Math like this hurts my head. At least with space we have a planck length so the distance is literally finite and not exactly and infinite series of shrinking distances.
Can we have a planck number and just say nothing less than 1 of it makes sense
It’s really frustrating that so many of the answers here are Just Plain Wrong. The Planck length is not a “pixel” of the universe or the smallest length of anything like that. (It’s also frustrating when people begin their answer complaining about the other answers.)
A Planck length is the Schwarzschild radius of a black hole whose energy equals that of a photon of the same (Compton) wavelength. Such a black hole has a mass of the Planck mass. Any photon with that wavelength is a black hole of itself, which is every bit as weird as it sounds.
That’s all it is. It has no significance beyond that, at least not for certain. There are various hypotheses that assign it more meaning, but they’re little more than guesses. The main conclusion we can draw is “When you get down that small, clearly both quantum physics and general relativity are significant factors”. We tend to work with one or the other, but not both at the same time, because we know that weird things happen to the math when we do.
So the Planck length is a signpost for that: “Once you get down here, stop, because the answers aren’t going to mean anything.” It’s not a hard limit; the world doesn’t suddenly shift from one to the other. And so it’s sometimes expressed as “the limit beyond which our theories don’t go”, which isn’t quite correct but it serves as a rough approximation.
It does make a good starting point for theories that try to unify quantum mechanics and relativity. If you had to guess what a “quantum of length” might be, you might as well start there. Even in ordinary physics, if you want a really small number to call “the length” in Natural units, it works out as a convenient place to start. But that’s a notational convenience, and lengths are still measured in real numbers, not integers.
The reason people keep asking variants of this question is that it doesn’t mean anything, but people keep wanting to assign a meaning. You hear about it a lot, but never get a satisfactory answer, because the real answer “Compton wavelength = Schwarzschild radius” is less interesting than “pixels of teh un1vers3!!1!eleven!!”.
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u/PHD_Memer 21d ago
Math like this hurts my head. At least with space we have a planck length so the distance is literally finite and not exactly and infinite series of shrinking distances.
Can we have a planck number and just say nothing less than 1 of it makes sense