London, Dec 20 (IANS) Using the latest satellite data that helps create an 'x-ray' view of the planet, scientists discovered a jet stream within the Earth's molten iron core.

"The European Space Agency's Swarm satellites are providing our sharpest x-ray image yet of the core. We've not only seen this jet stream clearly for the first time, but we understand why it's there," said lead researcher Phil Livermore from the University of Leeds in Britain.

"We can explain it as an accelerating band of molten iron circling the North Pole, like the jet stream in the atmosphere," Livermore said.

Because of the core's remote location under 3,000 kilometres of rock, for many years scientists have studied the Earth's core by measuring the planet's magnetic field - one of the few options available.

Previous research had found that changes in the magnetic field indicated that iron in the outer core was moving faster in the northern hemisphere, mostly under Alaska and Siberia.

But new data from the Swarm satellites revealed these changes are actually caused by a jet stream moving at more than 40 kilometres per year.

This is three times faster than typical outer core speeds and hundreds of thousands of times faster than the speed at which the Earth's tectonic plates move.

The European Space Agency's Swarm mission features a trio of satellites which simultaneously measure and untangle the different magnetic signals which stem from the Earth's core, mantle, crust, oceans, ionosphere and magnetosphere. 

They have provided the clearest information yet about the magnetic field created in the core, according to the scientists.

The study, published in the journal Nature Geoscience, found the position of the jet stream aligns with a boundary between two different regions in the core. 

The jet is likely to be caused by liquid in the core moving towards this boundary from both sides, which is squeezed out sideways.

"This feature is one of the first deep-Earth discoveries made possible by Swarm. With the unprecedented resolution now possible, it's a very exciting time - we simply don't know what we'll discover next about our planet," Rune Floberghagen, ESA's Swarm mission manager, said.