Fluorescence

Many chemicals (often called phosphors), some liquids, and many pigments fluoresce (emit visible light) when excited with shorter wavelength high energy (UV) photons.  

The moon flower, a large white trumpet flower that grows on a scrambling vine, opens at dusk. The petals fluoresce faintly, giving rise to the name. The editor has grown moon flowers at his home in Russell, Bay of Islands, New Zealand.

 > More