Jet Stream Found in Earth’s Molten Outer Core
The Earth’s core, which lies nearly 3,000 kilometers below the surface, is made of two layers.
At the very center of the Earth is the inner core, which scientists say is a solid sphere made of an iron-nickel alloy. Surrounding the inner core is the outer core of which is made of molten iron and nickel that’s believed to be between 4000-5000º Celsius.
New data gathered by the European Space Agency’s three satellite Swarm network is providing scientists with an x-ray view of the Earth’s core.
This information has led to the discovery of a jet stream flowing within the molten outer core.
Like the jet stream of air currents in the atmosphere, scientists explain that this jet stream in the outer core is a moving belt of molten material circling its magnetic North Pole and is traveling at a speed of about 40 kilometers per year.
Researchers who made the discovery say this jet stream lines-up with a boundary between two regions within the core.
From Nature GeoScience:
An accelerating high-latitude jet in Earth’s core
Observations of the change in Earth’s magnetic field—the secular variation—provide information about the motion of liquid metal within the core that is responsible for the magnetic field’s generation. High-resolution observations from the European Space Agency’s Swarm satellite mission show intense field change at high latitude, localized in a distinctive circular daisy-chain configuration centred on the north geographic pole. Here we show that this feature can be explained by a localized, non-axisymmetric, westward jet of 420 km width on the tangent cylinder, the cylinder of fluid within the core that is aligned with the rotation axis and tangent to the solid inner core. We find that the jet has increased in magnitude by a factor of three over the period 2000–2016 to about 40 km yr−1, and is now much stronger than typical large-scale flows inferred for the core. We suggest that the current accelerating phase may be part of a longer-term fluctuation of the jet causing both eastward and westward movement of magnetic features over historical periods, and may contribute to recent changes in torsional-wave activity and the rotation direction of the inner core.