Evidence suggests naturally-occurring quasicrystals had extraterrestrial origins

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Results from an expedition to far eastern Russia that set out to find the origin of naturally occurring quasicrystals have provided convincing evidence that they arrived on Earth from outer space.

Quasicrystal, with 5-and 10-fold rotational symmetries. Quasicrystals form a new class of solids whose properties cannot be described in terms of classical crystallography.

Writing in IOP Publishing’s journal Reports on Progress in Physics, Paul J Steinhardt and Luca Bindi reveal that new, naturally occurring quasicrystal samples have been found in an environment that does not have the extreme terrestrial conditions needed to produce them, therefore strengthening the case that they were brought to Earth by a meteorite.
Furthermore, their findings reveal that the samples of quasicrystals were brought to the area during the last glacial period, suggesting the meteorite was most likely to have hit Earth around 15 000 years ago. …

The group of researchers were on the look-out for naturally occurring quasicrystals – a unique class of solids that were first synthesized in the laboratory by Israeli scientist Dan Shechtman in 1982. He was awarded the Nobel Prize for Chemistry in 2011 for this discovery. …

Only one natural quasicrystal has been previously documented: a sample in the Museum of Natural History in Florence, Italy, that was located and identified by the two co-authors and their collaborators in 2009. They found the sample to have the symmetry of a soccer ball, with six axes of five-fold symmetry forbidden to ordinary crystals. This triggered a remarkable investigation to find the place where the sample came from, which, as Steinhardt states, involved secret diaries, smugglers, gold prospectors and bears.


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