Spring Equinox DOES NOT equal 12 hours of light

It’s something that we all learned in school. On the fall and spring equinox, we experience 12 hours of sunlight and 12 hours of darkness. But, I am here to tell you that, that is actually NOT TRUE! How so you say? I’ll explain. The following graph is a list of cities and their sunrise/sunset times for tomorrow, which just so happens to be the equinox.

If you notice, the days tomorrow are not 12 hours long, but more like 12 hours and 6 mins. So, what’s going on here? Well, there are 2 main reasons. The first is actually all in the definition of sunrise and sunset. Most people look at the sunrise as the second the sun is spotted over the horizon. But, actual definition says that sunrise is when the center of the sun rises over the horizon. It takes about 3 mins from when the first sliver of sun is seen and when we see the center of the sun. The same can be said for the sunset. Sunset isn’t when we see the last of the sun slide below the horizon. It’s when the center of the sun is on the horizon. That too takes 3 mins to occur, which gives us a difference of 6 minutes.

The other reason all has to do with the fact that your eyes are playing tricks on you. Or is it the sun playing tricks on you? You may “think” you see the sun. But, the atmopshere is great at bending light, so sometimes you may think you see the sun, but it’s really a mirror image of the sun.

So, if you’re keeping track, last Friday was when Oklahoma had 12 hours of light and dark. Our “equinox” was 2 days off. Oh well…



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