Ever since the launch of the Dinosaurs-Live! exhibition I have been trying to think of possible ways nature could produce coloured light. Standing in front of some of the realistic animatronic dinosaurs, I had attempted to imagine standing in front of the real thing, but I got confused by the lighting. How could the real dinosaurs, 230-65 million years ago, have been bathed in blue, green and red lights?
So, just as an intellectual exercise, how could nature have produced the colourful lighting in our exhibition, long before the arrival of the species that invented the LED?
My first thought was rainbows. But those do not project patches of colours onto objects; The colours of a rainbow are only noticeable if you happen to look at the right spot in the sky.
My next idea was colourful reflective surfaces. This was reinforced by the fact that many of the dinosaurs in the exhibition are illuminated from below, so maybe they could have been walking over some colourful reflective surfaces. But that would mean that the light from above (that hasn’t been reflected) would be white, which it isn’t. And I cannot think of any naturally occurring blue-, green- or red-tinted mirrors, either.
The best explanation I have so far is prisms. Maybe we are meant to be inside a large, dark cave, with the sun shining through some giant crystals at the mouth of the cave. If these crystals acted as prisms, they could have refracted the sunlight, splitting it up into the different colours that then illuminated different areas in the cave.
Can you think of another explanation?