2023-08-24 11:00:10
The vacuum, in essence, is a space devoid of particles. This implies that no sound can propagate there. At least, that’s what we believed until now. For the first time, researchers have demonstrated that it is possible, under certain very specific conditions, to make sound travel in a vacuum. According to the famous line from the movie “Alien”: “In space, no one will hear you scream”. Really ?
Sound waves cannot normally propagate in a vacuum, such as space, because there is no medium to carry them.
Image d’illustration Pixabay
Although it has always been accepted that sound cannot travel in a vacuum, a recent discovery has changed this perception. Indeed, scientists have demonstrated for the first time the possibility of transporting sound through a vacuum, but under certain very specific conditions.
The misconception that “in space no one can hear you scream” stems from the idea that space is mostly a vacuum, with no particles to carry sound. In reality, space contains traces of gas and plasma ( In physics, plasma describes a state of matter made up of charged particles (ions…), but these particles are isolated in huge empty areas .
The study published in the journal “Communications Physics” found that sound can travel through a vacuum. However, this phenomenon does not apply to human cries. To achieve this, the researchers used two crystals of zinc oxide (Zinc (pronunciation /zɛ̃k/ or /zɛ̃ɡ/) is an element…) and transformed the sound waves into ripples within an electric field. (In physics, an electric field is a field created by particles…) between these crystals.
Conceptual image of electrical sound disturbances moving through a void between two zinc oxide crystals.
Image credit: University of Jyväskylä
Zinc oxide crystals are called “piezoelectric”. When a force or heat (In common language, the words heat and temperature often have an equivalent meaning: …) is applied to these crystals, they produce an electric charge (Electric charge is a fundamental property of matter which respects the principle of…). Thus, the sound created by a crystal (Crystal is a common term for a solid with regular shapes, although…) can disturb the electric field (A field corresponds to a notion of defined space:) of a crystal neighbor. However, this disturbance can only travel a distance not exceeding the length (The length of an object is the distance between its two extremities…) of wave (A wave is the propagation of a disturbance producing on its way a reversible variation…) of the sound emitted.
The experiments have not always been conclusive. Often the sound was not transmitted perfectly, but in some cases the transmission was flawless. As Ilari Maasilta, a materials physicist (A material is matter of natural or artificial origin that man shapes to en…) at the University of Jyväskylä in Finland, pointed out, although the effect is often low, there are times when the energy (In common sense, energy designates everything that enables work to be done, to manufacture…) of the wave (A wave is the propagation of a disturbance producing on its way a sound variation…) is transmitted entirely through the vacuum.
These discoveries might have applications in the development of microelectromechanical components, such as those found in our smartphones.
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