Phenomena Smaller than Planck Length?

[Nous]

Perhaps you are already familiar with the (kind of) contrary positions on whether Planck length constitutes the smallest possible length. If not, here are a couple of brief articles that seem to adequately explain the positions:

Planck Length: The Smallest Possible Length

Planck length, minimal length?

The issue I wish to inquire about is whether there exist phenomena smaller than Planck length. Thus I would like to know which of the following statements best express your views:

1. It is possible but not necessary that there exist phenomena smaller than Planck length.

2. It is necessary that there exist phenomena smaller than Planck length in order to resolve dilemmas in theories of physics or in order to be consistent with theories of physics.

3. It is impossible that there exist phenomena smaller than Planck length, as such phenomena would be contrary to the principles of logic or of a scientific theory.

The term “phenomena” in the above statements can mean anything--an object whose location, momentum or energy is indefinite; a quantized or non-quantized force; a probability; an interaction of some sort, or something currently unimagined.

Indeed, just such slightly unimaginable phenomena are what are indicated by descriptions in the sources above. As the article published by Fermilab Today notes:

When you scatter a particle of light off another particle -- say an atom -- the atom's gravitational attraction to the light particle causes an intrinsic uncertainty in the atom's location. Mead used the uncertainty principle and the gravitational effect of the photon to show that it is impossible to determine the position of an object to a precision smaller than the Planck length.​

According to the explanation at Futurism:

If two particles were separated by the Planck length, or anything less, then it is impossible to actually tell their positions apart. Moreover, any effects of quantum gravity at this scale (if there are any) are entirely unknown as space itself is not properly defined. In a sense, you could say that, even if we were to develop methods of measurements that took us down to these scales, we would never be able to measure anything smaller despite any sort of improvements to our equipment or methods.​

Apparently phenomena smaller than Planck length would not be locatable in accordance with our quotidian notions of space and time. It seems that such smaller-than-Planck-length phenomena would exist in no particular (definable) place and at no particular (definable) time.


If there might be a statement regarding the existence of phenomena smaller than Planck length that expresses your view better than one of the above 3 statements, please give it.

 

[Jumi]

I've never heard of Planck's length being the smallest length, even though I've known about it for a long time. Despite the two articles making a case otherwise, I'd say it's perfectly possible for there to be things smaller than it.

 

[icehorse]

Apparently phenomena smaller than Planck length would not be locatable in accordance with our quotidian notions of space and time. It seems that such smaller-than-Planck-length phenomena would exist in no particular (definable) place and at no particular (definable) time.

First off, you've already put us in the quantum world, which is far, far, far away from being quotidian

My stance wouldn't be any of your 3, mine would be more like:

It's only ever so remotely possible that there exist phenomena smaller than Planck length, as such phenomena would be contrary to the principles of logic or of a scientific theory.

But in more day to day terms, "If not for the Planck length, Xeno's paradox would keep me from ever getting out the door."

 

[beenherebeforeagain]

I'd say it's perfectly possible for there to be things smaller than it.

And that it is currently impossible for us to measure them...

Doesn't mean they don't exist.
Doesn't mean we won't eventually be able to detect them.
Just means that right now, we can't.
No big deal, really...

 

[Twilight Hue]

I've never heard of Planck's length being the smallest length, even though I've known about it for a long time. Despite the two articles making a case otherwise, I'd say it's perfectly possible for there to be things smaller than it.

Of course. :0)

And I suspect things go smaller and smaller for Infinity as well as conversely larger and larger.

 

[Nous]

First off, you've already put us in the quantum world, which is far, far, far away from being quotidian

My stance wouldn't be any of your 3, mine would be more like:

It's only ever so remotely possible that there exist phenomena smaller than Planck length, as such phenomena would be contrary to the principles of logic or of a scientific theory.

Thank you for your more detailed statement. What scientific theory would the existence of smaller-than-Planck-length phenomena be contrary to?

 

[Nous]

And that it is currently impossible for us to measure them...

Doesn't mean they don't exist.
Doesn't mean we won't eventually be able to detect them.
Just means that right now, we can't.
No big deal, really...

Well, as the the last sentence I quoted from the Futurism article states: "In a sense, you could say that, even if we were to develop methods of measurements that took us down to these scales, we would never be able to measure anything smaller despite any sort of improvements to our equipment or methods." I think this is true.

 

[beenherebeforeagain]

Well, as the the last sentence I quoted from the Futurism article states: "In a sense, you could say that, even if we were to develop methods of measurements that took us down to these scales, we would never be able to measure anything smaller despite any sort of improvements to our equipment or methods." I think this is true.

might be true, but I would not be terribly surprised if sometime in the future (probably long after you and I are gone) it proved false...but I think we're pretty safe right now from a very pragmatic stance, of acting as if it's true...because it cannot be at this time tested....

 

[Nous]

might be true, but I would not be terribly surprised if sometime in the future (probably long after you and I are gone) it proved false...but I think we're pretty safe right now from a very pragmatic stance, of acting as if it's true...because it cannot be at this time tested....

How would one measure something that doesn't have an actual location (as Mead showed would be the case for phenomena smaller than Planck length)?

 

[beenherebeforeagain]

How would one measure something that doesn't have an actual location (as Mead showed would be the case for phenomena smaller than Planck length)?

Personally, I don't know. What I do know is that someone else, now or in the future, MAY be able to answer that question. I do not take our current version of knowledge as complete or final, just as pragmatically useful.

 

[Nous]

Personally, I don't know. What I do know is that someone else, now or in the future, MAY be able to answer that question. I do not take our current version of knowledge as complete or final, just as pragmatically useful.

I feel confident that the uncertainty principle will not be shown to be erroneous.

 

[beenherebeforeagain]

I feel confident that the uncertainty principle will not be shown to be erroneous.

okay...