Wednesday, July 11, 2012

Marcus Carey’s On the Marc: Siriusly,
old dogs can teach a few new tricks too


 

I found a really cool APP for my iPhone called “Night Sky,” and it’s free. If you hold it overhead it shows you the sky both above and below the horizon from your vantage point, including the names of stars and planets. It also includes the outlines of constellations by connecting the dots.
 

I don’t know if you are a stargazer, but from the time I was a boy my father taught me to find and identify stars and constellations in the night sky. In the old days, 50 years ago, he used to hold a cardboard wheel chart overhead and I, being much shorter, held a flashlight on it from below. We used to stand out in the driveway of our little house and study the night sky.
 

One thing I learned from those days was that, during this time of the year, we are in the “dog days” of summer. It is usually the hottest time of the year in the northern hemisphere. The term “dog days” has been used for centuries. In fact, it was a term used by the Romans and, before them, the Greeks. This time of the year gets its name from the fact that the star Sirius – the “dog star” – used to rise at about the same time as the sun, and Sirius is the brightest star in the constellation Canis Major (large dog). I say that the star “used to” rise with the sun, because it no longer does. Why? Well, get a load of this.
 

You probably know something about the Earth’s orbit. You probably know that, in addition to orbiting the sun, Earth also rotates on its own axis. But did you know that Earth’s axis “wobbles”? In fact, just as there is a predictable amount of time that it takes for Earth to make one rotation (24 hours) and a predictable amount of time that it takes Earth to orbit the sun (365 ¼ days), there is also a very predictable pattern to the wobble of its axis.
 

If one were to imagine an axle running directly between the poles of the earth and extending beyond the surface, that axle would make a little cone shape as the wobble pushes both ends of that axle around in a circle. How long does it take for the wobble to make a full circle? Twenty-six thousand years.
 

Recently a friend of mine who works for the FAA told me that at his airport they recently had to renumber the runways because the polar shift had proceeded beyond 2 degrees. This got me to thinking.
 

Earth is actually closer to the sun in the winter than it is in the summer, but because the tilt of Earth puts the northern hemisphere closer to the sun in the summer, it is our warm season. The opposite is true for the southern hemisphere.
 

So if Earth’s axis is shifting, that means that during some periods of time for about 13,000 years the northern hemisphere will get closer to the sun, and at other periods of time for about the next 13,000 years it will get farther away. Might this help explain why temperatures seem to be changing ever so slightly?
 

According to scientists, this phenomenon does explain why Sirius doesn’t rise with the sun anymore. Earth has wobbled off that pattern, and Sirius and the sun don’t show up at exactly the same time anymore.
 

The ancient Egyptians noticed that Sirius rose with the sun at about the same time as the Nile flooded and the weather got hotter. And any number of authors, poets, songwriters and cultural commentators have used the phrase “dog days” of summer to describe this time of year.
 

But of all the things for which we might use the phrase today it seems that the earliest recorded uses were all tied to the dog star Sirius. In those days before published calendars, before electronics, before satellites, GPS and before modern science had explained so much of our natural world to us, it was very common for man to look toward the heavens for guidance, not only spiritually, but for help determining when to plant, when to harvest and what was coming.
 

The other night I felt a bit nostalgic standing out in the middle of our farm, miles from any light pollution, looking up at the inky black sky peppered with silver light. I remembered the days of standing like that with my dad, naming the stars, seeing the constellations and wondering how they all got their name.
 

And putting my iPhone up overhead, moving it around and seeing it all come to life right before my eyes I marveled at how far we had come since the days of that cardboard wheel and the printed instructions, my little Boy Scout flashlight shining up at my dad’s hands as he guided me with his nightly lessons.
 

As I put the phone down and looked into eternity with my naked eyes, I knew that among those stars somewhere Dad was looking back down at me and smiling.
 

Sharing that experience with one of my sons made me realize that with modern technology not only can old dogs learn new tricks, but we can teach a few of them too. Siriusly.
 

Marcus Carey is a Northern Kentucky lawyer with 32 years experience. He is also a farmer, talk radio host and public speaker who loves history and politics. He is a prolific and accomplished writer whose blog, BluegrassBulletin.com, is “dedicated to honest and respectful comment on the political and cultural issues of our time.” He writes a regular commentary for KyForward.

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