The Earth's Inner Core May Be A Winter Wonderland Of Iron "Snow"


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A new study asserts that the Earth's inner core is covered with a thick layer of iron "snow" (Credit: The University of Texas at Austin/Jackson School of Geosciences)

The Earth's inner core, which boasts temperatures exceeding 9,000 degrees Fahrenheit (5,000 degrees Celsius), may not evoke images of a winter wonderland. Yet, a new study by a team of scientists led by Youjun Zhang, an associate professor at Sichuan University in China, asserts that the deepest part of our planet may be covered with a 200-mile-thick layer of "snow." However, before you rush to pack your skis, be aware that the "snowflakes" are not composed of frozen water crystals, but of tiny particles of iron!

As you probably know, the Earth's structure comprises several layers. The crust is the outermost layer on which we live. Right beneath lies the mantle, a warm, semi-liquid layer of rock that is always in flux. This is followed by a thin shell of liquid iron that forms the outer core. Finally, there is a solid inner core, which mostly consists of iron and is responsible for our planet's magnetic field.

Since collecting samples from the core is impossible, scientists study the area by analyzing signals from seismic waves as they pass through the Earth's structure. The waves of energy, which are caused by earthquakes, travel at distinct speeds as they traverse through the different materials, allowing researchers to determine the density and the composition of the various layers.

A better understanding of the Earth's inner core will provide valuable insights into phenomena that affect the entire planet (Credit: Derivative work: SrimadhavEarth cutaway schematic-en.png: USGS /Public domain)

Zhang and his colleagues were monitoring recent seismic wave data when they noticed a series of anomalies. The energy waves were moving slower than expected through the bottom of the outer core and faster than expected through the eastern hemisphere of the top inner core. This information, along with other experiments conducted to mimic the Earth's core, led the team to propose that the irregular speeds could be the result of a snowbank located in the inner core.

According to the scientists, the "snow" is caused by the crystallization of the molten iron at the base of the outer core. As the "snowflakes" sink, they settle atop the solid inner core, creating a layer thick enough to slow down the seismic waves at the base of the outer core. Similarly, the variation in snow pile size — lighter in the eastern hemisphere and more substantial in the western hemisphere — explains the more rapid pace of the seismic waves through the top inner core.

"It's sort of a bizarre thing to think about," study co-author Nick Dygert of the University of Tennessee said. "You have crystals within the outer core snowing down onto the inner core over a distance of several hundred kilometers."

Minerals from the melting magma rise and crystallize before cooling inside the magma chamber to become cumulate rocks (Credit: Woudloper /CC BY-SA -3.0 /

The researchers, who published their study in the journal JGR Solid Earth on December 23, 2019, compare the process to what happens inside magma chambers closer to the Earth’s surface. In this case, the minerals that solidify from the melting magma accumulate inside the magma chambers and compact, creating what are known as "cumulate rocks."

From forming a protective magnetic field around Earth that deflects solar winds to driving tectonic activity, the inner core plays a significant role in phenomena that affect the entire planet. Hence, understanding more about its composition and behavior is crucial for scientists to better understand how these larger processes work.


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  • lingyaofma
    lingyaofmaFriday, February 7, 2020 at 10:18 am
    It's snowing there, in the center of the Earth, which is really hot... And yet it still can't snow in Virginia. Which is really cold.
    • anonymous213409
      anonymous213409Monday, February 10, 2020 at 8:44 am
      Dude it can not be cold when the core is hot.
    • coolman155123
      coolman155123Thursday, February 6, 2020 at 11:59 am
      i want to go play in the snow in the middle of the earth it is so fun and hot why so hot thx m&m
      • boltblast
        boltblastMonday, February 3, 2020 at 8:31 am
        so cool
        • little_angel727
          little_angel727Saturday, February 1, 2020 at 8:09 pm
          Boiling hot&Freezing cold = NOT a best place for humans...
          • seanster
            seansterFriday, January 31, 2020 at 3:57 pm
            • cekuniwe-157667470716
              cekuniwe-157667470716Friday, January 31, 2020 at 8:20 am
              this is funny:)
              • awesomelm
                awesomelmThursday, January 30, 2020 at 1:43 pm
                so cooooooooooool
              • burnstar
                burnstarThursday, January 30, 2020 at 1:34 pm
                • lingyaofma
                  lingyaofmaFriday, February 7, 2020 at 10:19 am
                  Yeah, it's cool and all but what about why we exist?
                • hermantheworm
                  hermanthewormTuesday, January 28, 2020 at 4:32 pm
                  I love this article for its coolness!!!
                  • galaxygirl434
                    galaxygirl434Monday, January 27, 2020 at 3:37 pm
                    i love it when people discover something new about the earth or space