The dashed line is the illusion we see. It's our interpretation of the very real photons hitting our retinas.
And it creates a pillar of light that isn't really there.
I mean, this is barmy, right?
8/
When you see light pillars, like these over Pinedale, Wyoming (pic. David J. Bell), you're really seeing reflected light from ice crystals hanging in the air halfway between you & where these pillars *appear* to be.
You won't believe it at the time, though. (I wouldn't.)
9/
If you're thinking 'Does this happen with sunlight and moonlight too?' then full marks awarded!
Final point: where I haven't given credit in the thread to their original photographers and their *amazing* work here (none of these pics are mine except his one), I will be doing so fully in my upcoming newsletter.
Also: a bit off-thread, but since so many gamers are here shouting "loot boxes!", here's a plug for my favourite game, #TheLongDark, from @HinterlandGames & @RaphLife:
It'll make you feel much of the cold, glittery wonder in the photos in this thread.
And a final shout-out to @StephNx79, whose photo is at the top of this thread, which started me down this whole fascinating rabbit-hole of optical delightfulness:
I thought I knew the story of the "lost world" off the east coast of Britain, inhabited by Mesolithic people until rising sea waters engulfed it around 8,000 years ago...
But I didn't know about the *tsunami*.
Holy hell.
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What follows is my imperfect grasp of things.
Imperfect because I'm just an enthusiast who likes science - and also imperfect because, excitingly, the work is still going on, as part of one of the greatest prehistoric archaeological investigations in history.
2/
One September night in 1931, the British vessel Colinda hauled up its nets 25 miles off the Norfolk coast - and found something beautiful & deadly.
Embedded in a lump of peat was this 8.5 inch prehistoric harpoon, carved from bone or antler...
When I wrote about the Zanclean Megaflood filling the Mediterranean in 12-18 months (!) it was wistfully.
I'm English. Lovely place, England! But - Big Geological Drama? Not round 'ere, sadly.
Imagine my delight at what geophysicists have found in the English Channel!
1/
500,000 years ago, Britain was still part of the continental European landmass via a land-bridge - the Weald-Artois anticline, formed as rock buckled across Europe as the African plate ground northwards over tens of millions of years.
(This also made the Alps!)
But...
2/
...surely it was nibbled away gradually, as water crept in over thousands of years?
That was the assumption until recently.
But in 2015, bathymetric data collected by marine geophysicists at Imperial College showed 36 underwater “islands” suggesting a different story!
I recently learned something amazing about the Arctic - & my tiny mind is blown.
In my ignorance, I've always believed it's featureless & barren. But now I've learned what's underneath it - & if THAT was on dry land, it'd be a wonder of the modern world.
Buckle up!
1/
This is Mikhail Lomonosov (1711-1765): Russian polymath, scientist, writer - a lesser-known Isaac Newton.
He discovered the law of conservation of mass in chemical reactions, first saw Venus has an atmosphere, founded some of the key principles of modern geology...
2/
...and a town, a lunar crater, a *Martian* crater, a satellite, a porcelain factory (!) and an asteroid have all been named after him.
And at some point, as legend has it, he predicted there was something MASSIVE under the Arctic ice.
In Sept 2023, geophysicists over the world started monitoring an odd signal coming from the ground under them.
It was recorded in the Arctic, then Antarctica - then everywhere, every 90 seconds, regular as a metronome - for NINE DAYS.
What the HELL?
1/
In seismology, this is a USO: an Unidentified Seismic Object.
Perhaps if this discovery had leaked into mainstream news as quickly as potential alien biosignatures tend to do, we’d currently be seeing a big comeback for the HOLLOW EARTH ‘theory’.
Thankfully not the case!
2/
Instead, in the best collaborative tradition of modern science, researchers across the globe - 68 scientists from 40 institutions in 15 countries - joined forces to track down the signal’s source.
On the 21st July 1976, NASA released the very first colour image taken by the Viking 1 lander from the surface of Mars.
And....wait, what?
The Martian sky is BLUE?
1/
This is obviously not what anyone was expecting. Mars is...
Well, you can see it for yourself on a clear night, with your naked eye. It's noticeably red - about as red as Betelgeuse, tenth-brightest star in our night sky.
No blue. So - what? WHAT?
2/
The Martian atmosphere just isn't thick enough to be blue - just 600 pascals, vs the Earth's 101,000.
That scene in "The Martian" where the rocket's in danger of being blown over? No, sir. Not enough punch to it: space.com/30663-the-mart…