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xkcd #3077: de Sitter (xkcd.com)

submitted 6 months ago by schnurrito@discuss.tchncs.de to c/xkcd@lemmy.world

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Our anti-de Sitter club is small at the moment, but I've started corresponding with the conformal field theory people.

https://explainxkcd.com/3077/

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[–] knightly@pawb.social 9 points 6 months ago (5 children)

Spheres are examples of surfaces with positive curvature. Negative curvature (where the angles of a triangle add up to less than 180 degrees) is represented by this saddle shape:

[–] Hamartiogonic@sopuli.xyz 5 points 6 months ago (4 children)

If you draw a triangle on different parts of a toroid, would you get different angles?

[–] knightly@pawb.social 9 points 6 months ago* (last edited 6 months ago) (1 children)

Yup! That saddle is a shape of constant negative curvature. On a toroid, the inside of the hole would have negative curvature and the outside would have positive curvature.

[–] Hamartiogonic@sopuli.xyz 5 points 6 months ago

Wow. That would be truly bizarre kind of space to live in.

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