Rebel with a Nobel Prize: The Lesson of Daniel Shechtman - Evolution News & Views

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Rebel with a Nobel Prize: The Lesson of Daniel Shechtman

Dr. Daniel Shechtman's discovery did not sit well with the scientific elite and he made some people angry because of it. In 1982 Dr. Shechtman observed a crystal that did not obey the physical laws that crystals are supposed to obey. These crystals are now called quasicrystals, and they have changed the way chemists view solid state chemistry. Almost thirty years later, Shechtman received the 2011 Nobel Prize in Chemistry for his discovery.

What are quasicrystals? Before the discovery of quasicrystals, the prevailing paradigm in crystallography held that crystals are defined by a repeated unit cell and are mathematically constrained to only 2-, 3-, 4-, or 6-fold symmetry. Symmetry simply means that you can rotate the crystal's unit cell a certain number of degrees (e.g. 45 degrees, 60 degrees, etc.), and the unit cell will look the same as it did before you rotated it. This does not apply just to unit cells, but to 2-dimensional geometric figures as well.

For example, if you rotate a square 90-degrees, it will appear indistinguishable from how it looked before you rotated it. But if you rotate a square 45 degrees it does not look the same; it has 4-fold symmetry. If you rotate an equilateral triangle 120 degrees, it will look indistinguishable from before it was rotated, so it has 3-fold symmetry. If you rotate a hexagon 60 degrees it is indistinguishable from its initial position, so it has 6-fold symmetry because you can rotate it six times before you are back to where you started.

But symmetry is not the only important feature of a crystal. These unit cells have to pack themselves together tightly. Mathematically, only 2-, 3-, 4- and 6-fold symmetry can form crystals, otherwise there are gaps or holes in the structure. Think of a tiled floor. You will never see a tiled floor with all (regular) pentagons (5-fold symmetry) because they cannot pack tightly.

This nice, neat theory was overturned when Dr. Shechtman discovered a crystal with 5-fold symmetry. These crystals were later named quasicrystals. Generally, quasicrystals are crystals that display "forbidden" symmetry. An additional characteristic of a crystal with forbidden symmetry is that it is aperiodic. That is, it lacks a repeating pattern.

Mathematician Roger Penrose had theorized a 2-dimensional pattern consisting of 5-fold symmetry that was aperiodic. Shechtman's quasicrystals seemed to follow Penrose's pattern. Using X-ray diffraction studies, Shechtman found that his material (an aluminum-manganese alloy, Al6Mn) had all of the features of a crystal but it had forbidden symmetry.

Is This a Case of Information or Order Arising Out of Chemistry?

Quasicrystals are interesting because of their nonrepeating pattern. They have a complex, ordered structure arising from the chemical laws of an aperiodic crystal structure. One of the arguments that many intelligent-design proponents make (e.g., William Dembski and Stephen Meyer) is that nature or natural laws can produce order, but it is a simple and repeating order, as in a traditional crystal lattice. This is different from the kind of structure we see in DNA where there is specific and complex order that conveys information. In Signature in the Cell, Meyer argues that we do not see this kind of specified complexity arising from any known natural causes. Could quasicrystals be a counterexample -- a product of nature displaying specified complexity?

Quasicrystals are more complex than the traditional crystal, but they do not convey information. If I were to randomly type keys on my keyboard, producing a string such as "iyubalor09fbjd[,,]ikgts;hyweog," that would be a complex sequence. It is highly improbable that if I randomly hit the keyboard some more that the same sequence would appear. I have thus obtained a highly improbable, complex sequence out of randomness. But does the sequence convey information? No.

If I were to type the same sets of letters over and over, such as "asdfjkl;asdfjkl;asdfjkl;", this sequence has order and it has more complexity than if I had typed "ababababab," but does it convey information? No.

The quasicrystal is highly complex, highly ordered, and does not repeat like that second set of letters. Furthermore, it is mathematically predictable. But it does not convey information because it does not possess properties that can be translated into meaning or function. A DNA sequence contains information because the sequence is translatable into instructions to build a protein. Therefore we know that a DNA sequence is not just a random string of letters, but is something intentional, conveying purpose in the form of an instruction. The quasicrystal's structure does not convey information.

Although quasicrystals do not represent specified information, they have some very interesting uses. These crystals are made of metal alloys, so they are remarkably strong, like a metal, but are poor conductors. Their conductivity is even less than that of glass, although their properties are very similar to a kind of metallic glass. They have been used for mundane applications such as razor blades, and in lasers for eye surgery. Quasicrystals have been used for coating cookware, and have potential for coating surfaces that must stand up to extreme temperatures.

Ousted by the Scientific Community

Dr. Shechtman's story is truly inspiring. He became a rebel but ended up with a Nobel Prize. Instead of praise for his remarkable discovery, he was at first met with disbelief and a job transfer. Almost every news release reports that Dr. Shechtman was kicked out of his research group and his findings were initially rejected by many in the scientific community. The MSNBC report provides additional details describing how Dr. Shechtman's discovery was received by the scientific elites:

  • When he had returned to Israel after conducting studies at the National Bureau of Standards, he co-authored an article about his findings, only to find that it was initially rejected.

  • Shechtman recalls that Linus Pauling said publicly that "Danny Shechtman is talking nonsense. There is no such thing as quasicrystals, only quasi-scientists."

  • Finally, however, once people starting accepting Dr. Shechtman's results, many scientists went back to some of the anomalies in their research to find that they had observed quasicrystals, but had not realized it or did not report it.

Despite the jeers and rejection, Shechtman maintained that his findings were correct. Eventually, the definition of crystals had to be changed because the original definition was too restrictive. (See Marjorie Senechal's paper, "What are Quasicrystals?") Now the revised definition is based on having a discrete diffraction diagram, as opposed to adhering to 2-, 3-, 4-, or 6-fold symmetry.

Many of us who work with ideas that are not terribly popular with the scientific establishment can understand and sympathize with the rejection that Dr. Shechtman faced. Furthermore, as Reuters reported, Dr. Shechtman made a policy of ignoring personal attacks. While winning the Nobel Prize is a substantial accomplishment, his staying the course in the face of opposition, responding to ridicule graciously and scientifically, provides a lesson for us all.


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