Despite being essential to life on Earth, the magnetic field isn’t something we can actually see in itself, or ever hear. But, remarkably, scientists at the Technical University of Denmark have taken magnetic signals measured by ESA’s Swarm satellite mission and converted them into sound – and for something that protects us, the result is pretty scary.
Earth’s magnetic field is a complex and
dynamic bubble that keeps us safe from cosmic radiation and charged particles
carried by powerful winds flowing from the Sun. When these particles collide
with atoms and molecules – mainly oxygen and nitrogen – in the upper
atmosphere, some of the energy in the collisions is transformed into the
green-blue light that is typical of the aurora borealis, which can sometimes be
seen from high-northern latitudes.
While the aurora borealis offers a
visual display of charged particles from the Sun interacting with Earth’s
magnetic field, actually being able to hear the magnetic field generated by
Earth or its interaction with solar winds is another matter.
Our magnetic field is largely generated
by an ocean of superheated, swirling liquid iron that makes up the outer core
around 3000 km beneath our feet. Acting as a spinning conductor in a bicycle
dynamo, it creates electrical currents, which in turn, generate our
continuously changing electromagnetic field.
Launched in 2013, ESA’s trio of Swarm
satellites are being used to understand exactly how our magnetic field is
generated by measuring precisely the magnetic signals that stem not only from
Earth’s core, but also from the mantle, crust and oceans, as well as from the
ionosphere and magnetosphere. Swarm is also leading to new insights into
weather in space.
Musician and project supporter Klaus
Nielsen, from the Technical University of Denmark, explains, “The team used
data from ESA’s Swarm satellites, as well as other sources, and used these
magnetic signals to manipulate and control a sonic representation of the core
field. The project has certainly been a rewarding exercise in bringing art and
science together.”
It might sound like the stuff of
nightmares, but, remarkably, this audio clip represents the magnetic field
generated by Earth’s core and its interaction with a solar storm.
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