Does the shortest distance exists?

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Discussion Overview

The discussion revolves around the concept of whether there exists a shortest possible distance besides zero, exploring both mathematical and physical implications. Participants examine the nature of distances, particularly in relation to the Planck Length, and consider the limitations of measurement and meaningful distances in physics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question if there is a shortest possible distance besides zero or if there are no limitations at all.
  • One participant argues that mathematically, there is always a smaller nonzero distance by continually dividing by two, but acknowledges that zero is a limit.
  • A participant introduces the concept of the Planck Length as the "smallest meaningful" nonzero distance, suggesting that no event can occur over a distance smaller than this.
  • Another participant inquires about the implications of matter traveling a distance equal to the Planck Length, questioning whether it can travel any distance between the Planck Length and zero.

Areas of Agreement / Disagreement

Participants express differing views on the existence of a shortest distance, with some supporting the idea of the Planck Length as a meaningful limit while others challenge the notion of any limitations on distance.

Contextual Notes

The discussion includes assumptions about the nature of measurement and the philosophical implications of defining distances, particularly in the context of quantum physics and the Planck scale. There are unresolved questions regarding the practical implications of traveling distances at or below the Planck Length.

Harmony
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Is there a shortest possible distance besides zero? Or there's no limitation at all?
 
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Harmony said:
Is there a shortest possible distance besides zero? Or there's no limitation at all?
Good question. Check out my discussion of it http://thisquantumworld.com/topdown.htm" .
 
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Harmony said:
Is there a shortest possible distance besides zero? Or there's no limitation at all?

Strictly mathematically, both of your alternatives appear to be incorrect.

There is always a smaller nonzero distance -- just keep dividing by two.

There is also a limit: zero.


But is there a smallest meaningful nonzero distance? That is, some distance that no possible event can occur over a smaller distance, no matter how little time it takes?

Sure. That's called a Planck Length. Planck units are the "smallest meaningful" amounts of anything. Planck time is the smallest meaningful amount of time -- nothing can occur in less time, for example.

The Planck Length is something like 0.0000000000000000000000000000000000016 meters.

That's how far a photon traveling at c will travel in one unit of Planck Time. A proton is about 100,000,000,000,000,000,000 Planck Length units across.

Is there a distance shorter than one Planck Length? Can't you just divide that by two, and so on? Not meaningfully, no. You can conceive of a smaller length philosophically in your head, but that cannot express a valid measurement in the real world.
 
What will happen when a matter travel for a distance equal to Planck Length? The matter can't travel for any distance between Plack Length and zero, can it?
 

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