Can You See the Stars?
Twinkle, twinkle, little star…
Star light, star bright, first star I see tonight…
Have you looked at the stars lately? You probably aren’t seeing as many of them as you would have a few years ago. Our beautiful, dark, starry skies are slowly but surely being blotted out by lights–street lights, house lights, shopping center lights, all kinds of outdoor lighting that’s often too bright and pointing in unneeded directions. And we’re not just missing out on a great nighttime view; light pollution negatively affects human health, wildlife health, and how much energy we all use (and pay for!). Today’s blog post is brought to you by Dr. Georgia Bracey.
You can help scientists monitor light pollution and learn your way around the night sky by joining Globe at Night this year. All you need to do is go outside on a clear night during one of the dates below and measure the brightness of your sky. Go to the Globe at Night website for easy directions and star maps. Each set of dates has a group of stars (constellation) for you to find (in May it’s Bootes, a really cool constellation):
This year’s Globe at Night dates:
Compare what stars you see in your sky to the maps on the website or app. When you find a map that matches what you see, you send that information (data) to Globe at Night through your computer or phone. And that’s it! You’ve collected and shared data that will help map areas of light pollution all around the world.
So, let’s take a look at the data so far! One great way to display and visualize data is by making a map. Here’s a the map of the United States (go here to see the whole world) from just a few days ago. The brown and yellow dots show where people have measured the brightness of their night sky and sent their report in to Globe at Night. According to the map legend, different colors relate to different LMs… what’s an LM?
Sky brightness across the US. Hey, we need some data for southwest Illinois!
LM means limiting magnitude… a fancy way of describing the darkness of the night sky by the faintest star that you can see in the sky. If I can see a really, really faint star in my backyard sky, then my sky must be pretty dark! That really, really faint star may have a magnitude (brightness) of around 7… so my sky’s LM might be 7 and be shown on the map with a dark brown dot. On the other hand, if I can only see the super bright stars (because there’s so much other light around that blocks out the faint ones), my sky has a lot of light pollution. Those really bright stars might have a magnitude of 1 or 0, so my sky’s LM would be 1 or 0 and be shown as a light yellow dot on this map. By looking at the colors and where they’re located, we can see where skies are darker and where there is light pollution.
You can find a lot more information on light pollution and how to help by visiting the Globe at Night website AND Lisa’s earlier post on this blog. 😀 Globe at Night–try it!