Thread by @Mikeachim

Seeing the Northern Lights is one thing - but have you ever seen a *city* up there?

Yes, like that scene in ep. 1 of 'His Dark Materials'.

Because here's the weird thing: they exist. You can indeed see cities in the sky. There's actual science on this.

Stay with me. 🧵(1/)

That’s what Jesuit priest Father Domenico Giardina saw on August 14, 1643. Looking across the Strait of Messina (Sicily), he beheld “a city all floating in the air...so splendid, so adorned with magnificent buildings, all of which was found on a base of a luminous crystal.”

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If his record is to be believed - as he watched, the city shimmered and became a garden.

And then a forest.

And finally a landscape of vast armies, locked in combat over the ruins of buildings...

Before the whole thing disappeared completely.

Blimey.

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"DRUGS!" predictably scream modern critics of this account. Was he high?

It's true that by the 17thC, Jesuits had started drinking the tea of a psychoactive plant from Ecuador called Guayasa (similar to Yerba Mate).

But not priests. And no evidence of *him* doing it.

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BTW, his analysis of this was amazingly scientific: he guessed that minerals and salts “rise up in hot weather in vapours from the sea to form clouds, which then condense...to become a moving, polyhedrical mirror.”

This, 61 years before Newton's "Opticks". Dead impressive.

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Still, it's easy to write this off as delusion or fabrication.

Except - these floating cities keep appearing.

Here's one above Yantai City in East China, in 2019:



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And here's a REALLY eerie one from 2015, again in China:



A few atmospheric scientists think this one might be, ah, 'enhanced': nationalgeographic.com/science/articl…...

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But this image, taken in Alaska in 2016, certainly isn't:

adn.com/opinions/2016/…

And if floating cities aren't your thing...

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How about this terrifying sight, via apod.nasa.gov/apod/ap120415.…?

Having seen that bit in 'Interstellar' with the huge waves, this would make me lose my lunch. (I’m not sure from which end.)

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And if they don't float your boat, this pic should do the trick, taken earlier this year near Falmouth, Cornwall:

bbc.co.uk/news/uk-englan…

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I've been fascinated with this effect ever since I learned of it in @NaturalNav's magnificent "Walker's Guide To Outdoor Clues And Signs": uk.bookshop.org/books/the-walk…

(One paragraph --> many hours of obsessive reading-about. Excellent value for curious people, this book.)

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(And you can skip to the chase here by reading this newsletter, in which I nerd out wildly and perhaps incoherently on this topic in many directions:

everythingisamazing.substack.com/p/science-of-w…

This season is about optical illusions. Sign up if you like the sound of.)

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The atmospheric effect is called a Fata Morgana (after Morgan Le Fay, King Arthur’s treacherous, scheming half-sister).

It's a Superior Mirage, caused by light bending as it hits a low-lying layer of cold air.

It makes distant things closer....

And it makes them *float*.

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It also distorts them.

If you're lucky enough to see a Fata Morgana, keep watching it! As the air moves, the image will stretch, bend and twist in truly mindbending ways.

(Via epod.usra.edu/blog/2018/09/f…)

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These layers are called atmospheric ducts.

As Robert Macfarlane notes in 'Landmarks', a single globe-encircling duct could bend light indefinitely - so if your eyes were strong enough, you could "gaze around the whole earth and witness your own back and shoulders.”

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And of course it can happen to distant city lights when it gets dark.

Can you imagine your reaction to seeing something like this in the dead of night? Can you imagine it if you didn't have a clue what it really was?

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For more on all this, and for light-bending illusions on a vastly bigger scale (pictured), please have a read of this thing I wrote:

everythingisamazing.substack.com/p/science-of-w…

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Last one (a particularly barmy-looking example), courtesy of abc27.com/news/photograp…

Thanks for reading.

/Fin.

Update! Very happy to say that I *think* I just saw my first fata morgana:

https://twitter.com/Mikeachim/status/1464598514781073416

And it's because I was looking for it. A little knowledge sharpens your attention marvellously...

And more of it here seen, I think? Look how the buildings along the shoreline at Ardrossan are 'doubled up', with copies of themselves that are upside-down...

So great to see this in person.

And this is a gorgeously freaky-looking example of the floating-ship variety from @GrantBlackNZ:

https://twitter.com/GrantBlackNZ/status/1467920756596117506