[소리 과학의 미래] Light, particle, wave… A ‘noisy’ universe

We hear external sounds through our ears. Sound is transmitted through an ‘elastic medium’ such as gaseous air, liquid water, and various solids. Everyone is well aware that sound cannot be transmitted in an empty space without any material.

In that context, it can be thought that the universe is mostly composed of empty space and no sound is transmitted. However, it is worth noting that elementary particles are radiated from space in various directions and fill space, just like the solar wind, a huge flow of elementary particles. If elementary particles act as an elastic medium, sound can be produced or transmitted.

This means that the vibration of elementary particles can create sound, and the sound produced can be transmitted to the earth through a medium made of elementary particles.

Outside the Earth, space probes are also used to listen to the sound of the solar wind. The impact of elementary particles entering the elementary particle detection sensor is converted into sound. By converting it to an audible frequency that we can hear, we can feel the mysterious sound. Light from supernovae and neutron stars, as well as radio emissions from the sun or planets in the solar system, can be heard.

This means that the universe is never silent. It’s just that it’s not transmitted as direct sound that we can hear, so we can hear it by converting it into sound using a detector.

Radio waves, like sound, are essentially waves. Although they have different origins, they share the same character in terms of vibrational phenomena. We have evolved to hear only ‘medium vibration’ with the sensor of hearing. All wave phenomena can be converted into sound vibrations, and if we wish, the wave vibrations of surface waves and the vibrations of the aurora in the atmosphere can all be converted into sound and heard.

What is surprising is that even the cosmic radio background noise generated from the beginning of the universe, the Big Bang, or ‘cosmic background radiation’ can be converted into sound and heard. Recently, Dr. Wanda Diaz Merced of Harvard-Smithsonian Institute for Astrophysics, a sonic astrophysicist who has lost her sight since she was in her 20s, has studied the changes in the universe by converting them into audible sound. He applied ‘sonification’ technology to convert invisible cosmic light into sound so that it could be detected by the ears.

The universe is no longer a world of darkness or silence. The universe is full of light, particles, and waves. The National Aeronautics and Space Administration (NASA) provides a variety of sounds from space, so let’s feel the sounds of space with our ears. Now, the universe is approaching as a familiar and realistic object that can be felt through hearing. This will give us an opportunity to understand the universe more deeply.