Electromagnetic Spectrum

November 14, 2013

Scientists unlock the secret to pulling energy from the air

ElectromagneticSpectrumWikipedia

The electromagnetic spectrum, from low frequency to high. Visible light is only a tiny part of the spectrum. (Wikimedia)

We’re constantly using devices that emit energy in the form of radio waves or microwaves. We don’t think of those waves the way we think of light, but they’re basically just a different wavelength of light that’s beyond our range of perception. Our wifi routers, radio stations, cell phones, and cell phone towers all emit tons of this energy nonstop. In the modern world, even in a pitch-dark room, there’s still light that you just can’t see. Microwaves and radio waves are everywhere.

VisibleRadioWaves_NikolayLamm

What if you could see wifi? Artist Nikolay Lamm gives us this rendering of what the different channels might look like.

So if we have solar panels that get energy from visible light, why don’t we have a way to capture this invisible light?

Two students at Duke University have been asking that question and coming up with new ways to recapture that energy that would otherwise be wasted.

They’ve caught microwave signals like cell phones use and turned them back into useable electricity. They used “meta materials” to do it. Metamaterials are special materials that use a really finely detailed structure like a 3-D circuit board to get waves to do things they normally wouldn’t. It’s possible to use metamaterials to capture energy from all sorts of waves, including sound waves.

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Allen Hawkes, Alexander Katko, and Stephen Cummings of Duke University devised this array of metamaterial cells to capture useful energy from microwaves. Adding more cells captures more of the available energy. (Duke)

The efficiency of this proof-of-concept work is already about the same as current solar cells. From a strong microwave signal, they captured enough energy to recharge a cell phone battery.

A few years ago, a different group of Duke researchers demonstrated a way to get energy from radio waves.

October 17, 2013

What if you could see radio waves?

I mentioned before that there are colors we cannot see. The spectrum of light extends beyond the rainbow we know and into frequencies that only certain animals can see. But as it goes past that in both directions and further along that spectrum, it takes on a different character. Radio waves are a type of invisible very low-frequency light.

There are radio waves passing through your skull right now like light through water.

An artist named Nickolay Lamms visualized what wifi radio waves would look like, with different colors representing different wifi channels. If you could see wifi, it might look something like this:

VisibleRadioWaves_NikolayLamm

Different wifi channels represented by different colors. Image by Nickolay Lamm

September 25, 2013

Why a goldfish appreciates art more than you do

The link: The Perfect Yellow, and more

The Story:

There are colors we can’t see.  All around us, every day we’re missing out on something that certain other members of the animal kingdom take for granted.

Just like dogs can hear sounds outside our range of hearing, animals like birds and the boring old goldfish can see colors beyond what’s visible to us.

In terms of the full spectrum of light, we’re practically blind.  The light that’s visible to us is a tiny part of what’s out there.

Electromagnetic radiation

From ultraviolet to visible light to radio waves, they’re all different kinds of the same thing.

Some of the birds you see outside might look drab, but actually have brilliant colors in the part of the spectrum beyond what we can see.  They’re seeing something we can’t even imagine.

The NPR show RadioLab has an awesome story on this unseen rainbow.

Key points are:

  • An American scientist, Jay Neitz, has succeeded in giving the ability to see the color red to an animal formerly unable to see it.
  • He’s working on ways to bring color to colorblind people.
  • Neitz also says it might be possible to give people the ability to perceive colors beyond the normal human range.
  • But there may already be such people in the world.  There are some rare women (normal-looking mutants called tetrachromats) who were born with extra color receptors in their eyes, enabling them at least in principle to see extra color.

The Internet has allowed the discovery of such people to happen.  Before, it was much harder for researchers to connect with the small percentage of the population with this genetic variation.  British neuroscientist Gabriele Jordan has been searching for such people for two decades.  If you think you might be one, and ever plan to be in England, you can contact her.

Megan Arquette is a blogger and possible tetrachromat who was featured on a Japanese science show earlier this year.

Another is an Australian artist named Concetta Antico, whose genetics Jay Neitz is studying.

Study of tetrachromacy is still in its infancy.  Someday within our lifetimes, it may be possible for ordinary people to see what’s been right in front of us all along.  The limits of our perceptions represent a clear and definable limit to the human imagination. You can’t imagine what a bird sees any more than a congenitally blind person can imagine the color blue.

But we’re beginning to push those limits.