Sound waves pass through a vacuum. Credits: Zhuoran Geng and Ilari Maasilta
Iconic movie alien He once claimed: “In outer space, no one hears you scream.” However, physicists Zhuoran Geng and Ilari Maasilta of the Center for Nanoscience at the University of Jyväskylä, Finland, disagree. Their recent research has shown that, under certain conditions, sound can indeed be strongly transmitted through a vacuum.
Their findings were recently published in the journal Communication Physics, revealed that in certain scenarios, sound waves can “pass through” the vacuum gap between two solid bodies, provided these bodies are piezoelectric. These special materials produce an electrical response when exposed to sound waves or vibrations. Given that an electric field can exist in a vacuum, it can effectively transmit these sound waves.
The condition is that the size of the gap is smaller than the wavelength of the sound wave. This effect works not only over the acoustic frequency range (Hz-kHz), but also over the ultrasonic (MHz) and ultrasonic (GHz) frequencies, as long as the vacuum gap becomes smaller as the frequency increases.
In most cases, the effect is negligible, but we also come across situations, where full wave energy jumps through empty space at 100% efficiency, without any reflections. Thus, this phenomenon can be applied in microelectromechanical components (MEMS, smartphone technology) and in heat control, says Professor Ilari Maselta from the Center for Nanoscience at the University of Jyväskylä.
Reference: “Full Tunnel of Acoustic Waves Between Piezoelectric Crystals” By Zhuoran Geng and Ilari J. Maasilta, 14 Jul. 2023, Available here. Communication Physics.
DOI: 10.1038/s42005-023-01293-y
This study was funded by the Finnish Academy and the European Union’s Horizon 2020 programme.
2023-08-12 18:50:10
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