What Are the Multiple Signatures?

40% of a nuclear explosion energy goes into visible light. And so if you have a lot of nuclear bombs, then their atmosphere would have this air glow and we might be able to spot that. But what we're talking about here is seeing a change in the atmospheric chemistry which we usually detect from how the light from the planet star passes through its atmosphere or reflects off its atmosphere. So the light we get from these planets is not from any source on the planet itself, but from the star, which is why it's visible at all.