Bluemoon

Do you think, though, that the distubances of the Coulomb field of a charge travel superluminaly {as the authors claim] ?

Only that the actual [relativistic, "γ ≈ 1000" and limited to c] speeds are nigh-on unaltered for all of the accelerator's output range, compared to what Newton would have expected; though [reading between your lines] I can't see how that may impact on whether or not the "Coulomb field [is] carried rigidly by the moving charge".

Harmful content? Let me guess again: You think that the paper's authors' conclusions do not contradict the foundation assumptions of relativity theory; yes - ?

Do you mean that you think that if the source moves that its associated field (at all distances from it) does not change at the same instant?

I've just discovered the paper Measuring Propagation Speed of Coulomb Fields (PDF) which appears to show that the Coulomb field (& also gravitational fields) travel with infinite speed. The authors also dismiss a critique of their research here (PDF). The theory is way over my head, so I am wondering what the views are of the better educated on S.F as to the merit of the authors' conclusions.

Thanks for that practical suggestion Edwina Lee, I had intuitively thought that keeping everything spinning at equal speeds to be the best starting point as I, too, don't have the brain for a full analysis.

True, but: I idealised it to a sphere as I thought that that would be more analytically tractable though still keeping the molten chocolate. Yes. swansont: I only used the phrase in-turn in the physical sense to describe the mechanical structure [not the temporal sense]; I had supposed that the chocolate would be affected the same way regardless of the phasing of the gimble spins because as I see it: the rotations, when considered as framed in my OP, are commutative; each axis/(gimble)/rotation is defined relative to another (rather than per the convention) i.e: the y-axis/(gimble) sits in the z-axis/(gimble); and the x-axis/(gimble) sits in the y-axis/(gimble) and the sphere spins on that x-axis; and so: the orientation of the sphere after defined rotations of each of Those z, y & x axes/(gimbles) will not depend on the order of their execution.

It was an oversight but I should have stated the context to be that all of the axes/gimbles rotate with the same angular velocity. However: why should non-commutativity preclude an analysis? Although rotations can not be said to be be generally commutative, the sphere, none-the-less, spins; so surely that can be analysed? Anyway, I did some brief numerical analysis by hand and it seemed that the chocolate does just slosh about. steveupson: that's a wonderful resource {+1; although each video froze my old laptop for a, Very, long time; the whole lot took me over 4 hours to watch}. The 4D lecture reminded me of the Charisma Cleo video editor [made by Questech but neither still exist] which was popular with broadcasters in the 1990s. It would roll-up a 2D screenshot into an apparent sphere (or paper-dart or any other of a large selection of pre- or user- programmed 'objects') revealing the next camera shot behind it, the spherical image would then roll off into the 'distance'. I never knew but I now presume that Quaternions would have been the core tool of the algorithm in the processor [which was specified as a 'tailored' supercomputer](?)

Can anyone please tell me: in what direction does a point on the surface of a sphere accelerate when: the sphere is spun on an axis which is in-turn spun on an axis orthogonal to the first and that 2nd axis is spun on an axis orthoganal to the previous two: This relates to a brief discussion that I had with someone about the moulding of Easter eggs(!) Would the chocolate just slosh about or does it all get uniformly pressed to the inner surface of the sphere?

I now don't think that my question was aswerable. It looks like the whole issue of the Earth's charge is very much more complex than I ever imagined:- en.wikipedia.org/wiki/Atmospheric_electricity

elfmotat >" So Earth will start accumulating more negative charges ... " From where though? RE: OP:- " ... so what is the source of the electrons that offset this embedded Cosmic ray charge and how do they arrive? " Sensei What part of the OP:- " However, the Earth appears to have no net charge ...." is an invitation to post your Selfie ? Fuzzwood >" Also: http://en.wikipedia...._radiation_belt " ... and .... ? ! Enthalpy > ".. the solar wind, whch I'd say is the biggest contributor - if it's not the ionization of the upper atmosphere ..." Do they diffuse down or occasionaly discharge down as lightning? What of the Cosmic Ray sources? The surface flux on Earth is ~1000/sqm/s. I make that a charge of 80mC/s impacting over the Earth's surface ---> ~2.5MC/year and that's just the Earth! Over the Solar system or maybe the galaxy then something somewhere is surely getting Very negatively charged?

The Wikipedia article for Cosmic ray { http://en.wikipedia.org/wiki/Cosmic_ray} says that they are mostly positively charged and that electrons (beta particles) constitute about 1% of galactic cosmic rays. The ones that impact on the earth's rocky surface must remain trapped inside it forever. However, the Earth appears to have no net charge, so what is the source of the electrons that offset this embedded Cosmic ray charge and how do they arrive? Also, is it likely to be so that whatever the sources are of Cosmic rays, that they must, after 13 billion years, now have an enormous -ve charge; or that the positive partners to Earth's neutralizing electrons drift across space to neutralize that source (presumably after radiativley spiraling in).

Confidence in this project may explain the following directive by the US Senate issued in July :- "the Committee directs the Department of Energy to work with the Department of State to withdraw from the ITER project" https://en.wikipedia.org/wiki/ITER

Acme, your wiki link is intersesting, 60% is nearly plausible, but ... Strange >What proportion of UK power stations run on kerosene? Good point, I've only been able to find one:- Peterhead Power Station in Scotland which, presumably, must be because Kerosene/heating oil really are as expensive as I thought making my query mute. swansont >Do power stations sell all of their electricity at wholesale rates? I think so, because sometime last year SSE were told by the regulator that they had to stop selling theirs directly to their customers and instead sell it wholesale to the 'pool' and then buy/(bid for) it back as a 'pool' customer; and only then be able to sell it on to their customers. Otherwise if they wanted to they would even be able to profitably sell the oil-made stuff, 5p +60% = 8.4p, to the likes of me for the 12p that they do; (but they add some extras on, one of which is profit, that brings the price up to 16.5p +vat).

I suppose that it's burnt in a furnace.

Ten years ago, I had to take cold showers for 12 months after moving into a 'new' place that had no heating. It was ghastly. The most extreme feeling that it gave me was of how bad an experience it was but not hyper-aware; and It certainly left me feeling very awake in the mornings by an otherwise above average & quite persistent amount accompanied with a pleasant sense of relief that it was over. Having a warm shower (only very occasionally when visiting relations) was an utterly serene experience. I don't recommend it but I remember, years ago, hearing that it was popular in health spas.

The wholesale price of electricity in the UK at the moment is about 5p/kWh according to:- www.businesselectricityprices.org.uk/cost-per-kwh (RE:- " Over the past few years these have stabilised to between 4p and 5p per kWh. ") and the wholesale price of Kerosene (@ $1.62 to the £) is about £458/mt (45.8p/kg) according to:- www.thisdaylive.com/articles/falling-oil-price-as-window-for-subsidy-removal/192441 (RE:- " For Kerosene, the actual cost in a foreign refinery recently was $743 per metric tonne "). { I'm using 46.2MJ/kg as the heat of combustion for Kerosene according to:- http://en.wikipedia.org/wiki/Kerosene and 1kWh=3.6MJ } which leads to 3.6p/kWh ( 45.8 / 46.2 ) * 3.6 ) As such, these figures indicate that power stations in the UK are operating at implausibly high energy conversion efficiencies:- 3.6p / 5p * 100 = 72% I don't doubt at all that I've misunderstood something somewhere, but what?

MigL and elfmotat, I hadn't even vaguely imagined that such a simple scenario could have such a deep explanation; and I'm very glad that you've been able to give me some non-mathematical insight into it; but, MigL, while the "Paradox of a Charge in a Gravitational Field" article is a good article (and only a few weeks old too I see!), the last paragraph talks about energy vanishing [over the event horizon], would that be real energy (or some sort of virtual energy) and is that region of space-time accessible to anyone at all (or is it outside of the universe)? Anyway, they certainly merit a +1 each, thank you.

MigL> Newton says absolutely nothing about inertial and gravitational mass. So what does "Newton's law of universal gravitation" mean then? a free falling charged particle is not accelerating ... Why is it falling then? > particle is not accelerating as there is no force acting on it. Why do people speak of gravitational force then? > so it 'accelerates' upward at 1g and radiates. Where does the energy come from to produce the radiation then, and what is the magnitude of that radiation?

elfmotat> If it's moving uniformly then ... No! ---> "... when the rocket is acelerating at 1g ..." > it weighs the same as if it were accelerating at 1g. No, that's what I'm puzzled about. When it's doing 1g, the electron will be emitting radiation and the emitted energy will be causing a breaking-force on the electron that will show up as extra weight; that contrasts with the "rocket experiment"; (read on ....) studiot> Are you sure you posted this in the correct thread? I suppose so, given that my puzzlement arose from reading this thread. > Where did the 'rocekt experiment' come into this? Well long ago, I read that gravitational force can not be distinguished from acceleration, the example given was that someone inside a rocket capsule could not determine from an experiment whether or not they were on the launchpad or in deep space accelerating at 1g. The point is that vitality00 also asked at post #1:- and also does a charge radiate when it decelerates as well? The response was that it does. But then that leaves me puzzled as to how the acceleration due to the rocket engine could be the same as that experienced due to gravitation. I'm puzzled because the two 'truths' seem to me to contradict each other.

Robittybob1> So what colour was it to your naked eye? I assume it was green. What light mixes to form green, is it red and yellow? It looked ...{"early 1980s green LED"} ... green, (I don't think that any mix of non-green emitted light produces green). I suspect that red & yellow mix to give orange. (red & blue give magenta). Enthalpy> Thanks for that, (I gave you +1) John Cuthber> why Well, because whenever I've read about LEDs the explanation talks of a definite band gap (ie: one wavelength).

Well given that it can generate weak magnetic fields (as ajb says that it can) if the human body was also able to generate a charge separation between 2 places of itself (perhaps like an electric eel does) were the body then to be spun around an axis that was perpendicular to the charge dipole axis (& not on the mid point of that charge dipole axis) a magnetic field would arise that way (though I can't give you any calculations).

I'm not sure that I really understand this matter. Does this all mean that if someone measures the weight of an electron in the 'rocket experiment', that its weight will be measured to be the conventional rest mass if the rocket is static on the launchpad but weigh more when the rocket is acelerating at 1g in Deep space?

I was looking at the diffraction reflection of an illuminated early 1980s green LED using a CD in a dark room and the spectrum was red-yellow-green; why? I thought that LEDs were pure monochrome light sources. Also, a modern blue LED had green in its spectrum. Again, does anyone know why?

This is a bit of a problem, Sensei. Your data concurs with swansont's figure for the Sun's mass loss rate and that's ~3 times higher than the data given in the webpage that mathematic's link points to; which I guess originates from formal research. Yet your basis for the figure that you give seems robust (too). !!