geordief

I am fairly sure I have heard that it is the photon that is responsible for the electro-magnetic force Also I think I have learned that gravity is not modeled as a force in General Relativity but that is not to say that it is not modeled as a force (it causes acceleration) in Newtonian physics. In quantum -gravity ,perhaps it will be eventually modeled as a force (I have no good idea if that is possible) . .

So ,with no "detection" there is no field? Your "objects" are physical objects -not mathematical objects? Can they be "potential objects" ie the model/field shows the result if an object is placed at that position?

Amazing that Trump should,by all accounts be an anglophile ** and that he sets store in this invitation. Can the UK government make use of this need to extract a basic decency from the administration at least on the international stage? The queen is the head of the Commonwealth and Sudan has applied for (re?) membership. Can the Queen pull rank on Trump and insist that Sudan be removed from the 7 countries presently on Trump's list.? That would give her some time to keep the man outside the door . By all accounts the Queen (if she has her health) would be well up to dealing with the man and perhaps some good might come from the proposed visit . "Special treatment" for the Sudan may seem a paltry offering but it could be seen as another front perhaps. The Queen ,I am sure is no shrinking violet and may be quite up for the joust. ** if anything can be believed about the man

Seems like an interesting story " Instead of regularly repeating rows of atoms, a time crystal would exhibit regularly repeating motion." https://www.newscientist.com/article/2119804-worlds-first-time-crystals-cooked-up-using-new-recipe/ http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.030401

1) My idea was that a particle that was caused by some interaction would by definition be smaller than the "mother" particle and really that would be all that could be said in absolute terms(as to whether one particle was larger than another) 2) True

Is size relative in a similar way to simultaneity? Can you only say one particle is bigger than another based on a hierarchy of causation? Do the particles have to interact before any judgement as to comparative sizes can be made?

So is there a relationship between mass and the stress tensor? (It is the stress-momentum tensor ,is it? )

If someone has not had previously chicken pox I am led to believe that someone with shingles can infect them with chicken pox. https://www.cdc.gov/shingles/about/transmission.html Chicken pox can also be serious https://www.cdc.gov/features/preventchickenpox/

Are you qualified to give (medical) advice on shingles?

Thanks.Yes it is relevant . Sadly far ahead of my level so I can't profit much from it but I do think I can see the areas it goes into and asks questions of. I see the same author was the subject of another ,perhaps slightly related topic on another science forum site a year or so ago https://www.thenakedscientists.com/forum/index.php?topic=53806.0 Again ,well ahead of me to have any opinion.

I see.(interesting that Klaynos seems not to be ruling out that in theory the speed of sound could exceed c if I read that right)

Thanks.

Is MigL's implausibly stiff rod(no innuendo intended)not also a solid? So how does it allow faster than sound speed propagation? I know I am missing something

And the permittivity of a vacuum ? Is that considered to be another (universal constant)?

As an educational aid (mine) as the mass of the medium theoretically tends to zero does the speed of propagation of an embedded wave tend to c?

I don't think I can do that as I am a very slow learner and reader and would have to justify that expenditure of time.* Does my question need these other universes with their different posited universal constants to have significance (my question ,I mean)? *The book is very reasonably priced ,though and would be tempting to have in the house.

I am thinking of c and h although I think there may be others. What is the role of these constants? Are they interconnected and is it the aim of a TOE to find those connections? Is their role as mathematical "agents of conversion" more important than the actual value that is assigned to them? Posted in this section as there didn't seem an obvious choice among the Physics subforums....

Well ,we can as a limit and from an observer's frame of reference can't we? But I have agreed it is of little consequence.

Did my definition in the OP not work?"Edifices of the mind" ="mental construct" As for AI I am not versed in the area and so my description would probably be unsatisfactory.

Well my take was no doubt simplistic and not particularly useful or helpful here (just a special case I guess)

My take on this is that simultaneity only occurs when two events are separated by zero space and zero time (a rare occurrence). So, by my definition ,in this particular scenario neither observer can say that the 2 events are truly "simultaneous" They can only claim they are simultaneous in so far as they respectively observe them as such,which is why they disagree. If events are truly "simultaneous" according to my "higher" standard ,all observers will agree (perhaps trivially?)

Models can be seen as edifices of the mind that attempt to predict how the world works. This is a very skilled task. Can it ever be farmed out to AI? Are there any low hanging fruit that could be imagined for such a task? Are there rudimentary models that could be given to an AI machine for it to play around with and potentially improve? Is the idea totally preposterous?

Are all things defined by their opposites? If so, space is defined by the events that take place within it and by that measure would be equally "real" So can spacetime (as a different concept from the mathematical model) also be understood as a mirror image (or a negative image) of the events it "contains"?

Could artificial software be developed that took physical measurements and turned them into models?

How many posts are required to post attachments? Perhaps Timo Moilanen has not enough yet at only 6?