Light on Different Wavelengths
Our sun generates a lot of energy that is released into our galaxy, some of which penetrates Earth’s atmosphere. This energy is known as the electromagnetic spectrum and is made up of many types of ‘waves.’ We measure these waves in nanometres (nm) which equate to 1 billionth of a metre. The electromagnetic spectrum ranges from X-rays (2nm) to radio waves (10 metres). In between these two extremes, we find sunlight, and we refer to this as the solar spectrum.
Sunlight is made up of a blend of just three energy waves: ultraviolet (UV) radiation, visible light, and infrared radiation. We categorise these according to wavelength:
Within the ‘Visible Light’ range (light that can be seen by the human eye), wavelengths will correspond to different colours.
Each of these waves plays an essential role in the survival of all living organisms and in the maintenance of our planet itself. Infrared radiation, for example, supplies our earth with enough heat to support habitats and ecosystems. Plants harness and convert light energy from the Sun into chemical energy, which fuels our food chains and produces life-sustaining oxygen through photosynthesis.
Visible light helps illuminate the Earth, allowing us to see bright vibrant colours.
But there is a dark side to solar radiation.
Whilst research implicating infrared radiation in long-term skin damage is still being explored, UV and now the high energy portion of visible light (also known as HEV or blue light) are well known for contributing to skin damage. UV exposure results in DNA damage that increases skin cancer risk, whereas HEV exposure contributes to oxidative stress, hyperpigmentation and photoageing.