International Dark Sky Week

April 3rd, 2019

This week is International Dark Sky Week, in which we promote the protection of our natural nighttime sky. Although light pollution may sound like the world's least urgent problem, it is in fact quite serious.

A growing body of research suggests that the loss of natural darkness is harmful to humans. It has been linked to increased risks for depression, sleep disorders, obesity, diabetes and breast cancer.

It's an environmental problem. In the United States, residential outdoor lighting has the same carbon footprint as 3 million petrol cars. For nocturnal animals, the introduction of artificial light is devastating. Light pollution also affects diurnal wildlife, especially insects and migrating birds.

There is an economic cost. The United States loses an estimated $3 billion per year sending photons into the sky that provide no useful light.

Naturally, astronomers don't like light pollution. Even in the relatively clear Waikato sky, Hamilton lights obscure features such as the Andromeda Galaxy. From my back yard, the beautiful area around the Southern Cross is lost in light spilling from the Dairy Factory.

We are luckier than most developed countries. 99% of Europeans live in severely light-polluted skies. In Asia, it's normal for city-dwellers to live their entire lives without seeing more than a few of the brightest stars. I once met a middle-aged woman who thought that stars were fictional, like unicorns, something only seen in movies. Imagine her shock upon arriving in New Zealand and seeing the Milky Way.

Ten years ago it was almost impossible to convince local governments to listen to these complaints. Even now, it's common to be met with dismissive sneers when raising the topic. However, awareness is growing and I'm optimistic that local governments will take it more seriously in future.

In New Zealand, it helps that our skies are becoming recognised as a tourist attraction. The world's largest dark-sky reserve is in the South Island. Coupled with our view of celestial objects that can't be seen from the Northern Hemisphere, "astro-tourism" is a real opportunity—if we stop light-polluting the sky.

Protecting the night sky