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From my understanding (just a Quantum Physics I class, I could be wrong here) the Planck units quantize space or time to the extent that they define the smalles

From my understanding (just a Quantum Physics I class, I could be wrong here) the Planck units quantize space or time to the extent that they define the smallest thing we can practically measure due to Heisenberg's Uncertainty Principle, but they do not preclude that things can actually be smaller than that. That is, something like length or time can be continuous, but our measurements can only ever be discrete multiples of the corresponding Planck constants. For example, a really small object can have a length smaller than the Planck length, but we wouldn't truly know how long it was because the Planck length acts as a fundamental limit on the precision/granularity of our measuring instruments.

richrichardsson 9y ago
> For example, a really small object can have a length smaller than the Planck length, but we wouldn't truly know how long it was because the Planck length acts as a fundamental limit on the precision/granularity of our measuring instruments. Would that be, to all intents and purposes, undetectable by us then? If so then that might be a possible explanation of "dark matter", assuming all these things were individually smaller than the Planck length.
- spynxic 9y ago
  > Would that be, to all intents and purposes, undetectable by us then? In so far as our means for measuring particles doesn't change; namely, smashing things together at extremely high energies. If you suppose that there are methods for measuring sub-Planck length areas then one must assume that they involve either: energies lower than those believed to be needed (which doesn't necessarily come to a solution, but pushes the problem to even higher energies and shorter lengths) OR that there is a default force that keeps space-time stable unless high energies are approached. Note that both notions are mere speculation, the first on logic and the second on intuition about phase changes in states of matter.
FreeFull 9y ago
Also, it's possible that the actual quantum of space is larger than the corresponding Planck unit.

richrichardsson 9y ago

> For example, a really small object can have a length smaller than the Planck length, but we wouldn't truly know how long it was because the Planck length acts as a fundamental limit on the precision/granularity of our measuring instruments. Would that be, to all intents and purposes, undetectable by us then? If so then that might be a possible explanation of "dark matter", assuming all these things were individually smaller than the Planck length.

spynxic 9y ago
> Would that be, to all intents and purposes, undetectable by us then? In so far as our means for measuring particles doesn't change; namely, smashing things together at extremely high energies. If you suppose that there are methods for measuring sub-Planck length areas then one must assume that they involve either: energies lower than those believed to be needed (which doesn't necessarily come to a solution, but pushes the problem to even higher energies and shorter lengths) OR that there is a default force that keeps space-time stable unless high energies are approached. Note that both notions are mere speculation, the first on logic and the second on intuition about phase changes in states of matter.

FreeFull 9y ago

Also, it's possible that the actual quantum of space is larger than the corresponding Planck unit.