I don’t get it.
Hasn’t that explanation been out and accepted as the right analysis of the phenomenon for decades already ?
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The causeway was created by giants who had body temperatures of 840-890C.
That’s my takeaway.
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Looks like Fingal’s Cave is about 75 miles north of Giant’s Causeway.
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Do you wanna talk rocks, folklore, and natural wonders? Or do you want another ‘Tournament of the Trolls’ with yet another posting about gun control?
Thanks, TobinL 
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Thanks! I had no sense of scale between them, and I wondered if Fingal’s Cave could be the western edge of the same upwelling that made the Giant’s Causeway. NOPE!
Great story. Celtic myths and legends are always fascinating to me. My favorite is the Children of Lir, a story of four children whose step mother was jealous and with her Druidic wand turned them into beautiful swans who sang the most beautiful and enchanting songs. But they were cursed to live their lives for 900 years in the waters of the cold northern seas. In the end, they died and a monument was erected for them. Melancholy, but fun to read. Sad ending, but almost all Celtic myths are bloody and tragic. Hail the Folk!
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The Faerie Folk they be!
I answered taking into account both the title and the introduction of the article, which suggested that there was something new to say about the Giant’s Causeway formation. Which there wasn’t, only a recap’ of a geological analysis that’s been made I don’t know how many decades ago, and the amusing legend associated with the site.
Is that being a troll?
Apart from that, I really don’t get your line about gun control.
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Lucky you, if you haven’t seen the shit storms taking place on the gun control postings.
My point was that this posting was a lovely, refreshing contrast to the venom and rhetoric being flung about elsewhere on BoingBoing - that would be the Tournament of Trolls. Who cares if it was previously published for the enjoyment of rock nerds? Now, it’s being discussed politely and un-trollishly, without any references to Trump, Socialism, or gun control.
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Fook the fookin’ fookers.
– Flann O’Brien (Brian O’Nolan / Brian Ó Nualláin), aka Myles na gCopaleen
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Okay, this is a bit tricky to explain without lots of thermodynamics, but here goes…
The rocks contain crystals, but these are much smaller then the columns you see. And the columns are not exact hexagons - there are occasional 5- and 7-sided ones, so they aren’t crystalline as such.
The rock is not a single compound but a mixture of things with different melting points. Imagine trying to freeze an alcohol-water mixture. Water has a higher freezing point than alcohol, so the ice in equilibrium with an alcohol-water mixture has less alcohol, which is how freeze distillation works.
When the ice first forms, it contains less alcohol than the bulk solution. If you carry on freezing very slowly without stirring or anything (which is not how free distillation is done) the freezing front where the ice meets the water pushes a layer of the extra alcohol ahead of it. This freezing front may start off flat, but any finger of ice that sticks out through the layer of extra alcohol, and grows faster, so the freezing front becomes a set of fingers, with largely water middles, and the alcohol is at the edges where the fingers meet. If you freeze faster, then the fingers grow fingers, and you get tree-like structures called dendrites.
As far as I know, alcohol+water isn’t great at growing Giant’s Causeway-like prisms: I just chose it because it was familiar example. However, if you have a mixture of molten minerals, then you will get prisms with pure high melting-point centres, and a layer of the low melting point impurities at the boundaries.
The size of the prisms is determined by the rate the freezing front moves. The slower it moves, the freezing process has more time to sweep the junk larger distances, and you get bigger prisms.
I hope this makes some sense. I had a quick look for a video or even a good diagram, but I couldn’t find one. But there is no mystery that hasn’t been solved a long while ago.
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Yes, but I think you’re confusing Fionn mac Cumhaill (Finn Mac Cool) with Éthur Mac Cuill (a king of the De Danaan).
Tuatha de Daanan means “children of Danu”, and implies nothing of size; and anyway Finn’s not Sidhe. Wikipedia puts the Fenian cycle as the third cycle, between the Ulster and Historical cycles.
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It’s the ‘tuatha’ word I was on about: it’s the “us” word, with deep Indo-European roots. I’m an Indo-Europeanist by training [the ‘tuatha’/teuta’ cognates are not my own example - pretty well established], and so may well have conflated bits of my spotty and old knowledge of Irish folk/myth/culture per se. Thank you for the correction. Perhaps also interesting to you is the idea that Dan [or Danu] may well have been a major I-E deity: viz. the rivers Don/Dnieper/Dniester; Donetsk, Danmark, etc., etc. Also, compare the Old Irish kingship ritual of horse sex, drunkenness, slaughter, and the new king serving up horse stew with the Asvamehta of Vedic lore: pretty much identical.
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I like the extra bit in the Fionn-as-baby story where he squeezes water from a stone (actually a cheese).
Here’s a place in Iceland where you can see the basalt columns turn – evidently the ones on the right had their hottest point at top or bottom, whereas the ones on the left had their hottest point in front or in back.
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