Light allows us to see, travel safely and enjoy our towns and cities after dark.
However, when artificial light is excessive, poorly directed or used when it is not needed, it can create a growing environmental problem known as light pollution.
Light pollution reduces our view of the stars, wastes energy and changes natural darkness across large areas.
Its effects reach far beyond astronomy.
Losing the night sky
In places with strong artificial lighting, only the brightest stars may remain visible.
The faint glow of the Milky Way, which should be visible from a naturally dark location, disappears behind a brightened sky.
For most of human history, people could look up and see thousands of stars. For many children today, that experience is no longer part of everyday life.
Effects on wildlife
Many animals depend on natural patterns of light and darkness.
Nocturnal wildlife may use darkness to feed, navigate, avoid predators or reproduce. Artificial lighting can disrupt these behaviours.
Insects can become trapped around bright lights. Birds may become disorientated. Bats can lose access to feeding routes, while other animals may change their natural activity.
Reducing unnecessary light can therefore benefit astronomy, biodiversity and energy use.
Better lighting, not no lighting
Reducing light pollution does not mean switching off every light.
It means using light more carefully:
- direct it downwards
- use only the brightness required
- avoid illuminating empty spaces
- use timers or sensors
- choose warmer lighting where appropriate
- switch lights off when they are no longer needed
Light pollution is explored through demonstrations in The Starsmith school show, helping pupils understand both the science and the environmental importance of natural darkness.