I know, a lot of science writers and bloggers are publishing their “greatest hits” lists of space and astronomy events this week and next. A lot happened in 2019, some really good while other events were less than wonderful. I think it’s all worth examining. However, an article on that would rapidly take on book-size proportions and, others are doing it for me.

So, instead of inflicting on you MY list of orbital science accomplishments or pretty pictures from observatories, I’m going to talk about something else: our loss of the beautiful night sky. The stars are where we came from, and people have watched and studied them from the earliest times. They are a global heritage we all share.

Those of you who have followed me for a while know that I was involved in the production of a short video for the International Dark-Sky Association. It’s called Losing the Dark. It was originally made for planetarium domes and continues to get used in theaters around the world. We also made a flat-screen version for people to use in lectures and public presentations about light pollution. (You can get more info on the video here. It was produced a few years ago. In the course of six minutes, LTD outlines the challenges that light pollution pose).

Losing the Dark of Night

The image here shows what our planet looks like at night, from space. Lights in many places. I live in a reasonably dark-sky area, but many people do not. The problem is particularly pronounced in big cities. There, people might be able to see planets and a few of the brighter stars, as well as the Moon. So, as the video points out, many people have never seen the Milky Way. Kids grow up not knowing about the beauty of the night sky. Astronomers are, of course, quite sensitive to the loss of darkness. In the video, I coined the phrase, “We are losing the dark of night at the speed of light”. That sentiment is even truer these days than it was when I wrote the script.

So, what do we do? The video outlines simple steps that individuals and communities can take to curtail stray light. We don’t need to use unnecessary lights. When we do have outdoor lights, we should shine them directly where we need them (not up into the sky). And, we should use the correct lighting types for each situation. In more recent times, we use LEDs in streetlights, which saves energy. But, IDA and others have urged communities to use cooler LEDs. The cheapest, garish blue ones do even worse damage to health than the old incandescents did.

Overuse of lighting not only costs a lot of money, but it’s a waste of fossil fuels. We are moving toward more sustainable power sources, which is good. But, that shouldn’t stop us from over-spending on lighting up the night sky.

What Are We Saving?

So, one question I sometimes get when I talk about light pollution is: “Why should we care what astronomers need? Doesn’t everyone’s safety come first?”

Let’s deconstruct that. First, what astronomers need are dark skies to study objects in the sky. Serious science gets done from the ground on Earth, science that enables us to understand our own home as well as the rest of the universe. The nations of planet Earth do fund astronomy research money and provide other forms of support. So, let’s not waste that money and effort by removing the view of objects we’re paying people to study.

Second, lighting does not always equal safety. The IDA has an amazing page about the payoffs for proper lighting and safety. It explains why certain forms of outdoor lighting at night can actually NOT enhance safety and security. Properly lit pathways and buildings DO provide safety without impinging on the night sky. Furthermore, human health isn’t just about safety in dark situations. It also extends to our health. For example, light pollution has been shown to impinge on people’s sleep cycles (and circadian rhythms). Beyond human health, stray light affects the health of other living things on this planet.

Light and Life

A couple of months ago, I gave a presentation of Losing the Dark to a local environmental group. I also learned more about the effects of light pollution on insects and fish from another speaker on our panel. It was pretty eye-opening for me — and I think for many in the audience. It probably shouldn’t be so surprising to all of us that light affects life. All the living things on this planet had their evolutionary cycles controlled by light (or the lack of it). So, when our artificial lights change the conditions in which we all “grew up”, it’s naturally going to affect our life processes.

Use Light Wisely Starting Now

In the end, I know we’re not going to give up artificial light. Nobody’s asking any of us to do that. What I and others who advocate for dark skies to do to use lighting wisely. It’s that simple.

All of us, as well as the plants and animals who share this planet with us, will benefit. So, check out the IDA pages about light pollution. See if there’s something YOU can do to help mitigate light pollution, even in your own home or community. Make it a goal for 2020 and let’s slow the loss of the dark nights across our beautiful planet. We’ll all benefit.