
Wizard proposes turning map of the universe inside-out - mccosmos
http://web.archive.org/web/20020814124648/http://www.wizard.gen.nz/Articles/inside-out.html
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macawfish
I love this kind of thing. I often wonder how densities would map under such a
transformation. What would the density be of the "core" of the inside out
earth? What is the density of the universe sphere-reflected about the
geospheric surface of the earth? How does this change as you reflect about
different layers of the earth? How about sphere reflecting the universe about
the surface of a star? Or a black hole?

If anyone is curious, I made some experiments years ago to play with this kind
of perspective shifts. Make sure you check out the horse:

[https://hyperspectives.wondering.xyz](https://hyperspectives.wondering.xyz)

I also made a blender modifier that does Moebius transformations... There is a
patch on the hyperspectives page. But also this fork:

[https://github.com/micahscopes/Hyperspectives/tree/hyperblen...](https://github.com/micahscopes/Hyperspectives/tree/hyperblender)

Lately I've gotten into using Clifford algebra (conformal geometric algebra)
to do the same stuff. I'm slowly building tools for this... Stay tuned!

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quietbritishjim
If an unambiguous centre point _did_ exist, then flipping the coordinate
system from (distance to centre point, point on a n-1 dimensional hypersphere)
to (1 / distance to centre point, point on a n-1 dimensional hypersphere)
would be a trivial and uninteresting transformation. In other words, turning
the universe inside out does nothing to decrease (or increase) the difficulty
of choosing a centre point.

This transformation is its own inverse. Applying it to the coordinate system
in the article we find that the author has chosen the centre of the planet
Earth as their centre point; that is what makes their coordinate system
possible. This is totally arbitrary and does not solve any deep mysteries. The
stuff about turning the universe inside out is just waffle on top of that.

