Topic: so on youtube they're saying Planck lengths are related to black holes
boof started this discussion 2 years ago #113,648
the deal is that with uncertainty principle, to know precisely where a thing is having that radius, the associated energy has to be enough that its density means you've got balck hole or some shit
Anonymous B joined in and replied with this 2 years ago, 9 minutes later[^] [v] #1,258,322
I put my Planck length in your mom's black hole.
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boof (OP) replied with this 2 years ago, 32 minutes later, 58 minutes after the original post[^] [v] #1,258,337
Anonymous E joined in and replied with this 2 years ago, 4 hours later, 5 hours after the original post[^] [v] #1,258,349
you can't know precisely where it is, that's the whole deal with the uncertainty principle
boof (OP) replied with this 2 years ago, 4 hours later, 10 hours after the original post[^] [v] #1,258,356
well I guess the idea is that you can't get the smallest distance down to a precise single point because before you get there, you get to this Planck length that would necessitate so much energy that you effectively have a teensy black hole in the space
Anonymous E replied with this 2 years ago, 1 hour later, 11 hours after the original post[^] [v] #1,258,360
@previous (boof)
if you were trying to locate an object in spacetime you wouldn't even measure in plancklengths. they're not useful for that.
if you were trying to locate an object in spacetime you wouldn't even measure in plancklengths. they're not useful for that.
(Edited 26 seconds later.)
Anonymous B replied with this 2 years ago, 11 minutes later, 11 hours after the original post[^] [v] #1,258,361
Anonymous F joined in and replied with this 2 years ago, 3 hours later, 15 hours after the original post[^] [v] #1,258,392
@1,258,349 (E)
Absolutely false. The uncertainty principle is about pairs of incompatible measurements. It is not about individual measurements.
You can know position precisely. You cannot know, however, position AND momentum simultaneously.
So you can know where a particle is exactly, but this requires you know nothing about where it is going. Alternatively, you can know where exactly a particle is moving, but only if you know nothing about where it is.
Absolutely false. The uncertainty principle is about pairs of incompatible measurements. It is not about individual measurements.
You can know position precisely. You cannot know, however, position AND momentum simultaneously.
So you can know where a particle is exactly, but this requires you know nothing about where it is going. Alternatively, you can know where exactly a particle is moving, but only if you know nothing about where it is.
Anonymous E replied with this 2 years ago, 1 hour later, 16 hours after the original post[^] [v] #1,258,421
@previous (F)
You can't have absolutely precise measurements of either. you can measure with higher precision but as your measurements become more precise your knowledge of the other becomes less precise.
If you hypothetically knew with exact precision the momentum of the particle, you would have infinite uncertainty of its position; which is impossible since you're fucking measuring it from some known frame of reference.
You can't have absolutely precise measurements of either. you can measure with higher precision but as your measurements become more precise your knowledge of the other becomes less precise.
If you hypothetically knew with exact precision the momentum of the particle, you would have infinite uncertainty of its position; which is impossible since you're fucking measuring it from some known frame of reference.
(Edited 10 minutes later.)
Anonymous F replied with this 2 years ago, 11 minutes later, 16 hours after the original post[^] [v] #1,258,433
@previous (E)
> You can't have absolutely precise measurements of either
Nothing in quantum mechanics prevents you from obtaining measurements to any arbitrarily high level of precision for position or (separately) momentum.
Whether or not you could build a machine with infinite precision is another matter, but that has nothing to do with quantum mechanics and even less to do with the uncertainty principle.
> as your measurements become more precise your knowledge of the other measurement becomes less.
That is what I said, yes.
> You can't have absolutely precise measurements of either
Nothing in quantum mechanics prevents you from obtaining measurements to any arbitrarily high level of precision for position or (separately) momentum.
Whether or not you could build a machine with infinite precision is another matter, but that has nothing to do with quantum mechanics and even less to do with the uncertainty principle.
> as your measurements become more precise your knowledge of the other measurement becomes less.
That is what I said, yes.
Anonymous E replied with this 2 years ago, 3 minutes later, 16 hours after the original post[^] [v] #1,258,435
@previous (F)
And in reality that means you can't have absolute precision in either of the measurements, ever. The uncertainty doesn't actually mean the particle is everywhere all at once or moving at all speeds.
The Youtubers spouting off about the uncertainty principle proves that sub electron particles "is black holes" or whatever is just nonsense.
And in reality that means you can't have absolute precision in either of the measurements, ever. The uncertainty doesn't actually mean the particle is everywhere all at once or moving at all speeds.
The Youtubers spouting off about the uncertainty principle proves that sub electron particles "is black holes" or whatever is just nonsense.
(Edited 6 minutes later.)
Anonymous F replied with this 2 years ago, 5 minutes later, 16 hours after the original post[^] [v] #1,258,437
@previous (E)
> And in reality that means you can't have absolute precision in either of the measurements, ever.
This, again, has nothing to do with the uncertainty principle. What you're talking about doesn't have even anything to do with quantum mechanics. The same argument can be made for classical Newtonian mechanics too.
> The uncertainty doesn't actually mean the particle is everywhere all at once or moving at all speeds.
This has nothing to do with what we're talking about. The interpretation of the wave-particle collapse is another discussion altogether. An interesting one, but a separate one no less.
> And in reality that means you can't have absolute precision in either of the measurements, ever.
This, again, has nothing to do with the uncertainty principle. What you're talking about doesn't have even anything to do with quantum mechanics. The same argument can be made for classical Newtonian mechanics too.
> The uncertainty doesn't actually mean the particle is everywhere all at once or moving at all speeds.
This has nothing to do with what we're talking about. The interpretation of the wave-particle collapse is another discussion altogether. An interesting one, but a separate one no less.
Anonymous E replied with this 2 years ago, 1 minute later, 16 hours after the original post[^] [v] #1,258,440
@previous (F)
The topic is that someone on youtube said the uncertainty principle "means black holes". Which is probably a misunderstanding of "you don't know anything about its position" to mean it's literally everywhere. It just means you don't know. Fuckin' Youtubers, dude
The topic is that someone on youtube said the uncertainty principle "means black holes". Which is probably a misunderstanding of "you don't know anything about its position" to mean it's literally everywhere. It just means you don't know. Fuckin' Youtubers, dude
(Edited 2 minutes later.)
Anonymous F replied with this 2 years ago, 2 minutes later, 16 hours after the original post[^] [v] #1,258,443
@previous (E)
That's the topic of the thread. The only thing I cared to comment about was your claim that the uncertainty principle means you cannot know position to an arbitrary level of precision. That claim is false.
That's the topic of the thread. The only thing I cared to comment about was your claim that the uncertainty principle means you cannot know position to an arbitrary level of precision. That claim is false.
Anonymous E replied with this 2 years ago, 55 seconds later, 16 hours after the original post[^] [v] #1,258,444
Anonymous E double-posted this 2 years ago, 5 minutes later, 16 hours after the original post[^] [v] #1,258,447
@1,258,437 (F)
> What you're talking about doesn't have even anything to do with quantum mechanics.
I already said here: @1,258,360 (E) that plancklengths aren't used except to think about things at quantum scale. They were invented to discuss effects without having to even think about spacetime, essentially
> What you're talking about doesn't have even anything to do with quantum mechanics.
I already said here: @1,258,360 (E) that plancklengths aren't used except to think about things at quantum scale. They were invented to discuss effects without having to even think about spacetime, essentially
(Edited 3 minutes later.)
Anonymous F replied with this 2 years ago, 14 minutes later, 17 hours after the original post[^] [v] #1,258,452
@1,258,444 (E)
My mistake. You said absolutely. The distinction matters little though because the uncertainty principle also does not prevent you from performing such measurements. Just admit that you were wrong! It's okay. We all make mistakes.
I'm not just nit picking here. The uncertainty principle is an important one. Knowing where it comes from and what it implies is important. Quantum mechanics gets a bad reputation for being a confusing and difficult subject. Some of this I think is unjustified. The fundamentals of it are not that difficult and are surprisingly accessible. I genuinely urge you to learn more about it either through an entry level (non-pop-science) textbook or a lecture series for undergraduates. It's a seriously interesting subject and well worth the time and effort to get at least an entry level understanding (again, beyond pop-sci articles that are often wrong or misleading).
My mistake. You said absolutely. The distinction matters little though because the uncertainty principle also does not prevent you from performing such measurements. Just admit that you were wrong! It's okay. We all make mistakes.
I'm not just nit picking here. The uncertainty principle is an important one. Knowing where it comes from and what it implies is important. Quantum mechanics gets a bad reputation for being a confusing and difficult subject. Some of this I think is unjustified. The fundamentals of it are not that difficult and are surprisingly accessible. I genuinely urge you to learn more about it either through an entry level (non-pop-science) textbook or a lecture series for undergraduates. It's a seriously interesting subject and well worth the time and effort to get at least an entry level understanding (again, beyond pop-sci articles that are often wrong or misleading).
Anonymous F double-posted this 2 years ago, 2 minutes later, 17 hours after the original post[^] [v] #1,258,454
@1,258,447 (E)
Hey, that's fine. I wasn't commenting about the youtube video. I haven't watched it. I've heard of the general idea before about the supposed Planck length black hole connection, but don't know enough to say anything too informed about it.
I was only commenting on something that I do know about, and that was about what you said about the uncertainty principle.
Hey, that's fine. I wasn't commenting about the youtube video. I haven't watched it. I've heard of the general idea before about the supposed Planck length black hole connection, but don't know enough to say anything too informed about it.
I was only commenting on something that I do know about, and that was about what you said about the uncertainty principle.
(Edited 42 seconds later.)
Anonymous E replied with this 2 years ago, 8 minutes later, 17 hours after the original post[^] [v] #1,258,455
@1,258,452 (F)
I was just saying the Youtubers mentioned in the OP are dumb. Measuring the location or momentum of subatomic particle (with any level of precision) won't somehow turn it into a black hole. You not knowing something doesn't make all the possibilities true. Fuck Copenhagen.
I was just saying the Youtubers mentioned in the OP are dumb. Measuring the location or momentum of subatomic particle (with any level of precision) won't somehow turn it into a black hole. You not knowing something doesn't make all the possibilities true. Fuck Copenhagen.
(Edited 1 minute later.)
Anonymous F replied with this 2 years ago, 38 minutes later, 18 hours after the original post[^] [v] #1,258,459
@previous (E)
> Measuring the location or momentum of subatomic particle (with any level of precision) won't somehow turn it into a black hole.
Think about a conventional microscope. You can make better and better lenses until a certain point where no matter how good of a lens, it won't improve the resolution of your image because you will never be able to resolve objects smaller than the wavelength of visible light. That's where you have to move to an electron microscope. Or, if you wanted to stick with light, you'd have to use smaller wavelengths like X-rays (think X-ray crystallography). And smaller wavelengths means more energy, due to Planck's energy-frequency relation.
With quantum mechanics, this is all fine. Spacetime geometry does not dynamically change in QM, so QM does not predict a black hole will form no matter how much energy you have in any region. In general relativity, however, not so much.
That's the general idea as I understand it. Where the Planck length precisely fits into all this, I don't know. But one could somewhat easily figure out a minimal meaningful length by taking the lightest known subatomic particle and finding the shortest wavelength photon that you could collide with it without producing a black hole. Maybe some value close to or exactly related to the Planck length pops out of such an exercise. I don't know. But it's possible.
> You not knowing something doesn't make all the possibilities true.
I don't know what this means.
> Measuring the location or momentum of subatomic particle (with any level of precision) won't somehow turn it into a black hole.
Think about a conventional microscope. You can make better and better lenses until a certain point where no matter how good of a lens, it won't improve the resolution of your image because you will never be able to resolve objects smaller than the wavelength of visible light. That's where you have to move to an electron microscope. Or, if you wanted to stick with light, you'd have to use smaller wavelengths like X-rays (think X-ray crystallography). And smaller wavelengths means more energy, due to Planck's energy-frequency relation.
With quantum mechanics, this is all fine. Spacetime geometry does not dynamically change in QM, so QM does not predict a black hole will form no matter how much energy you have in any region. In general relativity, however, not so much.
That's the general idea as I understand it. Where the Planck length precisely fits into all this, I don't know. But one could somewhat easily figure out a minimal meaningful length by taking the lightest known subatomic particle and finding the shortest wavelength photon that you could collide with it without producing a black hole. Maybe some value close to or exactly related to the Planck length pops out of such an exercise. I don't know. But it's possible.
> You not knowing something doesn't make all the possibilities true.
I don't know what this means.
Anonymous E replied with this 2 years ago, 10 minutes later, 18 hours after the original post[^] [v] #1,258,463
Anonymous F replied with this 2 years ago, 3 minutes later, 18 hours after the original post[^] [v] #1,258,464
@previous (E)
You should stay away from physics topics. I don't think you have the maturity to really appreciate the subject. And why would you? You already know all the answers lol.
You should stay away from physics topics. I don't think you have the maturity to really appreciate the subject. And why would you? You already know all the answers lol.
Anonymous E replied with this 2 years ago, 19 minutes later, 18 hours after the original post[^] [v] #1,258,467
Anonymous F replied with this 2 years ago, 6 minutes later, 18 hours after the original post[^] [v] #1,258,468
boof (OP) replied with this 2 years ago, 6 hours later, 1 day after the original post[^] [v] #1,258,535
@1,258,455 (E)
I thought they meant not that anything actually turns into a black hole, but that the Planck length is analogous to absolute zero in that if you actually had a radius known that small, you lose the other thing's information utterly.
I thought they meant not that anything actually turns into a black hole, but that the Planck length is analogous to absolute zero in that if you actually had a radius known that small, you lose the other thing's information utterly.
tteh !MemesToDNA joined in and replied with this 2 years ago, 6 hours later, 1 day after the original post[^] [v] #1,258,555
Anonymous B replied with this 2 years ago, 5 hours later, 1 day after the original post[^] [v] #1,258,620
The length of my plank is the same as the depth of Greta's black hole whence come her greenhouse gases and carbon logs.