Everything posted by joigus
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Was there a real Jesus of Nazareth ?
Flavius Josephus was nearly contemporary --started giving his account a few decades after the "facts". While his focus wasn't on Jesus of Nazareth, he provides a good account on the contextual scenario for the appearance of such figure (relevance of the Essenes). IMO, this contextual scenario is very important and shouldn't be ignored. The case for the existence of a real Jesus, I think, is reinforced by the fact that these different "Jesus-like figures" had been appearing ever since the time of the Greek takeover of official Jewish religion that led to the Maccabean revolt (against the Seleucid kingdom) 200 y before. John the Baptist is a famous example. Another famous one is the Teacher of Righteousness from the Dead Sea Scrolls. While this teacher of righteousness has been robustly, IMO, ruled out as a good candidate for Jesus, his existence goes to prove that the existence of a Jesus figure is very plausible. Political/religious leaders, will tend to adopt strategies that suited their predecessors. And at the time it was very fashionable to go to the desert and start preaching alternative versions of the Jewish law that could find a wide-enough following. Life of Brian paints a hilarious picture of this cauldron of ideas and beliefs. Never mind how the collective memory works, by adding more and more layers of narrative that make the whole thing very confusing. Sometimes previous myths are refused into the new story --here I'm trying to address Richard Carrier's main arguments, although he's a scholar, and I'm just a person who tries to apply common sense almost every minute of the day. Similar cases can be made for David and Solomon, Mohammed, and even Gilgamesh. I'm in no doubt that there was (some kind of) a Gilgamesh king of Uruk. He probably didn't, almost single-handedly, kill a giant in the forests of Lebanon, as the Epic of Gilgamesh tells us, but he just didn't pop out of a vacuum. I'm relying heavily on memory, please correct me if I'm wrong.
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Hidden Jewels of Scientific Literature
Nice mix-and-match. Thank you for taking the time. I have to tell you, I had you very much in mind when I came up with the topic. Pre-Cambrian life fascinates me too. I absolutely relished S.J. Gould's Wonderful Life, which is perhaps more widely known. Thank you.
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Hidden Jewels of Scientific Literature
Sounds like a kind of topic that's particularly close to my heart. These ones too: As to, Duly noted. These kind of topics are a little bit off my radar. But the topic is fascinating. Thank you for the Peebles reference, @MigL. I think I'd heard about it, but haven't read it. I suppose it's a bit outdated now, but duly noted as well. Thanks all for the contributions.
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Hidden Jewels of Scientific Literature
Yes, you've mentioned it before. It seems to meet my criteria. I cannot be totally sure. I don't know the book. But that doesn't necessarily mean anything... I'm aware of the ambiguity of my request!
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Hidden Jewels of Scientific Literature
Is there a book, or a few, that not many people know, but blew your mind? The rules: 1) Scientific books: Anthropology, Biology, Chemistry, Engineering, Linguistics, Mathematics, Paleontology, Physics,... The lot! But mainstream science. 2) Not "bibles" of the scientific literature, but can be relatively unknown books from famous author. For example: Dirac's Principles of Quantum Mechanics is not allowed, but Dirac's Lectures on Quantum Mechanics, could be OK. Not best sellers. 3) They can be either technical, or popular science Here's mine: The Quantum Theory of Atoms, molecules, and Photons by John Avery It's a book by a quantum chemist that takes you on a journey of basically everything essential about the quantum. The title is very telling of what it does. Tell me about your hidden treasure.
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Is human language a result of our brain becoming 'digital'?
Interesting thread, even if in speculation land. When you say 'become', do you mean in evolutionary terms? I do believe language operates in some kind of discrete version of a continuous experience, but I have to do my homework on this thread yet...
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The Novak Djokovic Debacle:
Very much like wanting to participate in these forums but not abiding by the rules. The rules are for everybody.
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Was there a real Jesus of Nazareth ?
To me, this kind of question can be understood anywhere from, Did that Jesus really exist? (the particular one that the Gospels mention) to, Did some kind of Jesus really exist? (a character of the time whose figure morphed through the centuries into the one we know) The answer to the first one is (almost 100% sure): No The answer to the second one is (almost 100% sure): Yes Trying to determine very precisely, or beyond any doubt, something that's quite blurry to start with, I think is pretty hopeless. I remember an ad many years ago that said about a cosmetic product something like: Your hair will be 29.5% times more lovely (something like that.) Similar logic. Some Moses did exist too. Probably. And an Arthur, and an Achiles, but nothing like Charlton Heston, Sean Connery, or Brad Pitt, or the literary figures before them, embelished by the likes of the Bible's authors, Chrétien de Troyes, and Homer.
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Modern Humans older than previously thought
Neanderthals did indulge in some inbreeding though. That's probably bound to happen when the girl next-door lives, eg, 100 miles NE. My picture of human evolution is getting closer and closer to a turbulent river with thousands and thousands of eddies, and rivulets of genetic flow diverting off course and rejoining the main stream later, or getting lost forever. When I look at the crania of these humans in Jebel Irhoud... The experts say it's modern human, though they look so neandertalish. I don't know what modern humans are anymore.
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Does a Static EM Field Acquire Mass Due to Stored Energy?
It may be interesting to notice that the EM contribution to mass is negligible in most macroscopic cases. If you plug in the values of \( \varepsilon_{0} \), \( c^{2} \) and assume 'typical' values for the field \( \boldsymbol{E} \) the order of Volts/metre, volumes the order of cm3, you get for this charged macroscopic object a correction to mass of its uncharged state the order of one proton mass or thereabouts. This is, of course, due to the high value of the speed of light.
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Does a Static EM Field Acquire Mass Due to Stored Energy?
Agreed. Once you have any gauge field, you have mass. It's a package deal. It's a contribution to total mass. The Higgs is different, I think. But that's another topic.
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Does a Static EM Field Acquire Mass Due to Stored Energy?
I didn't mention the Higgs. I didn't mean to mention the Higgs. I don't think the Higgs has any bearing on OP. Why the Higgs came up at all is a mystery to me. EM weighs, that's all I meant to say. And that, I said.
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Does a Static EM Field Acquire Mass Due to Stored Energy?
OK. I don't know whether you retracted from your question or from a previous point. But keep in mind the Higgs mechanism is an ad hoc mechanism. Brilliantly insightful, to be sure, but ad hoc nonetheless. IOW: We don't really understand where mass comes from. It's nice to have a multiplet of particles that gives mass to everything else. The Higgs floats around while the Goldstone bosons from the multiplet (not the Higgs, this is not faithfully reflected in the literature) provide mass to all fermions and short-range bosons. But where do the completely disparate mass spectrum comes from? I don't think we've developed a picture in the way that the OP seems to suggest, that mass differences could be explained by means of field self-interaction, and self-interaction alone. That's a fair point.
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Does a Static EM Field Acquire Mass Due to Stored Energy?
Somebody would think it's a weak confirmation, but here's one: No charged particle with zero rest energy (relativistic mass) has been found. So the EM field has inertia. Always. To which I will add a prediction: No charged particle with zero rest energy (relativistic mass) will ever be found.
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Does a Static EM Field Acquire Mass Due to Stored Energy?
Thanks for confirming this. In the case that a classical calculation were valid, you would have to add the EM contribution to the mass as \( \triangle m_{\textrm{EM}}=\frac{\varepsilon_{0}}{2c^{2}}\int_{0}^{\infty}\left(\left\Vert \boldsymbol{E}\right\Vert ^{2}+\left\Vert \boldsymbol{B}\right\Vert ^{2}\right)dV \) Well, it's because it's really when you go down to something as elementary as an electron that the question becomes really intractable classically.
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Does a Static EM Field Acquire Mass Due to Stored Energy?
Now that I think about it, @exchemist wasn't necessarily talking about the electron... For some reason, I was thinking about the electron.
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Does a Static EM Field Acquire Mass Due to Stored Energy?
This calculation cannot be done classically. You've hit the same wall that a generation of physicists (Abraham, Einstein, Lorentz) and a notorious mathematician (Poincaré) hit a century ago*. If the electron is point-like and static (static cannot be, we know this from QM), then the Poynting-vector approach (that @Markus Hanke referred to) gives you infinity, as the integral of \( \frac{\varepsilon_{0}}{2}\int_{0}^{\infty}\left\Vert \boldsymbol{E}\left(r\right)\right\Vert ^{2}dV \) is divergent. So the classical calculation is nonsense. The possibility that the electron is a little sphere of charge is even worse, as it is impossible to make it relativistically consistent. The pedestrian way of seeing it is that discontinuous charge densities in space-time do not bode well for relativistic invariance. You need fields that are smooth everywhere. The modern way of dealing with it is using QED (the fully-relativistic, quantum-mechanical version) and attribute part of the energy to self interaction of the electron. We could phrase it as 'the electron tries to move, emits a quantum of radiation, and suffers radiation reaction.' These virtual processes contribute to the energy. Unfortunately, for all I know, nobody has come up with a way of plugging in the fields (involving the electron's charge), and deriving from there the mass of the electron. The mass of the electron has to be plugged in by hand. This, I think, is an outstandingly-good question. By no means just a good question. Edit: * A century-odd, which was also an odd century.
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Could someone give me an appropriate criticism for this?
Not a lot, to me at least. For example, as a definition of 'energy': Energy doesn't always result in translation. OTOH, not an operational definition. As to 'action': Yes, good physicists are in that habit, because they have good reasons to think space is finite, and action in a confined space leads to quantised energy, for the simple reason that space-time confinement leads to a periodicity. Continuous energy is probably just a theoretical extrapolation. Same reason why angular momentum cannot be even conceived of but as quantised, because it's the conjugate momentum to an angle, which always restricted to a confined space \( \left[0,2\pi\right] \). Action again: Time, mass, and length are not derived from action. It's the other way around. As to the conclusion: This doesn't even make a smidgen of sense to me. I'm sorry. But I do have a sense of what the problem is with this kind of definitions/'derivations': They lack the operational point of view, on which all of physics rests, they engage in a loose runaway of concepts and statements, and consequently they lead to whatever preconfigured picture was already in the author's mind.
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What is mathematics?
I know du Sautoy from the documentaries. 'The Self-Made Tapestry' does ring a bell, perhaps you mentioned it before. I have no idea about cement mixer patterns, but sounds interesting.
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Modern Humans older than previously thought
That seems to be the trend. The discontinuity of the fossil record is very important to keep in mind. I think we're in for more surprises. Dmanisi was another big big surprise in a different direction. Thanks for the link to Jebel Irhoud.
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Modern Humans older than previously thought
https://phys.org/news/2022-01-earliest-human-eastern-africa-dated.html?fbclid=IwAR3qOIHmKKO6EsILQUbh6DCngk5MjeQl3pI-ugX_n6yrHc5k-WPp5GhYkEM
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What is mathematics?
But I don't disagree with this. In fact: Let me add another definition of maths that I've heard to Marcus du Sautoy, if I remember correctly: Maths is the study of patterns
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What is mathematics?
Loved the poem. Thank you. Somehow I don't see zero so much as a geometric concept. I think it's more of an algebraic concept. You can do quite a bit of geometry without it (similarity of triangles, Thales theorem, Pythagorean theorem, and so on.) In a curvilinear space you don't really have zero curvature; and in a pseudo Euclidean space there are infinitely many points that have zero "distance" with respect to any one point. I think it's more of an auxiliary concept than really central to geometry. You can do some geometry without mentioning zero. You can't really start doing algebra or analysis without it. I don't disagree with this at all. Maths is a tool. And we'd rather use maths to make a hammer than use hammers to do maths. I even think maths is at the basis of language. Even people who say they hate maths, I think, have a simpler, more basic way of mathematically understanding the world. Perhaps less sophisticated, refined, or whatever.
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Today I Learned
Today I've learned about the phenomenon of chatoyance or chatoyancy: https://en.wikipedia.org/wiki/Chatoyancy and a beautiful sea snail called Voluta musica that displays this effect. It is an optical effect consisting in certain 2D patterns being perceived as 3D --if I understood it correctly. Thanks to @Genady and @StringJunky. 👍
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What is mathematics?
Ok. I trust you and Euclid. But keep in mind that when Euclid wrote his Elements, there was no distinction analysis/algebra/geometry, so when he wrote that, he didn't make a clear distinction was probably trying to introduce the minimal elements of analysis necessary for doing geometry. Obviously you cannot do anything at all in maths if you don't start out with some elements of algebra and analysis. But zero is the distance between two points only when they're the same point, and as for a coordinate, it doesn't mean anything that its value happens to be zero. So I don't think zero is a relevant part of geometry. There is no 'zero point,' as opposed to the real number zero in analysis, or the element zero in a ring (algebra), etc. That was kind of my point --no pun intended. Edit (addition): On the other hand..., 'that which hath no part.' I don't know what to do with that. I don't think Euclid was in his finest hour when he wrote that.