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Danijel Gorupec

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Everything posted by Danijel Gorupec

  1. My understanding: the way a privately controlled company moderates its social platform is a from of speech - that is, moderation is speaking. Companies are responsible about their moderation policies in the same way as speakers are responsible for their speech. Companies should have freedom in choosing their moderation policies under same rules as for the public speech itself. (Btw, I am not that much impressed with actions big companies did last few days... I hope you also agree that these came too late to be praised for either bravery, morals or foresight.)
  2. Is there such thing as a paint that looks like a glossy metal (like stainless steel or nickel-plated steel). For example, a cheaper sink tap might have a plastic handle, but 'painted' to look like metal - is this a paint or what? Is it something that I can simply buy in a store (I have no experience... maybe it is just that easy)? I need to make some ordinary carbon steel parts look shiny. I am thinking about nickel-electroplating but it seems a bit expensive where I am (and I am also afraid that there are different steel grades welded together in these parts and I am not sure if this can cause problems when electroplating). So, do I have a paint or some other option instead? (to be used indoors, occasionally touched by hands).
  3. I actually prefer chairs without armrest - so I guess it is individual (It is because I tend to pull my legs up, sit on a leg and perform other unsightly poses - armrests limit this. Another unhappy thing about armrests is that I sometimes like to pull myself and the chair almost under the desk, and armrests prevent this. In any case, I am a person who constantly wiggles on his seat.) Fiveworlds, I wouldn't dare to buy an expensive chair without testing it. It is one thing that you should not choose by just surfing the web (and/or asking other people - chairs are individual). But if something (corona?) prevents you from going out and testing chairs, I am pretty sure that whatever you choose it will be much better for you than a kitchen chair. So, go for it in any case.
  4. lol, anything discussed on this forum has a purpose... to be discussed on the forum. Seriously, don't you think the word 'purpose' is has a funny purpose - it is a word that actually tells something about a subject, while disguised as if it tells something about an object.
  5. I think that the strongest benefit of modern renewables (solar and wind) is that these technologies are compatible with private entrepreneurship. This drives efficiencies and lowers prices. Likewise, the biggest weakness of nuclear (fission) is that this technology is inherently under heavy government control (among else, due to possible plutonium production). For most countries this almost guarantees sluggish development, inefficiencies and high prices. I personally would accept to have underground nuclear power stations so that the surface remains uncluttered with wind towers and solar panels. At the moment it is not at all bad, but erecting 10 or 20 times more wind towers is a worrying thought to me. Can you be more specific on the Switzerland example. Is there enough wind power? Is there enough infertile land for solar power? I ask because Switzerland is not a very large country, yet it uses about 35MWh per capita (if I found correct data). Makes me wondering if Switzerland at all has a non-nuclear option if it would want to achieve energy independence?
  6. Yes, this is also my understanding. In fact, as I understand, the PingTang telescope can never use its whole dish to listen a single (point) source. But I don't understand what is the advantage, if any, in comparison to a synchronized array of small movable-dish telescopes? The price?
  7. Thanks.... Can you hint a possible mechanism? Just to get an idea. I understand a vaccine shot can protect from multiple strains of viruses, but I guess this is not the case with the corona vaccine.
  8. I still didn't read anywhere if we have an estimation how long the vaccine protection might last(*). Do you know? More generally, is it at all possible that a vaccine protection lasts longer than the protection obtained after getting over an actual illness? Finally, the controversial question, do manufacturers have a technology to program vaccine protection time? You know, like when you buy an iPhone and then it slows down once it suits the manufacturer. (* It does happen to me that sometimes I expect some information to have high visibility, but newspapers do not show much interest in it.)
  9. I guess there is some hope that some hydrothermal vents organisms from Earth could find a nice spot also in Europa ocean. Sure, I would support doing this only if we prove, beyond reasonable doubt, that the chosen world is sterile. And I still very much hope that Europa is not sterile. Another guess is that organisms that are left to evolve on another planet would soon turn inedible* - or better said, not directly edible, but with some advanced scientific cooking we should still be able to derive some nutrients and energy from them. (* pigs probably can never turn inedible, no reason to panic. But other, less palatable animals, probably will incorporate some poisonous chemistry into their metabolism as an adaptation to foreign worlds)
  10. I would much prefer a modern telescope than the wall between USA and Mexico. But i guess the US congress could still find valuable to debate about it.
  11. I don't assume malice, but I would accept only few reasons for the wreckage: - an earlier decision that maintenance expenses are too heavy and the telescope is to be left-on-its-own - a beyond-design-basis event If a maintenance program was in operation, then it was inadequate. Maintenance should maintain. The reason I mention this is because the above photo can be used by anti-scientists for their agenda ("look how they spend your money"). If the telescope was intentionally abandoned, that must be clearly communicated to the public.
  12. Why the antenna broke - funds withdrawal or incompetent/malicious management? It does not look like an accident to me.
  13. After how long? I guess they have reason to believe that the protection is not only temporary?
  14. Hmm... I have no doubt gravity exists even at atomic scales, but the question was about 'classical gravity'. In my understanding, 'classical gravity' would be a 'smooth' (non-quantum) thing that behaves perfectly predictable. Sure, it could be that at the atomic scale the gravity is (still) pretty much classical, but do we know this?
  15. Supposing that those areas remain stable as it is now. But I am not sure this is the case... Some people think that we are going through a mass-extinction phase right now, caused by rapidly changing environment due to human activity. In any case, it might be that at the moment the environment is changing too fast on the global scope that very large animals could thrive. My understanding is that large animals have difficulties in rapidly changing environments because they are generally slow to reproduce (and thus adapt by evolutionary change). Humans might be an exception because we have a technology that we can adapt instead of our own bodies.
  16. If it is a scam, that might tell us more about European Union than about nuclear fusion. From this single failure (of ITER) my first thought is that governments are incompetent, and only then that fusion might be a scam.... It will take several failures coming from different parties to convince me that fusion does not pay.
  17. Very nice, Moontanman... as you once proposed and I accepted as more logical.
  18. Thinking out loud... At the time, Einstein did not have to feel embarrassed because he didn't know how to reconcile his theory with QM. If one would be developing GR some 40 years later, he would be under some pressure to provide a theory that includes QM. Some guys/girls might abandon their work out of frustration... So maybe, we won't ever have GR as it is now, but we would directly have (eventually) a version given with QM in mind.
  19. @studiot Thanks. I obtained the book (obviously a different edition than yours). Looks fine, will try to read some interesting chapters in my spare time. I am considering electric and magnetic fields because I know them better. The gravitational field might be simpler from the potential energy point of view, but I wouldn't know how to handle its filed energy. Furthermore, the ultimate problem I am considering (what does it mean when we say that electron shifts its energy in magnetic field, like in the Zeeman effect) is related to electric and magnetic fields. @swansont Great that you introduced the capacitor example - it is simple enough that I can make some calculations (see below). But first to answer your 'philosophical' question... Yes, these are two ways of doing calculations. But, imo, not equivalent... The 'field energy' is more precise. Specifically, it precisely defines how the energy is distributed in space (energy density distribution). The 'potential energy' obscures this information. The energy distribution is important for the local energy conservation idea. Imo, if you cannot tell the energy distribution, then the idea of local energy conservation becomes moot. As I take the local energy conservation as a strong requirement, so I think that, at least in principle, we should be able to describe each form of energy by its energy density distribution... It is for this reason that I expect that each forms of potential energy is describable by field energy (or at least by some other way that does not obscure the energy distribution information). As you know from my other thread, I found one example (spin magnetic moment in external magnetic field) where I cannot relate the potential energy change to the field energy change and this itches me. Now the computations... they are striking... We consider a charged plate capacitor. During the experiment, the plates are moved from the starting distance d1 to the ending distance d2. We compute the potential energy change (first line of equations) and field energy change (second line of equations). CASE 1 - constant charge. Everything is clear here and everything fits nicely. The PE change equals the field energy change. CASE 2 - constant voltage. This is interesting. When we look at the system from the potential energy viewpoint, the total energy of the world does not fit! But when we look from the field energy viewpoint, everything fits nicely. Note that in the total energy of the world must include the energy in the idealistic battery that is used to ensure the constant voltage on the capacitor. Note that in the constant-V case the field energy decreases as we are separating the plates. However the energy that is 'pumped' back into the battery is twice the work done... The potential energy viewpoint would give balanced energy only if you avoid looking into the energy change of the battery. Once you peek inside your battery, your energy balance falls apart. So, if I didn't do any major mistake in my reasoning, it seems that the field energy is more precise and more fundamental than the potential energy. If one really, really wants to give a precise answer to the question 'and where is the energy stored' he/she should give the answer from the field energy viewpoint and should avoid the potential energy viewpoint. What do you think?
  20. I am investigating the relation between potential energy and field energy. I think electric and magnetic fields might be simplest to consider. Imagine a simple system of two small charged particles (not elementary particles) separated some distance apart. - we define that the potential energy of this system is U0. - we compute that the energy stored in the electric field is: E0 (note: we computed E0 by integrating the energy density formula for the electric field over the whole space. No need to consider our particles as point charges - say they contain uniformly distributed finite amount of charge in a small finite volume.) We slowly separate the two charged particles some distance farther apart. To do this, we invested some work W. What is now the potential energy U1 of the system? Is it: U1=U0+W? What is now the field energy E1? Does it equal to E1=E0+W? What is the change of the total energy of the system - does it equal to W? My opinion: Yes, the U1=U0+W; yes, the E1=E0+W; and yes, the total energy change equals W. Therefore the change in potential energy and the change in field energy represent the same thing. We should consider either potential energy or the field energy when we compute energy balance. We cannot consider both energy changes as we would be doing double-counting error (in our example, we might compute that the energy difference is 2W instead of W). Let's be stubborn and try the opposite anyway.... let's suppose that potential energy and field energy are two separate things. In this case we could claim: U1=U0+x*W E1=E0+(1-x)*W (where x is a number between 0 and 1) Using these claims the energy will still balance (the energy change is x*W+(1-x)*W=W), but the question would be what is the factor x? Is it x=0.5? Why? So, can we safely say that the change in the potential energy and the change in field energy represent one the same thing? Are there exceptions?
  21. Hmm... What do I do now - I don't find this answer that much revealing because I feel that terms 'interaction energy' or 'potential energy' are intentionally obscuring (they seem like aggregate terms used when it would be too complex to look into full details). Should I open another thread to clarify the difference between potential/interaction energy and field energy?
  22. I think, if our civilization continues without a reset, we will very soon start to intentionally change ourselves at a rate much faster than natural evolution could do. We will engineer our genetic codes (we will also install non-living implants into our bodies to obtain above-natural capabilities and we will even create self-reproducing machines not based on DNA that will continue to evolve themselves at an 'explosive' rate).... So, ironically, the 'intelligent design' might soon be thought as a mainstream
  23. I believe you introduced the concept of potential energy. Specifically, the potential energy of magnetic dipole in magnetic field. But isn't the idea of potential energy just a shorthand that we use? Isn't it always more precise to deal with the energy stored in the field? That is, I assume that the potential energy change (due to electromagnetic field) can always be represented as the electromagnetic field energy change. The trouble is that I continuously fail to relate the potential energy of our elementary-charged-particle-with-spin to the field energy! If the particle really changes its potential energy, and this is not mirrored in the field energy, should I then accept the the potential energy is something really fundamental (not just a shorthand)? I just cannot imagine the potential energy as a thing on its own. Oh, and yes... you might think that the energy shift of the particle is stored is in the magnetic field, but I don't think so (the energy stored in magnetic field seems to shift in a wrong way - it decreases when the electron shifts its energy up.)
  24. Thanks guys... I am glad that studiot used the term 'energy repository' as I think what bothers me is understanding how the energy is stored during these energy shifts. So could the 'spin' be a possible way to store energy? It would surprise me as the quantum spin is fixed (it can measure only two discrete values of identical magnitude). Here is what I think is the essence of my troubles: A simple atom, with only single electron in a state that only has spin magnetic moment (zero orbital magnetic moment) is immersed into magnetic field. Electron's energy shifts... But there is nothing measurable that changes about this atom. I expect that its orbital shape remains unchanged, and its spin (if measured) remains unchanged. Except, of course, its mass does change (from Einstein) - but is this it, is this mass change all that I should expect to happen with this atom?
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