The latest development is the ability of Swiss researchers to use sound waves to levitate — and then move — particles and objects in mid-air. Turns out, all acoustic levitation requires is blasting out sound at extremely loud levels (160 decibels – the deafening sound of a rocket launch) at a high enough frequency (24,000 hertz – the frequency of a dog whistle) that the human ear can’t detect. When those two conditions are met, some fascinating things start to happen. If you thought that gravity was the strongest force in the universe, think again – the Swiss researchers were able to defy gravity and move objects around a chess board-like device, mix particles in mid-air without touching them, and even levitate a toothpick. They even captured the mixing of molecules on a video scored to classical music.