[Bill S (OP)]

All good and interesting stuff, Geordief, but if the answer to the question is in there, it eludes me.

The question is straight forward, but the proffered answers always seem to amount to what my mother used to call "explaining something away"   

[geordief]

Well I was only giving an "opinion piece" as I can't answer the question with any degree of authority (my opinion was that you will not find such an example as it would probably "break causality" which is the fundamental bedrock   of the physical nature of the universe as we seem to experience it)

There are objects called "point particles" which I have heard about (without being able to understand as yet) but I do not think they would be the example you are looking for ,even if at first  they might seem to fit the bill.

[Bill S (OP)]

...my opinion was that you will not find such an example...

We certainly seem to be on the same page here.  I wouldn't even credit it with breaking causality. I think it's the ultimate oxymoron. 

I've no doubt that point particles, and other zero dimensional "objects" play a valuable role in maths and theoretical physics, but physical examples are a bit like Father Christmas; lots of impostors, but no "real thing". 

[geordief]

...my opinion was that you will not find such an example...

We certainly seem to be on the same page here.  I wouldn't even credit it with breaking causality. I think it's the ultimate oxymoron. 

I've no doubt that point particles, and other zero dimensional "objects" play a valuable role in maths and theoretical physics, but physical examples are a bit like Father Christmas; lots of impostors, but no "real thing". 

I just assumed I had not yet understood why they are actually termed point particles **and that my present level of understanding led me to imagine (perhaps as mathematical objects) them as other than what they will hopefully be seen as when the model has been understood.


I think when one is attempting to learn a model that one always creates a false picture of it in ones mind's eye  until one gets close enough to see it for what it is. (it is hardwired into  our way of thinking and learning--I always thought Hendrix said "excuse me while I kiss this guy" instead of "the sky"  )


**because they have zero dimensions of freedom (in the model)  is the closest I think I have got yet.

[Bill S (OP)]

I just assumed I had not yet understood why they are actually termed point particles **and that my present level of understanding led me to imagine (perhaps as mathematical objects) them as other than what they will hopefully be seen as when the model has been understood.

I suspect that they will never be more than mathematical tools, but, undoubtedly they are of real value in theoretical physics.  As such, even pedantic old farts, like me, have to acknowledge them.

BTW, I like the mondegreen.

[evan_au]

I just listened to this lecture by Carlo Rovelli (of Quantum Loop Gravity fame), on the subject of Time.
Presented at the Royal Institute in May 2018 (1 hour).
It's for a fairly general audience, but it was good to hear an expert explain his ideas in plain language.
At the end, a boy asks "what is half a Planck unit of time?". So obviously something had gotten across!

Audio: http://www.abc.net.au/radionational/programs/bigideas/the-mystery-of-time/9790674
Video:

[Bill S (OP)]

Thanks Evan.  I must try to fit it in soon.
I've just been given Rovelli's book, The Order of Time.  All I need is time to read it.
 

[Bogie_smiles]

I watched it and it was timely 

[yor_on]

I don't think they are mathematical tools Bill. They should be what creates dimensions, and that's what you need if you want to measure. Particles that are measurable is a containment (atom) inside those dimensions, well, possibly :) up quarks down quarks, mesons and baryons. The electron f.ex is a 'point particle'.
=

then you have gluons that are massless messenger particles for the strong nuclear force, interacting with quarks and itself, according to quantum chromodynamics (QCD).  "The strong force binds quarks together in clusters to make more-familiar subatomic particles, such as protons and neutrons. It also holds together the atomic nucleus and underlies interactions between all particles containing quarks." https://www.britannica.com/science/strong-force

btw: 'nuclear' just means a nucleus in this terminology, although we use the term in other ways too.