Quote:
Originally Posted by Z-man
I think your diminishing radio signal really only applies when said radio signal is in an atmosphere. In a vacum, there is no friction, allowing the radio wave to continue to propegate at the same wavelength and frequency. But solar wind and gravity may effect it a bit...
That said, anyone see the flick, "Contact" with Jodie Foster? Definately a "makes you think" movie...
-Z
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I did some reading, found this question addressed on a physics forum. Radio waves in free space do indeed obey the inverse square law, the strength of the signal diminishes with the square of the distance from the origin. It is not a question of the wave being impeded by atmosphere. It is because the signal when emitted has a certain finite amount of energy. As it propagates outward, that energy is spread out over the surface of a sphere, which is 4 x pi x r^2. When the radius of the sphere is 1 light year (6 trillion miles), that original finite amount of energy is spread over an area 4 x pi x (6 x 10^12)^2 square miles.