h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The Planck length is, according to Theories of physics, the smallest possible "chunk" of space. You cannot go smaller than that. It is theorized that at this level, "space" works like lined paper: there are lines, on which subatomic things are, and there is nothing between the lines. When the subatomic things move, they actually jump from one line to the next without crossing the space between those lines.

As we now appear to know, our universe is expanding and will keep expanding forever and ever. Will that mean, that the "gaps between those lines", the smallest possible size, will get larger and larger? Will the Planck length eventually be a meter or a mile or ten bazillion lighteternities?

Plank lines cannot expand. They are effectively interlocking, using a principle known as 'tongue and groove'.

Planck lines do not have a material existence, do they? They are just a simile to help us understand how the universe works. How, then, can they be interlocked by means of tongue/groove? (Or was Icy's post written by means of tongue/cheek, in which case I blame my inability to detect it on nightshift work or on 2legs?)

I'm sorry, yes it was a joke.

Tongue & groove is 'nut und feder' in German:

http://www.fachgebaerdenlexikon.de/typo3temp/pics/91bc194852.gif

As I understand it, a planck length is the shortest posdible distance it's possible to measure. So it's a bit like using a measuring tape on an elastic. Regardless of wether the elastic is stretched or not, you can't measure less than a millimeter on it.

Xan, the way it was presented to me (on youtube, I hasten to admit), the Planck length is not so much the smallest thing we can measure (in fact, we cannot measure it, at all, as we have to tools small enough to do the measuring with, not by a long way...), but instead, the smallest amount of space there actually is. We are so used to thinking we can divide space forever. There are 100 cm to a meter. There are 10 mm to a centimeter and so on. But with Planck lengths, there is nothing a Planck length can be divided into. Space cannot be dissolved more than that. The Planck length is the limit to space.

My question was... as space is expanding, does this lower limit of space expand, too?

And a great question it is.
It enters that expanding grey area between physics and philosophy
which has been expanding exponentially for more than 2500 years
creating an ever widening gap between what is thinkable and what
is observably and mathematically provable. Mind the gap.

~jwf~

Posting to move this over to brunel.

I personally like the John Archbald Wheeler 'quantum foam' model, in which space itself is conceived as a quantum gaseous* medium composed of free elementary quanta and quantum fluctuation particles that form spontaneously in it, at a level of disorganization well below Werner Heisenberg's uncertainty threshold, at which it becomes intrinsically impossible to make direct measurement of events of any kind.

(In order to do that, one needs particles or waves smaller than the phenomenon which is to be measured, which can be detected and measured themselves.)

In the unmensurable range, motion is always discontinuous, an elementary quantum is not constrained by the speed of light limit and can make quantum jumps any distance in time and space, leaving behind a hole, with exactly its own properties.

This may be the reason why space expands.

(Its been postulated that there may be only one elementary quantum in the entire universe and the larger plenum its embedded in, which at least might account for the identity of its properties everywhere its measured.)

To give some idea just how small that is, a mole of elementary quantum distances is to this day a distance so small that its still technically impossible to measure it.

A mole squared of elementary quantum distances is about like the distance between the orbits of the Earth and Neptune about the sun.

A mole of golf balls or hens eggs is somewhat smaller than the moon.

The rest mass of the neutron is somewhat smaller than the mass equivalency of a mole of elementary quanta, the discrepancy being in the amount of the spin and momentum statisics of the elementary graviton multiplied by the elementary quantum equivalency of the electron.

The discrepancy probably represents bonding energy, under the poly-electron model of baryonic structure, which for some reason does not manifest in its rest mass.

Similar discrepancies are found in the rest masses of atomic isotopes under the poly-hydrogen model.

The elementary quantum taken as a discrete particle has at least two momentum oriented bonding sites, one positive, one negative and at least four spin oriented bonding sites.

It takes a full unit of momentum to create a half unit of spin.




See also; 'vacuum fields' and 'string theory'.




* 'Quantum' substances in this sense include quantum fluids, superfluids like helium II or liquified electrons and quantum solids like superconductors, Bose-Einstein condensates generally.

I seem to understand less and less as I go farther and farther into this thread.

On the other hand, I enjoyed "Interstellar." If the people responsible for that film were to make a film about Planck, maybe I'd understand it then?

>> I seem to understand less and less as I go farther and farther <<
Yeah, it's a lot like walking the plank.

Gotta admit that ITIWBS seems to know his stuff. There's not
a whiff of BS in his post above; it sings confirmation and belief.

While the content is far beyond me, the tone is refreshing and
reassuring that given half a chance some scientific types can
and do try to explain their belief system to the cynics, skeptics
and iconoclasts.

~jwf~

yes indeed, Squigs

Must say though, that there was a time when I thought I was beginning to get a handle on this stuff... time, time.

ITIWBS, do not be discouraged, thank you for that posting...

...and, if you choose to start a convo based on it, please let me know


Rod

Some day I may understand it better. Thank you for explaining it, ITIWBS.

...at any rate, the smallest possible particle of space itself, the free elementary quantum...