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this post was submitted on 07 Aug 2025
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One of the most accurate and successful theories in physics contains the single worst prediction and isn't mathematically rigorous at all.
Doing calculations with it feels like doing vibes based maths, and you spend a lot of time doing things like: "oops divided by zero guess I'll cancel it out by multiplying by zero" and it works.
In engineering we have a simmillar thing for some cases where we replace 0 with a variable that is 0 at the limit but not 0 itself then continue on like nothing happened. It all cancels out at the end but feels so wrong.
Can you give an example?
In control dynamics u have a transfer function and need to determine the Routh-Hurwitz criterion it will sometimes give u division by 0 errors so u sub in a variable and say its almost zero but not quite and continue on like nothing happened.
Eg determining the stability of a system with characteristic eq of A(s) = 3s^4+6s^3+2s^2+4s+5=0
If u do a RH array u will end up with a zero which then will give u (4*0โ30)/0 so u sub in ๐ for 0 giving (4๐โ30)/๐ and continue on. That eq obviously evaluates to negative infinity. U are essentially just saying ๐ is an infinity small positive number ie it is the number next to 0 on the positive side.
EDIT: If the markdown is messed up the eq should be
A(s) = 3s**4+6s**3+2s**2+4s+5=0When using ** as super notation
Well, that's a relief! That's a completely different kind of engineering than I studied, so I can stop being worried that there was something I was supposed to have learned but didn't.
Its general mechanical background stuff
My degree is in civil.
Ahh. Mechanical before shit starts to move.
ฯ=โ10
Physics in general has not caught up to the fact that locality isn't a thing. Nobel prizes were handed out for this in I think 22... And people still think the notion of spacetime can be taken seriously. It can't.
What does that mean?
Which part
locality. what was it supposed to be? and why doesn't it actually exist? what model "replaces" it, if any?
maybe the meaning of spacetime isn't obvious either, and I just misunderstand what it means
locality wikipedia page
In short locality states that things are only directly affected by their immediate surroundings. This is provably untrue in quantum mechanics.
Thanks!
You know how you get COVID from being in the same room as someone who sneezes on you or something? It's that.
Non locality is when you get COVID from someone the next state over.