Tyr-Ziu Saxnot
06-27-2016, 12:30 PM
http://www.forbes.com/sites/trevornace/2016/06/27/forbidden-symmetry-found-in-4-5-billion-year-old-meteorite/#10c29fce446e
un 27, 2016 @ 09:00 AM 50,881 views
'Forbidden Symmetry' Found in 4.5-Billion-Year-Old Meteorite
Trevor Nace ,
Contributor
I cover geology, earth science, and natural disasters
Until recently, crystals with ‘forbidden symmetry’ were thought impossible to naturally occur. Yet, a 4.57 billion-year-old meteorite was found in the far northeastern region of Chukotka, Russia exhibiting crystals with naturally occurring ‘forbidden symmetry‘ for the first time. Dr. Paul Steinhardt from Princeton University led a research team to characterize the nature and occurrence of this enigmatic quasicrystal.
The unorthodox arrangement of atoms, coined forbidden symmetry, had previously been replicated in laboratory experiments and was thought to be too energetically unstable to occur in the natural environment. However, a quasicrystal has been found within the aforementioned meteorite, the second one ever to be found and both within the same meteorite.
A quasicrystal is akin to a crystal structure of a mineral, which is ordered, but not periodic like that of a normal crystal. For example if you were to lay 4-sided or 6-sided tiles along the floor, they will neatly fit within one another. However, if you were to do the same with a five-sided or 10-sided tile, there would be resulting gaps in the tile floor, requiring different size/shape tiles to fully fill in the floor. This is a representation of the ordered but not periodic nature of quasicrystals with forbidden symmetry.
At this point its unclear how the quasicrystals exhibiting forbidden symmetry were created. During impact, the host meteorite would have been witness to temperatures up to 1,000 degrees Celsius and pressures as high as 100,000 times that of normal atmospheric pressure. Its unclear whether the forbidden symmetry found in this meteorite is extraordinary or commonly found within our solar system. In addition, understanding how these crystal structures form will provide clues to new and unique methods in which nature can build crystals under extreme circumstances.
un 27, 2016 @ 09:00 AM 50,881 views
'Forbidden Symmetry' Found in 4.5-Billion-Year-Old Meteorite
Trevor Nace ,
Contributor
I cover geology, earth science, and natural disasters
Until recently, crystals with ‘forbidden symmetry’ were thought impossible to naturally occur. Yet, a 4.57 billion-year-old meteorite was found in the far northeastern region of Chukotka, Russia exhibiting crystals with naturally occurring ‘forbidden symmetry‘ for the first time. Dr. Paul Steinhardt from Princeton University led a research team to characterize the nature and occurrence of this enigmatic quasicrystal.
The unorthodox arrangement of atoms, coined forbidden symmetry, had previously been replicated in laboratory experiments and was thought to be too energetically unstable to occur in the natural environment. However, a quasicrystal has been found within the aforementioned meteorite, the second one ever to be found and both within the same meteorite.
A quasicrystal is akin to a crystal structure of a mineral, which is ordered, but not periodic like that of a normal crystal. For example if you were to lay 4-sided or 6-sided tiles along the floor, they will neatly fit within one another. However, if you were to do the same with a five-sided or 10-sided tile, there would be resulting gaps in the tile floor, requiring different size/shape tiles to fully fill in the floor. This is a representation of the ordered but not periodic nature of quasicrystals with forbidden symmetry.
At this point its unclear how the quasicrystals exhibiting forbidden symmetry were created. During impact, the host meteorite would have been witness to temperatures up to 1,000 degrees Celsius and pressures as high as 100,000 times that of normal atmospheric pressure. Its unclear whether the forbidden symmetry found in this meteorite is extraordinary or commonly found within our solar system. In addition, understanding how these crystal structures form will provide clues to new and unique methods in which nature can build crystals under extreme circumstances.