Planck length and the expansion of space.

[Sorcerer]

Does the planck length stretch as space expands, or are more planck lengths created in between?

I'm just confused over this, because if a planck length is an indivisible unit which is used as a constant, yet its size changes then, it's not much of a constant is it.

But ...if more planck lengths appear within space as it expands, then space isn't really "stretching" is it, as I've always had the analogy given to me, it's actually creating more space between points in space.

Or is it something else?

[hoola]

I do think "it" is stretching, in that virtual particles are a main mechanism of space and when the creation/annilalation orbits get elongated, they persist for longer periods of time. This allows the particle energies to persist longer than normal, so the local environment has more exposure to those energies in a sort of "pulse width modulated" expression...and the longer the pulse width ( caused by the oblongation of orbits) the more intense the gravitational effect seems to develop in the area. After a certain point the elongation is so extreme, as at a black hole horizon, they separate. At this point maximum gravitation is expressed, as a high finite value...this is to say there seems to be a causal relationship between the two things but may be a result of gravity more so than part of it's mechanism...

[Strange]

Does the planck length stretch as space expands, or are more planck lengths created in between?

 

The Planck distance is just a unit of measurement. It is based on universal constants rather than arbitrary human things like the length of the King's arm. As such, it doesn't change. So, yes, as the universe expands the number of parsecs, kilometres, furlongs and Planck units between distant object increases.

 

I'm just confused over this, because if a planck length is an indivisible unit which is used as a constant, yet its size changes then, it's not much of a constant is it.

 

I don't think that the Planck length is indivisible. I think that string theory and the various theories that describe space as "quantised" work at much smaller scales than the Planck length.

 

But this touches on the big problem in unifying relativity (expanding space) and quantum level things. For general relativity to work mathematically, space must be smooth and continuous. To describe things at the quantum level, it is not smooth. This makes it impossible to combine the two theories.

 

But ...if more planck lengths appear within space as it expands, then space isn't really "stretching" is it, as I've always had the analogy given to me, it's actually creating more space between points in space.

 

Either "space is expanding" or "more space is being created" are reasonable analogies. They are both misleading by suggesting that space is "stuff" which can be created or stretched. What is really changing is geometry: the distance between things (whatever you measure it in).

Edited August 31, 2014 by Strange

[Nicholas Kang]

 

The Planck distance is just a unit of measurement. It is based on universal constants rather than arbitrary human things like the length of the King's arm. As such, it doesn't change. So, yes, as the universe expands the number of parsecs, kilometres, furlongs and Planck units between distant object increases.

 

So distance and displacement of an object isn`t constant anymore?

[Delta1212]

 

So distance and displacement of an object isn`t constant anymore?

Distance isn't constant for a number of reasons.