The Lost Dark of Night

Mar 20, 2015

United States of America at night - a composite assembled from data acquired by the Suomi NPP satellite in April and October 2012
Credit NASA

In this episode of Our Island Universe, we look at how many stars you can see at night. Thanks to light pollution, you can't see very much.

Learn more about Starry Nights events in your area.


What Do We Lose When We Lose The Night?

We do not see the night sky here in the Valley the way that our predecessors just 50 years ago would have seen it. The Milky Way, our home Galaxy that once shined brilliantly overhead against the black of night, has almost disappeared completely from our sky. It is estimated that ~90% of Americans now live in areas where they no longer see the Milky Way at all. Does it matter that we don’t? Do we need to see the stars? What do we lose when we lose the night?

This issue of light pollution is so much more than just the disappearing stars. Light pollution — the overuse and misuse of artificial light at night — wastes money, wastes energy, endangers our physical, mental, and spiritual health, takes a tremendous environmental toll, and erases the stars from our skies. The International Dark-Sky Association estimates that one-third of all lighting in the U.S. is wasted, at an annual cost of about 30 million barrels of oil and 8.2 million tons of coal worth a total of about more than $2 billion.

Worst of all, we have bought into the idea that more light makes us safe. Smarter use of light makes us safe, saves cities & homeowners money, is better for our health and our environment. We can have responsible lighting that ensures our safety and security without polluting our nights. 

Many fixes are simple, like turning off lights when they’re not being used, installing motion sensors and shielding the light so that it is directed downward onto the ground, where it’s needed. Now is the right time to learn more about how we can light our homes, businesses and cities thoughtfully.

Let’s bring back our dark, starry nights that generations of Americans took for granted.