Summary: Light at night (LAN) is now an established environmental problem, not only for astronomers but for the population at large. It has serious ecological effects that are wide ranging, and its environmental effects may be more serious than ever imagined. The ecological and environmental consequences are examined and emphasis is stressed on resolving the problem before it is too late.
Introduction: A casual glance at NASA images of the Earth at night reveals the lights of thousands of cities. The larger cities will contain millions of street lights, along with commercial, sports and decorative lighting. Most of these lights are on all night, every night, three hundred and sixty-five nights a year, (fig 1), so they must be having a measurable ecological and environmental effect. The most obvious effect of all this excessive lighting is the light pollution suffered by astronomers.
AUTHORS/INSTITUTIONS: C. Henshaw, Health Studies and Training Centre, North West Armed Forces Prince Salman Hospital, Tabuk, SAUDI ARABIA