Exploring the Planck Wavelength: The Smallest Possible Measurement

In summary, the conversation discusses the concept of a smallest possible meaningful wavelength, which is believed to be the Planck length according to current theories. This is because anything smaller than the Planck length cannot be described by existing theories and would result in a breakdown of ordinary physics. This is illustrated through a hypothetical scenario involving a particle's Compton wavelength and its gravitation.
  • #1
ryan albery
67
1
It there a smallest possible wavelength? And if there is, what is that wavelength?
 
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  • #2
You should rephrase your question to:
"Is there a smallest possible meaningful wavelength?"
Yes, the Planck length would be. Anything below Planck length isn't meaningful. Things become practically pointless after Planck length, indescribable, dimensionless, etc.
 
  • #3
Fuzzystuff said:
You should rephrase your question to:
"Is there a smallest possible meaningful wavelength?"
Yes, the Planck length would be. Anything below Planck length isn't meaningful. Things become practically pointless after Planck length, indescribable, dimensionless, etc.

With the caveat that this is true for current theories. One of the points of unification or a new theory would be to describe the sub-Planckian realm.
 
  • #4
I'm don't think I follow... is there anything smaller than a Planck length?
 
  • #5
ryan albery said:
I'm don't think I follow... is there anything smaller than a Planck length?

If there is, it is not describable by current theories. Whatever that is, cannot be described by GR, QM, and so forth.
 
  • #6
The following argument may be wrong, but it explains why everybody believes that at the Planck scale ordinary physics breaks down.

Consider a particle with a Compton wave length; this length describes somehow its localization. Consider the gravitation of that particle and its Schwarzschild radius. Now assume that its Compton wave length becomes smaller than its Schwarzschild radius. The particle (according to classical GR) would collaps into a black hole.

If you now set Compton wave length = Schwarzschild radius and solve the equation you will get the Planck length.
 

FAQ: Exploring the Planck Wavelength: The Smallest Possible Measurement

What is the Planck wavelength?

The Planck wavelength is the smallest possible measurement of length in the universe, according to the principles of quantum mechanics. It is equal to 1.616 x 10^-35 meters.

Why is the Planck wavelength significant?

The Planck wavelength is significant because it represents the scale at which quantum effects become important. It is also the scale at which scientists believe the fabric of space-time becomes "foamy" and no longer smooth.

How is the Planck wavelength calculated?

The Planck wavelength is calculated using the Planck constant, the speed of light, and the gravitational constant. The formula is: λ = √(hG/c^3), where λ is the Planck wavelength, h is the Planck constant, G is the gravitational constant, and c is the speed of light.

Can the Planck wavelength be measured?

No, the Planck wavelength is considered to be a theoretical limit and cannot be measured directly. It is smaller than any current technology can detect.

How does the Planck wavelength relate to other units of measurement?

The Planck wavelength is much smaller than any other unit of measurement, such as the nanometer or the Angstrom. It is also much smaller than the size of an atom, which is typically measured in picometers. The Planck wavelength is orders of magnitude smaller than these units.

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