It's one of the most basic questions we can ask about the world around us: why is the sky blue?

When light from the Sun reaches Earth, some colors of light are absorbed by particles in the atmosphere, but others are scattered, which means that the photons in question are deflected to a new direction. Other than absorption of light, scattering is the main phenomenon that affects color.

When I was a child my two granduncles, Uncle James and Uncle Charlie, lived in a house with the most incredible garden. Uncle Charlie was, and still is, an excellent gardener and there was an abundance of beautiful, brightly coloured flowers. Uncle James was a keen ornithologist and he kept a number of tropical birds, including a peacock. We visited them only occasionally and entering the garden, populated by vibrant flora and incredible, exotic creatures, felt like entering a magical wonderland. But the thing I found most fascinating on our visits was the peacock.

“Eureka!” has been the classic phrase associated with scientific discovery for over 2000 years. It is easy to see why – it entered the vocabulary thanks to an entertaining story of political intrigue, profound scientific insight, skilled detective work and shameless public nudity. Archimedes: the archetype of the mad scientist. But the image is not quite right. The real phrase uttered by scientists just before they discover something new is actually something closer to “Hmmm. That’s funny…”