The science show VSauce presents a bewildering hail of facts that change the way you look at the world. They might even change the way you look at looking.
I’ve posted before about the fact that the spectrum of light we see is only a tiny fraction of light’s total spectrum, but I never realized how tiny.
If the entire practical spectrum of wavelengths was laid out linearly from New York to Los Angeles, the visual portion we see would only be the size of 100 nanometers.
So there’s the light we see, and then there’s light that we can’t see. Radio waves and microwaves are really just different frequencies of light, or what scientists call “electromagnetic waves”. The full spectrum goes from a wavelength of 1,000 meters (extremely low-frequency radio waves) to 0.0000000000001 meters (gamma rays). Visible light goes from .0000004 meters (purple) to .0000007 meters (red). The difference between 400 nanometers and 700 nanometers is nothing compared to the size of the whole spectrum.
So that’s how small a fraction of the electromagnetic spectrum we see.
Then again, maybe just laying out the full range of practical wavelengths doesn’t really give a meaningful idea of how “big” the spectrum is. It could be that visible light is a bigger sliver than this visualization would suggest. I’m no physicist, so correct me if I’m missing something here. Or just tell me what you think.
Another surprising thing:
A cell-phone camera can reveal that your TV’s remote control is really a flashlight that shines an invisible color. Take video of the remote’s tip while you press its buttons, and you’ll see it lighting up on the cell phone’s screen even though you can’t see it with your own eyes. It’s shining an infrared color that’s invisible to our eyes.