Quasicrystal With Forbidden Atomic Symmetry Found On Ancient Meteorite
Quasiperiodic crystals of an aperiodic nature, or simply quasicrystals, are crystals of a forbidden atomic symmetry that, until the 6 years ago, we did not think could occur in nature. The first quasicrystal, known as icosahedrite, had a 5-fold atomic symmetry and was discovered in 2009 by a team of researchers led by Professor of Physics at Princeton, Paul Steinhardt and Luca Bindi of the University of Florence. It was found inside of a 4.57 billion year old meteorite recovered from a remote region of northeastern Russia. In March of 2015, the researchers discovered another type quasicrystal in a different part of the same meteorite, this one with a decagonal (10-fold) atomic symmetry made from the highly unlikely combination of nickel, iron, and aluminum:
"The top panel shows an X-ray tomography image (similar to a “CAT” scan) at two different rotations of the whole mineral grain. The brighter and the darker regions are copper-aluminum metals and meteoritic silicates, respectively. The bottom panel shows a scanning electron micrograph image of the quasicrystal (QC) in apparent contact with another mineral, olivine (Ol). Source: Paul Steinhardt." (2)
These substances maintain the same characteristics of any crystal, a crystalline structure comprised of an orderly arrangement of atoms that, when observed under a microscope, span infinitely in all directions to form an endless geometric pattern. What makes quasicrystals so special is that, where ordinary crystals contain periodic and mathematically simple atomic arrangements of translation symmetry, quasicrystals contain intricate, aperiodic atomic arrangements. These unique arrangements do not contain repeating periodic patches, yet the structure in its entirety is still perfectly organized in a rotational symmetry making it much harder and more durable than any of the crystalline solids found on Earth thus far.
“The finding of a second naturally occurring quasicrystal confirms that these materials can form in nature and are stable over cosmic time scales,” - Steinhardt (1)
"Selected area (a) and convergent beam (b) electron diffraction patterns collected with a TEM along the ten-fold axis. These patterns, consisting of sharp peaks (or Kikuchi lines) arranged with ten-fold symmetry, are the characteristic signature of a decagonal quasicrystal." (1)
Considering the only two quasicrystals ever discovered were both from an extra terrestrial body, it is difficult to discern what the exact conditions are for this to occur and if it may have occurred on the Earth long ago during its creation. In addition to their durability, these substances have a low friction and they are poor conductors of heat, making them ideal for protective coatings can be used for air/space craft technology and even non-stick cookware. Having discovered a second, unique, naturally formed quasicrystal, this raises the question, what other types of these aperiodic crystal structures can be formed by nature? Is it possible that there are entire planets where the variety of these quasicrystals are as common as our local crystalline substances?
“We know there was a meteor impact, and that the temperature was around 1000 to 1200 degrees Kelvin, and that the pressure was a hundred thousand times greater than atmospheric pressure, but that is not enough to tell us all the details. We’d like to know whether the formation of quasicrystals is rare or is fairly frequent, how it occurs, and whether it could happen in other solar systems. What we find out could answer basic questions about the materials found in our universe.” - Steinhardt (2)
"The new mineral is the grain shown in panel (a). The ten-fold symmetry is evident when the mineral is hit with x-rays (b). Aiming the beam from a different direction results in paterns as in (c) or (d) in which the spots form along horizontal lines that are equally spaced. Source: Paul Steinhardt." (2)
Sources
Bindi, L., N. Yao, L. S. Hollister, C. L. Andronicos, V. V. Distler, M. P. Eddy, A. Kostin, V. Kryachko, G. J. MacPherson, W. M. Steinhardt, M. Yudovskaya, and P. J. Steinhardt. "Natural Quasicrystal with Decagonal Symmetry." Nature.com. Nature Publishing Group, n.d. Web. 29 June 2015. (1)
Zandonella, Catherine. "Second Natural Quasicrystal Found in Ancient Meteorite (Scientific Reports)." Princeton Journal Watch. N.p., n.d. Web. 29 June 2015.(2)
Lifshitz, Ron. "The Definition of Quasicrystals." ARXIV. N.p., n.d. Web. (3)
Replies
Order+aperiodicity=design. DNA certainly belongs to such category of things.
Yes, so true. If they could recreate the design, it could change our world. I think it comes from an older region of space than ours.