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If a tree falls in space, and it's frequency is modulated by multiple octaves and digitized, does it make a sound?

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Guardio is a secure browser extension  that keeps you and your information safe. You can get a seven day free trial of Guardio by clicking on the link in the description and experience a secure digital world today. [ intro ] If you’re like me, you can’t wait to see what amazing image the James Webb Space Telescope is going to release next.

They’re downright gorgeous, even though these nebulas and galaxies don’t really look like that…at  least to the human eye. Because they aren’t photographs. They’re constructs of data  gathered from invisible bands of the electromagnetic spectrum.

Some people might even say these  images aren’t real images at all. And now, scientists are  something similar with sound. You may have even heard some  space recordings yourself. like this [ SPACE AUDIO ] So that raises an important question.

Are all these space sounds actually lies? The answer is kinda complicated. Unlike light, sound waves… also known as acoustic waves… need a medium to travel through.

They’re only transmitted when there are particles close enough together to get  pushed along by their neighbor, and then push their neighbor along. Most of space is practically empty, so you don’t get sound waves  traveling between planets. But wherever there is stuff, you can have sound.

And that’s why scientists have plopped a few microphones down on  space rocks with atmospheres, like Mars [ MARS AUDIO ] and Saturn’s moon Titan. In 2021, the Chinese Zhurong  rover captured the sounds of its own deployment onto the red planet, and NASA’s Perseverance rover has  picked up the sound of Martian wind , its wheels across the ground, and even the beat of the  Ingenuity helicopter’s blades. These are all real, extraterrestrial sounds.

They just might sound a  little strange to our ears, because Mars’s atmosphere has a lower density and temperature than Earth’s does. But not every space sound is  something that humans can perceive. Typically, we can only hear sound waves that have a frequency between 20 and 20,000 hertz To visualize that, you can picture  yourself bobbing around in the ocean, with a new wave peak washing over you between 20 and 20,000 times in a single second.

Anything outside that range is still a sound wave, but it’s not something we can detect and process with our fleshy anatomy. And there are plenty of these  inaudible acoustic waves in space, typically in the form of  pressure waves that wash over us much slower than twenty times a second. So if we want to ‘hear’ them, we not only need an instrument  that can detect them.

We have to do some processing to  shift them into audible frequencies. This is similar to the way  astronomers present data from invisible parts of the  electromagnetic spectrum, like the stunning images from Webb, and many other hard-working space  telescopes with less street cred. In the sound realm, the Insight lander on Mars  is equipped with seismometers that can pick up sound-like waves from Marsquakes and atmospheric disturbances.

These are typically around 10 Hertz, well below the range of human hearing. But by shifting the pitch up a couple of octaves, scientists can paint a pretty good  picture of these events with sound alone. Like in September 2022,  mission specialists reported that they’d detected the sound of a  meteoroid striking the red planet, which sounded like this… [ Meteor AUDIO ] The whoosh is the object  entering the Martian atmosphere, and then the weird bloop is the sound  of the meteorite hitting the ground.

But this technique has also  been used to help us listen in on even more deep and distant sounds. At the heart of the Perseus galaxy cluster, some 230 million light years away, there’s a black hole accelerating the  matter that swirls around it into jets, and these jets compress and expand the gas  surrounding the galaxy, creating ripples. Back in 2003, astronomers  figured out that these ripples were basically acoustic waves, albeit far, far, below the range of human hearing.

In fact, they represent the deepest  sound in the known universe. In 2022, science communicators worked  with NASA to reprocess the data,. We now have the opportunity to  hear the roar of this black hole, pitched up an incredible 57 octaves. [ Blackhole Audio ] The eerie groan is created as our proverbial  microphone moves around the black hole, because the sound waves aren’t  the same in every location.

So if these space sounds are  lies, then they’re white lies. They merely extend the range  of our normal perception. But there are other sounds  that are downright deceitful.

Take the surprisingly subtle  chirp of colliding black holes [ Blackhole AUDIO ] they’re not acoustic waves at all. Instead, they’re other kinds of waves, translated into sounds to help  us understand them better. Sometimes it’s much easier  for us to hear patterns, than to pick up trends from dry data in a graph.

NASA Webb’s First Full-Color Images, Data Are Set to Sound And the black hole merger chirps  are a representation of ripple s in the fabric of space-time itself. There are even new attempts  to turn pictures into sound, by using different musical instruments to represent the location and  intensity of light in an image. For example, that’s how we can “hear” Webb’s image of the cosmic cliffs of the Carina Nebula… [ Instrumental Nebula Audio ] So sure, space sounds aren’t  always quite what they seem, and some of them may even seem  more like art than science, but there are real benefits to  painting a picture with sound.

Not only are these representations helpful for non-visual learners  and the visually impaired, they also offer scientists the opportunity to pick out patterns that the eyes might not see. Like in 2012, a scientist from  the University of Michigan was listening to raw data recorded from our Sun. He heard a distinctive hum, and  the pitch of that hum suggested it was coming from the  Sun’s surface as it rotated.

Ultimately, that sound  helped him and his colleagues figure out a new way to measure  the Sun’s surface temperature. So sometimes, it’s worth  bending the truth just a little, to give us the best chance at  understanding our universe. Thank you for watching this SciShow Space video!

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