studiot

Thank you for your reply. I understood what you said. I was just pointing out that the use of the present tense of the verb to be instead of the future tense, is self contradictory and would be self contradictory if so used in the future. You have introduced probability. Too many folks misunderstand probability and the fact that probabilities of both one and zero are special and different from all other probability values. Since you wish to use a probability of 1 consider A Probability of 1 has three different meanings and it is encumbent on the user to specify which. 1) A probability of 1 states that some A has always happened in the past and must always happen in the future. 2) A probability of 1 states that the event has always happened in the past and is expected to happen in the future, as we have no better information. 3) A probability of 1 states that whatever has happened in the past our best guess is that it must (will) happen in the future. This should go a long way to answering the interesting 'philosopical problem' you raised.

Surely this is an oxymoron, planted firmly in the middle of the only question you have asked.

You have work to do on your magnets. I suggest you study Halback arrays. https://en.wikipedia.org/wiki/Halbach_array You might be able to knock up a home made prototype using fridge magnets to study the mag fields. However remember that conventional electric motors work on somewhat similar princples and all of them have trouble starting because of symmetry. So they all have various arrangements to provide an initial impulse and then rely on mechanical inertia to take the rotor round to the next driving position.

'Earth' tends to be british terminology and 'ground' american terminology for the same thing. I'm sorry if I introduced that confusion into the thread. There is also separate symbol for chassis, as opposed to either earth or ground. Further an earth can be an AC earth or a DC earth or both in circuit theory. This is very common. Symbols also vary on this. http://lednique.com/ground-earth-chassis/

How is any of this relevant to your OP question ? None of it is at variance with what I said, though it may be a dangerous practice.

Without more details it is difficult to say more. The general phenomenon is called triboluminescence and reverse triboluminesce, the latter seems to be what you are describing. Here is a modern paper on generating sound via laser. https://pubs.acs.org/doi/abs/10.1021/jp034904t Look here for the photoacoustic effect https://en.wikipedia.org/wiki/Photoacoustic_effect

Well since you couldn't be bothered to reply to anyone in your earthing thread, which has nothing to do with displacement current and you don't seem to want to reply to comments in this one I see no purpose continuing. If there were any other previous threads I don't recall them.

Pipe (and other) flow is not a supportable analogy for electricity. However I do not disagree that considerable current does flow in some open circuits, for example lightning. But I did not read any further. Have you abandoned you previous electricity thread ?

I like this solidly subject for a Science website, instead of all that political claptrap. +1 I lke to distinguish three distince uses for an 'earth' in electricity. All three satisfy a common definition in electrical circuit theory. Note 'circuit theory' here refers configurations of electrical 'circuit elements', whether they contain a complete loop or not. 1) As a protective element. 2) As a refernce element for voltages. 3) As a shielding element against electromagnetic fields. All three uses can be described by a "single terminal element whose potential (voltage) does not change. regardless of the current input or output to that element." Note this is different from a voltage source which is a two terminal element. Of course such an element is an 'ideal element', like most other elements. So there are no perfect earths in real world practice, only better or worse approximations. I think this covers all your examples, and then some. Equally I see no reason for this to be a speculation but as a reasonable comment and soruce of discussion on everday practice.

Thank you for your reply. I suppose it all hangs on your definition of 'truth'. In Mathematics truth means 'consistent with the axioms'. Note that this does not mean 'derivable from the axioms'. Other disciplines employ different meanings. In Philosophy you can have irresistible forces and immovable objects. In Physics you can't have these things. You also need to beware of differences in terminology. You used the word 'ideal', so beloved of ancient Greek philosophers. In Physics this means possessing certain specific properties as in ideal gas or ideal conductor. But in Mathematics, an ideal is a particular algebraic structure which has even more variation because you may have a left ideal or a right ideal !.

Nonsense. It collapsed a long time ago.

Since you like latin/french derivations and asses here is what the french ass herder said about the difference between the words etre and suivre. Je ne suis pas ce que je suis, si je suis ce que je suis, je ne suis pas ce que je suis.

Perhaps it is worth mentioning that there is at least one further meaning and parts of speech for 'wind', after all it's what roads in Somerset do.

Another way to look at this is to take E = mc2 and combine it with E = hf to obtain f = mc2 / h In words The wave function of a state with energy E vibrates at a frequency given by this equation.

Just to add a little to swansont's post (+1) @kba I advise you look at Earnshaw's theorem. https://en.wikipedia.org/wiki/Earnshaw's_theorem This classical theorem applies to systems with centres of charge (gravitational, electric, magnetic) and the field interactions between them. It basically states that for any system with two or more poles, rest is an unstable state so such a system must be in motion. But it does not state that the field or the interactions are caused by the motion.

Nonsense. Science was sufficiently advanced for Cavendish to measure the gravitational attraction of stationary bodies as small as a few kg placed near each other before 1800.

I don't see any good reason for welcoming a new member inthis way so I am adding a reversal to the negative vote. That does not mean in any way that I agree with kba's proposition. If is a very very big word. Why should the gravity of the Sun have changed significantly, or indeed at all ? Where is the evidence supporting this. A couple of comments. Instead of resurrecting a long dead thread from an obvious crank I suggest you start your own discussion. (Talk to a moderator and ask to split this off) In suggesting this I am doing you the service of assuming you are amenable to rational discussion. You will need to take into account that any change in gravity will have affected many things, not only the dinosaurs. All of these things will have left an evidential trail. And we have found no such evidence to date. In fact proper evidence of the most probable sequence of events was released earlier this year from the Dakota dig and 15 year investigation.

I'm sorry, I have told you something very important about Fields and you have failed to address this point each time you have replied. Instead you have introduced all sorts of irrelevant material.

Thank you for taking the time to actually think about my proposition. +1 Yes that is basically what I mean but I will provide some examples. As to self consistency it is fundamental to mathematics. Have you heard of The german 'Erlangen pogrom', Felix Klein and David Hilbert ? The most famous mathematicians of their day set out to axiomatize the whole of mathematics in a systematic and self consistent way. There was mush upset and furore when they failed and Godel came along and proved that such a task will always result in failure. However the idea is so seductive that another group in France also tried this under the banner 'Bourbaki'. There was an original soldier called Bourbaki. Subsequently it became the name of a secretive group of elite mathematicians which has continued to this day, despite knowing that the goal, like the holy grail, cannot be achieved. You will often find references to the terminology, structures and definitions set up by these two groups when reading about mathematics. As to an example of what I mean. In maths you cannot have an axiom system that containsIn physics consider the atom, for instance Axiom1 for all a, b : a + b = a - b Axiom2 [math]a,b \ne 0[/math] Axiom 2 directly contradicts axiom 1. In physics you can have two principle that may pull in opposite directions for example 1) Systems tend to minimum energy 2) Systems tend to maximum entropy Physics allows both agents to coexist, the result being a balance between the two. The atom exists as a balance between the twin opposite forces of attraction and repulsion. A book on a table does not fall to the gorund because the table is pushing it up just as hard as gravity is pulling it down. This is what I mean when Is say that maths wants to make everything part of a grand consistent scheme where everything always works with everything else, whereas physics allows schemes where everything pulls 'every which way'.

Externet I love that Newton quote. +1 🙂

I just have visions of megalithic mercury man scratching his head when he came to this signpost. Today, of course, he would just use a Falkirk Wheel. 🙂

Don't you think these are rather adversarial ? I agree that stone age Man knew nothing about the core of the Earth. But serious work began in the rennaisance with studies of gravity. Later work by that reclusive genius Cavendish was able to establish that it must be made of something very dense by careful gravitational measurement. The late 19th century brought new tools to bear with the beginnings of seismology by Ernst yon Rebeur-Pasebwitz, techniques that have continued to develop ever since. Current work in Canada, Sweden, Antarica, out in space and elsewhere continues to probe the working of the core via the Earth's magnetosphere, which can only be generated in the core. A good book to read here is 'Aurora' by physicist, Melanie Windrush who specialises in this stuff.

I didnt say it did or that it didn't. I said This, for your information and in accordance with the rules of the English language reffers to the last named nound, this this case "thread" I even added, for clarity, the reason why this thread is not about consciousness. Please read the postings of others before you react. I have other mundane things to do this evening, like the wahing up, before the evening film.

I'm sorry you have completely missed the point of this thread. This is not about consciousness I carefully separated it out from a thread about that subject, because it is not about consciousness. You were having, let us call them discussions, with the moderators in that thread. This thread is there to help you understand what they and others are saying to you about Science.

Fair questions. Jasper said "all sciences" , in which I include Mathematics. The point is that Mathematics is (or would like to be) axiomatic based. Whereas Physics has no axioms, only principles. In fact whilst is is a requirement of a system of axioms in Maths to be self consistent, Physics (and many other sciences) is a study of the opposition of different agents and what happens when the result needs to satisfy both (or them all) in some way. Does this answer your question ?