Sunday, December 25, 2011

Optical Metamaterials and the Hercules Beetle

You may recall that objects have particular colors because, at the molecular level, light rays at certain frequencies (corresponding to certain colors) are reflected while at other frequencies the light is absorbed. In other words, an object’s color has to do with its chemistry. But, as David Tyler points out here, coloration can also arise from repeating, detailed submicron geometrical structures at the object’s surface. These surface structures are finely tuned to interact with and control the incoming light, including controlling the frequencies, and hence color, of the reflected light. In these cases, the object’s color has to do with its repeating surface geometry, rather than its chemistry.

That’s interesting because not only can surface structures be designed and fabricated to have a certain color, the structure can also be designed to be sensitive to environmental factors, such as temperature and humidity. Therefore one can construct a panel whose color indicates an environmental reading. Scientists and engineers are busy researching and developing these and other applications for these so-called metamaterials.

But those scientists and engineers were not the first to create metamaterials. Once again, the biological world has “been there, done that,” and has many of its own such metamaterials. One study analyzed the hercules beetle which changes color in high humidity due to an incredibly complex three-dimensional carapace surface structure. As the study explains:

The elytra from dry specimens of the hercules beetle, Dynastes hercules appear khaki-green in a dry atmosphere and turn black passively under high humidity levels. New scanning electron images, spectrophotometric measurements and physical modelling are used to unveil the mechanism of this colouration switch. The visible dry-state greenish colouration originates from a widely open porous layer located 3 micro-meters below the cuticle surface. The structure of this layer is three-dimensional, with a network of filamentary strings, arranged in layers parallel to the cuticle surface and stiffening an array of strong cylindrical pillars oriented normal to the surface. Unexpectedly, diffraction plays a significant role in the broadband colouration of the cuticle in the dry state. The backscattering caused by this layer disappears when water infiltrates the structure and weakens the refractive index differences.

According to evolution all of biology arose via random causes such as mutations. No, natural selection didn’t help—it just killed off the bad designs. The hercules beetle and its fantastic optical metamaterial (and everything else in biology) must have arisen by a long, long series of random mutations, which just happened to lead up to marvelous designs.

Religion drives science, and it matters.

4 comments:

  1. Cornelius Hunter said...

    According to evolution all of biology arose via random causes such as mutations. No, natural selection didn’t help—it just killed off the bad designs.


    Wow CH. When I suggested Santa bring you a new argument, I didn't mean a strawman so dumb even most YECs would be embarrassed to use it.

    Natural selection not only helps, it's an integral and essential part of the iterative process of evolution. "Killing off" the bad designs and letting the ones that work survive to pass on their heritable traits is critical to how the whole process works.

    I know it's been pointed out a hundred times:

    Random genetic variations by themselves don't produce the evolution of new traits. Selection by itself doesn't produce the evolution of new traits. But the iterative process combining both variation and selection (along with the heritable traits) can and does produce amazing new features.

    I know you know it too, which is why your posting that sort of rancid garbage in the OP reflects so poorly on your character.

    You could be better than that CH. You should be better than that.

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  2. Merry Christmas Dr. Hunter, thank you for all your work. At about the 29 minute mark of this following video is a similar example of what you are discussing in your article;

    Amazing Animals - Design vs Darwinism - Chris Ashcraft - video
    http://www.youtube.com/watch?v=rYfbAWMrCHA

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  3. Thorton: "I know you know it too, which is why your posting that sort of rancid garbage in the OP reflects so poorly on your character.

    You could be better than that CH. You should be better than that."

    That would depend on how he defines "better"

    Given his goal, I don't think he knows how to do much "better".

    He has to know the theory well enough to strategically misrepresent it this degree. And he has to know what assumptions to hide, which are shared by his target audience.

    Nor can he actually do research as it would require him to actually present some sort of theory and the results might not suit his agenda. The best he can do is look for other people's research that he can misrepresent.

    In other words, one doesn't pull of this sort of elaborate, disingenuous front based on ignorance. He knows exactly what he's doing.

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  4. Cornelius,

    But those scientists and engineers were not the first to create metamaterials. Once again, the biological world has “been there, done that,” and has many of its own such metamaterials.

    Imagine that. A simple beetle beat highly intelligent scientists and engineers. By at least 6,000 years.

    ReplyDelete