What Happens To Sound In Space?

[David Jerome]

I know that there's no sound in space...but why exactly? I know the air on earth is a "conductor" for sound, and there's no air in space...but what happens to sound waves in space? Is any sound even generated, or is it that human ears simply can't pick it up? What would happen to the sound waves, if an astronaut played a boom box in space?

 

Thanks for any help you can offer.

[joekgamer]

All sound is is a series of pressure waves, which propagate due to the atoms in the material "knocking" together. As there are no atoms in a vacuum, there can not be, by definition, any sound. To more directly answer your question, nothing "happens" to the atoms in space, there just isn't anything for the source of the sound to hit.

[CraigD]

Welcome to hypography, ****! :) Please feel free to start a topic in the introductions forum to tell us something about yourself.

 

I know that there's no sound in space...but why exactly?

Polymath’s short explanation is right. Here’s a bit more elaboration, which I started last night, but forgot to post:

 

Sound can travel through solids, liquids, and gases, but not through vacuum. So, if an astronaut played a boom box loudly enough in space, he would be able to feel its case vibrating through his gloved hands, and, faintly, vibrations traveling through the air in his suit to his ears. If he held the speaker grill against his helmet, he would hear it loudly.

 

If he let go of the boom box and let it float free of any solid connection to him, he wouldn’t hear or feel any sound.

 

Space is not quite a perfect vacuum, so a really, really loud “speaker” in space could transmit sound of a sort through it. Such “signals” usually aren’t called “sound”, but “shock waves”, and are believed to be important in triggering the formation of stars and planetary systems - you can read some more about this at this old post.

 

Like more obvious mechanical motion, vibrations through any medium are eventually absorbed by that medium, heating it. Because a boom box in a vacuum wouldn’t transmit any of the sound energy it generates beyond its case (assuming it’s not being held by an astronaut, attached to a solid surface, etc.), it would be heated more than if it were played in the usual airy environment.

[Turtle]

snip...

 

Like more obvious mechanical motion, vibrations through any medium are eventually absorbed by that medium, heating it. Because a boom box in a vacuum wouldn’t transmit any of the sound energy it generates beyond its case (assuming it’s not being held by an astronaut, attached to a solid surface, etc.), it would be heated more than if it were played in the usual airy environment.

 

good stuff in the snip craig. :thumbs_up on the temperature, i was thinking more about the cold. if the boom-box was some standard-issue box i expect the cold would distort the fine alignment of the permanent magnet that rides in the speaker coil which might make the speaker not work at all. then, presuming it did work, the cone would be brittle from the cold and likely fracture in short order. then, presuming neither of those happened, speaker cones are designed with the pressure of air in mind, and lacking the pressure to hold it back -and of course forth- i expect the cone would rip in short order.

 

all of this of course could be eliminated by simply using an electomagnetic bell as the sound source as is used in school lab experiments wherein the bell is put in a vacuum jar, set ringing, and then the air is withdrawn and the dimishing sound is observed, thus demonstrating why there is [virtually] no sound in space.

Edited April 25, 2012 by Turtle

[David Jerome]

All sound is is a series of pressure waves, which propagate due to the atoms in the material "knocking" together. As there are no atoms in a vacuum, there can not be, by definition, any sound. To more directly answer your question, nothing "happens" to the atoms in space, there just isn't anything for the source of the sound to hit.

Wow, I didn't see there was a reply to this.

 

Thanks so much for your responses. That clears up a lot of my questions.

 

And yeah, I guess I should introduce myself, Craig. I'll do that.