|Photo by Matthew Hoelscher|
Recently, Dr. Roberts and his colleagues solved a decades-old puzzle about how silvery fish like herring and sardines get their mirror-like skin. The basic mechanism behind this camouflage technique has been known for sometime (the secret is layers of guanine crystals in the fish's skin). But according to some basic physics principles, the silvery fish are too silvery: there are physical limits to how much light a normal reflective surface can reflect. The fish skins go beyond those limits and scientists couldn't explain why (humans have made artificial reflectors that also go beyond these limits, but with different techniques than those in the fish skin, and only in the past 10 years). Roberts and his team have found the secret of the flashy fish skin, and the new results may find their way into man-made reflectors and other optical technologies.