Natures wonders: fish invisibility cloak (Introduction)

by David Turell , Saturday, November 21, 2015, 18:22 (3288 days ago) @ David Turell

Shades of Harry Potter. Fish can turn invisible with 'platelets' in their skin polarizing light:-http://phys.org/news/2015-11-scientists-camouflage-mechanism-fish-ocean.html-"In a paper published this week in Science, a team led by researchers at The University of Texas at Austin reports that certain fish use microscopic structures called platelets in their skin cells to reflect polarized light, which allows the fish to seemingly disappear from their predators.-"Polarized light is made up of light waves all traveling in the same plane, such as the bright glare you sometimes see when sunlight reflects off the surface of water.-"Under the surface of the water, light tends to be polarized. Many fish—and sophisticated modern satellites—have the ability to detect variations in such polarized light.-***-"'I think it's a great example of how human applications can take advantage of evolutionary solutions and the value of evolutionary biology," said Cummings. "It's important for people to recognize that we take advantage of evolutionary processes and solutions all the time and that even our military does.'"- "Many fish that live in the open ocean are silvery, which allows them to reflect light as a mirror does. For many years, experts assumed this was the main means of camouflage among such fish, but this camouflage approach works well only if the surrounding water appears uniform, as it does to human eyes. Polarized light turns out to be an important component of the underwater light field, and it is not uniform but instead highly variable. Using mirrors for camouflage in such an environment can actually backfire and make it easier to stand out in the open ocean."-Comment: One of nature's clever tricks, and is a good example of our use of bio- mimicry when our navy uses it.