joigus

Forever? Trying to play @dimreepr here.

I think the answers that you got here are more than enough to go by. But let me try and add a very strong inkling that the quantum must be more fundamental. There is a well-known result of formal (mathematical) quantum mechanics called Ehrenfest's theorem, which tells you that whatever evolving quantum configuration reproduces classical physics at least for the expected values. So classical mechanics is somehow in the guts of quantum mechanics. But there is no way that you can get the quantum with all its peculiarities from classical mechanics. The closest you can get to that is very vague, but it does exist. It's called the Hamilton-Jacobi equation. Some people like to say that, had William Rowan Hamilton spent one more sleepless night, he may have surmised something like quantum mechanics was plausible. But I think that's an overstatement. How would he have figured out the need of a fundamental constant like \( \hbar \)?

And the spoken one:

I couldn't agree more. That doesn't mean definitions are free from responsibility to be useful. 👍

Consider me a ramshackled old monument* that needs your attention from time to time. And is very thankful for it. The uses of the present continuous that I can remember are, 1) Pointing out, reminding, or plainly informing the listener about the activity the speaker is involved in at the time of speaking: I can't talk now, I'm working 2) Pointing out, reminding, or plainly informing the listener about a future activity the speaker already --at the time of speaking-- has made arrangements for. It's impossible for me to attend, I'm seeing the doctor at that time 3) Pointing out, reminding, or plainly informing the listener about an annoying habit they indulge in: You're always talking back to me To which I would add: 4) Quite deliberately using function 2) for emphasis, when the speaker is only signaling their firm intention: I'm not talking to you anymore! And that much is what I remember, although there may be other, literal of figurative. But English is very rich indeed, and what it may lack here and there in grammatical structures, it makes up for in creativity. I've always been a fan of, I must be going** *Maybe not a monument, and just a piece of work. **Top that! A modal with "be going"

LOL. Thanks. Yes, I took a quick look at the Wikipedia page, but I couldn't figure out, was he a terrible teacher? To @StringJunky: Going over your example I realised it's perfectly OK to use perfect future tense in some cases. What threw me off the tracks in the particular example was the combination of the action (making cakes, rather a short-term action), the time adverb "once", and the use of the perfect future. The overall effect of this accumulation of elements results, to me, in a very unnatural sentence. Again: "Once I make another cake, I will have possessed three cakes" I'd rather say: "Once I make another cake, I will have three cakes" What I mean is, frequency adverbs, as well as time adverbs, strongly constrict the tenses. E.g., "I often visit old monuments" Is OK. But, "I'm often visiting old monuments" is awful, from the point of view of good English grammar. Perfect? This largely depends on the state of the apple.

It doesn't make sense to me, which doesn't mean it doesn't make sense. What does it mean to add half Planck's mass from one to the ratio Hubble's time/Planck's time? I can't make heads or tails of it. Where did you get it from? Mmmmm. I think I have an intuition of what you're trying to do there... Think Hubble-to-Planck units. Also, what's the purpose? I'll get back to you. In the meantime, perhaps someone can answer.

Thank you. I know. I possess an almost inexhaustible patience, but I don't own it. I can own a car, or a house though. They are always on my mind. I will have owned them all by the end of 2022. But I will have never possessed them. I was once trying to explain this to a student who insisted that gerunds are nouns.

You're right. It makes perfect sense. It's just that I rarely ever hear or read that use of verbs denoting possession. And I'm wondering why that is. I've searched on Google, and I get about 3'900'000 occurrences of "I will have owned," and 393'000 of "I will have possessed." It is perhaps relevant to say that most of them --and the first pages of them-- are from grammar sites, and not real language in use. But let me add that that doesn't necessarily mean there's anything wrong with them. Perhaps it's something people are less likely to say for some reason. To take an extreme example, "my dog funded the project" is a perfect from the grammatical and syntactical point of view, though it's unlikely that we would ever hear or read that anywhere. I can't say I'm familiar with his work... Perhaps for good reasons...

English verbs... Who needs them. The answer is everyone! I like to think about English verbs in different degrees of "malleability". They go all the way from modal verbs --which I like to think of as verbal particles, rather than "real" verbs--, going through stative verbs --reflecting status, rather than "fixed for all time", at least in my understanding--, down to ordinary action verbs. But the most important difficulty with this categorisation --with any categorisation perhaps-- is that these qualities change with time and with how people --with special focus on native speakers-- actually use these things. Language changes, and if people somehow agree that it's OK to say "I'm loving it" --never mind McDonald's"--, then it's OK to say "I'm loving it."

I'm sure there's a gif of the gaps too. There's a gif for everything!

Your examples and your explanations are pretty good too, Studiot. And you're always willing to help, which is priceless. But the truth is some academic material out there focuses on producing contorted expressions that only contribute to complicate things much more than need be. Language is not mathematics, and I see students suffer every day on account of some expressions being too artificial; and other times too formal. Language should be learnt by impregnation, not by "problem-solving" techniques. I'm very much willing to hear native-English speakers tell me if "I will have possessed whatever" is an expression they would use in any conceivable context, because, if it is, I will gladly include it in my toolkit. Please, fill me in on this one, cause I'm always willing to learn. This is not past perfect; it is present perfect: https://www.oxfordlearnersdictionaries.com/grammar/online-grammar/present-perfect-simple-and-present-perfect-continuous Past perfect is I had eaten the apple. It's used to express a past event or situation with reference to an event or situation that happened further back in the past.

"I will have possessed 3 cakes" is not natural English. It's not idiomatic. It's just an artificially-made, laboratory-of-language-like, awkward, pull-out-of-your-academic-ass, unnecesarilly-contorted expression. Very much in the way of: I will have meant I will have believed I will be possessing But, hey, that's just my two-cents opinion as a Cambridge-certified, professional teacher of English that I am. Reason? Because all those verbs are stative verbs. Language is not combinatorics.

This example is so abominable. I can't picture in my mind any English-speaking person in any situation saying it. "Once I make another cake, I will (possess, own, have) three cakes." This is much more natural IMO. Part of the reason is that verbs indicating ownership are generally stative verbs and don't allow you to do these things (use progressive tenses or other 'complicated' tenses. Example: I'm owning this car. I was owning this car. I will be possessing the house of my dreams. Let alone, I will have possessed 3 cakes. That's bad bad English IMO. Future perfect is used to project your mind to a time in the future with reference to a previous action or event (already in the future) which is necessary for the second action or event to happen. Example: Once I finish the exercise book, I will have mastered all that's necessary to become a practicing programmer. Pay attention to the verb. "own" or "possess" (stative) is not the same as "master" or "learn" (non-stative). Main uses of 'will': Prediction or wondering about an uncertain future, or expressing the will of a course of action, or asking someone for favour, help, etc: "Will you marry me?" "It won't rain tomorrow" "What will happen to him?" "If I study hard I will become a lawyer!" Also for promises (long term) or spontaneous offerings (now): "I will help you with your homework" "I'll answer the phone" "I will get back to you ASAP" On the contrary, "going to" future is for 1) Situations in which you predict the future in the presence of the evidence or a stong clue: "If you keep eating like this, you're going to die of a heart attack" "Stop monkeying around, you're going to break something!" "Look at those clouds, it's going to rain" I've + participle is present perfect, and it's for a completely different use: Recent past or past that's still relevant for some reason (news to the listener, even if it's happened in a remote past, etc.)

Energy is only conserved in GR only when your metric doesn't depend on time or, more technically, when you have a timelike Killing field that's a symmetry of your metric. So no, energy is not conserved in general relativity. This is particularly notorious in cosmological models. Think about it, we only have a sensible conserved energy when the "physical recipes" for how systems evolve do not depend on time. The big bang is a notorious exception. Inflationary models are a parametrisation of this behaviour that we wouldn't expect in this day and age of the universe. I hope that helps.

Seems like you fell off somebody's shoulders.

In the words of a conspicuous member of these forums: A big part of it was that I was under confinement at the time, and for some reason I still don't get, parks and open spaces with perfect ventilation and solar UV exposure (that I used to visit with my bike or just walking) became extremely dangerous for the authorities (I love to get lost and see a minimum amount of members of my own species). Serendipity.

Quantum mechanics is puzzling in every which way you look at it when you approach it with a classical mind. Counterfactual definiteness is certainly one of the most bizarre ones. In order to clarify to anyone not totally familiar with the term, as well as check that we're talking about the same thing: Quantum systems have the ability to reveal their information and react accordingly (mostly by breaking their interference patterns) even when a detector that hasn't clicked is placed somewhere in the setup where the wave function takes significant values. The detector that hasn't clicked but was here, thus reveals that the other detector would have clicked, had we bothered to put it there. This happens even when no entanglement is involved (for just one particle: Elitzur-Vaidman bomb tester, etc.). It also happens, of course, for numbers of entangled particles. So yes, it happens when there's an observer (detector) even if it doesn't observe anything! And I agree that reductionism has a problem with entanglement.

making one big anti-symmetric tensor thing at that point. Sorry, @Markus Hanke.

I know I'm not British, but I'm more of a Cambridge man, if I had to choose. To me it's doctor Marlettto, and nothing would please me more than see her idea come to fruition. Maybe it's just the great paradigm change we need. To me, it's up there with Kelvin's knots, Poincaré's tiny rigid electron, and other ideas. If anything, just much less naive than those of the great men. But the reason I think it won't work is because impossibility principles are formulated (finally) as logical obstructions. You need the logical framework in order to find the obstruction. Otherwise, what does it obstruct?

There is no such thing as classical entanglement. Entanglement is a purely quantum phenomenon. There are several ways to talk about it. The one I prefer is the most general one. There is entanglement whenever you have two particles in a pure quantum state (maximally determined) and you cannot factor out the common state as a product of one state (for one particle) times another (for the other). The probabilities do not check with those of independent statistical collectivities. Some people call entanglement what really is maximal entanglement (maximum maximal confusion, or equal probabilities between the 1-2 and the 2-1 --exchanged-- states), which is peculiar in and of itself. I see no end to the confusion of terminologies. But as Swansont and Markus have stated before, it's not the hallmark of a distant interaction, but of a past one. Another way people like to characterise it is by saying that the state of both particles is more determined (or exhaustive) than the state of just one of them. It's It checks with what I know. This you cannot do with classical fields, because, eg., the electromagnetic field at one point is just one entity that's built up from the contributions of all the sources in the universe, making one big vector thing at that point. In QM, on the contrary, you have a phase space of "thingies" (1)x(2)x(3)... etc., so it's nothing like the classical case. You can have things like (1)x(2)+(1)'x(2)'. "Identity", so to speak, can be "scrambled". This is very peculiar. Some people talk about "classical entanglement" simply because they confuse the principle of superposition for classical fields with the principle of superposition for quantum states (that only when combined with composite states being so-called "tensor products" produces this situation. Entanglement is a consequence of the fact that the simplest physical systems are particles (the 1-thing, the 2-thing, the 3-thing,...) and fields (their values everywhere) at the same time. I'm not being very clear, and I know it, but I'm ready to be corrected/clarified/completed by other users, including you, of course. I apologise, @studiot, for my handwavy and cursory way to put it, but I find your topic fascinating and I hope to be able to contribute more significantly later --hopefully. One last thing before I say something stupid on account of being too tired today: There is no such thing as the quantum numbers. Quantum systems have incompatible sets of those. None is better than the other. That's why Pauli's definition: doesn't really cut it. Particularly severely for spin. Really looking forward to continuing this discussion.

I'm sorry to join my voice to those that of the party poopers here, but I'm pessimistic about how you can make "negative principles" (principles of impossibility) the constructive groundwork for physics. They have immense heuristic value as a guide, but sooner rather than later you must assume plausible relations between the variables that implement those principles and make them "natural" or "obvious". So I think it's the other way: Impossibility principles by themselves don't allow you to build. I've been aware of this quantamagazine big anouncement for a while, but didn't make much of it, TBH. And I wish I were wrong for many reasons. Among others, it is very much in tune with my way of thinking of about 20[?] years ago --which would be a very nice revival of my youth years--, that I gave up on account of not really leading anywhere useful. "It is impossible to determine position and momentum at the same time" doesn't give you HUP all the way down by any means. Let alone the reason why it's true it works. But maybe there's a lot I ignore about this new idea. And I can give several more examples. Swansont has perfectly illustrated how it works with SR.

Yeah, I loved your lowdown too.

Hi. Welcome to the forums. Please, take a look at Section 2 point 7 of the guidelines. https://www.scienceforums.net/guidelines/ A sphere is never "approximated by a point" when calculating gravitational forces outside the sphere. It's just that the field of both objects happens to be the same. That's called Newton's theorem, and in the case of General Relativity, Birkhoff's theorem. A different case would be if the matter distribution were not spherically symmetric. Molecular bonds are a completely different matter, and you really need some quantum mechanics to tackle them...

Absence of chlorophyl for reasons Studiot explained highlights the carotenoids. I suppose carotenoids take longer to be chemically degraded, but I really don't know.