The SUN sounds amazing, it makes a blasting static sound like pink noise through my guitar amp. I was really digging the sound of the sun and turned it up loud while I ate dinner. It started to go down and the sky turned a deeper blue color. I switched the amp to the distortion channel and cranked the gain up all the way to hear the details. The camera was focused on a patch of blue sky through the trees. After a minute of acclimation, I heard the faintest layer of coherent sound through the intense pink noise static. I sat down next to the amp and listened very hard! It sounded like tones. At first I did not believe my ears and blew it off. A minute later it was there again, it sounded like voices! It had to be radio interference, I thought. To test this, I put my hand in front of the lens to block the light from outside. The noise blast went away, and the voices were gone. If it was normal radio interference it would have been clear through this experiment, would you agree?. I moved my hand back away and the noise blast returned. I will swear that in this noise I heard something like a conversation between a man and a woman… and some tones inbetween. It was impossible to recognize the words or syllables, but it had the pitch fluctuations and broken intervals of speech.

Thus the fact is, I heard voices from the sky, in the sound of the sun.

So now the question is what kind of technology could be causing this??! I’ve never heard of commercial open-air lightwave communications - it seems foolish… light doesnt go around corners.

After the sun was down completely, the noise and voices were no longer to be heard. I will try again tomorrow and record anything interesting.

*** UPDATE 6/1/08: INEXPLICABLE PHENOMENON EXPLAINED! ***

I followed up the original sun listening session with a more controlled experiment. This time I recorded the sound of the sunrise at dawn. I focused on the same patch of blue sky as before and recorded for about 20 minutes. The pink noise of sunlight gradually rose above the amplifier’s hiss, and the recording showed a nice increase in amplitude as the sunlight brightened. As before, faint sounds were audible beneath the roar. I repeated the control experiment of blocking light to the camera with my hand. This time, I was able to hear the voices regardless of whether the sun entered the camera… so my original conclusion is now in question. Listen for yourself. It sounds like Christian radio…. “Jeeeeezus Christ!”

Sound of Dawn

Lets stay on the topic of charging capacitors with solar cells but think more creatively. What’s a solar cell made of, and what is a capacitor made of… can they be combined into one device, basically a flat capacitor that absorbs light and stores it as charge to be used later? Traditional photovoltaic (solar) cells are essentially large area semiconductor diodes based on crystalline silicon, while newer and more efficient photovoltaics are being designed with layered films of material such as titanium dioxide particles and carbon nanotubes. Capacitors are built with layered structure as well. The basic structure of a capacitor is a pair of conductive surfaces separated by a thin insulating material; these are typically wound into a tight spiral roll which is why capacitors are often cylindrical in shape. Recently a special class of capacitors has come on the market, known as electric double-layer capacitors, capable of storing thousands of times more charge than ‘normal’ caps of the same size. Instead of the traditional spiral construction, supercapacitors rely on the huge surface area of activated carbon granules.

So photovoltaics and capacitors are both sandwiches of some sort, right? Can they be combined to make a flat capacitor that charges itself in the sun?

I searched and found an article dated 2004 in a physics journal that reports the creation of such a device, called a photocapacitor. Japanese scientists combined dye-coated titanium dioxide, activated carbon, and a platinum-coated glass electrode into a six-layered structure and observed its successful conversion of light to charge. Hopefully this technology can be developed to the point that it is practical for commercial use. If that becomes possible, the cost of utilizing solar energy could decrease because the need for expensive batteries to maintain power during dark cycles would be obviated. And fewer batteries are always a good thing for safety and the environment.

Maybe somebody can figure out how to assemble a DIY photocapacitor based on the article I cited above? Supercapacitor-grade activated carbon is available, as is high quality titanium dioxide. Transparent conductive glass seems a little trickier to find commerically, but here is one example. Somebody should give it a try. Don’t forget to patent it if it works, b/c you could become stinking rich.

update: in 2005 the same laboratory reported a moderately improved version of their original photocapacitor, using three electrodes instead of two. This design gave a five-fold increase in energy storage density.

What surprised me was this: the UV-LED works as a remote control for neon lamps. I have several power strips in my office. You’re probably familiar with the kind that has a neon bulb illuminating the power switch. That’s the flickering orange glow inside the switch - a small glass envelope containing neon gas and two electrodes. Anyway, I’m getting ahead of myself. Here’s what happens. Standing in the dark office, nothing is emitting light. I click on the UV-LED, and immediately, the neon bulbs in my two power strips respond by illuminating with their typical glow. I’ve always wondered what governs these things. If you’ve ever watched them sit there and flicker, you might wonder if its due to variations in AC line voltage, or some other characteristic of the gear drawing power from the power strip. Maybe thats true - but right now I’m able to control the neon lamp from across the room with my UV-LED, with near 100% accuracy. It’s a surprisingly sensitive phenomenon. From ten feet away, I’m pointing the LED at the power strip. For every flash I make with the LED, the neon lamp in the power strip responds instantly by flickering its orange glow.

Hypothesis as to why this works? A neon lamp only glows when the voltage across its terminals exceeds a threshold value. I suppose that somehow the power strip lamps are biased to a point near emission but not quite. The ultraviolet photons from the LED hit the neon atoms, and provide the extra tiny bit of energy to pop an electron up into an excited state. From that point, the orange glow takes place automatically.

I was a “C” student in college physics though.

Can you think of alternative explainations? Or perhaps something clever that can be done with this phenomenon? I’m going to sleep on it.