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Sudden ice loss in Antarctica affecting Earth’s gravitational field

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By NewsGram Staff Writer

In a recent research, a team of scientists have published that Antarctica is experiencing a sudden increase in ice loss which is causing small changes in the gravitational field of the Earth. Since 2009, multiple glaciers along a vast coastal expanse have disappeared in the ocean.

“To date, the glaciers added roughly 300 cubic km of water to the ocean. That’s the equivalent of the volume of nearly 350,000 Empire State buildings combined,” a lead study author Bert Wouters at the University of Bristol said.

“The fact that so many glaciers in such a large region suddenly started to lose ice came as a surprise to us. It shows a very fast response of the ice sheet: in just a few years the dynamic regime completely shifted”, added Bert.

The changes were detected by the CryoSat-2 satellite, operated by the European Space Agency.

The ice loss in the region is so large that it is causing small changes in the gravity field of the Earth. Such a change can be detected by another satellite mission, the Gravity Recovery and Climate Experiment (GRACE).

In the last two decades, the ice shelves in the region have lost almost one-fifth of their thickness, thereby reducing the resisting force on the glaciers.

“To pinpoint the cause of the changes, more data need to be collected. A detailed knowledge of the geometry of the local ice shelves, the ocean floor topography, ice sheet thickness and glacier flow speeds are crucial to tell how much longer the thinning will continue,” Wouters concluded.

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Earth’s Mantle May Have Generated its Early Magnetic Field: Research

Magnetic fields form on Earth and other planets that have liquid, metallic cores, rotate rapidly, and experience conditions that make the convection of heat possible

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In a study appearing in the journal Earth and Planetary Science Letters, Scripps Oceanography researchers Dave Stegman, Leah Ziegler and Nicolas Blanc provide new estimates for the thermodynamics of magnetic field generation within the liquid portion of the early Earth's mantle. Pixabay

Where did our planet’s magnetic field come from? According to new research, Earth’s mantle, not its core, may have generated planet’s early magnetic field.

The Earth’s mantle is made of silicate material that is normally a very poor electrical conductor.

Therefore, even if the lowermost mantle were liquid for billions of years, rapid fluid motions inside it wouldn’t produce large electrical currents needed for magnetic field generation, similar to how Earth’s dynamo currently works in the core.

In a study appearing in the journal Earth and Planetary Science Letters, Scripps Oceanography researchers Dave Stegman, Leah Ziegler and Nicolas Blanc provide new estimates for the thermodynamics of magnetic field generation within the liquid portion of the early Earth’s mantle.

Stegman’s team asserted the liquid silicate might actually be more electrically conductive than what was generally believed. “Currently we have no grand unifying theory for how Earth has evolved thermally,” Stegman said.

“We don’t have this conceptual framework for understanding the planet’s evolution. This is one viable hypothesis.” New research lends credence to an unorthodox retelling of the story of early Earth first proposed by a geophysicist at Scripps Institution of Oceanography at University of California San Diego.

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The Earth’s mantle is made of silicate material that is normally a very poor electrical conductor. Pixabay

It has been a bedrock tenet of geophysics that Earth’s liquid outer core has always been the source of the dynamo that generates its magnetic field. In another paper, Arizona State geophysicist Joseph O’Rourke applied Stegman’s concept to consider whether it’s possible that Venus might have at one point generated a magnetic field within a molten mantle.

Magnetic fields form on Earth and other planets that have liquid, metallic cores, rotate rapidly, and experience conditions that make the convection of heat possible.

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If Stegman’s premise is correct, it would mean the mantle could have provided the young planet’s first magnetic shield against cosmic radiation. It could also underpin studies of how tectonics evolved on the planet later in history.

“If the magnetic field was generated in the molten lower mantle above the core, then Earth had protection from the very beginning and that might have made life on Earth possible sooner,” Stegman said. (IANS)