I’m off to bed. I can’t deal with that blackboard.
It’s a wave. When it moves it does so in the same way that all waves move.
It doesn’t have to move though. Certain types of wave stand still. They are (unimaginatively) called ‘standing waves’.
Think of a piece of string - a bell rope is a good example. If you twitch the bottom of the bell rope you’ll see the twitch travel up the rope, hit the ceiling where the rope passes through, bounce off the ceiling and come back down the rope again. That’s a travelling wave.
If you were to clamp both ends of a string, like a guitar string, then pluck it in the middle the ends would stay fixed but the middle would oscillate from side to side. In general the string would look like half a wave. The string would move (sideways) but the wave wouldn’t move along the string. That’s a standing wave.
I think they use the word ‘even’ not because the light is powerful but because the particles of light (sometimes it’s better to think of light as particles rather than waves) have zero mass. We’re familiar with the fact that really massive things struggle to escape gravity. I can throw a tennis ball further upwards than I can throw a bag of cement. But the gravity of a black hole is strong enough that it can even keep hold of things which have zero mass (particles of light).
Don’t get distracted by ‘light’ being the opposite of ‘heavy’. That’s a different meaning of light.
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When I did O Level Physics light travelled in straight lines. When I did an A level Physics course at nightschool a while later it travelled in waves.
I have no idea how it travelled at Degree level as I never travelled that far.
In free space the direction of travel of a light wave is a straight line (usually called a light ray). If anything gets in the way of the ray (mirror, lens, opaque object blocking part of the wavefront, warm air above a hot desert etc) it can change the light’s direction.
In the case of light waves themselves the thing which is changing is not something tangible (like a piece of a rope, or like water carrying a water wave) but instead it’s a pair of coupled fields - the electric and magnetic fields.
The last time I looked (thick end of 40 years ago) it typically took good physics undergraduates a few weeks, or maybe a few months, to get their heads around the idea of light as waves in the electromagnetic field rather than as waves in some sort of independent medium. A lot of people who aren’t physicists aren’t forced to struggle with the concept for long enough ever to get to grips with it. From roughly the 17th century to the early part of the 20th century the best minds in the business struggled with this problem, postulating a substance called the luminiferous aether for light to travel in. In fact there’s no such thing.
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Like plumbers for instance? 
(and 99% of the rest of us!)
Weeeeelll … people who more-or-less teach themselves can still come to grasp it. Einstein had a physics education but he was working as a clerk in the Swiss Patent Office when, in 1905, he published four exceptional and novel papers - one on the photoelectric effect, one on Brownian motion, one on special relativity and one on the equivalence of mass and energy. He didn’t get an academic job until 1908. He won the 1921 Nobel Prize for Physics for his general contributions to the field but the work they particularly picked out was the 1905 photoelectric effect stuff, not the relativity.
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There is hope! 
Great example 
There is no hope !
Great thread on Twitter
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Mr Sagan’s version
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Is maths allowed here?
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I tried it for the third digit (n=3). The answer I got was 3.229 … which rounds to 3, when the correct answer is 4. Did I do something wrong or is the formula optimised for large n, since ‘everyone’ knows the first few digits of pi ?
Something else I learned about Simon Plouffe was that as well as working out this formula he also briefly (1975-1977) held the world record for memorising the digits of pi - he could recite the first 4096 of them.
Serious mathematicians really aren’t like the rest of us.
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This is cool, lasers and everything!
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“I’m very stubborn …” she said. “I like a challenge and I don’t give up easily.”
Sounds like she’s got what it takes.
I have a soft spot for small, (relatively) cheap but very clever experiments which eliminate huge volumes of theoretical possibility.
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The oldest plant ever to be regenerated has been grown from 32,000-year-old seeds.
Mind. Blown.
https://www.nationalgeographic.com/science/article/120221-oldest-seeds-regenerated-plants-science
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A Russian team discovered a seed cache of Silene stenophylla, a flowering plant native to Siberia, that had been buried by an Ice Age squirrel
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Let’s hope they don’t also unearth a 32KYR plague virus…
Then again . . . Humanity is the greatest danger this planet has ever faced, so p’raps not…
Excellent and fascinating, thanks for sharing Paul.
Been looking for it for a while - be nice if we could get some actually clear skies, been misty/foggy here which with background light pollution is making it a sod to spot.