studiot

This is most interesting to learn that N America is suffering from invasive species. I woner what they are ? I ask this because in Europe we are generally concerned with the reverse by species such as the N American squirrel and mink.

Can you decribe what you think this problem might be ? As is so often the case thermodynamics in general and temperature in particular provides counterexamples. A traditional mercury thermometer measures temperature by expansion movement. A modern non contact thermometer may measure temperature colour, and a null balance electronic thermometer may measure temperature by potentiometric opposition. BTW clock's don't measure time they measure time difference. It is impossible to measure time with a single clock reading.

A small comment here. People are failing to distinguish between a wave and a wavefront, which is only an infinitesimal part of a wave. Thank you for bringing this website to my attention, I have not heard of it, but see it has been going some years on and off. +1

What about a test model ?

Very Helpful, guys. +1

NEW YEAR Since I don't want to end the year on bad terms with anyone, perhaps you would all just apologise to me now.

It isn't really metaphysics, it follows directly from the setup of a fixed (note I say fixed as described by MigL) block universe. It is easy to see in a fixed block how this can arise, using Omar Khayyam's scrolls, I mentioned earlier. Suppose a particular scroll was written showing event points as coloured circles. Suppose further that a bright young reader observes that a blue event circle always seems to follow from a green circle. So the entire scroll is like the entire fixed block universe. It is all there from start to finish or end to end. Our bright scholar deduces a 'physical law' that the green event is the 'cause' of the blue one. But of course it is just that the scroll was written that way. Of course it could have been written many other ways. So there are alternative possible laws. Correlation does not imply causation etc. O K had more sagacious words about the scroll and the block and time.

Thank you. Can I take it that we are agreed that there is a fundamental difference between time and space ? And further that this is relevant to the 'block universe' model ? Here is a proposal The fixed block universe doesn't only violate causality, it make a total nonsense of it. And since most of Physics is concerned with causality in one way or another, most of Physics with it.

I'm sorry I really have no idea what this means. I am also trying to identify points where we agree and where we disagree. I would be grateful if you would do the same. Please answer these questions Would the equations of electrostatics be any different if there was no time ? Would the equations of mechanical staticsl be any different if there was no time ? Would the equations of gravitostatics be any different if there was no time ? Would the equations of standing waves be any different if there was no time ?

I agree that form is related to space. However a space point (I should not really have said point particle.) is different from any other point in a space, by definition. Fourier methods define temperature at any space point in say a heated bar. Are you saying these are wrong ? There is a deiiference between definable and measurable. It's to do with the points no one seems to want to take up that I mentioned when I first entered this thread.

Temperature of a point particle ? With respect to yourself and Markus, I think the viewpoint is too restricted.

I don't know how my offerings on the nature of time got mixed up with a discussion of gravitation or even why gravitation is being discussed. Gravitation is not dependent upon time or models of how time works. I would argue that starting off with a thread by linking relativity to the nature of time is likely to lead to confusion since you cannot effective discuss the former without an effective model of the latter. So establishing that model is the first step and somehow the three should really be separated, but time, relativity and gravitation fit that song (the nature of) Time, Relativity Gravity makes three. In terms of Omar Khayyam, and the block universe, I am thinking in terms of the operation of twinrod scrolls, corresponding to past, present and future.

I would think you were actually taught rather more than 'electricity is a movement of electrons' Electricity is usually the general term for the phenomenon of several effects we lump together and call 'electricity'. That would include 'static electricity' , electric current, ionic mobility and a whole host of other effects. Which one are you particularly interested in ?

I agree there are a lot of misunderstandings, but omar khayyam and I can think of another interpretation of the block universe than the either of ones put forward in your vid. The Migl's video does make the very important point about the meaning (or lack of it) of 'simultaneity'. However the whole idea depends upon which you consider more fundamental, the floor you are standing on, or some x,y,z,t coordinate system.

FYI, English is more subtle than that. It offers the means to distinguish the order of events, with or without duration measurement.

If you have never yet seen a full description of the idea how can you be so convinced it will not work ? As I understood the OP, airbrush was asking for alternative methods to laser initiation. So I think this is a separate subject.

I can google this question as well as anybody else. So here is some commentary on an extract from a good reply article. Not that it is not only a question of initiating the fusion, but sustaining that fusion for long enough for it to produce enough energy for it to become self sustaining. Simple Fusion is more common than you think, simply firing a neutron or alpha or other particle into a nucleus can produce fusion. But that is only for one atom at a time. Nature takes a statistical approach in the stars since if you have a container of gas and either wait long enough or large enough or some combination of the two, two particles will eventually collide fast enough to provide the kinetic energy for initiation. In the laser approach you have to keep supplying the initiation energy since the process is a continual series of match strikes, rather than a continuous flame. This avoids the containment problem, but much of the energy is then needed to keep the matches striking. So the problem is a trade off between initiation, containment and sustainability.

This is particularly @Ghideon Now that that the repair is done and forgotten here is an update. The river has been in spate over the weir system during the last few days and I observed the different flowpatterns at the failure point abd the rest of the weir sidewalls. The first photo is the normal laminar flow as it tumbles over the weir, ducks down in a U, rises up again and carries on in the same direction. In the second photo against the failure wall, the water ducks down, rises backs up and flows back over the top of itself forming a vortex with a horizontal axis perpendicular to the wall. I have indicated the difference with flow arrows on the pictures. I would imagine that the vortex picks up small stone which grind against the sidewall constantantly boring into it along the axis line.

The second statement is more nearly correct but it is far from complete as there are other eqyally important considerations. Western people tend to wear more tightly fitting clothes than other cultures from hot countries. Both the men who wear white and the women who wear black in arab countries wear long very loose garments that have a layer of air between the clothing an most of the body. This layer is very important in keeping things cool.

It is important to distinguish between both factors, That give four possible situations. 1) Two types of CD 2) Two types of degradation All types of CD are subject to scuffs and scratches and greater damage. Some of these can be polished out. All types are also subject to the chemicals from fingers over a much longer timescale. This trpe of degradation only affects the surface and can be cleaned / polished out. Cds that are made by mechanical stamping of physical pits are not subject to degradation of the pits over human timescales, but these discs may suffer surface damage that makes them not properly readable. CDs that are made by creating flat areas of chemical change with a writing laser are susceptible to both light (yes storing these in a lightproof box will extend their life) and other chemical degradation that is not light related. The chemical used vary for patent reasons. Some brands gained a very bad reputation for loosing all the readability after a year of two. What more is there to say?

Yes and no . Writable / rewritable media will deteriorate with some. Some earlier chemical formulations were more unstable than others. More recent ones are better but do not have an indefinite life. Mechanically pressed media have an expected life of hundreds of years, no one really knows how many becasue they haven't been around long enough to start failing. Of course this excludes media that was defective from the beginning or physically damaged later.

Actions are the proof of (good) intentions, not weasel words. Your thread has reached post 6 but you still have not complied with requests from other members nor polite instructions from the moderators to comply with the rules here. I am reporting this thread for you yanking our chain.

I really don't see how this is relevent to anything I said. Perhaps that is because I did not spell out my line of thinking in so many words. What is the use of a thousand witnesses and all angle camera footage if the authorities refuse/fail to act ? It is not the threat/fear of being seen it is the threat of being caught and punished. About the culture, there are also things I liked about Saudi culture, they appear more honest that most cultures I have visited, sadly including my own.

+1 for helping kenny count up to 4. However be careful about 'induction'. Mostly induction only redistributes charges in a body. Extra charge have to come from somewhere else, by the law of conservation of charge.

LOL. +1 As a (now retired) applied mathematician I have done applied maths work for Airbus, and British Gas in the past. Gas dynamics and engine vibration dynamics were probably the highest level engineering maths I did. But there was a wealth of lower level stuff from bridge analysis to geophysics and geodetic work ... the field is very wide indeed. Good luck.