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Everything posted by joigus
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Trying very hard to picture Pope Francisco as a bouncer in a club --unsuccessful so far.
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Could someone give me an appropriate criticism for this?
joigus replied to Abhirao456's topic in Quantum Theory
Got it! The chicken!!! -
Could someone give me an appropriate criticism for this?
joigus replied to Abhirao456's topic in Quantum Theory
@Abhirao456 You may be interested in this: https://en.wikipedia.org/wiki/Sokal_affair It's very much related to what @iNow's point. -
Could someone give me an appropriate criticism for this?
joigus replied to Abhirao456's topic in Quantum Theory
Not a single useful rule to be applied empirically have I found there. Nor a single useful rule to be applied in an explanatory way. Many pompous words, that's all. You should have to find an expert in cosmogony, the mind, matter, ethology, and what not, to be 100% sure whether he's making any sense at all. For the time being, I will stick with other's opinions that it's mostly word salad. Just to clarify, I'm not a professional theoretical physicist, although I've had all the training, and keep up-to-date reasonably well. But my approach is very much on the mathematical/conceptual side. But don't go just by me, or any other theoretically-minded person. Science is heavily constrained by experiment. No matter how deep and far-reaching your theoretical analysis may appear, if you can't make a prediction or retrodiction (explanation of what's already known) pretty quickly, you're probably just playing freely with words or concepts. That's a good test. -
Longitude, Sailing pre 18th Century, and under-rated carpenters/Inventors
joigus replied to beecee's topic in Other Sciences
Very interesting, @beecee. Funny that this man probably saved millions of lives and yet nobody calls him "saviour". -
Could someone give me an appropriate criticism for this?
joigus replied to Abhirao456's topic in Quantum Theory
It's BS at its grandest. 🤣 -
Has the Riemann Hypothesis has been proved here ?
joigus replied to Boson Quark's topic in Analysis and Calculus
Thanks a lot! That's certainly something to follow up on. -
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I've been working on the idea for 37 years now. I'm glad you deem I'm getting closer. It means a lot. What's different is different; and what's the same is the same. Enough said.
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Fields (vector fields, tensor fields...) are neither covariant, nor contravariant. Covariant or contravariant character apply only to coordinates. The need for that distinction comes from having two bases, mutually dual \( \left(\boldsymbol{e}^{i},\boldsymbol{e}_{j}\right)=\delta^i_{j} \), whenever that distinction has to be made. Certainly not here.
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Fields are neither covariant, nor contravariant. Covariant or contravariant character apply only to coordinates. The need for that distinction comes from having two bases, mutually dual \( \left(\boldsymbol{e}^{i},\boldsymbol{e}_{j}\right)=\delta^i_{j} \), whenever that distinction has to be made. Certainly not here. I didn't say light speed is constant. I said photons don't slow down. It's different. I need a slow glass, lately.
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I'll repeat that last bit, as it didn't come out right. I meant: \( 2.998\times10^{8}\textrm{m}\textrm{s}^{-1} \)
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No. That must be it. This post will serve me to test. Thank you. Edit: It is. Thank you
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Hi, @Dave. Great work. Thank you. I've found some issues though: 1) I always seem to appear in anonymous mode. I've tried clearing cookies, but it doesn't seem to work. 2) I cannot edit my posts anymore 3) Some inline maths don't seem to compile after refreshing Point 3) seems to be due to introducing by copy and paste in rich-text format. Probably not an issue, but as I wasn't able to edit my comment, I couldn't fix it.
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Wow. That's quite a bunch of physical concepts completely wrongly understood. Let's leave aside the fact that "contravariant tangent fields" doesn't mean anything. Photons are never "slowed down", and light doesn't need any specific action on it in order to keep its original velocity. Light moves at fixed, universal speed \( 2.998\times10^{-8}\textrm{m}\textrm{s}^{-1} \), not as a consequence of being "stunt", but of space-time symmetries. I meant \( 2.998\times10^{8}\textrm{m}\textrm{s}^{-1} \). For some reason I can no longer edit, after the sofware update.
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The short answer is yes. Energy in mechanics depends on position and velocity, and those are frame-dependent quantities. I hope that answers your question. How satisfactory the answer is depends on how general you want it to be.
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Rainbow mountains in China, Iceland, and Peru. China: Zhangye national geopark: https://en.wikipedia.org/wiki/Zhangye_National_Geopark https://en.wikipedia.org/wiki/Zhangye_National_Geopark Iceland: Landmannalaugar region. From https://www.kimkim.com/c/iceland-best-hiking-regions https://en.wikipedia.org/wiki/Landmannalaugar Peru: Vinicunca mountains: https://bookatrekking.com/en/trekking/peru/rainbow-mountain/ https://en.wikipedia.org/wiki/Vinicunca In all three cases I've provided links to both tourism-oriented websites, and a Wikipedia articles with more details about geological aspects. Some of the different colours can be attributed to differential oxidation/composition of the strata. In other cases, like the Icelandic one, sulfur from volcanic activity must be involved. The photos may be oversaturated in some cases.