WHY: 2015 has been named by the United Nations as the International Year of Light (light2015.org). Light has had many obvious benefits for human mankind, but it also poses some relevant threats: the everyday-increasing excess of light thrown by humans to the sky seriously threatens to remove forever one of humanity’s natural wonders, the view of our universe.
More importantly, it has also an adverse impact on our environment and economy (energy wasted to the sky costs 2 billion US$ per year in the USA and 6,3 billion € per year in Europe) and on the health of hundreds of species, including pathologies in human beings (e.g., stress, insomnia). Many professional and amateur scientists are already fighting against light pollution. However, it is necessary to increase social awareness about the importance of preserving the darkness of our cities and environment.