner inner core.

This week, another group of scientists announced to the world that, according to evidence at hand, it might just be that our planet's mantle packs a secret, previously unknown layer.

New insights into Earth's anatomy

As shown in the image below, it's the planet's crust that supports oceans, mountains and all lifeforms. The mantle sits right under the crust. It's basically a layer of molten, pliable rock and has the crust resting on it.

Every once in a while, bits and pieces of the solid shell encompassing Earth get pushed down into the mantle. When this happens, scientists expect them to keep sinking at a steady pace until they are finally destroyed and vanish.

The thing is that, for reasons still unknown, many of them stop and hang around at a depth of about 930 miles (approximately 1,500 kilometers) below the surface for the Earth for a while before continuing their descent.

Writing in the journal Nature Geoscience, researchers with the University of Utah in the US argue that this behavior is mostly likely due to the presence of a secret layer in the planet's mantle that acts as a bumper of sorts.

What's so special about this layer?

In a series of laboratory experiments, the scientists showed that, when exposed to conditions like the ones documented 930 miles below the planet's surface, perfectly average rocks become about 300 times stiffer and stronger.

This indicates that the depth at which most slabs of rock stop for a while in the mantle before continuing their journey might be home to a layer of insanely strong rocks keeping them from passing through.

“Most layers are defined by the minerals that are present. This layer isn’t defined by the minerals present, but by the strength of these minerals,” researcher Lowell Miyagi said in a statement.

Interestingly enough, the scientists say that the existence of this stiff layer inside Earth's mantle hints that the planet's core is hotter than estimated and might also explain why different volcanoes produce distinct magma.

Image details Earth's anatomy
Image details Earth's anatomy

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Earth argued to pack a secret layer in its mantle
Image details Earth's anatomy
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