Why are the Blue Mountains…..blue?
It’s true, they look blue. When looking at the mountains from a distance they take on an intense blue haze that has baffled many visitors to the Blue Mountains.
What causes this blueness, the depth and intensity of which is often quite remarkable? In 1955 the Town Clerk of the City of Blue Mountains asked this question of the Department of Physics at the University of Sydney. Professor Harry Messel, replied:
“The haze which appears to surround any distant object is due to an optical phenomenon called ‘Rayleigh scattering’. This effect, first investigated theoretically by Lord Rayleigh, causes the rays of light which impinge on small particles to be scattered in various directions… Since the atmosphere is always laden with small dust particles, water droplets and the like and since even the air molecules themselves contributed to some extent to the scattering… if an observer look sat a distant object with the intervening atmosphere illuminated by sunlight, eyes will receive the blue scattered rays of sunlight to reflect the object itself. Therefore any distant object will always appear to display”
So now you know, and can show off to your friends and family with your newfound science – Rayliegh scattering!