As we move into September, the sun is setting early enough to allow us to go outside and look into the nighttime sky without having to stay up too late. But what should one look for? Before television and computers were invented, the nighttime sky was of intense interest to people all over the world. Among the ocean of stars were a few that stood out in patterns that we call “constellations.”
There are a few constellations, like the Big Dipper, that are so bright that they are easy for us to locate. Among them is a constellation called Cassiopeia. The story of Cassiopeia has been thoroughly covered in the movie, “Clash of the Titans,” but I will give a brief synopsis for those who haven’t seen the movie in a while. Cassiopeia was the beautiful Queen of Argos. One day, she boasted that her daughter, Andromeda, was more beautiful than Aphrodite. Angered by this hubris, Zeus decided to destroy Argos by releasing the Kraken. Andromeda is offered as a sacrifice to appease the monster, but Perseus swoops in to save the day by killing the Kraken with the severed head of Medusa. This story has multiple forms.
There are two key problems associated with stargazing. First is the fact that culture, religion and at least 2,000 years of human history separate us from the the people who named the constellations. What was obvious to them is far less apparent to our 21st-century imaginations and the patterns are often lost on us. Thus, it is difficult to imagine the Cassiopeia constellation showing a woman sitting on a throne. Instead, we see a “W.”
The other big problem with stargazing is the fact that the stars move. The Earth rotates daily, the Earth orbits the sun annually, and as a result the stars can change places. Stars easily seen in winter are almost impossible to see in summer, and vice versa. Everything depends on where you are, the direction you are looking in, and (most importantly) when you are looking.
When one considers the technology that is available today, my approach to astronomy may seem outdated. Stargazing apps are available for various electronic devices and even a 4-year old child could easily find Cassiopeia. The problem is that it is so easy that the information is just as easily obliterated from the mind by the next thing that pops up. If you want to actually remember something, you have to put a little time into it.
If you have the technology, then use it to find Cassiopeia, but then turn off the device and give yourself a chance to use your brain. Give this constellation a chance to etch itself into your mind and allow yourself to use the virtual reality of imagination to understand what you are looking at and how it might look at different times of the day.
Go out on a clear August night and find a spot where you have an unobstructed view of the northern sky. Do this at 9 p.m. and you will see the Big Dipper resting on the northern horizon with the two bright stars of the right-hand edge of the “dipper” lining up to point at Polaris (the North Star). Shift your attention to the right and you should see the wonky “W” of stars that we know as Cassiopeia. At this time of year the W is slightly tilted to the west. If you were to go out at 4:15 a.m., when my beautiful wife Susan wakes up for work, you would discover that the W has moved southwest and has rotated so that it is upside-down; wonderful evidence that Earth is spinning.
I’ve included two versions of a photo that I took in my driveway at 9:10 p.m. on Aug. 23. In one I have included the horizon to give a sense of perspective. In the other I’ve labeled the main stars of the constellation and added lines that connect them. Note that I left just a little bit of one of the trees as a reference point.
The top star on the right-hand side is called Beta Cassiopeia (henceforth known as Beta Cas). This yellow giant lies some 54 light years from Earth. A “light year” is a measure of distance, rather than time. It refers to the distance that light can travel in one year. Since light moves at 186,000 miles per second, and since there are 31,536,000 seconds in a year, that amounts to … times 80,000 … carry the five … about 5.86 trillion miles. Thus, Beta Cas is a paltry 316 trillion miles away.
Below Beta Cas is Alpha Cas, an orange giant that lies some 228 light years from Earth. Alpha Cas is approaching the end of its life and is generating an enormous amount of light, but it appears no brighter than Beta Cas because it is so much further away. We needn’t worry about losing Alpha Cas, however, for the lives of stars are measured in millions, even billions of years.
Move to the left and you find Gamma Cas. This star is known as a variable star, which means it has a disc of material thrown off its surface due to its extremely fast rate of rotation. Over time, as gases spin off the star’s surface, the shape of the cloud changes, or is variable. This star is somewhat more difficult to see because it is about 550 light years from Earth. Finally, we come to Epsilon Cas, a blue giant that lies some 410 light years from Earth. This star has exhausted its hydrogen supply and is now entering the later stages of its life as well.
All of the science pales in comparison to the simple beauty of seeing stars that you know. Grab a lawn chair, perhaps even a friend, and go out to look at the stars. There is nothing on TV that can match to the sensory experience of the sights, sounds and smells of a summer evening.
Bill Danielson has worked for the National Park Service, the US Forest Service, and the Massachusetts State Parks. He has been a professional writer and nature photographer for 19 years and he also teaches high school biology and physics. Visit www.speakingofnature.com for more information, or go to Speaking of Nature on Facebook.