When we stumbled upon this photo on Inhabitat, our first reaction was how lovely it was. Then we read the article. And discovered that it really isn't lovely. It's light pollution. This image from NASA shows the earth at night. And what it means, according to night sky activist Anthony Arrigo, is that we're so wasteful that sky glow (light escaping into the night sky and causing a glow over urban/suburban areas) costs the US between $5-10 billion per year. You read that correctly -- and it doesn't include all outdoor lighting, just the outdoor lighting that's so misdirected that it lights up the night sky.
Glare and light trespass (your neighbors' unwanted light shining onto your property or into your home) are other results of improper outdoor lighting. When you go home tonight, open up all the shades and curtains, turn off the lights, and after your eyes have adapted to the dark, look at any light shining onto the ceilings or walls. This is light trespass. What can you do? Read more about it here, be aware, and if you have outdoor light fixtures, use them only when needed, and consider how they actually perform at night. (One place to look for light fixtures is Starry Night Lights.) Images: Inhabitat