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Sun. Jan 26th, 2020

Deep inside the Earth, iron ‘snow’ is falling year-round

 

A team of international researchers at the University of Texas at Austin is suggesting that deep down under the ground beneath us right now; there is a surreal, incredibly hot snowglobe of sorts, only the snow if made of iron. The findings confirm a similar idea from a Russian geologist, Stanislav Iosifovich Braginskii, from the early 1960s.

According to UT News:

“The snow is made of tiny particles of iron – much heavier than any snowflake on Earth’s surface – that fall from the molten outer core and pile on top of the inner core, creating piles up to 200 miles thick that cover the inner core.
The image may sound like an alien winter wonderland. But the scientists who led the research said it is akin to how rocks form inside volcanoes.”

The scientists studied signals from seismic waves passing through the Earth and found aberrations as the waves passed through the base of the outer core. They believe the waves slow down as they pass through a slurry-like layer.

In addition, the waves move faster in the eastern hemisphere, suggesting the core is asymmetrical, or not perfectly round.

From the University of Texas at Austin website:

“The slurry-like composition slows the seismic waves. The variation in snow pile size – thinner in the eastern hemisphere and thicker in the western – explains the change in speed.”

When Braginskii proposed there was a slurry later between the inner and outer core back in the 60s, it was dismissed since, at the time, scientists believed the intense pressure and heat in the core ruled out the possibility of crystallization. Newer research has shown that Braginskii’s idea is possible.

Researcher, Nick Dygert, an assistant professor at the University of Tennesse, remarked at the team’s findings:

“It’s sort of a bizarre thing to think about,” Dygert said. “You have crystals within the outer core snowing down onto the inner core over a distance of several hundred kilometers.”

Now it is believed that the inner core grows as the iron snowfall accumulates upon it, shrinking the outer core. The researchers compared the process to what happens inside magma chambers near the surface of the planet, where minerals crystallize and form “cumulate rocks.”

snow_core-01-768x576.jpg
“A simplified graphic of the inner Earth as described by the new research. The white and black layers represent a slurry layer containing iron crystals. The iron crystals form in the slurry layer of the outer core (white). These crystals ‘snow’ down to the inner core, where they accumulate and compact into a layer on top of it (black). The compacted layer is thicker on the western hemisphere of the inner core (W) than on the eastern hemisphere (E).” Image and caption via University of Texas at Austin

This latest research builds on the 1906 work of British geologist Richard Dixon Oldham who analyzed seismic readings from an earthquake. The geologist concluded that the Earth had a dense inner core that prevented the waves from penetrating all the way.

Building on Oldham’s work in the early 1930s, Danish seismologist Inge Lehmann, who referred to herself as “the only Danish seismologist,” studied waves recorded from around the world. (see more in the video below)

When she studied waves from an earthquake in New Zealand in 1929, she concluded there was a liquid outer core surrounding the solid inner core.

From the American Museum of Natural History:

“A few P-waves, which should have been deflected by the core, were in fact, recorded at seismic stations. Lehmann theorized that these waves had traveled some distance into the core and then bounced off some kind of boundary. Her interpretation of this data was the foundation of a 1936 paper in which she theorized that Earth’s center consisted of two parts: a solid inner core surrounded by a liquid outer core, separated by what has come to be called the Lehmann Discontinuity. Lehmann’s hypothesis was confirmed in 1970 when more sensitive seismographs detected waves deflecting off this solid core.”

Today, we know the core is solid iron, created by pressures from gravity three million times the gravity on the surface. The hot churching mass of the inner core generates electric currents, which in turn create the magnetic field surrounding the planet.

Without that magnetic field, life as we know it would not exist since cosmic radiation would bombard the surface constantly. So the molten core with what could be iron snowfall is critical for all life.

You might say it’s always snowing in hell.

More from the Science Channel:


Featured image: Snowflakes via Pixabay

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