This is huge news (albeit a half year old) that changes our understanding of clouds, and any other form of water evaporation. Light at 45 degrees, and with a specific polarization, has the potential to be more efficient at evaporation than heat is. It may have applications in food processing, to reduce the energy of spray evaporation. The scientists involved wanted to be sure that this was really happening, so they tested and documented 12 different ways to verify it.