In space, no one hears you screaming because sound cannot propagate in a vacuum. But if we convert electromagnetic activity into sound, it suddenly becomes very noisy. And our Earth is no exception; in particular, in and around the magnetic field created by the molten core of the Earth.
This barrier, called the magnetosphere, is considered one of the vital components for a life-supporting planet that protects us from the sharp radiation of the solar wind. And the stronger the wind, the louder the magnetosphere sings.
Like charged particles from the flow of the solar wind to the magnetosphere, some are reflected from the shock region in front of the magnetic field back to the Sun. This “burst” then interacts with the solar wind, which is still flowing, creating instability in the plasma and leading to magnetoacoustic waves.
Scientists on Earth then translate these magnetoacoustic waves into sound – strange tweets and whistles – to understand the dynamics of the interactions between the solar wind and the magnetosphere.
Now for the first time the song of the Earth and the Sun was recorded during a solar storm, when the solar wind blows in the wildest and most ferocious form into space.
Four spacecraft in low Earth orbit, known collectively as the Cluster Mission, conducted by the European Space Agency, took six solar storms from foreshock, a region upstream of the Earth's bend, where the solar wind first hit the Earth's magnetosphere.
The audio files of these electromagnetic waves show that the waves in the magnetosphere created by the solar storm are much more complex than previously thought.
“Our research showed that solar storms radically change the foreshock region,” says physicist Lucille Turk of the University of Helsinki in Finland, who leads an international team of researchers. "Like a storm changing foreshock settings."
As you will hear in the video below, the magnetosphere is never calm. Particles and radiation always come from the sun, which creates a certain level of calm sunny weather, chirping.
During a solar storm – when a large-scale magnetic eruption occurs on the surface of the Sun, sending charged particles flying into space (and, if it hits the Earth, often producing really pretty auroras), everything becomes much more dramatic.
In normal calm weather, the magnetosphere produces low-frequency waves in which one frequency prevails. During a solar storm, the pressure of the solar wind pushing the frequency of the waves becomes much higher. In addition, a number of these high-frequency waves are superimposed on a complex network, and not on one dominant frequency.
“We always expected a change in frequency, but not a level of complexity in the wave,” Turk said.
A nose strike between the magnetosphere and foreshock is an additional barrier between the waves and the Earth, but we know that the waves do not bounce back to the Sun – there is too much pressure from the solar wind.
Rather, these foreshock changes propagate all the way to the Earth’s surface in a matter of minutes; or they can cause fast jets in the magnetic shell, which cause geomagnetic disturbances, which, in turn, can affect communication and navigation equipment and electrical systems.
Turk and her team are now trying to understand how these complex wave superpositions are generated.
The study was published in Geophysical Survey Letters,