Saturday, December 05, 2009

Are there echoes in space?

One search term that seems to send people to this blog is the question of whether or not there are echoes in space? I figure I might as well go ahead and answer it: It depends on what types of echoes you are talking about.

Normal sound echoes
NO. Normal sound travels through the air (or water) through compression waves. Without a compressable medium, such as a gas or fluid, these waves cannot exist. Therefore, no echoes. Now it is possible to hear sound through touch, otherwise known as conduction. I did an experiment with conductive sound in one of my gerontology classes as an undergrad. Freaky stuff. However, I don't remember any echoes while doing it and I'm really not sure there can be echoes that way, since echoes are sound waves that bounce back from another point. Still, in space, you probably wouldn't be hearing conductive sound through all the insulation keeping you from either boiling or freezing to death.

Radio and other electromagnetic wave echoes
YES. Electro magnetic waves can travel through space and they can bounce off of things and create distortions that are also considered echoes. However, without the proper receiver, you're not going to hear a thing.

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