joigus

Final preparations for James Webb telescope: https://blogs.nasa.gov/webb/2021/12/18/nasas-webb-space-telescope-launch-confirmed-for-dec-24/?utm_source=FBPAGE&utm_medium=NASA's+James+Webb+Space+Telescope&utm_campaign=NASASocial&linkId=144816059&fbclid=IwAR1B123ZizvSW9293DGEWK3OACEfQfmuH5CUoqnOFji34qmP0k6HHqLzxbI We may be entering a new era of astrophysics and cosmology. Fingers crossed. After LIGO's enormous success, this looks very promising. Primordial BHs are my favourite explanation of DM.

This has reminded me of, (My emphasis.) Interesting approach, the 'cognitive' one. Angel = hidden mechanism that people (especially in ancient times) indulged in very often --anthropomorphisation of just about everything they didn't understand. I value this approach. I wish I understood it better. I rather lean towards the archaeological/historical perspective,* which is the direction in which I've tried --unsuccessfully, I have to say-- to bring the discussion. To me, the closest we can get to understanding how or why these old timers came up with this angel stuff, is by digging under the ground and then thinking rationally about what their possible motivations must have been. The fact that these intermediaries between people and the gods had wings --Sumer, Akkad, Babylon's cherubim-- does not surprise me at all. Birds appear as symbols of deities as far back as Gobekli Tepe --end of the last glacial period ca. 11000 years ago. In other early human settlements birds also appear depicted as taking the decapitated bodies of the dead. The bird appears strongly in Egypt too. It must have symbolised a connection between the living and the dead for obvious reasons. In the case of Gobekli Tepe, it's vultures we're talking about. Now, it doesn't take a long stretch of the imagination to conjecture a possible reason why people believed that vultures were sacred beings in charge of helping the transit of the deceased to the netherworld. One small step, I think, takes the average Bronze-Age sophisticated mind from different kinds of birds to different kinds of angels. * They're not mutually exclusive, of course.

Verily I say unto you that the platypus of the Lord you will face in the centuries to come, and it will have the appearance of a mixture betwixt a beaver --which, again, you're clueless about-- and a duck. That would've been pretty convincing.

So do platypuses, but the Bible seems to have been clueless about them.

OK. I don't really know. But I know better than to believe in angels. The best vantage point is that of asking questions. Like, Why do angels have two bird-like wings, like avians, and no mechanism to correct for direction (tail wings) which is essential to fly? Are their wings just ornament? The design that's presented in current mythology is a desaster, from an engineering POV. Perhaps they use a bat-like design with membranes that can bend more freely? Do they succumb to temptation? Or perhaps they did only before the beginning of history, and then things went perfect OK from then on? And thousand and thousands more questions that I won't entertain anymore, because there's only so much time I can spend on a monumentally stupid idea, like 'angels exist'. Bots do exist, OTOH.

When you formulate these language 'suspensions', you open up infinity to me. For example: Only people who think they know better... ...are entitled to buy convenience food. Or, Only people who think they know better... ...have read the writting on the wall. Or, ...

Cherubim are mythical creatures with wings that protected the entrance to temples all across the Levant. It probably comes from a word of Akkadian origin, 𒅗𒊒𒁍 karābu , which means 'to bless'. Successive morphings of both the concept and the imagery, have happened throughout the centuries, to end up with the Christian ones. Josiah king of Judah was the first, to the best of my knowledge, to try to unify aspects of ancient Middle-Eastern religions into a cohesive monotheism --very much for political reasons. Akhenaten of Egypt excluded --that was a very different kind of monotheism, IMO. There goes Ashera --wife of Yaweh--, which becomes a stick; there comes (reborn) Baal-Zebub --very abundant on hilltops, with the form of a bull--, which becomes the lord of the flies --another name for Satan--, etc. And of course, the ancient Hebrews had a bunch of other deities, which had to be conveniently fused into the general concepts of either helpers of God, or enemies of God. None of these things is proven beyond any doubt, but they're well understood, and very cogently so, if you study the history of the times, especially after the Assyrian-domination century and the annexation of Israel by Judah, and you pay attention to what's being discovered underground (archaeology). And if you get even the remotest idea of what happened in Constantinople during the first centuries AD, it's no mystery that we still talk about them several millenia after these things were concocted. I forgot to say: Quetzalcoatl, the fethered --if not winged-- snake, is not real either. Nana Mouskouri, OTOH, is real enough. I suppose what I mean to say is: No, there are no angels.

I will add my voice to Studiot's here in formulating some criticism. I'm having more and more doubts, not so much about the correctness of the result that you can produce vortices of air that propagate following a wave equation inside a cavity or resonator, but rather about the --at the very least ambiguous-- suggestion that these vectorial waves would propagate through open air to a certain extent mimicking light waves in the vacuum. That's at least what the announcement seems to suggest. Perhaps it's a matter of how you voice your results. The exaggerated claim I think is implied in the wording, by the editors of SciTechDaily. I think this is overstating what the authors meant, although they did call it 'sound'. There's no fundamental principle of physics that forbids vortices to form in the air. AAMOF, they form on a regular basis. It's more difficult for me to discern from the article that these vorcices would propagate through open air satisfying a wave equation, and not breaking down due to dispersion --which seems to me to be the inevitable physical consequence from an intuitive POV. (My emphasis.) Eqs. 1-8 seem indeed to imply wave equations for the so-called microrrotation field. I don't see why this merits the name of 'sound.' Neither is it sound from a formal definition, nor would it be experienced as such, IMO, by a listener. Its solutions I would call travelling eddies; meaning a travelling, rotational gust of wind, rather than sound. As Studiot says, sound is a pressure wave, which is a scalar. These wave equations would hold inside the medium --resonators--, I think; so you would need a wave guide made of a battery of these resonators, I suppose. The general idea that I get from it all is that they've found perhaps an interesting way to build an analogue model of light with guided waves of moving air, plus a mechanism for switching incoming sound waves into these travelling-eddy analogue of light. I don't mean any of this to be a hard-nosed criticism, but just the kind of questions I would pose to the authors, in ordet to get a more precise idea of what this is about.

LOL. Also definitive proof that not all angels have wings...

'Humans hold a tenure on Earth' is not the way I like to look at it. It's not us who have a tenure on Earth. We're a product of Earth. Earth has us by the short and curlies rather.

Why would Jesus return verses? Because of spelling mistakes?

This is a brilliant point I was thinking about. Only laziness prevented me from ellaborating. OTOH, the collision seems to have been a head-on hit. A lot of collisions are at an angle. Examples are the Thea-Earth collision or the Chichxulub even. We seem to require a head-on collision at nearly zero relative velocity --otherwise we would be talking about a huge amount of debris flying off in all directions. Wildly different results depending on collision parameters. The Mercator projection heavily distorts anything close to the poles, and is more accurate near the equator, as I remember.

Christian rock. Thank God it was rock, and not elevator music.

No amount of thinking can ever beat a hotline to the gods. The line was busy, but after waiting for some hours, Jesus has told me that your argument including the uncertainty principle is quite robust.

I already made those points and you didn't bother to answer. What's the point?

Hold on, I've got Jesus on the phone, and he's telling me you got him completely wrong.

This is the problem. Some people take what really are dumbed-down verbalisations of salient aspects of physical theories, and run away with them. Add Jesus to the mix, and you've got this post. Energy could not possibly have been infinite at the big bang. I think you mean energy density. Energy = -infinity makes even less sense. Energy is positive definite, otherwise you have non-causal behaviour. x-posted with @Phi for All

No, no. It was just a slip. Certainly Curie's law I would call emergent, and by Curie's law I mean, https://en.wikipedia.org/wiki/Curie's_law But it has nothing to do with pressure. Magnetization is purely an average of microscopic fields, but how it relates to temperature (the law itself) has emergent features no doubt. But we were talking about pressure, and of course Curie's law has nothing to do with it. It was a 'Curiean slip'.

Indeed. And every minute I can think of more and more examples of why this 'idea' can't even get off the ground. But, Agreed.

(My emphasis.) OK. So to clarify further. I said, It sounded like I meant force is not present in the parts, but that's not what I meant. And, of course, that's not true. What I meant by 'pressure is not chunks of little pressure' is that it doesn't work like force, it has a qualitatively and quantitatively different law (in most cases it's not directional, it has an equation of state that relates it to other emergent variables, rather than Newton's vector or Lagrange multi-variable equations of motion.) It's related to temperature, which is clearly emergent, or highly-derived, if you wish. It's not the same as, e.g., the macroscopic version of Maxwell's equations, which are essentially the same. If you take the properties of matter into consideration, you do have to introduce de D, H fields to complement the E, B fields, by including \( \varepsilon \), \( \mu \), but the equations are pretty much the same. Now, the way I understand it, the latter is definitely not emergence, but just averaging. Although some people might argue that in some sense it is.

Sorry, that's nothing to do with pressure. Mistake.

This is hands down one of the silliest ideas I've ever heard. Just to add a couple more to what Studiot already said: What about nicely-deposited billions-year-old sedimentary rocks, and surfaces of rock with the unmistakable fingerprint of ancient tides and water waves? What about the perfectly-preserved fossils (billions of y.o.) of stromatolites? How did they survive the crash? Do you have any idea of the range of collision velocities for astronomical bodies?

Myriads of directional vectors have as only effect, to all intents and purposes, just one scalar value. These forces are directional; pressure is a scalar. These forces are wildly time-varying; pressure is constant or smoothly-varying. Etc. OTOH: When a system of the order 1024 variables can be effectively handled with 3 variables for all that matters, I call that 'emergence'. This pressure satisfies qualitatively different laws that cannot be thought of directly in terms of Newton's laws. It satisfies different laws, like the Van der Waals law, or the ideal-gas, the Curie law or any other equation of state. So it's not the same, it doesn't behave the same way, and it cannot be described in similar mathematical terms. I see your point that there is kinda like a microscopic version of pressure, but I think that laws that go with it are an important criterion when it comes to judge when some quantity is emergent. In any case, it's a matter of defining a boundary.

Very interesting points are cropping up. Later, I would like to have a go at @StringJunky's example of a wave as an example, perhaps, of something we don't tend to think of* as 'emergent', but it really satisfies the essential criteria. Also, I would like to have a go at @TheVat's mention of Lee Smolin's efforts to realise space-time as 'emergent'. This, IMO, would require to construct space-time, as built up of more elementary building blocks, which might just be a matter of the description --see below. But now I would like to contribute the following observation. Sometimes emergence appears as a result of correlation: 1) StringJunky's Mexican wave (many elements and strict correlation in behaviour) But sometimes not: 2) Ideal gas: Pressure, temperature, and a host of thermodynamic variables, are relevant precisely because the particles are non-correlated in their behaviour (actually, completely non-correlated). \[ \left\langle x_{i}x_{j}\right\rangle =0 \] \[ \left\langle p_{i}p_{j}\right\rangle =0 \] In this case,** it is precisely because the individual dynamical variables are completely uncorrelated (statistically flattened-out, so to speak), that we can talk about the system in terms of variables that do not bear any relationship whatsoever with the microstates. It is entirely possible that this question of emergence is one that has to do with the description we wish to do --or find ourselves bound to do for practical reasons-- than with any condition that the system imposes upon us. *This is possibly because the wave equation in terms of differential calculus was worked out by some of the Bernouilli's mathematicians so long ago, when the concept of 'emergence' was not in the toolkit of scientists. **Now that I think about it, this is a very special case of correlation --very much in the vein of what Hanke said before.