Matchbox Twenty’s Bright Lights.
CeeLo Green’s Bright Lights Bigger City.
My personal favorite is Sara Bareilles’s Bright Lights and Cityscapes.
There is no shortage of songs about bright lights–perhaps it’s a testament to how prevalent we’ve made them. Think about it for a moment: We love candles and think they improve any occasion. We’re scared of dark alleys, so we’ve dotted them with streetlights. All of this, however, comes at a cost.
What is light pollution? It is a familiar concept disguised in a term that not everyone might know. Light pollution is simply the phrase to describe excessive light in an area and all the consequences that come along with it. There are four main components to it:
- Sky Glow
This component of light pollution is often the most familiar to people and simply describes the brightening of the sky around highly populated areas. In the picture above, you see that the area of cloud immediately above the city is a light orange and fades closer to black as you move away from the city. You might be surprised to learn that a certain amount of sky glow actually comes from natural sources! These include sunlight reflecting from the moon and starlight scattering in the atmosphere, but don’t really come into play with the type of light pollution we’ll be talking about. Most of the negative effects of sky glow come from man-made light such as streetlights or building lights. Interestingly enough, the brightening effect becomes exaggerated in dusty or cloudy environments as the light bounces off the tiny particles in the air. This means that the areas with poor air quality (many particles in the air) will experience more sky glow from less light.
This is the component of light pollution that most affects astronomers. Over time, skies have only gotten brighter and fewer areas than ever are able to see the Milky Way Galaxy. It also means all but the brightest stars are no longer available to a casual backyard observer. For many, this means that any sky-watching session requires at least a half hour drive from home.
2. Light Trespass
This is a component of light pollution that affects your personal health–it describes light that crosses boundaries into areas where it is no longer desired. You may have experienced this firsthand on a sleepless night as a light outside your bedroom window streamed mercilessly through your blinds. If so, then you understand how this type of light pollution can hurt our quality of life. Luckily, it is easy to cut down on this type of light pollution by changing the shape and types of lamps that we use along our streets.
Unfortunately, we are not the only victims of light pollution. When unnatural light reaches places it should not, wildlife can be harmed in the process as well. Countless sea turtles, who rely on moonlight to guide them home, have been led astray by streetlights along the Florida coastline. Many other animals who rely on the natural light and dark cycle have also developed irregular feeding and mating behavior.
Glare is another type of light pollution that can be detrimental to our personal happiness. This is an unpleasant type of lighting that can bother you even if you’re not trying to sleep, because it affects your vision at night. It is an irony of light pollution as extra brightness results in lowered visibility. Glare is the result of excessively bright lights and forces you to squint. The uncontrolled light becomes the brightest object and actually interferes with your ability to see important things such as a driveway or the sidewalk. The key detail of this component is that it causes physical discomfort in people. It can be annoying, or even painful.
This last type of light pollution is a combination of the last three. When too many lights are placed too close together, it becomes distracting and difficult to understand what you’re looking at. It results in a generally brighter ambiance in an area and prevents our eyes from ever becoming fully dark-adapted.
This and other types of light pollution can be dangerous in urban areas because, without dark-adapted vision, any area that isn’t well-lit becomes disproportionately dangerous. The distraction that the excessive lights create can also lead to accidents when drivers can’t figure out what they’re seeing in time.
While most of us know of light pollution as something that only affects those who want to see more stars from their backyard. By breaking down all the types of light pollution that exist, however, we see that light pollution is more than that and is detrimental to many different aspects of our lives. It is not only a tremendous waste of resources, but also harms our quality of life. Whether or not you’re an astronomer, light pollution has an effect on you.