In a groundbreaking study, scientists have demonstrated that sound can indeed travel through the seemingly empty expanse of a vacuum. 

Contrary to the popular belief, reinforced by the iconic tagline of the 1979 sci-fi film “Alien” – “in space no one can hear you scream,” researchers have found a way to transmit sound in conditions that mimic the vacuum of space.

The Science Behind the Sound

Traditionally, sound waves travel by vibrating through the particles of a medium, such as air or water. In the vastness of space, which is mostly a vacuum with no particles, this transmission was thought to be impossible. However, in this innovative experiment, scientists managed to “tunnel” sound waves across a vacuum between two zinc oxide crystals. They achieved this by converting the vibrating waves into ripples within an electric field shared between the two crystals.

The Role of Zinc Oxide Crystals

Zinc oxide crystals are piezoelectric materials, meaning they produce an electrical charge when subjected to force or heat. When sound is applied to one of these crystals, it generates an electrical charge that disrupts nearby electric fields. If another crystal shares this electric field, the magnetic disruption can traverse from one crystal to the other across a vacuum. This disruption mirrors the frequency of the sound waves, allowing the receiving crystal to convert it back into sound on the other side.

Limitations and Potential Applications

The sound transmission has its constraints. The disruptions cannot travel a distance greater than the wavelength of a single sound wave. Moreover, in many experiments, the sound wasn’t flawlessly transmitted between the crystals, with parts of the wave getting distorted or reflected. 

However, there were instances where the crystals perfectly transmitted the entire sound wave. “In most cases the effect [sound transmitted] is small, but we also found situations, where the full energy of the wave jumps across the vacuum with 100% efficiency, without any reflections,” commented study co-author Ilari Maasilta, a material physicist at the University of Jyväskylä in Finland.

This discovery holds promise for the development of microelectromechanical components found in various modern technologies, including smartphones.

Research Paper