Why Our Ears Can't Hear Anything in a Vacuum

In splashy science fiction movies, you (and the characters) can hear the sounds of explosions, laser fire and ship engines in space. But in real life, those sounds would not travel through space, because sound needs a medium through which to travel, and space is a near-perfect vacuum.

What is A Vacuum

• A vacuum is a place where there is no matter, including air. Space is a near-perfect vacuum. In a vacuum, our ears cannot detect sounds because of the nature of sound waves. Whether or not there is anything to hear is a different matter.

How Sound Waves Travel

• Sound is produced through vibration. Sound waves need a medium through which to travel, such as air. The waves get from one place to another by bouncing molecules off of each other, causing them to move through the air.

Sound in Other Media

• You may have noticed that you can hear sounds when you are swimming underwater. In space, there are not enough molecules for a sound wave to form; however, water is a medium through which sound waves can travel. They can also move through solids and gasses.

Does the Sun Create Sound?

• According to NASA, the burning of the sun does make sound, but with very low wavelengths, so the sound does not travel beyond the sun itself. However, the sun vibrates, and scientists record wave oscillations (which resonate), in order to study the sun's properties.

Recorded Sounds From Space

• There are audio collections of sounds recorded from space. You can find some of them at the University of Iowa listed in the Resources below. These were not recordings of sound waves, but of radio waves or plasma waves, which can travel in a vacuum.