Everyone will hear you scream in space: physicists have learned how to transmit sound in a vacuum, but there's a problem

The famous slogan from the sci-fi horror movie "Alien" may have to be modified somewhat, as the statement that "no one can hear you scream in space" has suddenly become outdated. Physicists have managed to invent a method that allows waves to be transmitted in the space vacuum.

This is stated in a study published in the journal Communications Physics. However, like most breakthrough ideas, this one has a limitation.

As you know, sound on Earth is transmitted by vibrations moving through the air. And the density of the air can change the way we hear sound: so your voice on Mars, Venus, or Earth will sound completely different.

In space, however, sound simply cannot "travel" through space, since there is no air, and therefore nothing to vibrate. That is why neither screams nor explosions make any sense in a vacuum and are accompanied by complete silence.

But this may all change in the near future. A pair of Finnish physicists from the University of Jyväskylä's Center for Nanoscience, Juoran Geng and Hilari Maasilta, have managed to make sound waves transmit through an airless void. The only problem is that their method currently works only over fairly short distances.

In the language of science, the method is based on the use of piezoelectric materials to convert sound waves into an electric field that can cross a vacuum and then be converted back into sound waves on the other side.

According to physicists, piezoelectric materials include crystals (such as tourmaline and quartz), certain types of ceramics and polymers, and some semiconductors such as zinc oxide.

The peculiarity of these materials is that they produce an electrical voltage when they are pressed, bent, stretched, or subjected to vibrations.

Therefore, to communicate in space, a person will need to stand in front of a piezoelectric plate and speak to it. The sound will make the air vibrate, and these vibrations will pass through the plate, creating an electric field. This field will pass through the vacuum, pushing and pulling charged particles - such as those in the second piezoelectric plate on the other side of the vacuum. In this way, your scream will travel from one plate to the other in the form of an electric field, but upon encountering the second plate, it will be transformed back into a sound wave.

The researchers admit that in most cases, the effect of sound transmission in this way was not very large, but they found cases where "the full energy of the wave jumps through the vacuum with 100% efficiency."

The main problem with the idea is that the gap between two piezoelectric materials must be smaller than the length of the sound waves being transmitted.

If you take an average person, their scream can travel from 1 to 12 meters. The deepest sounds a person can hear have wavelengths of about 18 meters.

As Inverse notes, Geng and Maasilta say their method could be useful in tiny systems that combine electrical and mechanical parts, such as some types of sensors, or even for temperature control. Other teams of engineers have been experimenting for several years with ways to use sound waves to move heat.

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