ALAN is the acronym for 'Artificial Light at Night' (don't start on the topic of - 'artificial'). Basically as humans have created a lit environment - for use in daylight and at night, the natural environmental conditions that humans evolved under has been replaced by an artificial environment. Is that good or bad or does it matter?
I came to the issue of light pollution through astronomy, as a child I was able to stand in the backyard of a suburban home in Sydney and see the Centaurus arm of our galaxy and in particular a dark nebula in the constellation Crux - the Southern Cross, the constellation that Australia and many Australians have used to identify ourselves as a nation, a constellation that is now fading as the increased level of light pollution floods the night sky.
One aspect of ALAN investigated at the conference was the social concepts and policy and use of lighting, in both interior and exterior uses. A curious aside to one of the talks was a topic of 'Film Noir after black-and-white' by Dr Will Straw of McGill Institute for the Study of Canada, McGill University,Qc, Canada. Dr Straw's talk by concentrating on the lighting conditions used in film noir contrasted the ideas of dark as threatening with the idea of light as safety and surety, light being an answer, solution or possibly saviour revealing the truth - light can only be good.
Well away from the days of film noir we use light to obviously extend our days and presumably our productivity - again increased productivity must be good and so light must also be good. We even extend our natural day by using a technique of daylight savings so we adjust our clocks to use more of the natural day. However by increasing our use of the day, this increases the load and energy demands on the human body, the human body responds to sleep by repairing damage to the body.
So is artificial light at night preventing the body from repairing damage? If that damage isn't repaired then what is the immediate, short term and long term consequences of human health?
Our relationship to light is complex and without doubt the answer may well be complex, although the easiest solution is to turn off the lights.