Science, Ridicule and Redemption
The Nobel Prize in Chemistry for 2011 has been awarded to Daniel Shechtman of the Technion, the Israel Institute of Technology in Haifa, for the discovery of quasicrystals. Quasicrystals are non-repeating regular patterns of atoms that were once thought to be impossible. Most people would agree that this is the type of unexpected discovery that deserves a Nobel Prize, but this is not just the story of an amazing scientific revelation. After first discovering evidence for quasicrystals in 1982, using an electron microscope in a US government lab, Shechtman was expelled from the lab and subjected to years of ridicule by other scientists. You see, quasicrystals were thought impossible by crystallographers at the time and even though Shechtman had evidence backing his claim, he was ostracized by mainstream science.
In quasicrystals, we find the fascinating mosaics of the Arabic world reproduced at the level of atoms: regular patterns that never repeat themselves. However, the configuration found in quasicrystals was considered impossible, and Daniel Shechtman had to fight a fierce battle against established science. The Nobel Prize in Chemistry 2011 recognizes a breakthrough that has fundamentally altered how chemists conceive of solid matter. Schechtman's battle for acceptance also illustrates the dark underside of modern science, revealing scientists as stiff necked, hidebound conservative thinkers who bask comfortably in the close-minded shelter of scientific consensus.
Three decades ago, atoms inside a crystal were believed to be packed in symmetrical patterns that repeated periodically. For scientists, this repetition was at the very heart of the definition of a crystal. On the morning of April 8, 1982, while examining a sample of quickly cooled aluminum and manganese alloy, Shechtman's electron microscope revealed atoms packed in a pattern that could not be. Even he had problems accepting the evidence in front of his eyes. He recalled saying to himself “Eyn chaya kazo,” which in Hebrew means “There can be no such creature.”
What Shechtman saw was a diffraction pattern unlike any he had ever seen before—concentric circles, each comprising 10 bright dots. The initial evidence pointed to an impossible symmetry. “10 fold???” he recorded in his notebook. Further examination indicated that the sample alloy's atoms were arranged in a pattern that appeared essentially the same when rotated by 72°, a fivefold symmetry. Shechtman's discovery was extremely controversial—such a pattern was considered impossible by accepted scientific theory and his colleagues dismissed the report out of hand.
When he defended his findings, he was asked to leave his research group at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland. After telling Shechtman to go back and read a crystallography textbook, the head of his research group dismissed him for “bringing disgrace” on the team. In an interview this year, in the Israeli newspaper Haaretz, Shechtman said, “people just laughed at me.” He recalled how Linus Pauling, a colossus of science and a double Nobel laureate, mounted a “crusade” against him.
But the idea of fivefold symmetry did not offend the sensibilities of others, particularly those outside of the field of crystallography. One of the early supporters of quasicrystals, at least in an abstract sense, was Sir Roger Penrose, the Oxford University mathematical physicist. In the 1970s, he created “aperiodic” tiling patterns that never repeated themselves. Penrose came up with a set of just two rhombuses that created a pattern with the requisite mathematical properties. Phi, the so called golden ratio (φ = (1+√5)/2), plays a pivotal role in these Penrose tiles.
Two Penrose tiles create a quasi-periodic pattern.
This mathematical work led a number of chemists to wonder if atoms could adopt a similar pattern. Crystallographer Alan Mackay built a model with circles representing atoms at the corners of Penrose's tiles and calculated that it would produce a diffraction pattern with 10-fold symmetry, similar to Shechtman's experimental result.
Tiling using Penrose kites and darts.
Others soon followed. Paul Steinhardt, now at Princeton University. Steinhardt and his then student Dov Levine published a paper shortly after Shechtman's linking his observations to Penrose-like structures and coined the term “quasicrystal.” But the defenders of scientific dogma were not convinced until a quasicrystal could be grown big enough to perform x-ray diffraction on. Finally in 1992, the International Union of Crystallography changed its definition of a crystal from a regular repeating array of atoms to “any solid having an essentially discrete diffraction pattern.”
Still, much of the old guard did not accept the existence of quasicrystals. Despite Shechtman traveling to his lab in Palo Alto and giving him a personal hour-long lecture, Linus Pauling never accepted quasicrystals. Pauling, a dominant figure among US chemists, died in 1994, reaffirming Max Planck's famous dictum, “Science advances one funeral at a time.”
In an interview with the Guardian, Penrose said, “I once asked Shechtman if he knew about my tilings when he saw the things he saw. He said he did, but that he didn't have them in mind when he was looking at them.” Following Shechtman's discovery, scientists have produced other kinds of quasicrystals in the lab and discovered naturally occurring quasicrystals in mineral samples from a Russian river. A Swedish company has also found quasicrystals in a certain form of steel, where the crystals reinforce the material like armor. They have produced scissors and needles using this technology. Scientists are currently experimenting with using quasicrystals in different products such as frying pans and diesel engines.
Interestingly, periodic mosaics, such as those found in the medieval mosaics of the Alhambra Palace in Spain and the Darb-i Imam Shrine in Iran, long ago provided illustrations of quasicrystalline patterns. Islamic architects and mathematicians were creating quasi-crystalline patterns some 500 years before similar patterns were described in the West. In those mosaics, as in quasicrystals, the patterns follow mathematical rules—they are regular but never repeat themselves. Sometimes there are answers all around us but we remain blind to them because we are convinced we know better. Shechtman's battle eventually forced scientists to reconsider their conception of the very nature of matter.
The Darb-i Imam shrine in Iran, built in 1453.
What lessons should we all learn from this episode of science—ridicule followed decades later by redemption and accolades? When asked by a representative of the Nobel committee what discovering quasicrystals taught him about science, Shechtman replied:
Oh, it taught me ... This is a very good question! You know, it taught me that a good scientist is a humble scientist, somebody who is willing to listen to news in science which are not expected. Because discoveries today are really not expected – if they were expected they would have been discovered a long time ago. So something new, that is forbidden by some laws ... people have to listen to this. In most cases, the news is not really news. But in some cases, discoveries are made and should be listened to. So, I think the main lesson that I have learned is that a good scientist is a humble scientist who is open-minded to listen to other scientists when they discover something.
This illustrates the danger of consensus science, where the often unthinking voices of the majority drown out the voice of new discovery. The slaves of dogma shout down the voices of skeptics who dare question the status quo. This is but the latest example of the dual nature of modern science: on one hand, the science establishment can stifle innovation and suppress new discoveries if they disagree with wide held beliefs within the scientific community; on the other hand, given time science is self-correcting and eventually new, more correct theories replace aged dogma. A good scientist listens to others when they discover new things, they are open-minded and they are humble.
Another important point: Shechtman's observations were empirical, the result of experiment; the “impossibility' of his discovery was theoretical. Shechtman published all the details of his experiment, allowing others to reproduce his work and verify his observations. The scientific consensus of the day was in disagreement with observed reality and, as is always the case when theory conflicts with reality, theory looses.
Look to the advocates of anthropogenic global warming—they are not open-minded and they certainly are not humble. Time after time, new observations have shown current climate theory to be inadequate. Instead of empirical evidence, climate scientists produce computer models. So, the next time someone tries to claim global warming is settled science because it is the “consensus view,” just remember the impossible quasicrystals. And when those brave scientists who dissent from climate change doctrine are called deniers and worse than criminals by alarmist blatherskites, recall the travails of Daniel Shechtman and his eventual triumph.
Be safe, enjoy the interglacial and stay skeptical.