You may think that light pollution isn’t something extraordinarily important. You may believe that every other type of pollution has a larger impact on the environment than light pollution does. You may not even have heard of it before. It may not be polluting our lakes, our air or the Earth’s living creatures, but light pollution is serious, and it needs to be addressed by everyone.

Light pollution, or “sky glow”, is the glow you can see at night above cities and towns. Light pollution is a problem that has been accompanying man ever since he started his first fire some 15,000 years ago, and technology has only made it worse. Light pollution is the stray light that comes from streetlights, billboard signs, buildings, parking lots, sports arenas and any other source of illumination that is reflected or directed into the atmosphere. Light pollution is made worse with air pollution, as the small particles that float in the air serve to scatter and reflect the light, compounding the problem. The effect of light pollution is to reduce the contrast, and therefore the visibility of dimmer objects in the night sky, which affects professional, as well as amateur astronomers. Light pollution has obscured our view of constellations, meteor showers, and even the planets.

Light pollution exists on every continent except Antarctica. Urban light pollution means that one-fifth of the world’s population can no longer see the Milky Way with the naked eye. Many city kids, even if they did peer through the orange smog above their heads, would probably see only a handful of stars. We have lost our view of the stars, and we have mucked up our nighttime environment as well. Astronomers are calling for the dark places on Earth to be preserved as national parks, so that we do not lose completely our window on the Universe.

Light pollution impacts astronomical research and can even affect human health. The excess illumination also affects wildlife in various ways from altering migration routes to eating habits and breeding behavior, to name a few.

Lots of people find the ever-brightening night annoying, and animals that are programmed to prefer the dark may avoid brightened habitat. Sea turtles can get lost searching for a beach to lay eggs, and their hatchlings may confuse over-lit beachfront resorts for the ocean horizon, wasting precious energy needed to find the sea and escape predators. Because their necks aren’t yet long enough to see things far away, baby turtles rely on the mirror image of the moon to guide them to the sea, to begin their new life. A car may even hit a particular turtle, which was thinking the light from a nearby city was moonlight reflecting off the ocean waves. Birds that live in and around cities can die because of sky glow, too. The abundance of bright lights can blind them, leading to countless collisions with buildings, billboards and other tall structures.

These are merely a few of the possible negative effects light pollution has on our world. A very serious issue in our modern-day society is that light pollution is a terrible waste of energy.

Reducing light pollution is not difficult. Light pollution is the easiest type of pollution to end. On an individual level, people can help reduce much sky glow by using lighting only when necessary and by choosing well shielded lighting fixtures. The stars above us are a priceless heritage—not only for astronomers but for all humans. More of our children should be able to look up at night and see that the Milky Way is not just a candy bar.