What Does A Scream Sound Like In Space?

As you look down on the Earth from the confines of a deteriorating spaceship (and think about how Carl Sagan was wrong — it does not at all resemble any kind of "pale blue dot"), it will likely come to your immediate attention that humans are not comfortable exposed in the vacuum of space. Given the dire nature of your situation and the certainty of your impending death, you might be inclined to scream. What would it sound like it?

It depends. As Mental Floss reported, mechanical sound waves can only travel through a molecular medium — like the molecules of solids, liquids, or gases — and there aren't many of these in the vacuum of space (per Science Alert). For example, on Earth, according to ENT & Audiology News, every cubic centimeter of air contains about 25,000,000,000,000,000,000 molecules. The "vibration" of these molecules coming in contact with each other is what allows sound to be conveyed across distances. In space, solar wind (which actually pervades the apparent emptiness of outer space, according to Science) contains far fewer elements: about 5 protons per cubic centimeter (per ENT & Audiology).

Molecules, Waves, and Mechanical Vibrations

Space is not entirely barren, and scientists have recently learned the distribution of gases is greater than we thought (via Science Alert). If there are gases to provide some kind of medium, it's technically possible that sound can travel through it. However, the materials in space to provide that medium are still so scarce that the sound will be entirely imperceptible. (Technically, it sounds like molecules pressing against each other, but not very much and not very many.)

Although the sound of your scream may be diffused into a mute vibration inaudible to human ears, that's only if it's coming from your mouth. You can, however, hear someone scream over the radio. Unlike sound waves, which are mechanical, radio waves are electromagnetic. Electromagnetic waves do just fine in outer space and don't need the same distribution of solids, liquids, or gases to travel (that's how space radios work, according to Mental Floss).

So does your scream make a sound in space? Yes. Can you hear it? It is unlikely — however, if you're in this situation, you probably have much more pressing problems to deal with.