radiation travels in a straight path. Even then, it wasn't until Italian inventor and electrical engineer Guglielmo Marconi developed long-range radio transmission technologies around the turn of the 20th century that our species really started broadcasting its existence out into the void. (Also note that wavelength and frequency are the same thing just measured reciprocally: you can convert one to the other using $\lambda = \frac{c}{f}$, where $\lambda$ is the wavelength, $f$ is the frequency, and $c$ is the constant speed of light.). As radio signals leave earth, they propagate out in a wave form. Because of this inverse square law, all of our terrestrial radio signals become indistinguishable from background noise at around a few light-years from earth. I would have already calculated the possibility to be peaceful and united. Radio Waves propagation (Intuitive Understanding of Wave propagation). Why Didn't the Soviets Ever Make It to the Moon? The wikipedia article on Horizon seems technically accurate, describing light horizon. The common frequencies in use today in the civilian sector are VHF and above- which degrade very rapidly after a certain distance. It's a daunting reality to consider when we're thinking about the possibility of making contact with any intelligence that might be out there. Now consider that our species started broadcasting radio signals into space only about a century ago. Your email address will not be published.