14 DAY TRIAL // It sometimes happens that lava released during volcanic eruptions cools to form odd-looking hexagonal columns. Such bizarre nature-made structures are part of the Devils Tower in Wyoming and also form the so-called Giant's Causeway in Northern Ireland.
For years, researchers have been trying to figure out how and why lava every now and again cools into such shapes. Now, at long last, a team of scientists with Dresden University of Technology in Germany think they might have solved the puzzle.
It all comes down to how lava behaves when cooling
Most things in nature are random. Perfect shapes, be they spheres, squares or, in this case, hexagons, are more our thing. All the same, it looks like nature is too sometimes capable of achieving what looks like mathematical perfection.
In a report published earlier this week in the journal Physical Review Letters, the research team explain how, looking to determine why lava occasionally creates hexagonal towers, they ran a series of computer simulations.
The simulations were built taking into account the characteristics of lava when hot and when cooled. The scientists found that when lava initially begins to cool and shrink, cracks form in it randomly.
These fractures are created intersecting at 90-degree angles because this is the best way for energy to be released. Then, as the cooling and the shrinking continue, the cracks are forced to grow and intersect at 120-degree angles.
The result is a hexagonal pattern that is maintained even as the lava completely cooled. Then, erosion comes along and the hexagonal fractures are shaped into the peculiar hexagonal towers.
“Basalt columns with their preferably hexagonal cross sections are a fascinating example of pattern formation by crack propagation,” the Dresden University of Technology team write in their paper, as cited by Phys Org.
“Junctions of three propagating crack faces rearrange such that the initial right angles between them tend to approach 120°, which enables the cracks to form a pattern of regular hexagons,” they add.
Of course, there's also the mythical explanation
These scientists might be convinced that the patterns of cooling and shrinking of lava make the best explanation for nature's very own hexagonal columns, but at least when it comes to the Giant's Causeway in Ireland, there's also a mythical explanation.
Thus, there are stories that this weird topographical feature is in fact the remains of a causeway built by an Irish giant by the name of Fionn mac Cumhaill so that he could cross the North Channel and fight a Scottish giant named Benandonner.
