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A comment on Alternative interpretations of classical physics (2019). Parent comment

Re:Alternative interpretations of classical physics (2019) by leephillips on Tuesday March 23, 2021 @08:18AM (#26554154)
Norton’s dome is intriguing; other departures from determinism in classical physics include “space invaders”: in some many-particle systems a particle can develop an infinite velocity, which sends it “out of world”; then time reversibility means it can enter the world unpredictably. I mention both of these in an article about unsolved problems in classical physics: http://arstechnica.com/science/2014/08/the-never-ending-conu...
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Re:Alternative interpretations of classical physics (2019) by martincmartin on Tuesday March 23, 2021 @10:15AM (#26555274)
Doesn't conservation of energy preclude this? If all particles start with finite energy, and only finite energy is added to the system, won't the total energy stay finite? Or are you assuming an infinite potential somewhere, e.g. gravity from a point "planet"?
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Re:Alternative interpretations of classical physics (2019) by leephillips on Tuesday March 23, 2021 @11:22AM (#26556086)
The examples I know of all involve gravitational or similar potentials, so there is unbounded negative energy available from 1/r. But you can still get singularities without collisions: Xia, Annals of Math. 135 411–468 (1992).
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Re:Alternative interpretations of classical physics (2019) by cozzyd on Tuesday March 23, 2021 @06:25PM (#26561110)
At least a few of these seem to be cases where the concept of a point particle breaks down.

There are similar problems in E&M at caustics that are solved by remembering that E&M waves have non-zero wavelength.

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Re:Alternative interpretations of classical physics (2019) by jayd16 on Tuesday March 23, 2021 @12:56PM (#26557225)
>which sends it “out of world”

Wouldn't any system have to include this "out of world" particle? Doesn't its inclusion mean "the world" simply grows at that infinite rate?

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Re:Alternative interpretations of classical physics (2019) by twic on Tuesday March 23, 2021 @08:46AM (#26554352)
> Take a simple bottle of milk like the ones pictured here, with a cylindrical section below a tapering segment.

Those bottles are rectangular!

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Re:Alternative interpretations of classical physics (2019) by leephillips on Tuesday March 23, 2021 @08:53AM (#26554407)
They are rectangular cylinders. The shape works for the problem under discussion.
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Re:Alternative interpretations of classical physics (2019) by wodenokoto on Tuesday March 23, 2021 @09:07AM (#26554508)
I thought you where making up words, saying “rectangular cylinder”, but apparently it’s a thing:

https://www.quora.com/Geometry-What-is-a-rectangular-cylinde...

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Re:Alternative interpretations of classical physics (2019) by leephillips on Tuesday March 23, 2021 @09:22AM (#26554634)
A cylinder can have any cross section.
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Re:Alternative interpretations of classical physics (2019) by selimthegrim on Tuesday March 23, 2021 @12:49PM (#26557142)
Norton doesn't understand the principle of virtual work and should go back and read D'Alembert and Lanczos.
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