Two photos from around sunset Friday evening tell a neat story about how light passes through our atmosphere and how clouds can interrupt and change the view.
Those are shadows cast by the setting sun to the west as the light passes by (and gets blocked by) a downpour about 12 miles west of Huntsville in the Madison area around 7:15 PM.
We call the dark lines on the sun’s side of the sky ‘crepuscular’ rays; the lines on the opposite side of the sky appear to radiate from the antisolar point: the point exactly opposite of where the sun is positioned. We call those anticrepuscular rays.
In other words, it’s not a conspiracy theory come to life over Alabama.
Don’t believe me?
This is what it looks like from above when that happens as the International Space Station orbited above the North Pacific Ocean (latitude 14.3, longitude -102.4) on 19 May 2011 at 12:20:26 GMT. (7:20:26 AM CDT)
Clouds and their long shadows photographed as the International Space Station orbited above the North Pacific Ocean (latitude 14.3, longitude -102.4) on 19 May 2011 at 12:20:26 GMT:
Those shadows happen more often than you would think (as do crepuscular and anticrepuscular rays).
It’s the same ‘shadow,’ by the way, you just see the part of the shadow on the sun’s side of the sky more often than the fainter, less contrasted view on the opposite side.
The above photo from the International Space Station is a great example of how light travels in a straight line (physics experts just heard nails on a chalkboard). Light is both a particle and a wave, and as long as there is nothing blocking it, that wave will travel in a straight line. Yes, it’s true that light also scatters when it hits something (that’s why we’re actually able to see anything at all), and it can be bent by gravity, refracted in water or a pane of glass, etc.; however, in general it can be understood that light follows a straight line pattern. That’s why we get straight shadows like those seen here. (Straight is in the eye of the beholder, by the way.)
Rainbows are another way we can see how light behaves in the atmosphere. Sunlight enters the raindrop and refracts causing the different wavelengths of light to disperse into the color spectrum we know as ROY G BIV (red orange yellow green blue indigo and violet).
If you’ve never seen anything like this before, do yourself a favor and stop to enjoy the view a bit more often! You’ll be surprised at all the neat things you’re missing up there!
Looking for the forecast? It’s always online at WHNT.com/Weather and in the “Daily Forecast” section on Live Alert 19!
-Jason
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