Sunday, January 15, 2012

Nobel Prize in Chemistry 2011 for quasicrystals

Nobel Prize isn't all about following the hard and fast rules of Nature. When you come across an observation that's not explained by existing rules, you gotta find a new explanation, no matter how long the journey is. You just gotta believe your eyes provided that everything has been done right. Not only that, you have to fight hard to prove your point, because people don't have good forgeteries, as Peter Mitchell (pioneer of chemiosmosis theory in mitochondria) said it.

Dan Shechtman Nobel Prize in Chemistry in 2011 was such an example.

When he observed a sample of alloy consisting of aluminium and manganese, he saw this in the diffraction pattern:

quasicrystal diffraction
A concentric ring of dots. It has a regular pattern but they do not repeat themselves. Hence, atoms in the solid are arranged in a regular but never repeating pattern. For this reason, it's called a quasicrystal.

Colleagues put him down. He was even asked to leave his research group for defending his findings. He was called to be "wrong according to the textbook. One of Dan's fiercest critic was Linus Pauling (Nobel Prize in Chemistry & Nobel Peace Prize laureate). Despite this he never gave up and worked to have his discovery published in a journal.

Eventually, Dan's findings was reconfirmed by other scientists. The discovery of quasicrystal even compelled the International Union of Crystallography to change the definition of a crystal from "a substance in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating three-dimensional pattern" to the broader "any solid with a discrete diffraction pattern" to accommodate future discoveries.

How to explain a structure with a regular but no repeating pattern? Islamic art has done it a few centuries ago. With a minimum of two types of tiles, you can create a pattern that never repeats itself.

aperiodic tiling

I'm sure more substance with the attribute of quasicrystal will be discovered along the way. Who knows advanced materials with properties we've never thought before come from this?

You may call it strange or impossible. Quantum mechanics was called impossible at first, but without it we'll never enjoy computers today.

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