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Re: [Phys-L] Sound waves in space?

On 03/23/2013 09:38 AM, Dr Keith S Taber wrote:

If 'space' /*is*/ defined technically/operationally, then where does it begin?

Operationally: If the sky is black and stars come out in the daytime,
you're in space. (Eclipses don't count.)

Technically or at least officially: It begins 50 miles up. This is the
US criterion for awarding "astronaut wings".