Privileged Planet: giant internal magnetic waves found (Introduction)

by David Turell @, Wednesday, May 25, 2022, 13:52 (36 days ago) @ David Turell

Another part of our magnetic protective shield:

https://www.sciencealert.com/giant-magnetic-waves-have-been-discovered-oscillating-arou...

"scientists studying satellite data of Earth have identified something inside Earth we've never seen before: a new type of magnetic wave that sweeps around the surface of our planet's core, every seven years.

"This discovery could offer insight into how Earth's magnetic field is generated, and provide clues of our planet's thermal history and evolution – that is, the gradual cooling of the planetary interior.

***

"'We combined satellite measurements from Swarm, and also from the earlier German Champ mission and Danish Ørsted mission, with a computer model of the geodynamo to explain what the ground-based data had thrown up – and this led to our discovery."

"Earth's magnetic field is the subject of much fascination for scientists. Research to date suggests that the invisible structure forms a protective 'bubble' around our planet, keeping harmful radiation out and the atmosphere in, thus allowing life to thrive.

"But the magnetic field isn't static. It fluctuates in strength, size, and shape, has features we don't understand, and is gradually weakening over time.

"The reason that activity inside our planet is important is because that's where the magnetic field comes from. It's generated by a dynamo – a rotating, convecting, and electrically conducting fluid that converts kinetic energy into magnetic energy, spinning a magnetic field out into space around the planet.

"That fluid is (mostly) the molten iron inside Earth's outer core.

***

"These waves, known as magneto-Coriolis waves, are huge magnetic columns aligned along Earth's rotational axis, strongest at the equator.

"They sweep around the boundary between the core and the mantle with an amplitude of around 3 kilometers (1.86 miles) per year, and move westward at a rate of up to 1,500 kilometers (932 miles) per year.

"'Their existence suggests that other magneto-Coriolis waves might exist with different oscillation periods, which we are unable to detect to date, due to a lack of data.

"'Magnetic waves are likely to be triggered by disturbances deep within the Earth's fluid core, possibly related to buoyancy plumes," Gillet says.

"'Our research suggests that other such waves are likely to exist, probably with longer periods – but their discovery relies on more research.'"

Comment: the magnetic field is our important protection from nasty rays outside Earth, that would kill all life


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