The
interior of the Earth is everything from peaceful. The world is teeming with
activity deep below our surface, from plate tectonics to convection currents
that move through the heated magmatic fluids deep beneath the crust.
Scientists have discovered something inside Earth that has never before been observed through satellite data analysis: a novel kind of magnetic wave that circles the surface of our planet's core every seven years.
This finding may provide light on how Earth's magnetic field is created and reveal details on the thermal history and evolution of our planet, or the slow cooling of the planetary interior.
Geophysicists have long postulated about the
presence of such waves, but their theories assumed that they occurred over
considerably longer time scales than what has been demonstrated by
current study, according to Nicolas Gillet of the Université Grenoble Alpes in
France.
"Instruments located on the surface of
the Earth that detect the magnetic field indicated that there may be some sort
of wave movement, but we needed the worldwide coverage provided by observations
from orbit to clarify what is truly happening.
"To explain what the ground-based data
had indicated, we combined satellite measurements from Swarm with those from
the earlier German Champ mission and Danish rested mission, along with a
computer model of the geodynamo, and this led to our discovery," the authors write
For scientists, the magnetic field of the
Earth is a source of great intrigue. According to research to far, the
invisible structure creates a shielding "bubble" around our planet
that keeps dangerous radiation outside and the atmosphere within, promoting the
survival of life
However, the magnetic field is dynamic. It has
characteristics that we don't comprehend, changes in size, form, and strength through time.
.
Because the magnetic field originates inside
our globe, internal activity is significant. It is produced by a dynamo, which
is an electrically conducting fluid that rotates, convects, and
converts kinetic energy into magnetic energy by spinning a magnetic field
around the planet.
The molten iron in the Earth's outer core
makes up the majority of that fluid.
The Swarm satellites from the European Space
Agency are a trio of identical probes that were put into orbit in 2013 to
research the activity inside the Earth, with a focus on the magnetic and
dynamic activity coming out of the core. Gillet and his group found the
intriguing new waves in this data.
After that, they looked at information gathered between 1999 and 2021 by additional ground- and space-based observatories and discovered a trend.
Large magnetic columns oriented along the Earth's rotational axis, known as magneto-Coriolis waves, are strongest at the equator.
They migrate westward at a velocity of up to
1,500 kilometers (932 miles) each year and sweep around the border between the
core and the mantle with an amplitude of around 3 kilometers (1.86 miles) per
year.
Due to a lack of data, we have not been able to discover other magneto-Coriolis waves with other oscillation periods, but their existence suggests that they may exist.
"Magnetic waves are likely to be triggered by disturbances deep within the Earth's fluid core, possibly related to buoyancy plumes," claims Gillet.
Our
findings indicate that other similar waves are certainly possible, maybe with
longer periods; however, their identification requires additional study.
For
the time being, new discoveries could be utilized to investigate the interior
of our planet in novel ways, including the core, which is challenging to
research, as well as the core-mantle boundary. This is because waves carry
information about the medium through which they travel.
The team's research has been published in PNAS.
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