How the World Would Look If Air Were Truly Transparent

For the purposes of this question, I'm going to assume that "truly transparent" means that air and its constituents are no longer able to absorb and re-radiate incident radiation, which in visible light seems to be our definition of transparency. To make things much more fun, let's make this true over all wavelengths. » 3/11/14 3:20pm 3/11/14 3:20pm