From a distance, our star, the Sun, looks like a calm, glowing yellow ball,
but in reality, it is an extremely violent sphere of unimaginably hot plasma.
Deep inside, at its core, the light and warmth we experience each day is created during a
fierce process called nuclear fusion. At the surface, which is the first visible layer called
the photosphere, matter rises and bubbles like a boiling hot cauldron. And Emanating from the Sun
is also a strange wind, but not like a soft whistle, instead like a hurricane's
scream. It is this intense wind, called the solar wind, that we are about to listen to.
The solar wind is matter in the form of a plasma, which is basically superheated electrically
charged gas, being blown out from the Sun in all directions across the solar system.
This stream of highly charged material is coming out of the Sun all the time,
at about a million tonnes per second. It travels through the solar system,
interacting with anything that gets in its way, such as other planets. We can see it
interacting with Earth in the form of magnificent aurora above the polar regions, for example.
But seeing the solar wind in our northern and southern skies isn't the only way we can
experience this powerful solar phenomenon because thanks to the Parker solar probe,
which is exploring the Sun like never before, we can hear it as well.
The audio clips you are about to listen to is not "sound" in the way that we hear it here on Earth
because, in space, there isn't much of a medium for sound waves to travel through.
But the data captured by the Parker solar probe does share some similarities with sound on Earth.
The Parker Solar Probe measures pressure waves in the particles that make up the solar wind, and In
our daily lives, we hear pressure waves as sound. So by measuring the frequencies and amplitudes of
these pressure waves in the solar wind, scientists can turn the data into audio clips that we
can listen to. The whooshing and whistling noises you are about to hear are the pressure waves from
the hot, electrically charged plasma that is radiating out of the Sun's wispy outer layers.
Out of the six audio clips we are about to hear, the first
two are the most bizarre, in my opinion. So let's listen to each clip, and afterwards,
I will provide a bit more information about what we are hearing before moving on to the next one.
These almost unsettling audio recordings are called whistler mode waves and
are very low-frequency pressure waves that are caused by energetic electrons
bursting out of the Sun's corona, the outermost part of the Sun's atmosphere.
The electrons follow magnetic field lines that stretch away from the Sun out into
the solar system's farthest edge, spinning around them like they're riding a carousel.
When a plasma wave's frequency matches how frequently those electrons spin,
they amplify one another. And to us, it sounds like a chaotic roaring or a screaming hurricane.
The following audio clip is a lot less unsettling but still just as alien.
This audio recording was created from a Langmuir wave. Which is similar to whistler
waves but are instead very high-frequency pressure waves that, when translated into
sound, make an almost ethereal, high-pitched wailing. Next, we will hear two clips,
each containing strange chirps and squeaks.
These peculiar chirping sounds come from dispersive waves,
which quickly shift from one frequency to another as they move through the solar wind.
These shifts create a sort of "chirp" that sounds like wind rushing over a microphone.
According to scientists, they're rare near the Earth,
so researchers believed they were unimportant.
But closer to the Sun, they discovered these waves are everywhere, and nobody knows what causes them.
Last but still just as fascinating, we have an audio recording different from the other five
we have listened to so far because this one isn't the sound of hot plasma waves
but instead microscopic dust colliding with the probe's sensitive instruments.
Resembling old tv static, what you are actually hearing in this audio recording is hundreds of
microscopic impacts. Dust from asteroids and comets that have been torn apart by the Sun's
immense gravity and heat collide with the spacecraft at speeds close to half a million
kilometres an hour, which is more than a quarter of a million miles an hour. Each collision you are
hearing is actually dust bursting apart and chipping away a tiny bit of the spacecraft.
By listening to plasma waves, like those we have heard in this video,
scientists can attempt to unravel some of the Sun's greatest mysteries. Such as why is the Sun's
corona so much hotter than its surface, and how do the particles in the solar wind have so much
energy. But for us, the viewers who are not working on solving these captivating mysteries,
listening to the bizarre sounds of our closest star is nothing short of incredible.
I hope you enjoyed this video. If you did tap the like button,
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miss an upload. If you want to find out more about space, then why not
check out one of these videos? Thank you all so much for watching, and I'll see you next time.