Eavesdropping the Universe: In Space, No One Can Hear You Scream… But You Can Hear It

Eavesdropping the Universe:

In Space, No One Can Hear You Scream… But You Can Hear It

The universe is a pretty big place. In our local Milky Way Galaxy there are more than 200 billion stars, spanning a massive ~100,000 lightyears across. Outwith our galaxy, there are trillions more galaxies. That’s pretty massive. So massive, we can hardly leave our small systems orbit (that reality permits).

Even getting to our nearest moon, planet or star is an achievement. This is why people are generally stunned by the beautiful pictures of nebulas and deep space, it seems like science fiction come to life. But everything is just so damned far away, so the only way we can truly get a grasp of what it’s like on the other side of the universe is through very powerful, expensive cameras. We can see pretty far (thanks to the likes of projects like the new James Webb Telescope) however, unless wormholes are discovered prior to this blog being released, we will be remaining pretty stationary on earth. We can listen to the universe though, and with some data translation, can hear it.

The obvious thing you may think is, ‘how can we listen to something so far away?’ the sharp might ask, ‘how can sound travel through a vacuum?’, or the deductive might ask, ‘what about gasses in space, is that not a medium?’

You would be right in thinking sound doesn’t travel in space, to a degree. As there is no air in space vibrations cannot travel. However, where there is air, sound can travel. If we had instruments sensitive enough to pick up the most minute vibrations, we would find the universe buzzing with charged particles.

I felt compelled to think about this after re-watching Contact (1997), in which an astronomer picks up encoded signals from space. It got me thinking about the ‘wow’ signal, how black holes emit a note 57 octaves below middle c and how everything in our universe vibrates. When we listen to the universe, what does it say back?

Plasma

The normal sounds we hear, which are created by pressure waves which vibrate through the ear then into your eardrum. In our universe, plasma waves permeate. which we can use to measure through electromagnetism. These plasma waves bump magnetic fields back and forth, but the rhythmic discord would be inaudible to humans. The folks over at NASA like to test this, using their bespoke Van Allen Probes (more specifically the waves instrument, a component of the Electric and Magnetic Field Instrument Suite and Integrated Science designed to translate this data. The spectral graphs that display the fluctuation field data, with the warmer colours indicating the washing over of plasma waves.

Black Holes

Here is an example of how using the environment of space, in this circumstance large gaseous clouds in a galaxy cluster can act as the necessary medium for sound to travel. In the below sonification of Perseus, in which pre-existing sound waves could be re-synthesised into a range audible to human ears (up about 57/58 octaves). Essentially, these sounds are being scaled up roughly 144 quadrillion and 28 quadrillion times higher.

Gravity

Another type or vibration (or more likely warping) comes from gravity. Remember those gravitational waves discovered a few years ago? Well, we can hear them! When two extremely dense objects begin to spin with one and other, gravitational pull can be such that the actual fabric of spacetime can be rippled. Like dropping a stone into a pond and measuring the ripples as they hit the shore. But the pond is a million light years away and the ripple only measures a 1/10,000the the width of a proton.

Planets

Each planet has a song. Not like Hotel California, but a unique frequency assigned by the amount of charged particles and the magnetic field of the planet (or structure). This is an old technique, which we can thank Voyager 2 for (what a time the 80’s was)! In a flyby trip through Jupiter, Saturn and Uranus, the probe registered electromagnetic fluxes and disturbance (not actual sound) and these were translated by scientists to create the ‘song’.

It’s a topic I could write a series about, but for the sake of brevity I’ll cap it here.

SD

P.S. In the meantime, NASA has a very informative page on the signification of various celestial objects, here.