Iron 'jet stream' detected in Earth's outer core

[nitpicker]

http://www.bbc.com/news/science-environment-38372342

Iron 'jet stream' detected in Earth's outer core

By Jonathan Amos
BBC Science Correspondent, San Francisco

19 December 2016

From the section Science & Environment

Scientists say they have identified a remarkable new feature in Earth’s molten outer core. They describe it as a kind of "jet stream" - a fast-flowing river of liquid iron that is surging westwards under Alaska and Siberia. The moving mass of metal has been inferred from measurements made by Europe’s Swarm satellites. This trio of spacecraft are currently mapping Earth's magnetic field to try to understand its fundamental workings.

The scientists say the jet is the best explanation for the patches of concentrated field strength that the satellites observe in the northern hemisphere. "This jet of liquid iron is moving at about fifty kilometres per year," explained Dr Chris Finlay from the National Space Institute at the Technical University of Denmark (DTU Space). “That might not sound like a lot to you on Earth's surface, but you have to remember this a very dense liquid metal and it takes a huge amount of energy to move this thing around and that's probably the fastest motion we have anywhere within the solid Earth,” he told BBC News. Dr Finlay was speaking here at the American Geophysical Union (AGU) meeting in San Francisco, just ahead of the official publication of the research in the journal Nature Geoscience.

Most people will be familiar with the atmospheric jet stream - the high-altitude, rapidly flowing belt of air on which aeroplanes ride to get to their destination more quickly. Dr Finlay and colleagues want us to envision something similar but made of metal and 3,000km down, under our feet. They assess the jet to be about 420km wide, and say it wraps half-way around the planet. Its behaviour will be critical to the generation and maintenance of the global magnetic field, they add. “It's likely that the jet stream has been in play for hundreds of millions of years," said Dr Phil Livermore from Leeds University, UK, and the lead author on the journal paper.
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