The European Space Agency recently obtained one of the clearest "x-ray" views inside the Earth using new data from Swarm, a series of satellites launched in 2013, and what they found was remarkable: a large jet stream of molten iron flowing under our planet's surface, much like the jet streams of air in the atmosphere.
The blistering hot jet stream of molten iron flows westward in a circular daisy chain pattern about 260 miles wide that sits under the geographic north pole—below Alaska and Siberia. It's flowing at a fast pace, too—geologically speaking that is—at about 25 miles per year. That is hundreds of thousands of times faster than the speed at which the tectonic plates at the crust move.
The Earth is like an onion—a ball of rock, molten lava, and metal that a cosmic giant could peel apart in layers, if it so desired. Our planetary onion is made up of four main layers: the crust, which you're standing on right this moment; the mantle, a rocky silicate layer 1,800 miles thick that makes up 84 percent of Earth's volume; the outer core, a fast spinning layer of molten iron and nickel where the jet stream was found; the inner core, a giant musket ball of iron that is the same temperature as the surface of the sun.
No one has ever seen the core before, but scientists have been able to deduce its presence and makeup by studying the globe's magnetic field, which it creates by spinning at a faster rate than the Earth itself.
Thanks to Swarm, the ESA satellites that orbit poles at various levels and decipher all of the magnetic signals picked up from the Earth's innards, scientists were able to compile information into the "x-ray" picture of the core that revealed the presence of the lava jet stream for the first time.
"The European Space Agency's Swarm satellites are providing our sharpest x-ray image yet of the core," said lead scientist Phil Livermore of the University of Leeds in England in a statement. "We've not only seen this jet stream clearly for the first time, but we understand why it's there," he said.
Scientists think the jet stream has to do with liquid in the outer core being squeezed within the core's boundary layers. The more we learn about the jet stream's larger role in the manipulation of the earth's magnetic sphere, however, the more we'll learn about how our planet operates.
"We know more about the Sun than the Earth's core," said co-author Chris Finlay, of the Technical University of Denmark in a public statement. "The discovery of this jet is an exciting step in learning more about our planet's inner workings."
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