De Sitter came up with a mathematical model for space-time to satisfy the field equations of Einstein's theory of general relativity. The "curvature" of that model can be positive, zero or negative. When negative, it is called an Anti-de Sitter Space. So the note on the door is a pun on that.
Hate to be that girl, but there are a few situations where it is capitalized: at the beginning of a sentence, and in cases where only the surname is used in a sentence. F.e. "Dat schilderij van Van Gogh is prachtig."
unintentionally and in retrospect with a lot of foresight De Sitter brilliantly explained what goes on in the space between the ears of certain people on the (extreme) right side of the political spectrum. 🤪🤣😜😙
Could be both. And alt text isn't just for the visually impaired. As someone who is both meme impaired and celebrity impaired, I often find them quite illuminating.
🤔 I don't think anyone is advocating for the alt text to be used to explain the joke. In fact I think that'd be an abuse of a feature designed for accessibility, degrading the experience for those users.
I had to look it up, and almost fell down a rabbit hole of reading about hyperbolic geometry. I highly recommend playing the game Hyperbolica, it is very cool and mind-bending to experience something that seems so familiar but bizarre at the same time.
No, maybe it's way more immersive in VR, I hope it is. The creator deserves sales. I was just poor and couldn't justify keeping it when I felt done in an hour.
All the stuff about Lorentzian manifolds is a bit of a distraction. It's important background, but not the main story. It's just saying it's the kind of spacetime you always have to have in general relativity. The bit about curvature is the key thing.
In the time it took me to read that properly I have grown a beard.
I am now stroking the beard and nodding. I am thinking about the scary teletubbies sun baby.
It's about the shape of space and the emergent properties of spaces with the most possible symmetries. A symmetry in space correlates with a conserved property (like conservation of momentum), so different shapes make for different physics. Anti-de Sitter space has negative curvature.
approx:
"maximally symmetric"->there is no origin or 'central point', if you move or rotate the space around you will look the same.
'constant curvature'->the ratio between the circumference of a circle and its diameter stays the same (but isn't necessarily pi).
'negative curvature'-> ratio>pi.
I tried to stay in the character limit but I should specify that this ratio generally depends on the radius/diameter of your circle; the larger the radius the more the ratio will differ from pi, while a small circle will have a ratio close to pi.
Comments
Guess it looks bigger when you're inside 😁
That's my Con-Formal Field Theory
https://www.math.columbia.edu/~woit/wordpress/?p=13184
3077 is 17×181
This rampant anti-Dutch sentiment has gone too far! Too far, I say! Boo! Boo!
... and FIE on you for your pun, sirrah. Fie!
As a fan: Hee hee hee.
https://en.wikipedia.org/wiki/Willem_de_Sitter
kind of a natural transition available
One is a secondary punchline; the other is a description of the visual elements of the comic for the visually impaired
I would want a description of the image and all the text in it. I would also want the traditional XKCD mouseover text, tagged as such.
Alt text: https://explainxkcd.com/3077#Transcript
It was strange how I got zero motion sickness from it that way, but watching someone stream the flat version did.
I am now stroking the beard and nodding. I am thinking about the scary teletubbies sun baby.
"maximally symmetric"->there is no origin or 'central point', if you move or rotate the space around you will look the same.
'constant curvature'->the ratio between the circumference of a circle and its diameter stays the same (but isn't necessarily pi).
'negative curvature'-> ratio>pi.