On a clear night a century ago, thousands of stars would have been visible to most people on the planet. Today, that’s only true for a minority — those living in rural areas far from urban settings. For the rest of us, the sky is relatively empty. Folks in the suburbs might see a few hundred; city dwellers, dozens. In the biggest, brightest cities, people are lucky to see a few. Our own lights have blocked them out.
Image Source: NASA via Visible Earth.
The image above shows our lights shining up into space. While large areas remain unlit, they are not where most people live.
In the Continental U.S., even the best star-gazing spots reveal fewer stars than they used to. In 1971, Tucson began regulating outdoor lights to protect the observatories located in the desert nearby. A recent study shows that those regulations, which have been strengthened over the years, have helped keep degradation of the night sky view in check.
Read my new column for NRDC’s This Green Life to learn more about light pollution, its effects on wildlife and human health, and and easy steps you can take to help reduce it through small changes to your outdoor lighting.