Sending signals at optical wavelengths might be a viable alternative to radio wavelengths
A) only between civilizations around solar-type stars whose eyes have evolved to see such radiation
B) over relatively short distances where absorption by interstellar matter would not be a problem
C) as long as the light transmitted is a different color than the light given off by the parent star
D) over all distances as long as the intensity of the signal is strong enough

Question

Quizplus · Accepted Answer

Optical wavelengths experience less absorption by interstellar matter compared to radio wavelengths, so it is more feasible to send signals over relatively short distances without significant signal loss. Choice A is incorrect because it assumes the existence of civilizations with eyes evolved to see optical radiation, which is not a necessary requirement for the feasibility of optical communication. Choice C is not necessary since it is possible to filter out the starlight using appropriate filters. Choice D is incorrect because even with strong enough intensity, optical wavelengths could still suffer significant absorption by interstellar matter and thus not be effective for long-distance communication.

Sending Signals at Optical Wavelengths Might Be a Viable Alternative