Why should we keep our nighttime skies dark?

Is it important to keep our nighttime skies dark? There has been significant debate lately about this topic, spurred by the growth of satellite constellations. Closer to the surface of Earth, there have long been debates about how much lighting human society really needs. We spoke to John Barentine, the Director of Public Policy at the International Dark-Sky Association. He explained what IDA does and he shared his thoughts on why this is such an important topic. 

What is the International Dark-Sky Association’s mission and what does it do?

IDA’s mission is to preserve and protect the nighttime environment and our heritage of dark skies through environmentally responsible outdoor lighting. We work toward achieving our mission by advocating for the active protection of the night sky; educating the public and decisionmakers about effective night sky conservation practices and public policies; and promoting sustainable markets for appropriate outdoor lighting design and lighting products. 

How should humanity manage the tension between conserving dark skies on the one hand and exploring space (especially via satellites) on the other hand?

We should be mindful that the night sky, and the orbital space around Earth of which it is a part, is the common heritage of all humanity, as much of a shared resource as air or water. Ideally, we should work together for its shared benefit and its conservation. There is existing law – namely the Outer Space Treaty of 1967 – that aims to create that notion of consensus and cooperation. But as is often the case, the pace of technology’s advances is much faster than the law right now. Whether the night sky is meaningful to enough people will in part dictate the next chapter of this story.

How did you come to be involved in dark sky conservation and what advice do you have for people who would like to get involved?

By training, I am an astronomer and worked for many years in research and observatory support. But at heart I was, am, and always will be an amateur astronomer who loves both the universe and the night. In my current work in dark-sky conservation I find a distinct sense of fulfillment and purpose. And because I believe strongly in the value of science in society, this work allows me to promote scientific inquiry and thinking in my daily activities.

Anyone can become involved in protecting the night, and everyone has a meaningful role to play if they choose. It can be as simple as looking at the outdoor lighting around one’s home and making small changes that keep light out of the night sky and the nighttime biological environment while enhancing visibility, safety, and security. It can be talking to one’s friends, family, and neighbors about the issue, or advocating to elected officials and other decisionmakers. If we believe in the value of the resource of nighttime darkness, I’m convinced that we’ll live our convictions and serve as models for others to follow.