Discover Magazine has opened its archives for free. That's great news for people interested in popular science and science-based fiction. I've been browsing around and found some neat science-fiction related articles.
For example, in April 2006 Discover published an article, "What cephalopods can teach us about language" about special chromatophores, or pigment-containing cells, which are found in octopuses (octopi?), squid and other cephalopods. Muscles change the shape of the chromatophores, which causes the cells to change color.
Morphing in cephalopods works somewhat similarly to how it works in computer graphics. Two components are involved: a change in the image or texture visible on a shape's surface and a change in the underlying shape itself. The "pixels" in the skin of a cephalopod are organs called chromatophores. These can expand and contract quickly, and each is filled with a pigment of a particular color. When a nerve signal causes a red chromatophore to expand, the "pixel" turns red. A pattern of nerve firings causes a shifting image—an animation—to appear on the cephalopod's skin. As for shapes, an octopus can quickly arrange its arms to form a wide variety of them, like a fish or a piece of coral, and can even raise welts on its skin to add texture.To see what that looks like, watch this great National Geographic video of an octopus changing colors. The color change appears to be under visual control, but the exact mechanism is a bit of a mystery, because cephalopods do not appear to have color vision.
In the interactive companion to the article, "Why Not Morph?", Discover issues a challenge to write a story using the science of chromatophores:
Suppose humans had chromatophores that could alter body appearance allowing it to blend perfectly with the background. Think about it. Then, write a science fiction story about a genetically modified individual who has been given this camouflage ability. Remember that good science fiction is based upon science fact.I'm not aware of any stories in which humans have color-changing skin. However a example of color-changing humanoids are the genetically-enhanced Suliban of the Enterprise universe, who can blend into their surroundings using subcutaneously-implanted pigment sacs. According to creator Brannon Braga the modification was indeed inspired by octopus skin.
If you know of any other examples, please share them in the comments!
Tags:science fiction, chromatophores, skin color
Image from the Ocean Planet Exhibition at the Smithsonian.