Light pollution. Sounds niche, right? Maybe it is, but it's something that affects us all, including you!
The effect of light pollution - or the lack of it - can be experienced in our own backyard in Canberra, as Mount Stromlo Observatory required dark skies for many decades when observational research was taking place. Canberra's older suburbs are unusually dark - this is because there is limited street lighting in these areas, partially to limit the light pollution for Mount Stromlo.
Light pollution is the inappropriate or excessive use of artificial light that blankets the naturally dark night sky. The impact light pollution has on us and Earth is quite extensive; excessive light interferes with human circadian rhythms, the environment and ecosystems, observational astronomy and culture.
Our sleeping patterns have become largely disturbed since the introduction of artificial light. The human brain essentially has a clock that governs when we feel sleepy and when we should be awake. Light from the environment we are in turns the hands of the clocks. Typically, the clock runs off the 24-hour solar day, so when the sun goes down at night and we encounter less light, we start to feel sleepy. Then as the sun rises in the morning, our brains tell us to wake up. Artificial light now interferes with this natural pattern, especially at night - delaying our sleep and pushing back the clock.
It is also evident that our use of artificial light creates a lot of energy waste and impacts the behaviour of animals in our environment. Energy waste is created by lights being left on outside when they are not in use, unshaded lights that shine up into the sky for no reason, and lights simply being left on at home. Lights require energy production, placing a demand on resources from our environment, especially if this energy requirement is not met by renewable energy sources.
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A specific example of how light negatively impacts animals is hatching turtles. Turtles that have just hatched on a beach will use the light from the moon that reflects off the water to find their way to the ocean. Artificial lights from beachfront infrastructure can confuse the hatchlings and cause them to move towards these lights. This puts them at risk of dehydration and being exposed to predators.
Not only is the pristine night sky important to astronomers, it has played an integral role in bringing people together throughout history, influencing culture and being a reference point for location and guidance. Stories about different constellations can be found in Aboriginal and Greek culture, the movement of stars signalling different events and seasons.
Admiring the Milky Way and taking in the grand expanse of the natural sky inspires and motivates, it reconnects us to the universe and helps us find our place within it. Artificial light clouds our ability to gaze at the night sky, ultimately creating a great loss of natural beauty in our own lives and discontinuing the creation and telling of stories.
Light pollution is bright and obvious and it is essential that we reduce our consumption and use of artificial light to better the environment around us. Simple ways each and every one of us can do this include installing sensor lights outside our homes, only turning on lights when they are truly needed, placing shades on lights (and petitioning local councils to place shades on lights), and educating others about the impact of light pollution.
- Tegan Clark is a student at the ANU studying Astrophysics.