Luciferase is a protein (enzyme) that is produced by fireflies and catalyzes a reaction allowing them to “glow” at night.
why might it be useful to scientists to learn the genetic code for the production of luciferase?

Luciferases are widely used as reporter gene in the study of promoter sequences of genes, they are also at the origin of the method of ATPmetry. as well as in pyrosequencing: ATP sulfurylase then converts this pyrophosphate (PPi) to ATP which is then used, coupled to a luciferin, by a luciferase. Oxyluciferin and a light signal are then produced.

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.