Scientists believe they have identified a groundbreaking new feature deep in the Earth’s molten core.

A new study, published in the journal Nature Geoscience, details evidence of a “jet stream” of liquid iron flowing westwards under Alaska and Siberia, 3,000 km below the Earth’s surface.

The discovery came from measurements made by Europe’s Swarm satellites, which map the Earth’s magnetic field to better understand its workings.

According to scientists, the stream is moving at about 50km per year.

“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,” one of the paper’s authors Dr Chris Finlay from the National Space Institute at the Technical University of Denmark (DTU Space) told BBC News.

The molten iron flow is in some ways similar to the atmospheric jet stream - the high-altitude, belt of air that allows aircrafts to travel more quickly to their destinations.

Scientists believe the jet to be roughly 420km wide.

“It's likely that the jet stream has been in play for hundreds of millions of years," said the paper’s lead author Dr Phil Livermore from Leeds University.

Scientists believe the stream was created due to its proximity to two different boundary regions in the Earth’s core.

When the molten liquid approaches the boundary from both sides, it gets propelled out to form a jet stream.

"Of course, you need a force to move fluid towards the tangent cylinder," said Professor Rainer Hollerbach, also from Leeds and another co-author on the paper.

"This could be provided by buoyancy, or perhaps more likely from changes in the magnetic field within the core."

Scientists are not yet sure of the depth of the flow.