studiot

Well if this really is the long goodbye, perhaps you will at least try to answer questions from your next victims.

That's an interesting point of view, How does it play out with p, d, f orbitals where the max probabilities are more remote from the centre ?

Yes you understand that physics correctly, but things are a bit weirder than you have presented since what you have said is incomplete. Let us call the Earth E, the Traveller T and the Star S. So there is a relative speed between T and S of 0.8c. Which means that they are not in the same frame. So we must convert the 3Ly separation to one frame or the other the T frame or the S frame, it does not matter which. This will give us the 'proper distance' between T and S. The proper distance Lo is always longer than the measured distance between moving objects and is the same in all frames. So we use the formula [math]L = {L_0}\sqrt {1 - \frac{{{v^2}}}{{{c^2}}}} [/math] Substituting the given data [math]3 = {L_0}\sqrt {1 - \frac{{{{\left( {0.8c} \right)}^2}}}{{{c^2}}}} = {L_0}\sqrt {1 - 0.64} = {L_0}\sqrt {0.36} = 0.6{L_0}[/math] [math]{L_0} = \frac{3}{{0.6}} = 5[/math] light-years This is what I mean by your original statement was incomplete. (no criticism intended I am being detailed in order to help) Because you originally stated that S is 5 Ly from Earth. Since this is the 'proper distance' it must already be corrected for any motion between E and S, which you have omitted to say. It is possible, though not generally the case, the S will not be also moving relative to E. Just to add that when you start to combine the effects of two relative velocities the calculation becomes more involved. You can't simply add them up. Note here that it does not matter whether T is travelling towards S or away from it, but T must just be passing E when the measurement is made.

One of the issues we faced is that new wiring, even if extending or replacing existing, has to be to the new colour code. This is all fine and dandy if all the wiring is new but it also means you can have dirty brown connecting onto red, blue connecting onto black and green/yellow connecting on to green. Not ideal.

Yes there were accidents due to red green colour blindness mixing up the earth and the line. +1 for the colour blindness issue. The opportunity was taken to harmonise with the european dirty blue and dirty red/brown when the first change was made. Pity because it had to be changed again when yellow stripes were added to earth. Of course the American colour convention is quite different, as is their wiring layout.

And you are clearly not a trained diver. The carbon dioxide reflex will happen despite a functioning brain, as every diver is taught to control.

It's what you do every night. 🙂 It is interesting to note that in a Newtonian analysis centrifugal force is not a force. But in a D'Alembertian analysis of the same situation, it is.

What do you mean by 'occurs' ? Are you asking if there are any primitive organisms/lifeforms that have a rudimentary nervous system but no brain ? I don't know the answer to this, perhaps a biology special;ist can answer it. But Galvani started investigating this hundreds of years ago. Or are you asking if a more complex organism can be kept alive after its brain has stopped functioning ? Well 'brain death' is one reason for doctors switching off life support systems on patients whose bodies still have living functionality, including neuro(sub)systems that still function.

I like the idea of fundamental interactions, as opposed to fundamental forces. +1 Davy specifically asked about forces so it would be a better idea to find out what we mean by a force before throwing it out, lest we throw the dog out in mistake for the cat.

I already did and you didn't answer. You also ran away from my comment about religion.

It is a question of speed. The electrons in an ordinary vacuum tube are not moving fast enough to warrant more advanced mechanics such as relativistic dynamics. Sub atomic particles in particle accelerators, and natural particles cosmic rays in nature achieve speeds such that relativistic calculations need to be employed. For most normal interactions the electrons 'orbiting' the nucleus in atoms are not moving fast enough for relativistic calculations to be needed. So the Schrodinger theory of wave mechanics uses classical (newtonian) evaluations of the dynamics. There is a more advanced theory making relativistic corrections due to Dirac.

Before offering any discussion I would be interested to learn what you understand by a 'Force' ? I ask this because your question is clear cut black and white yet most things in Nature become more complicated than that when we enquire more deeply into them, often much more complicated. Forces and how they operate, what other physical quantities they affect or need and so on fall into the category of being much more complicated. Even when considered in a newtonian manner, gravity operates differently from say electromagnetism, although there are similarieties as well.

I'm not sure I understand what you are getting at here. Surely solenoids are beyond grade 10 ? Yes as the length of wire making the solenoid increases so will the resistance (I think that is grade 10) but the resistance of winding wire in any coil is generally insignificant compared to the magnetic effect causing an opposition to change of current, which is called reactance. I don't think reactance comes into it until later grades, but I will explain if you wish. Swansont mentioned that each turn or loop of the coil adds to this effect so the number of coils is significant. This is rather like (but not exactly the same as) the force that can be generated by a pressure depends upon the area the pressure acts over. The larger the area the greater the force a given pressure will generate. You have probably done something like this in mechanics with say the principle of the hydraulic lift

Perhaps I did not state my case very clearly. I was just trying to point out the illogicality of stating that a device which cannot increase in temperature needs any form of cooling, which was matthew's proposal not mine. It has always been my case that in fact the device must increase in temperature, unless something is actively done to cool it. Of course any such active cooling automatically becomes part of any thermodynamic system and should be included in any thermodynamic consideration. If the device needs cooling there must be an energy inflow promoting heating. But such would run contrary to the proposal that the device converts all energy input to electricity.

My mistake, apologies. I meant to say "But if you choose to define efficiency as the conversion of just radiation the correct frequency, then yes 100% conversion efficiency is theoretically possible." Consider a gambler at las Vegas who claimed he could beat the system. So he put a dime into the slot, pulled the handle and out came a dollar. Hey this has a 1000% efficiency he says. Now applying that to radiation say you fired one photon at a time at the photocell and got a small burst of current as a result. After the first photon converted, you could say that is 100% conversion efficiency. Assumed maybe, but not stated in your description. It doesn't matter since a photocell that does not absorb heat will not need to be 'held at temperature'. However you are still allowing the hot object to radiate sort of according to the the laws of Physics, but disallowing the cold object (photocell) from doing the same thing.

You will go far with your approach +1 I agree with swansont, it's not a waste.

You can't pick and choose which Physics Laws you will allow to operate and which you will suspend. (That could be a subject for speculation, but this is Modern and Theoretical Physics) The best you can do is to show that the effect of the Law you wish to suspend is insignificant. Then you can ignore it. But you have not done this. All objects will heat up if placed near to an object at a higher temperature. They will also radiate heat in their own right, something you originally ignored. I have already said that there are different definitions of 'efficiency', stemming from the basic one. And you are still ignoring that. I also said that two such measures are absorbtivity and emissivity, that you are ignoring. 100% absorbtivity is a theoretical possibility. But 100% absorbtivity does not make for 100% conversion. Swansont has already told you that any conversion cell can only convert certain frequencies by virtue of the only available conversion mechanism. Energy at all other frequencies emitted by the emitter and absorbed by the cell will be converted to - heat. But if you choose to define efficiency as the conversion of just radiation the correct frequency, then yes 100% conversion efficiency is possible. But as Swansont has said several times and I have now pointed out, Thermodynamics requires there to be a frequency spread of the radiation from a body at 1000oK. Since this effect is highly significant at this temperature, it cannot be ignored. Swansont also said That is why there is a Physics Quantity known as 'the work function'. https://en.wikipedia.org/wiki/Work_function This is also linked to what is known as the threshold frequency, below which any radiation from the emitter could not generate electricity. And we have already noted that Thermodynamics requires some of these lower frequencies to be present. https://www.electrical4u.com/work-function/

Well of course an unconnected battery is a simple example of a voltage without a current. That was the easy one. So a current is a coordinated movement of charge. That can occur if the charge carriers are moved by something that affects their other material properties (remember I said they were all material ?). Since they all have mass, some force that can move their mass and they wil take their charge with them. For instance a thermal current, or a photocurrent in suitable electronic devices can be observed to flow when there is no voltage supply connected. A particularly interesting example employs Newton's Laws of dynamics to light up the screens of old fashioned cathode ray tubes. Here the electrons are initially accelerated by a voltage, but then they pass beyond the electric field and move under Newton's First Law until they hit the phosphor to make it glow.

So it is not then a possibility.

When you have two opposing forces clearly the stronger one will 'win', regardless of how the forces are generated. The Magdeburg Hemispheres is a famous experiment to demonstrate this. https://en.wikipedia.org/wiki/Magdeburg_hemispheres Clearly the atmouspheric pressure force will win until Guerike harnesses enough horses. Then the horses will win. Similarly a given gravitational force can be stronger than, weaker than or even equal to a given electromagnetic force.

I have never heard such rubbish. When I was in primary school we did an experiment where we laid out different colour objects in the sunshine and measured their respective temperatures after a few hours. Even at the age of 9 I knew your statement to be wrong.

If you start from basics you would not make statements such as this Basics. 1) Heat flows from a hotter body to a colder one. This is non negotiable. 2) General possible modes of heat transfer are:- Convection, conduction, radiation. Radiation is the appropriate mode in this case, although since you have not properly described your system, you have not excluded the other two.

I was afraid this was another back door attempt to introduce religious dogma. It seems my fears were justified. Have you not heard of feedback and feedforward systems ?

No I am sorry if I did not make this clear. I think your youtube demonstration is a hoax or fake. We have discussed such demonstrations here before, if anyone can remember the reference. Hidden under the table or behind the background screen will be a generator of a changing magnetic field. The magnets you see are just showmanship.

This is not a thermodynamic model of this It is simply a discussion of one of the three participants in your proposed process. You have a temperature difference of 700oK. Why would it not increase ? It is just plain wrong to suggest that then photcell is neither an emitter nor an absorber of radiation. There is no electric circuit described in your opening post or your thermal model. Forget exergy, entropy and go back to basics. If you start from there you might be able to come up with something sensible.