Blue Mountains

The Blue Mountains, located in New South Wales, Australia, is a mountainous region located approximately 48 kilometres west of the City of Sydney. The area is a sandstone plateau dissected by gorges of up to 760 metres in depth with the highest point being 1,190 metres above sea level. A large part of the Blue Mountains is incorporated in the Greater Blue Mountains Area World Heritage Site and its constituent seven national parks and a conservation reserve.

The Blue Mountains have been known to the Indigenous Australians for generations, and although the mountains were for many years thought to be impassable by white folk, the view that there was bound to be productive land beyond the barrier of these mountains eventually prevailed.

Why are the called Blue Mountains? The name derives from the bluish tinge the range takes on when viewed at a distance, which is caused by a process known as Mie Scattering. Mie Scattering occurs when incoming uv radiation is scattered by particles within the atmosphere. When Mie Scattering occurs incoming radiation lengths mix as no wave length is predominant over another (unlike Rayleigh Scattering where shortwave length radiation is predominant during the day and long at sunset, hence blue skies and red sunsets) creating a blue-greyish colour to any distant objects (such as mountain ranges or even clouds). It is widely believed that the blue colouring of the mountains is created by light reflecting of eucalyptus leaves and although this is a romantic idea, unfortunately it is just folklore.

When you visit the Blue Mountains don't forget your trekking boots. Some of the best bush walks Australia has to offer are in this area. And as it is only a 90 min drive from Sydney you definitely have to make a stop there and if it is only for the nice picture of the 'three sisters'.