We don't hear it, but there's a place deep beneath the earth's surface that is constantly moving - from plate tectonics to convection currents - long been studied and documented by scientists. However, there are also other "more elusive and dynamic" processes occurring deep down below our feet.
Experts recently recorded a never-before-seen discovery inside the Earth's core: a giant magnetic wave sweeping around the surface of our planet's core every seven years, ScienceAlert reports.
This new type of magnetic wave is said to provide insight and clues of our planet's magnetic field, thermal history, and evolution, including the cooling of the Earth's beating heart - the molten interior.
WIGAN, ENGLAND - NOVEMBER 23: A drone flies past Luke Jerram's 'Floating Earth' at Pennington Flash on November 23, 2021 in Wigan, England. The floating Earth will hover over Pennington Flash for 10 days from November 19, as part of a celebration of Wigan and Leigh's watercourses and is the first time one of Jerram's globes has been floated on an open expanse of water.
While the existence of such waves remained only in theory for a long time, geophysicists thought they took place over much longer time scales than what research shows.
However, "measurements of the magnetic field from instruments based on the surface of Earth suggested that there was some kind of wave action," says geophysicist Nicolas Gillet of the Université Grenoble Alpes in France in the European Space Agency.
He adds that they needed the global coverage offered by measurements from space to reveal what is actually going on.
Swarm Mission Reveals a Fascinating Discovery
Using satellite measurements from Swarm which comprises three identical satellites, along with earlier German Champ mission, Danish Ørsted mission, and a computer model of the geodynamo, the researchers were able to assess the given ground-based data.
To date, the Earth's invisible structure that is the magnetic field served as a protective 'bubble' around our planet, protecting us from harmful radiation and allowing life to thrive. However, the magnetic field isn't static, it fluctuates constantly in strength, size, and shape - a process not fully understood.
The trio of Swarm satellites have been helping scientists analyze data and gather new insights into many of Earth's natural processes, including space weather. Upon thorough examination, scientists conclude that measuring the Earth's magnetic field from space is "the only real way of probing deep down to Earth's core."
Also read: Astronauts in their First Long-duration Space Missions Show Changes in Their Brains
Fascinating New Waves
The researchers studied data from other ground- and space-based observatories collected between 1999 and 2021 and found a pattern of waves known as magneto-Coriolis.
These waves are "huge magnetic columns aligned along Earth's rotational axis, strongest at the equator," sweeping 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, scientists reported.
This finding suggests that magneto-Coriolis waves might exist with different oscillation periods which have not been detected before due to lack of data. Given that the Earth's core is a difficult field to study, the newly-discovered waves help probe the interior of our planet in new ways.
"Magnetic waves are likely to be triggered by disturbances deep within the Earth's fluid core, possibly related to buoyancy plumes," Gillet says, noting that the study published in PNAS suggests that "other such waves are likely to exist, probably with longer periods - but their discovery relies on more research."
Related article: Shattered Commet: The Tau Herculid Meteor Shower may Appear on May 30