The Great Expanse

This month’s challenge is written by a guest, Mozghon Rajaee, a grad student at the University of Michigan and a friend of mine. This month you’re challenged to look up–way up!–past the trees to the night sky.  Night sky viewing can be done any time of the year, but with summer vacation here, it might be easier to involve the whole family.  Get outside and stay away from the streetlights.


Several years ago someone asked me if I knew what the current phase of the moon was.  Since I was working as a naturalist at that time, it was expected that I knew the answer.  It turns out that I had no idea. Do you have any idea what the current phase of the moon is? What constellations are visible this time of year?  Nowadays, the necessity of watching the moon and talking about fortnights is less relevant, but it used to be how we told time—holidays were (and some are) marked by moon phases (a fortnight is the time from a full moon to a new moon, and vice versa).

Photo by author

Photo by author

The longest day of the year, or the summer solstice here in the Northern Hemisphere, is coming up June 21.  It marks the time when we’re most tilted toward the sun.   Constellations get a bit more press because of the Greek mythology associated with them, for example, but it’s not so easy to look up to the sky and identify constellations. Here in southeast Michigan this is a challenge as we are faced with not only cloudy skies, but also light pollution.  Light pollution is exactly how it sounds—it’s light that shines out toward the sky or beyond the necessary area for people to see, creating a haze that lights up the sky unnaturally.

Light Pollution comparison--Utah (courtesy Wikimedia commons)

Light Pollution comparison–Utah (courtesy Wikimedia commons)

Go outside on a clear night, if you’re near businesses or homes with a lot of lighting, or even if you’re just in a metropolitan area, you’ll notice that it is difficult to distinguish stars and planets in the sky because of the light pollution. The inability to see stars is surely an annoyance, but there are also ecological concerns. For nocturnal animals or for all animals that depend on the amount of light and darkness in a day, altering the night sky can have a significant impact on feeding, migration, and breeding. Birds, insects, bats, frogs, turtles, and even squid are thrown off by artificial lights. A few years ago Michigan created an International Dark Sky Park, the Headlands, one of only 15 that exist in the world. The park is a 600-acre plot of old-growth forests outside Mackinaw City, and has a low-light, clear view of the sky. The county has even passed an ordinance to keep light pollution low in surrounding areas. While a visit to this Dark Sky Park would be grand, you should still be able to go stargazing in southeast Michigan or your neighborhood—just search out areas of low light or more seclusion. If you want to go stargazing and actually recognize constellations and spot the Andromeda Galaxy, there are books and tablet/phone applications that can help you.  Just surveying the sky and observing seasonal changes can be a great exploration.

Saguaro NP (Photo courtesy of author)

Saguaro NP (Photo courtesy of author)

If you’re trying to make out dimmer stars, sometimes it works best to view it in your periphery. (Biology tidbit: This utilizes averted vision through the biological make-up of your eyes. Your eyes have two types of photoreceptors: cones and rods. The cones, which allow you to see in color, are located in the center of your retina and are not very sensitive to light.  Rods are located on the periphery of your retina and are extremely sensitive to light, but only give you sight in black and white.  Once you let your eyes adjust to low light, it’s the rods in your eyes that allow you to see at night and make stargazing possible.  Using these mechanisms, if you look at stars straight-on, they may not seem as bright as when you view them to the side of your vision.  Give it a try to see if you notice the difference!) Here are a few extra tips to make for the best sky-viewing: Make sure you turn off as many outside lights as you can or at least move away from street lights.  Give your eyes some time to adjust to darkness; it usually takes about 20-30 minutes.  The more your eyes adjust to darkness, the more stars you’ll be able to see.  Look at some books or pictures of constellations before going stargazing; you just might recognize a few! As fun as a full moon is, the bright light makes it difficult to stargaze, so keep track of the moon and take advantage of new moons!

— Mozhgon Rajaee is a graduate student at the University of Michigan studying environmental health.  Her research has focused on health in a small-scale gold mining community in Ghana and policies on environmental quality around schools in Michigan.


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