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robheus
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What happens to the Planck length due to the expansion? Does it grow with the scale factor?
robheus said:What happens to the Planck length due to the expansion? Does it grow with the scale factor?
marcus said:here are some things that are not changed
the size of a molecule
the distance to the sun
the length of a ruler
the size of the north american tectonic plates in the Earth's crust
the distance to Alpha Centauri
the Compton wavelength of an electron
fundamental constants like G, hbar, and c.
none of these things are affected by the expansion of largescale intergalactic distances
themagicdude said:...
2. Physical distance. This is the distance you would measure with an ordinary apparatus. This one increases with the scale factor of space's expansion. However, due to the gravitational attraction between bodies that are close together, the distance between objects that are close to each other (Earth and Sun, etc.) does not increase noticeably with the expansion of space.
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marcus said:no
planck length is defined using fundamental constants G hbar c, which are not changed by expansion.
most things we are familiar with are not changed by expansion
here are some things that are not changed
the size of a molecule
the distance to the sun
the length of a ruler
the size of the north american tectonic plates in the Earth's crust
the distance to Alpha Centauri
the Compton wavelength of an electron
fundamental constants like G, hbar, and c.
none of these things are affected by the expansion of largescale intergalactic distances
The Planck length is the smallest possible length scale in the universe, representing the scale at which quantum effects become significant. It is important because it is a fundamental constant that is used to understand the behavior of particles at the subatomic level.
According to current theories, the Planck length remains constant regardless of the scale factor. This means that it does not change as the universe expands or contracts.
The scale factor is a measure of the expansion or contraction of the universe. The Planck length is a fundamental constant that does not change with the scale factor, but it can be used in calculations to understand the behavior of particles at different length scales.
While the current consensus is that the Planck length remains constant, there are some theories, such as loop quantum gravity, that propose a minimum length scale that may change with the scale factor. However, these theories are still under investigation and have not been widely accepted.
The Planck length is incredibly small, being approximately 1.6 x 10^-35 meters. It is much smaller than the size of an atom, which is around 10^-10 meters, and even smaller than the size of a proton or neutron, which are approximately 10^-15 meters. It is only relevant at the subatomic level.