studiot

BBC documentary tonight 2100 on BBC2 Friday 24th April

The point I was trying to make is that (as Einstein said) we should get the Physics right first and adjust the maths to fit. Ttwo observers, A and B with B moving past A at velocity v. At the instant B is coincident with A, a light pulse is generated. The (postulated) Physics of Relativity says that : Postulate (2) says. Both A and B see the light pulse moving away in all directions at the same velocity c, as measured in their respective frames. Since the velocity is the same in all directions, both A and B will see an expanding sphere of light surface. Postulate (1) says both must see the same physics ie see the same expanding shape. So all this is self consistent. But it is not consistent with a Galilean transformation when you try to write the equations of a sphere in one frame and transform them into the other frame via a Galilean transformation. This is incompatible with postulate (1).

Thank you +1

at distance = Earth v Alpha Centauri. And why are we allowing this viewing of a youtube?

Not necessarily. There are several considerations in play and you nearly have the theoretical justification leading to the following equation between reactants A and B. Rate = Rate Constant x concentration of A x Concentration of B. Theoretically we note that in order for a reaction between two molecules A and B to take place, they have to be in the same place at the same time. So it is reasonable to suppose that the probability of a molecule being in a particular place at a particular time is proportional to the concentration (not the total number) of thaose molecules. [math]rate \propto \left[ A \right][/math] or [math]rate = {c_A}\left[ A \right][/math] But the rate is also proportional the probability of finding B in the same place is [math]rate = {c_B}\left[ B \right][/math] combining these we have [math]rate = k\left[ A \right]\left[ B \right][/math] Where k is the combined constant for both proportionalities. But I also said look at the definition of 'rate' Rate is the time rate of change of concentration (not total quantity) of one of the reactants [math]rate = \frac{{d\left[ A \right]}}{{dt}} = \frac{{d\left[ B \right]}}{{dt}}[/math] This is why I said 'mathematically'. But I also said theoretically. In practice we find that experimentally this works for some reactions but for others the rate is actually proportional to some fractional power of the concentrations [math]rate = k{\left[ A \right]^\alpha }{\left[ B \right]^\beta }[/math] Again sometimes we can deduce reasons for this but the ultimate arbiter is to measure alpha and beta.

If you think so, perhaps you can say why ? Then you might be able to answer your own question. But you should also look at your definition of rate of reaction. Mathematically the answer is no.

Remember my 'layer model' ? There is a layer heirarchy in programming as well. Starting at the bottom with the binary that is loaded into the electronic hardware (for electronic engineers) All the way up to database languages like Access/Visual Basic for semi technical humans. Such humans would not want to spout a load of binary to ask the question "How many arch bridges are there with three or more spans, made of steel, carrying a railway and a pipeline across a river in my database ?"

Simple examples A very important and commonly used technique in programming is iteration (repeating an action perhaps many times) You obviously need to keep count of the number of repeats (iterations) in some way (how is not important to your question). If you only had one type of number - a full real number accurate to the maximum accuracy of the computer - then your operations would be incredibly wasteful of computer capacity. So we do not count by 1.000000000000000000000000000 + 1.000000000000000000000000000 = 2.000000000000000000000000000 but use integers, ie 1+ 1 = 2 iterations. There are actually other quite a few numeric data types in use eg for money, date, rounding etc. We use constants and variables in normal mathematics, the same happens in computing so that expression can be evaluated. This leads on to strings and character variables to enable databases to be searched for a specific word eg London.

negative exponential.

Yes it is easy to loose sight of the Physics if you simply stick to mathematical formulae. Yes it is necessary to write the equation in that form to express the fact that if a light pulse is emitted at the origin of the frame at t = 0 then there is a 3D spherical expanding wavefront of light with the equation x2 + y2 + z2 = r2. for any given r. That is the r2 is on the other side of the equation from the 3D spatial coordinates. If we now take t as a parameter we recover the negative sign. Of course to generate a line segment with the Euclidian norm we have to use ict not t. It should be noted that the second postulate means that all inertial observers see an expanding sphere in their own frame. This allows us to create the equation x2 + y2 + z2 - c2t2 = x'2 + y'2 + z'2 - c2t'2 Where the primes on the coordinates denote the second inertial frame. Leading to the Lorenz transformation and other consequences. Does this help?

It's complicated by the fact that the electron in general doesn't return to the ground state by the same sequence of energy levels it jumped up. Some transitions are forbidden, for spin and other reasons. This is why for instance luminescence occurs and the difference in timing accounts for the difference ebtween phosphorescence and luminescence. Well would all appreciate full English words in your answer.

At 2 minutes in the speaker says " so long as the second measurement is taken in the same direction as the first" Therefore you have the same difficulty identifying 'the same direction' at distance as 'the same time' at distance - a point raised by the OP

At 1minute 25 seconds in the speaker says After measurement (ofspin) the particle maintains its spin Then immediately says So measurement changes the spin Anyone any comments?

My point is that all the above are fixed packets of energy. A magnetic field is a distribution. OK but note that your picture includes the second agent, working with the magnetic field, I have taken pains to include. I am a little puzzled by the picture of the hand. Current is allocated to what seems to be the thumb. The force or motion (mechanical agent) should be allocated to the thumb and I would say your picture is trying to offer the left hand rule.

OK I am going to make some guesses here. First guess English is not your first language? Are you using a translator? Secondly you state "gamma ray bursts" Second guess you do not mean the gamma rays themselves, you mean something about the bursts (of gamma rays) observed by astronomers. Perhaps their pattern of occurrence in the sky or time or connection to some other events. So you need an astrophysicist, astronomer or cosmologist perhaps acting like a clinical epidemiologist. Alternatively if you actually want to discuss something about the gamma rays themselves then a good test of your hypothesis will be "Does it also apply to X rays?" since X rays are essentially the same thing as gamma rays, except they are artificially produced, whereas gamma rays are natural.

'Copying' is more complicated process than simple reactions and is usually effected by genetic processes. Your wish for alchemical transmutations is just not possible and was abandoned hundreds of years ago. Why don't you learn some real chemistry, based on the real world experience of the last few hundred years? It is really fascinating.

Faraday's Law tells us that a changing magnetic field will induce an EMF/current in a conductor in move past. I know of no corresponding law for the generation of photons, do you ? The situation is quite different since the electrons already exist in the conductor, and are free enough to be given an arbitrary amount of energy from the magnetic field / motion interaction. The is no specific quantum of generation requirement. The production of photons would would be a quantum effect such that the transferred energy exactly matches that of the photon.

Welcome dentre and techgeekk. @dentre Is this coursework? Posting your actual problem might elicit more detailed help. @techgeekk +1 Hope to see more of your posts in future.

I see that you have lots of knowledgeable answers. +1 sensei. Before answering this, I would like to make two points. Firstly it would be helpful to tell us where you are in your studies of this. Are you in school or colllege studying some form of computer science and is the establishment shut because of the virus ? Is this the beginning of your course? Secondly in computer science there is something known as the 'layer model'. This allows people to concentrate on a relevent part of the whole. It makes the study easier and more manageable. Here is a link to the model applied to data processing. https://www.bmc.com/blogs/osi-model-7-layers/ Applying the model to computer architecture separates the electronics theory (at the bottom) from the hardware (next) to bus structure to the data structure to the input/output structure and so on. It is good to have such an overview map of things to talk about and relate to.

It still applies, but not in the same way. In SR the expression is global, which is why we can use it for spacemen visiting Alpha Centauri etc. In GR it is strictly local, a point function which varies from point to point as gravity varies. s is the single scalar invariant for SR. In GR there are up to 14 invariants here is a pdf about this. https://www.researchgate.net/publication/243698965_Invariants_of_General_Relativity_and_the_Classification_of_Spaces Edit: On second thought it might be better if I worded this differently. That is the trouble when you try to oversimplify a complicated matter. I will add to this later today as it might give a false impression.

@fredreload Just to amplify this, you have probably picked up somwhere that "the EM field is mediated by photons". This is not the same thing as "made of photons" at all and not useful in the current situation.

Let us examine your idea of oscillating electrons between the poles of a powerful magnet, which in theory would work, but faces some practical issues. Firstly why would the electron stay there or oscillate? Present day machines manipulating electrons generally use auxiliary methods to achieve these aims, very often a combination of electrostatic and magnetic fields. One such is the electron spin resonance machine used in chemical analysis. This works in the 28 -30 MHz range ie microwave so does not quite reach visible. I already mentioned (and linked to) the Kerr effect. Kerr cells are one way to measure the relativistic effects and speed of visible light.

Interesting you should post this the day the BBC publishes this graph suggesting the opposite in the UK. https://www.bbc.co.uk/news/health-52361519

Your opening post was longish and rambling. Most readers have expressed the same opinion (in different ways) that they couldn't readily determine your actual point. So can you please sum this point up for us in a short paragraph so we all know what we are talking about?

Do I not get to choose who I reply to now = =? Or are you interested in the thread? As I recall you started off hoping to manipulate electrons in a magnetic field in order to generate visible light. Perhaps I have the wrong impression but posts 3 and 4 were from members offering avenues to explore to achieve this goal. Whether they were right or wrong, I can't see why you turn wish to turn your back on such advice.