The Great American Eclipse of 2017

Aug 27, 2017

I’m continuing the topic of the upcoming solar eclipse known as the Great American Eclipse.

The states the eclipse will traverse are, in order: Oregon, Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina, and South Carolina. Twelve million Americans live in the eclipse band; but 200 million are within one day’s drive. For Mary and me, it’s two days, but we’re going anyway.

Did you know the sun has an atmosphere? Obviously, it is nothing like our atmosphere; but there is an area of gas extending away from the surface. There is a thin layer of low-density gas near the surface of the sun called the chromosphere. The part of the chromosphere closest to the surface of the sun is cooler; but, amazingly, the further from the sun, the hotter it gets.

And just like we have layers in our atmosphere, the sun’s atmosphere has two layers. Just past the chromosphere is the corona. It extends out from the sun a very long way, about 10% of the way to earth. It’s significantly hotter than the chromosphere; in fact it is far hotter than the surface of the sun itself! I know, you’d think it would have to be cooler, since it’s millions of miles away from the sun and all that. Trust me, the explanation won’t fit in this blog post.

We cannot see the sun’s atmosphere, not the chromosphere nor the corona. Even though they are hotter than the sun, we still can’t see them.Eclipse At least, not with the naked eye. The reason is density. The atoms may be hotter but there are not many of them. So, the density of the sun’s atoms outshines the relatively scarce atoms in its atmosphere. Think of a tree full of green leaves with just three dark green leaves. You’re not going to see those few dark leaves amid all those other leaves.

During the total solar eclipse today, those of us in the eclipse band will get to see the sun’s atmosphere with our naked eyes. For two whole minutes, the light from the surface of the sun will be blocked, allowing us to see the less bright atmosphere around the sun. Cool! (Well, not really cool. The sun’s atmosphere is hotter than the sun. But you know what I mean.)

My astronomy book says the inner atmosphere, the chromosphere, will appear pink and the much larger outer atmosphere, the corona, will have a pale white glow. I’ll let you know. Silly? Sure; you have a TV. But what fun is that?

 

Please be sure to review my previous post on: The Total Solar Eclipse of 1919 

Lt. Col. Gene Doremus grew up on a dairy farm in upstate New York in a very large family: eight brothers and six sisters. After nine enlisted years in the Air Force, he became an officer and served twenty-two more years, retiring as a Lieutenant Colonel. Most of his career was in munitions or aircraft maintenance where he proudly served on the deployed headquarters staff during Desert Shield/Desert Storm. His claim to fame came immediately after 9/11 when he led the U.S. Central Command’s Joint Munitions Office for Operation Enduring Freedom. Retiring in 2005, he taught JROTC for six years.