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View Full Version : Sunsets are red, skies are blue, but why?



ConcinusMan
09-03-2011, 06:13 PM
Our sun puts out relatively white light. When that visible light is separated by the colors that make up white light, we see the colors of the rainbow.

Each color represents a different wavelength of light. A short wavelength will appear blue. A long wavelength will appear red. We cannot see with our eyes, a wavelength longer than red light.(called infrared) but we can feel it. It's heat, and we feel it whenever we are in the sunlight. A ceramic heat emitter bulb does put out light. But we cannot see it and neither can our snakes. We can only feel it's warmth. In fact, our snakes can't even see red light. They can only feel it's warmth. But we can see it with our eyes.

The molecules and particles in our atmosphere cause light to bounce off of them and scatter. Blue light, being the shortest wavelength, scatters easily. The blue you see in the sky is really just blue light being scattered and bounced off of the molecules in the air.

But the sun and the moon appear to be redder when they are closer to the horizon. Why? The same reason the sky is blue.

The closer to the horizon that they are, the more atmosphere that their light has to pass through to meet your eye. Since the atmosphere scatters blue light, the only color (wavelength) able to make it all the way through to our eye, is red light.

There's another wavelength that we cannot see. It's a shorter wavelength than violet light called "ultraviolet". Insects can see it, many animals can see it, but we can't. It's the same wavelength that can give us a nasty sunburn. Even shorter wavelength than that is deadly radiation. It's a good thing that our atmosphere scatters and or deflects most of that or life wouldn't exist on our planet.

Part of the sun's spectrum is radio waves. That also is really just another wavelength of light that nobody can see. So if you really think about it, those radio broadcasts you listen to, are traveling on a wave of invisible light!

Even though our garter snakes do not need ultraviolet, they can see it, even though we cant, and like us on a sunny day, it can lift their spirits and provide a psychological benefit. However, never expose an amelanistic (albino) animal to UV light. They have no protection from it. No melanin to deflect it. It will burn them and possibly cause cancer in the long term.

I thought of all of this because right now there is so much smoke in the air that the sunlight that makes it though is red. It's quite eerie. There's a strange red cast on everything around me.

That's pretty much all I had to say for now.

ConcinusMan
09-03-2011, 06:33 PM
OK, now for all of you interested in photography, what is photography? The lens brings in and captures light, of course. Just like our eye does.

An infrared camera is able to "see" heat, because heat is actually light below the red spectrum that we can see with our eyes. That's right, anything that is warm is actually "glowing" with light just outside the red spectrum and just outside our visible range. The camera simply converts that heat to a shorter wavelength of light so we can see it.

Now what about the "white balance" setting on your camera? Well, since our sun puts out white light...

Set your camera to "incandescent" and it filters out most of the yellow/red light to compensate for the fact that most incandescent lights put out mostly yellow/red light (and heat/infrared)

Set it to "florescent" and it filters out the blue end of the spectrum.

Set it to "daylight" and it filters out nothing, expecting a full white light spectrum from the sun.

So, in order for me to get true real-life color in the following photos, I use the "daylight" setting. But everything appears yellow and/or orange. Why? because all that smoke is blocking most of the blue light and only letting in the red end of the spectrum, much like a sunset would.

So, the photos you see here, are true to color, but only because the light coming in really is that yellow/orange! Obviously if the full spectrum of the sun was making it through, things wouldn't look so orange. In this case, and under these conditions, setting my camera to "incandescent" would make things look normal. However, things aren't normal right now. Things outside really do look this orange because of all the smoke!!

http://img29.imageshack.us/img29/5992/light003large.jpg

http://img546.imageshack.us/img546/4608/light002large.jpg

For the best true to life color, bright natural light from the sun gets better results. Outside on a cloudy day, with camera set to "natural daylight" white balance setting, or in the shade on a sunny day yields the best results if you want to capture the true color of your snakes. Certain colors are hard to capture. Especially florescent colors. That's really just light hitting an object that changes it's wavelength. Most cameras can't capture that.

RedSidedSPR
09-03-2011, 06:39 PM
Wow... Interesting. I mean, I knew it, but it's still cool!

EDIT: didn't know all that camera stuff though! Sweet!

ConcinusMan
09-03-2011, 06:42 PM
did you notice there's a bird sitting on my shoulder? heehee. I refuse to grow up. Kids have all the fun that way.:D

Starling96
09-03-2011, 07:02 PM
Lol my mom gets those kind of birds all the time in her rear view mirror ;)
and it is weird how the color is