The Center of Our Planet Earth Has Patchy, Variable Weather
We all know about the weather on our planet, but what about weather that occurs in the center of the Earth? Scientists have found that the temperature 3,000 kilometers below the surface of Earth is much more varied than previously thought.
"Where the mantle meets the core is a more dramatic boundary than the surface of Earth," said Hrvoje Tkalcic, one of the researchers, in a news release. "The contrast between the solid mantle and the liquid core is greater than the contrast between the ground and the air. The core is like a planet within a planet. The cneter of Earth is harder to study than the center of the sun."
Temperatures in the lower mantle reach around 3,000 to 3,500 degrees Celsius and the barometer reads about 125 gigapascels, which is about one and a quarter million times atmospheric pressure. Variations in these temperatures, though, affect the speed at which travel through Earth.
In this latest study, the researchers examined more than 4,000 seismometers' measurements of earthquakes from around the world. Then, the scientists ran a complex mathematical process to unravel the data and build the most detailed global map of the lower mantle, showing features ranging from as large as the entire hemisphere down to 400 kilometers across.
So what did they find? The map revealed the seismic speeds varied more than expected over these distances. These differences were probably driven by heat transfer across the core-mantle boundary and radioactivity.
"These images will help us understand how convection connects Earth's surface with the bottom of hte mantle," said Tkalcic. "These thermal variations also have profound implications for the geodynamo in the core, which creates Earth's magnetic field."
The findings are published in the journal Scientific Reports.
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