What Bird Feathers and Beer Foam Have In Common

Rational Egoist writes "Researchers at Yale University have found that some of the brightest colors in bird feathers are created through structures similar in origin and composition to that of beer foam. Unlike with most colors in nature — which are produced by pigments — the bright blue colors of Bluebirds and Blue Jays are actually produced by sponge-like nanostructures. These structures are formed in quite the same way as beer foam. From the article: '[Researchers] compared the nanostructures to examples of materials undergoing phase separation, in which mixtures of different substances become unstable and separate from one another, such as the carbon-dioxide bubbles that form when the top is popped off a bubbly drink. They found that the color-producing structures in feathers appear to self-assemble in much the same manner. Bubbles of water form in a protein-rich soup inside the living cell and are replaced with air as the feather grows.'"

Comments

Re:UV illumination

[blincoln]

Humans with OEM corneas, at least. Artificial corneas don't absorb UV light.

Even with an artificial cornea, our eyes aren't sensitive to UV in the sense that some insects and birds are. We don't have UV-specific receptors, so we would see it as more white light, or more of whichever colour receptors were most sensitive to it.

I'd be curious to know if people with artificial corneas can see the UV patterns on flowers, even if they can't really tell that it's a different colour, just that there is a bright/dark pattern that people with natural corneas can't see. That's one of the easiest ways to determine useful UV sensitivity.

Incidentally, our eyes are mildly sensitive to near-infrared too, in the same no-specific-receptors sense. You don't need artificial corneas to take advantage of that either - just some NIR-bandpass goggles and a bright source of illumination, like a sunny day.