Ever wondered what a black hole sounds like? Well, if we’re being honest, it probably sounds like becoming a spaghetti and death, which are not very nice things. Understanding our pain, however, NASA comes with its most recent instalments of its sonification series, helping us hear space, but in a pleasant way.
You might be wondering what sonification is; in essence, it’s a process through which NASA turns astronomical data in the form of images into sounds. The data comes from NASA’s telescopes, such as the Chandra X-ray Observatory. Such images are then processed into sounds using an algorithm that, crucially, doesn’t change the original content of this data in any way. You could think of it like listening to an audiobook instead of reading it yourself.
The results are quite enjoyable, and surprisingly striking.
You can hear space in this
The first is a sonification of an image of the Chandra Deep Field South region of space. The image itself is notable as it is “the deepest image ever taken in X-rays” according to NASA, and represents “over seven million seconds of Chandra observing time”.
The colored dots that might seem like stars here are, in fact, individual galaxies and black holes — mostly supermassive ones. The colors of these individual dots dictate the tone produced as the bar moves throughout the picture from the bottom towards the top. White light on the picture is recreated as white noise, and the musical frequencies you’ll hear are given by different X-ray frequencies captured in the photo. In the image you see, these had to be heavily compressed but are shown in red, green, and blue for low, medium, and high-energy X-rays, respectively. However, keep in mind that the sound you’ll hear recreates the whole, uncompressed spectrum. Finally, the seter position of the sound tells you whether the source of light being sonified lies to the left or right of the image.
Next, the Cat’s Eye Nebula. This was formed by a star that’s slowly running out of atomic fuel (helium), which makes it belch out huge quantities of gas and dust. These form spectacular clouds that linger around the star.
The image used here contained both X-ray data around the center, recorded by Chandra, and visible light data from the Hubble Space Telescope, mostly focused on the structures expelled by the star.
Instead of a bar scanning the picture from bottom to top, here NASA uses a clockwise scan — it looks a lot like those radar lines you’d see in 90s action movies. When this line encounters light, pitch is produced: the farther away from the center it is, the higher the pitch. Brighter lights are also louder. X-ray data is reproduced in harsher notes while visible lights sound smoother.
It’s a very immersive tune.
The last installment in NASA’s sonification gallery is Messier 51, also known as the Whirlpool Galaxy, a spiral galaxy quite similar to our own.
The sonification moves radially from the top of the image in a clockwise motion. This time, the radius of the galaxy produces different notes on a minor scale. Each type of light (infrared, optical, ultraviolet, and X-ray) is represented here. The sound is… very eerie. Pleasant, but eerie. A constant, low hum is produced by the bright core of the galaxy, while other sources of light along its diameter produce short, striking sounds that almost sound coherent. I like this one the most out of all three, it’s just brimming with personality.
These three sonification projects were led by Dr. Kimberly Arcand, a visualization scientist at the Chandra X-ray Center (CXC), with astrophysicist Dr. Matt Russo and musician Andrew Santaguida (both of the SYSTEM Sound project).
If you liked these as much as I did, you’ll be delighted to hear that NASA has a whole gallery of sonification projects you can browse through, and listen to all of them here.
