3 body problem and acoustic design in virtual reality

"3 Body Problem" is hot on Netflix. This sci-fi TV show is at the top of Netflix's weekly chart for the third week from April 8 to April 14 since it started on March 21. So far, 35 million hours of the show have been watched worldwide.

I love the original sci-fi series by Chinese author Cixin Liu. I read the books in 2015, and it had a profound impact on how I see the world. Even now, I still remember how I felt after reading the novel. I walked down the street watching people and cars go by, feeling like I was seeing them for the first time. It made me realise that my existence on this planet, at that moment, was just by chance.

In the story, the aliens live on a planet within a system forming by three suns. Predicting the movements of three interacting bodies is impossible, known as the 3 Body problem. It's a genuine intriguing mathematical puzzle. No one has found a solution yet to predict how such a system moves. When the planet's orbit is dominated by one sun, its movement is steady. But we can't predict how long these steady periods last. When entering chaotic eras, the weather changes unpredictably between extreme cold when the planet is close to two of the suns, and extreme heat when it's far from any suns, sometimes within minutes.

A sophisticated virtual reality game, called Three-Body, plays a big role in the story. The game mimics the physics on the aliens' planet to help their supporters on Earth (Earth-Trisolaris Organization) understand their problems. The simulations are so real that players can feel, smell, and even taste objects in the game. As an acoustician, I am interested in sounds. The game certainly did not simulate acoustics accurately.

Netflix/Getty Images/Ringer illustration

Sound changes a lot depending on the environment it travels through. As the 3-body planet swings between extreme cold and heat, the atmosphere changes a lot. When it's hot, sound travels faster. The increase of sound speed will increase resonant frequencies of our vocal tract, and consequently raise the pitches of our voice. When it's cold, it has an adverse effect. So, if we lived on the three-body planet, we'd sound strange, sometimes like a squeaky mouse (when it's super hot) and sometimes like an elephant (when it's super cold). When it's super hot and the planet is close to both suns, the suns' gravity could pull air towards them, making the air less dense. This would make sounds quieter. Adversely, sounds could be a lot louder.

NASA's video on sound provides a fascinating insight into how the atmosphere influences soundscape.

In physics and engineering, we've made many advanced software packages for physical simulations. Acoustical engineering has programs like Treble, Odeon, and CATT. As hardware gets more powerful, many virtual reality games are starting to include physics simulations to make them more realistic. For sound effect, programs like Project Acoustics, Steam Audio, and Wwise add-ins for Unreal or Unity game engines are trying to make sound based on the laws of physics.

Einstein said, "The eternal mystery of the world is its comprehensibility." In a way, our reality is controlled by math, manifested in physics and engineering. Maybe one day, physics and virtual reality games will come together, creating games based on the fundamental laws of physics. In this virtual world, acoustic design is probably just as important as in our real world.