Is it possible for something to be smaller than a Planck length?

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Discussion Overview

The discussion revolves around the concept of the Planck length and whether it is possible for something to exist that is smaller than this fundamental scale. Participants explore the implications of quantum uncertainty and the nature of measurement at such small distances.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that the Planck length is significant because it represents a scale where quantum uncertainty dominates, making measurements at smaller scales potentially meaningless.
  • Others argue that the Planck length is merely a human-defined unit of measurement, implying that nature may not adhere to such definitions.
  • A participant references an Insights article that discusses the Planck length, indicating that this question is frequently raised within the community.
  • Another participant notes that while there have been updates to physical constants, the definitions of units like the kilogram remain tied to arbitrary standards, suggesting a need for reevaluation of such measures.

Areas of Agreement / Disagreement

Participants express differing views on the significance of the Planck length as a limit to measurement, with some emphasizing the role of quantum uncertainty and others questioning the relevance of human-defined units. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Limitations include the dependence on definitions of measurement units and the unresolved implications of quantum mechanics at scales smaller than the Planck length.

multiversetheory
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After watching a youtube video 2 years ago, the video said the smallest thing known is at Planck length, but could there be something smaller than Planck length
 
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Not the best response someone can give, but so the reason the plank length exists as a term is because this is the distance that which light travels in the plank time. Below this distance, quantum uncertainty takes over and essentially means that all your measurements are meaningless. Measurements are measurements because they do not change, for one. The uncertainty principle states that position and momentum uncertainty has a minimum value. You can never exceed a certain amount of accuracy during measurement. Yadda yadda yadda, I think that this ends up indicating that at such short distances and times if anything is going on down there, you have no idea what it is.
 
multiversetheory said:
After watching a youtube video 2 years ago, the video said the smallest thing known is at Planck length, but could there be something smaller than Planck length
Yes, just as there can be something smaller than a meter or smaller than a foot. It's just a man-made unit of measure. Nature really doesn't care.
 
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Nugatory said:
This question comes up often enough that we have an Insights article for it: https://www.physicsforums.com/insights/hand-wavy-discussion-planck-length/
From the above Insights article:
"There is a push towards making our human units based on physical constants, like defining the meter in terms of the speed of light, but at this time the kilogram is still the mass of a brick in France." [2015]

I understand the physical constants have since been updated. Perhaps this article could be updated and/or linked with the current definitions. I also believe the self-deprecatory 'hand wavy' description in the title and text to be unnecessary as the reasoning seems sound. Thanks.
 

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