Leaderboard

Not forbidden to anyone. Of course, if someone wanted to hihack it with their pet theory, that would be against the rules. Challenging is how science progresses.

I always put myself in the other persons shoes. I am 6 years older than my wife (she says 7, which is totally wrong, as we met slightly over a month after her 24th birthday, and I was 30, and would not turn 31 for almost a full month). We met on a blind date so no PC concerns I know of at this time. But I always ask myself...what if we had met and I was subordinate to her, or she to me? What kind of perpetrator might I, or (I would hope) she, have been?

My understanding of 'interpretation' in this context is a description which gives the same results as other interpretations. So it's impossible to distinguish between e.g. a version of the Copenhagen interpretation and the many worlds interpretation by prediction or experiment. If you can distinguish it's not an interpretation; it's a theory. I would interpret that as saying other people do not share your preference for a particular interpretation. BTW as interpretations are in practice imprecise rather than rigorous, I've never found a rigorous, generally accepted version of the Copenhagen interpretation. Measurement is an interpretation based concept; It's questionable that measurement has any causal influence. From https://en.wikipedia.org/wiki/Copenhagen_interpretation

I don't know much about the US system but the team I manage does include software engineers. You say you'd be working as one, do you really mean you'd be working as a software engineer or would you be doing programming for a company who don't really know what software engineering is? That could make a big difference to you when you come to get your next job. A pretty simple interview question for an entry level software engineer might be something like "what importance do you place on quality assurance and what tools and practices have you employed to demonstrate this in a particular project?" I'd suggest you need to think about this role, it's prospects both in the company and what you might want to do career wise next, after collage. You might also be interested to know that for university graduates we look at their a-levels as well (equivalent age to high school in the USA).

Rubbish. Members are not forbidden. Unfounded baseless nonsense is. What’s a shame is that some members seem incapable of posting anything other than unfounded baseless nonsense.

Biggest plausible risk that keeps coming to my mind is this: You drop out of school. The economy then tanks. Market crashes. The employer you thought you could join must lay people off, or worse still goes out of business completely. You’re then left standing with your junk in your hand waving in the wind with no income, no diploma, and a much harder time executing this plan for GED. You’d have nothing but the plan, which is about as helpful as a tutu on a sow. My perspective is also a bit different from yours as I have a whole family counting on me to survive and I’ve also been through an economic collapse before, so my risk tolerance is skewed lower accordingly.

I find the notion that deflection of moving charges was unexplained in physics instruction before 1962 to be highly dubious

Before you do that second line read this. Fresnel was the first to propose a luminerferous aether, named as such in 1818 nearly half a century before Maxwell showed that electromagnetic fields are capable of supporting waves and longer before Hertz proved it experimentally. But centuries before this some sort of transmission medium was assumed. https://en.wikipedia.org/wiki/Timeline_of_luminiferous_aether I am ignoring all the off topic stuff about modern cosmological theories.

It is easy to loose sight of the ingenuity of the natural universe and in this case human ingenuity. We should guard against this and not try to force our limited theories on what we observe. This applies to both sides of the discussion. Firstly let us dispel this failure of logic, both from a theoretical point of view and a phenomenological one. The logical progression of the above runs Waves can be regarded as a sequence of phase linked single oscillators, each one performing its activity in turn. Many working model demonstation machines are constructed like this. For this model to be successful there must be oscillators. What you call the substrate, and most call the medium, comprises this sequence of oscillators. Now for some human igenuity. Why is it necessary for all these oscillators to exist, even when they are not oscillating? Why can they not pop up into place like ducks in a shooting gallery when they are needed. And pop down again when they are no (ie the wave has passed their location) ? Alternatively why can they not be laid like the railway tracks in the Wallace & Grommit movie, directly infront of the travelling train or wave? And pulled up again behind the train. One classical view of EM radiation is that "It carries its own medium along with it", so doesn't need an inplace medium lying around like sound does. Very neat and tidy, don't you think? It is even possible to construct a simple mechanical model to demonstrate this. Suppose you had a conveyor belt carrying ducks of graded height, graded according to a wave pattern. The ducks generally lie flat(horizontal) but flip up just before arriving at a target point and flip down again immediately after passing it. If you watched this point through a rifle sight you would observe a sinuous wave passing, going up and down in height (amplitude). But if you sighted anywhere else along the gallery you would see nothing. So you would have to conclude that there is no permanent medium along the gallery. Now you have also said. No this is not true, even by your own words and constitutes a failure of logic since it should read "all other tests except for the existence of a medium" Otherwise you cannot take the (logical) step/deduction Therefore there must be a medium. This was indeed the situation in the early part of the 19 century, but the situation changed dramatically with the discovery of the photoelectric effect and became no longer true. There was no known mechanism for the threshold to occur with any known wave equation. Or there was no known wave equation that could model the threshold. (Note some thresholds do occur in wave theory for example total internal reflection and all sorts of ideas like this were examined.) So we then had a failure of EM radiation to act in accordance with expectations to explain. The description I posted about the Maxwell mechanical vortex theory of a medium does not have these properties. Further in that source in a part I did not post, Maxwell himself is reported as saying that he derived to to exactly fit his famous four equations, But that he could not accept it as it was too cumbersome and that there must be therefore some other explanation. Post#5 here https://www.scienceforums.net/topic/117405-currents-and-symmetry/

Given that English is not your first language, some of the ideas I was trying to convey, might have gotten lost in translation. If you would require a 'substrate' or medium, for EM waves, you would need to model some pretty fantastic properties. One property is that, to support the highest speed possible for a disturbance travelling in it, it would need to exhibit extremely high ( near infinite ) stiffness. Stiffer than diamond, or even neutronium. The other property is that it needs to offer very little ( near zero ) resistance to objects travelling through it, or else Michelson-Morley would have detected something. These properties are at odds with each other. And since we have working models that DON'T require a 'substrate' or medium ( very extensively tested ), we choose to keep it simple, and cut away anything unneeded with Occam's razor. The aether 'substrate' or medium, is simply NOT needed

What is the essence of distance? Why is it that the wave cannot transverse faster or slower across it? Why can it not arrive sooner or later?

Yes, what then? In my opinion they are intimately related. Let's take an example. Imagine a very weak photon source, emitting about one photon every minute. All around it, but at a distance of one light second (=300,000 km) we have photon detectors. Now according to Maxwell (no photons, just waves) every minute a circular wave front expands into space. According to QM however, we only have a 'probability wave', and the photon is detected at only one detector. At the moment of detection, I know immediately that none of the others will detect a photon. So the event 'measuring a photon' and 'not measuring a photon' are entangled. If behind every detector would stand a human observer, one could send a message to all the others when measuring a photon and tell them that at timepoint 5:09h she knew that nobody else had measured a photon, based on the fact that she already had measured it. So the entanglement follows directly from the wave character of the probability distribution. The power of real entanglement experiments (also known as EPR, or Bell experiments) is that we have positive measurements on both sides, not just a lack of a measurement. But they are expressions of the same phenomenon. So, what then? No. We do not need realtime measurements. If two detectors at a great distance of each other are in the same inertial frame they just can make their measurements, notice the exact time of measurement, and then later compare their measurements. There is no faster-than-light communication. See here. The mathematical theory of QM is unambiguous: entanglement must exist. Do not forget, it was theoretically derived before it also was measured. So there is no problem to solve. The only problem is that we, humans, cannot picture this based on our daily concepts.

I don't. Or, at least, they shouldn't be. It may be simply that, if the soil is too dry for the pH meter to work, the plant dies anyway.

From what I've read, they are. I think the best way is to standardize a sample size, mix with a standard volume and then litmus it. Would you think so?

Surely the pH is a measure of the acidity of the water in the soil, not the soil itself? So a pH meter will not give any sensible reading when placed in kiln dried sand. I think that some pH meters are actually a form of conductivity meter. These could obviously be confused by the presence of conductive minerals in the soil.

It's not quite that simple, though. Neutrinos travel (slightly) slower than photons but are far more penetrating because they don't interact the same way. You have to look at the interaction probability as well. Alphas are more likely to interact owing to their larger charge. They will ionize surrounding atoms, which causes them to lose energy and slow down. Neutrons will tend to penetrate better than protons, because even though they have roughly the same mass, the neutron has no charge. Alphas don't. They have a pretty well-defined penetration depth. "The range of alphas of a given energy is a fairly unique quantity in a specific absorber material." https://sciencedemonstrations.fas.harvard.edu/presentations/α-β-γ-penetration-and-shielding There's a plot here of what the alpha count typically looks like with distance. https://physics.stackexchange.com/questions/308359/does-alpha-radiation-penetration-depth-decrease-exponentionaly-with-distance/308428#308428

2) Yes 1) Consider the relative strengths of the four fundamental forces. This table is from Wolfram Science http://scienceworld.wolfram.com/physics/FundamentalForces.html This is why gravity doesn't strip the electrons out of atoms. I think they try to keep the paths of the accelerated particles horizontal in large scale accelerators. Also there are regular repeater coils or E/S deflector plates in the installation. Perhaps someone with direct experience of these things will chip in here, especially if they have a better answer?

The transmission medium original question was air. Further alpha and beta rays are both charged and particulate. The particulate part says that it depends upon the nature of the source and the particle density. The charge says that there is interaction with airborn particles. In fact transmission through a medium usually follows an exponential decay type law. This also applies to EM radiation, but the coefficients are such that air is virtually transparent to gamma rays, over distances measured in less than hundreds of kilometers.

Traveling to the Moon was a matter of solving known engineering problems, it was not considered theoretically impossible. Exceeding c is an entirely different animal. It is a fundamental limit built into nature itself. You bring up the matter of "weight". But weight is not the issue. "Inertia" or the resistance to further change in velocity is a better way to look at it. It takes energy to overcome inertia. This was known even before Relativity came on the scene. In Newtonian physics, it takes 1/2 joule of energy to acceleration a 1 kg mass from 0 to 1m/sec. The amount of energy needed to any given speed is found by E= mv2/2 The kicker added by Relativity is that energy itself carries inertia. So when you add energy to the 1 kg mass to accelerate it up to 1/m per sec, you are also adding to its inertia. When you try to accelerate it further, you have to supply more energy than you would have without the added inertia. But this extra added energy increases the inertia even more. The amount of energy rises a lot faster than it does under Newtonian physics. The equation that give the amount of energy is E = mc2(1/sqrt(1-v2/c2)-1) The amount of energy heads off to infinity as v approaches c. The flip side of this is that no matter how much energy you add, you always end up moving less than the speed of light. This is not to say that the speed of light limit is all about energy. This is just one consequence. It goes deeper than that. It actually delves to the very nature of space and time itself. Another consequence of this is how we add velocities together. Again, under Newton, it is quite simple. we just add them directly. So, for example if you are on a railway car traveling at 60 mph, and you walk from the back to the front at 5 mph relative to the car, According to Newton, you would be moving at 60+5= 65 mph relative to the tracks. But in Relativity, with its altered nature of time and space, you have to use the formula: (5+60)/(1+5(60)/c2) = ? Now c = 186,000mps = 669,600,000 mph, so if you do the math you will get an answer really, really close to 65 mph, but just a tad less. The difference becomes more apparent as the velocities added up get closer to the speed of light. This also applies when you are adding up velocities for an accelerating object. In Newtonian physics you could have an object that accelerate up to 0.1c, and then accelerate another 0.1c, and then another, etc so that after each stage, its velocity would look like this: 0 0.1c 0.2c 0.3c 0.4c And after ten of these you would reach c However, with Relativity, the velocity doesn't add up like that. You can accelerate up to 0.1c, and then accelerate (as measured by you) another 0.1c, but will end up moving at only 0.198c relative to where you started. You can then accelerate by another 0.1c, and another, etc. Your pattern of resulting velocities will be: After 10 such accelerations, you have only reached a little over 3/4 the speed of light. Also note that each successive acceleration results in a smaller and smaller change of velocity. The increase in velocity shrinks at a rate such that no matter how many times you try to add speed(or by how much), you always end up with a velocity less than the speed of light relative to where you started.

Scare quotes have meaning where I come from, but it doesn't make "fix" the proper description of the introduction/use of the aether. Isn't that moot? The aether was dropped before QM, and was dropped because of SR. There's no overlap. The aether is a purely Newtonian classical physics issue, that was dropped pretty quickly after we had a good model of electromagnetism.

No, you had proposed the aether as a fix, not its removal. The aether was not a fix.

It wasn't a "fix" because it wasn't a response to anything being broken. It was assumed to be there. But then someone tested to confirm it (M-M) and someone investigated the ramifications of the invariance of the working theory (Einstein)

No. We had a model that explained electromagnetic waves before the aether. We had exactly the same model after the aether was disproved. Nothing changed. So it can't have been vital. But I suppose you are right in that a model was proposed, tested and then rejected. This is what will, inevitably, happen to some (maybe all) of the current hypotheses for dark matter, etc. Because of evidence. So we should not attempt to create and test new models to explain new evidence? We should just ignore it? Of course it is conclusive. The measurements that Zwicky made have been repeatedly confirmed. And then similar measurements were made within galaxies. And then gravitational lensing observations have been confirmed this. And so on and so on. Do you have any reason (evidence) to say that all these many measurements are wrong? (Maybe I should as a moderator to split these posts to Speculations where you will have to properly defend you views.)

Those are completely different sorts of reasoning. One is not based on evidence, the other is. Can you explain what the similarity is, instead of just repeating the same thing. So, what should we do about the evidence? Ignore it because we don't have an explanation? Or come up with some models and test them (you know, do science)?

I don't understand the comparison you are making. The aether was an assumption made for no reason (ie. no evidence). When tests were done to test the various aether models, no evidence was found. And, as noted, the aether would require physically impossible and contradictory properties. So this seems to be completely different than the examples you give, which are entirely based on evidence. Dark energy is an explanation for the observations we have made (ie. evidence). There are multiple hypotheses for what dark matter could be (including various forms of matter, different ways of modifying gravity and others). These are all being tested by looking for further evidence predicted by each model. The same is largely true of dark energy: there is evidence that needs explaining. People are looking for more evidence to confirm or rule out various possible explanations. And inflation is a hypothesis to explain aspects of the early universe. There are alternative hypotheses. Again, people are looking for evidence to confirm these or rule them out. In all cases, we don't know what the explanation is, but there is evidence that requires an explanation. Do you think we should just ignore the evidence? What are you suggesting? how are these analogous to the aether?

You also say the ether was not vital. Let me not even try to show you how flawed your reasoning is.

This is an incredible discussion. It's a shame that this topic is forbidden for some members.

We thank you for the great contribution made in clarifying absolutely nothing we have been discussing, other than a first course in English. But we still thank you nontheless. The two of you are amusing with your dislikes of my non-physics posts... but I completely understand.