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Comment by gotocake | Hacker News Reader

Fun fact, the toroidal cat is actually a stable gravitational configuration along with a spheroid. There are upper and lower bounds on angular momentum and mass of course, but within those bounds you can have a toroidal cat orbiting its primary!

Wait, what’s a cat again?

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Complete tangent, but I’ve always wanted to ask someone else who thinks about toroidal gravitational physics: in the center of a toroidal cat (planet) of sufficient mass, does gravity “cancel out”, or are you instead being “pulled apart” in every direction at once, as if on a medieval rack?

Cancels out. To pull something apart, there would have to be a gravitational gradient, meaning the object would have to be pretty huge relative to the toroid.

AKA Spaghettification

https://en.wikipedia.org/wiki/Spaghettification

Both.

At the very center of the hole, everything cancels. But it is unstable. As you head in any direction, you will get pulled further. Which means that there are also tides pulling you apart.

At the center of the solid ring of the torus, everything also cancels. But this time the tides are squishing you together. Which is why the configuration is stable.

isn't that the same type of cat physicists used to proof the buttered-cat paradox ?

Actually the buttered cat hypothesis has been proven with much less exotic cat shapes. I recall seeing a paper showing that a cat with dimension n=1 and zero rotational inertia would spontaneously begin spinning as a result of the presence of a "butter field." Of course the experimenters ran out of point cats and had to go to the store to get more syrup shortly after completing the experiment, so it has been rather difficult to replicate. However the authors assured readers they would attempt replication at the next breakfast fundraiser for the department.

Thank you for an opportunity to revive this video - https://www.youtube.com/watch?v=Z8yW5cyXXRc

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