Orders of Magnitude - From Quark to Superstring Theory

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Discussion Overview

The discussion revolves around the orders of magnitude in length from the size of the visible universe to the size of quarks and superstrings, particularly focusing on the significant gap between quarks and the Planck length associated with superstring theory. Participants explore the implications of this gap and the potential existence of unknown entities or phenomena in between these scales.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants express curiosity about the large gap in orders of magnitude between quarks (~10^-15) and superstrings (~10^-33), questioning the absence of intermediate scales.
  • Others suggest that while there could be "stuff" in between, it is not necessary, highlighting the uncertainty surrounding the Planck scale.
  • One participant notes that the gap is perceived as odd and wonders if there is a fundamental reason for it, though acknowledges that no such reason is currently known.
  • Supersymmetry and the concept of extra dimensions are mentioned as possible explanations for bridging the gap, though these remain speculative.
  • Participants clarify that strings are not necessarily the smallest objects known, and that string theory is still a developing concept rather than an established theory.

Areas of Agreement / Disagreement

Participants generally agree that the gap between quarks and the Planck length is significant and raises questions, but there is no consensus on whether there must be entities in between or what the implications of this gap are.

Contextual Notes

The discussion reflects limitations in current understanding of physics at the Planck scale and the nature of superstring theory, with unresolved questions about the existence of intermediate scales and the implications of the observed gaps.

RobinsonUK
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Fascinating looking at the various orders of magnitude (in terms of length), from the size of the visible universe (~10^25) to the size of a quark (~10^-15), and all orders inbetween.

But then I read about Superstring theory and how these strings are at the Planck length, around 10^-33. Why the huge jump from quark to string? Surely there must be loads of "stuff" in-between?

Apologies if this is a daft question!
 
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Surely there must be loads of "stuff" in-between?
Why?
The Planck scale (length, but also all other Planck units) is far away from everything we know. That means there could be something in between, but it does not have to.
 
It doesn't mean it has to, but this huge gap is kind-of odd to me. I wondered whether there was a fundamental reason why there's a huge jump in magnitude before we get to the smallest of the objects we know about.
 
RobinsonUK said:
It doesn't mean it has to, but this huge gap is kind-of odd to me.
It looks odd to scientists as well - and it is one of the reasons why many scientists expect that new physics is not so far away from current physics.
Supersymmetry is one possibility, and extra dimensions can lower the Planck scale.

I wondered whether there was a fundamental reason why there's a huge jump in magnitude before we get to the smallest of the objects we know about.
If there is one, it is not known yet.

Strings are not "the smallest objects we know about". String theory is - even if you are optimistic - a concept how we might get a new theory at some point in the future.
 

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