This July and August will be a good time to view our Milky Way galaxy. The key is to select moonless nights and be far away from artificial light.
And that artificial light turns out to be a problem. There is such a thing as light pollution.
Light pollution, or sky glow, is the brightening of the night sky caused by headlights, streetlights, buildings, and outdoor advertising. It is a global issue, as more than 80% of the earth is impacted by it, and 99% of all Americans live under it.
If you are interested in how the Eastern Shore fares in light pollution, a light pollution map has been created from thousands of satellite photos. There is an interactive map, or the NASA Blue Marble Navigator. Google Earth users can download an overlay of light pollution. The countries that are the biggest light polluters are highly industrialized small countries such as Singapore, Qatar, and Kuwait.
Apparently, light pollution can affect human health, animal behavior, and animal migration. Artificial light can impact our circadian rhythm and sleep. Blue light, found in cell phones, computer devices, and LED lights, reduces levels of melatonin. Based on scientific discoveries about the health effects of artificial light, the American Medical Association (AMA) is advocating reducing light pollution and conducting research on its impact.
Nocturnal animals are also negatively impacted by light pollution. Prey animals are more vulnerable in light-soaked nights. Artificial lights can impact nighttime croaking by amphibians, which is part of their breeding ritual. Light pollution can disrupt other nocturnal reproductive activities. Large numbers of insects (which birds depend on) are killed by artificial lights.
Scientists believe that animal migration is partly guided by the moon and they believe that artificial light can impact migration memory, causing birds and sea turtles to go off course, especially on moonless nights.
Scientists classify light pollution into three types: glare, clutter, and light trespass. Glare is excessive brightness that can cause visual discomfort (such as headlights), this is problematic for migration and animals such as deer. Clutter is bright, confusing, and excessive groupings of light sources (for example, Times Square in New York City), which can also impact migration patterns. Light trespass is when light extends into an area where it is not wanted or needed (like a streetlight illuminating the sky instead of the ground below). In fact, most outdoor lighting is poorly positioned, sending wasted electricity up into the sky.
There are several organizations actively involved in reducing light pollution. The National Park Service (NPS) is monitoring light pollution in some parks. The International Dark Sky Association (IDA) is dedicated to awareness and certifies parks for the NPS. Recently, the IDA approved the first U.S. dark sky reserve. A 1,416 square mile Central Idaho Dark Sky Reserve is one of 13 other dark sky reserves throughout the world.
Another problem with light pollution is that it is difficult to see the stars. But if you want to try to see the Milky Way, it will be visible in the evening from July through early October.
Accounting for moonlight, these dates will be the best times to view the Milky Way:
- July 28 – Aug. 7
- Aug. 26 – Sept. 6
- Sept. 24 – Oct. 5
The best time is right after sunset. However, go to a place with total darkness. We should be able to see the band of the Milky Way, and a small telescope or a pair of stargazing binoculars will make it more visible. On the low horizon, we should also be able to see Sagittarius, home to our galaxy’s black hole.
For those of you who have a boat and are experienced boaters, the rivers and Chesapeake Bay have less light pollution. As for me, I intend to get in my car and drive to a dark landscape, keeping my fingers crossed that I will be able to see it. Because, well, it is cool.
Angela Rieck, a Caroline County native, received her PhD in Mathematical Psychology from the University of Maryland and worked as a scientist at Bell Labs and other high-tech companies in New Jersey before retiring as a corporate executive. Angela and her dogs divide their time between St Michaels and Key West, Florida. Her daughter lives and works in New York City.
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