Donuts and Funhouse Mirrors

An Interactive Audio Lesson about the shape of the Universe

By Chris Uehlinger


This lesson can be controlled using a few different input methods:

  • Keyboard - Press the right and left arrow keys to go forward and backward, press the "R" key to refresh.
  • Click/Touch - Use the controls in the lower right corner to go forward, go backward and refresh

The Shape Of The Universe

Closed Universe
Flat Universe
Open Universe


  • Our tiny universe has 100m2 of space.
  • There is no edge.
  • There is no center.
The rectangular universe printed on a flat sheet of paper The universe folded into a cylinder The universe folded into a cylinder The universe folded into a deformed donut shape
Vsauce video about being inside a spherical mirror.


Closed Universe
Flat Universe

Things that are still true:

  • Our universe has no edge and no center.
  • Expansion has no direction and is measured in (distance/time)/distance, not distance/time.
  • The universe started from a point of infinite density.

The Math of Infinity

\( \frac{\infty kg}{100 m^2} = \infty \frac{kg}{m^2} \)
\( \frac{100 kg}{\infty m^2} = 0 \frac{kg}{m^2} \)
\( \frac{\infty kg}{\infty m^2} = ? \frac{kg}{m^2} \)
\( \frac{\infty kg}{\infty m^2} = \infty \frac{kg}{m^2} \)
\( \frac{\infty kg}{\infty m^2} = 0.00001 \frac{kg}{m^2} \)
Hotel Infinity Video


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Space Ship Icon
Geanie Paek
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Egorova Valentina
Reviewed by Max Goldstein.