A fast-flowing molten iron river was discovered under Alaskan and Siberian soil, revealing interesting data about Earth’s core and its magnetic field. The large jet stream is about 1,864 miles (3,000 kilometers) below the surface, and it is more than 260 miles (420 kilometers) wide.
Scientists discovered the hot river using information from the European Space Agency’s (ESA) trio of satellites called Swarm. The analyzed data shows that the jet stream has tripled in speed since 2000 and reaches high temperatures that keep metals in a liquid state.
The river is currently circulating westwards at between 40 and 45 kilometers per year deep under Siberia, and it is heading to Europe beneath Earth’s surface.
‘We know more about the Sun than Earth’s core’
Chris Finlay from the Technical University of Denmark and part of the team that found the molten iron river stated that there is little information about Earth’s core compared to information about the Sun. Thus, the discovery of an accelerating jet stream beneath Russia and Canada is crucial data to understand better how our planet’s core functions.
Phil Livermore of the University of Leeds, UK, also the leader of the team, said that the the jet stream has not been seen until now, despite the researchers have been studying the liquid core under the surface and its movements for years.
The ESA Swarm satellites were crucial to discover the jet stream. They were launched in 2013 to study Earth’s magnetic field variations. The three satellites can measure magnetic changes as deep down as 3000 kilometers below Earth’s surface.
Livermore explained that having the trio of satellites allowed the team to rule out fields from elsewhere such as the ionosphere and the crust, providing high-resolution observations of the fluctuations at the core-mantle boundary alone. The data was used in models to predict how the variations in Earth’s magnetic fields will behave in the future.
ESA Swarm satellites function as an X-ray machine that for the first time revealed the accelerated molten iron river and why it is there.
The new jet stream and its importance to understanding Earth’s magnetic field
Earth’s core itself is a solid lump smaller than the Moon. It is mainly composed of iron with a temperature of around 9,800 degrees Fahrenheit (5,400 degrees Celsius) -almost as hot as the surface of the Sun which reaches 9,941 degrees Fahrenheit (5,505 degrees Celsius).
Surrounding the core is Earth’s outer core: a 1,242-mile-thick (2,000 kilometer) layer made of liquid nickel and iron. Differences in temperature, composition, and pressure in this layer create movements and whirlpools in the liquid metal. Those phenomena combined with Earth’s spin, generate electric currents which produce magnetic fields.
Scientists were tracking two massive but unusually strong lobes of magnetic flux when they found the jet stream. The two lobes were originating from the core-mantle boundary, located beneath Canada and Siberia respectively. Magnetic lobes motion can only originate from the physical movement of molten iron. Thus, researchers used them as markers to discover the iron river.
Livermore explains that as the iron jet moves, it drags the magnetic field with it. He said that the team cannot see the flow of iron itself but the motion of the flux lobes. Those lobes were the phenomena that Swarm satellites detected and tracked, leading them to the molten iron river.
Livermore added that the jet could have a southern counterpart, but the absence of flux lobes in the region makes it impossible for the team to track it.
Still, the northern iron river flowing to Europe allows geophysicists to understand better how Earth’s core behaves and what influences our planet’s magnetic field. Understanding how the field is generated will reveal how it will behave over time. Scientists would know when the magnetic field will weaken and reverse if they understand how it functions.
Other studies showed that Earth’s magnetic field has been weakening at about five percent per century, especially since the 1800s. The recently discovered jet stream is essential to predict when the north and south magnetic fields will trade place, a normal phenomenon that happens every thousand years.
“The more we understand the core’s behavior at various time and spatial scales, the more we can hope to understand the beginnings, renewal, and future of our magnetic field,” says William Brown of the British Geological Survey’s geomagnetism team.
The jet stream rapid flow is a mystery
Scientists failed to explain why the molten iron river is moving faster. They say it could be related to the rotation of the inner core, which rotates faster than Earth’s crust. Livermore said that the acceleration could be due to the magnetic field, a complex theory since the flow of the river generates the magnetic field.
The hot iron river is moving at about 50 kilometers per year. It might not appear a surprising speed, but people has to consider that the jet stream is a thick liquid metal that needs high amounts of energy to move around. Finlay told the BBC News that the new jet stream is probably the fastest motion within the solid Earth.
Source: New Scientist