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Everything posted by sethoflagos

  1. I once held this view, and to a certain extent it served a purpose. But in recent years I've come to think differently. Whatever else it does, life appears to be an extremely efficient way of producing novel structures from simpler lower entropy resources. And not just by the evolutionary process of 'faulty' self-replication, but also in the reshaping of local environments, and now exponentially so in the products of our technologies. As agents of the 2nd Law of Thermodynamics, life processes appear capable of converting homogeneity to diversity many orders of magnitude more effectively than non-biological processes. And while the 2nd Law does not consciously create each new biological structure (obviously), it spontaneously redistributes energy flows away from preexisting pathways and into any new outlets made available to it, and hence actively favours and fuels evolutionary divergence. The 2nd Law favours us because we provide it with new avenues to explore, and has provided us with a broad array of individual drives and preferences to maximise the production of those new horizons. So ... ... existentialism appears to be strongly encouraged by the 2nd Law. Even if it can seem a little scary at times.
  2. Thanks! Two neon atoms in an otherwise empty small box. They collide. Where is the sound?
  3. I think you know very well that the air inside the Albert Hall is not condensed matter. Therefore it doesn't support normal modes of oscillation. Therefore it doesn't transmit phonons. When I visualise High C, I visualise some emergent residue of say 10^30+ air molecule collisions. A residual vector of the time averaged exchange of momentum having some detectable periodicity in the vicinity of 1046.5 Hz. Trying to ascribe a spatial size to a momentum vector, or an emergent property such as sound seem to me as ludicrous as assigning a spatial size to temperature, the colour green, or perceived beauty. Or photons come to that.
  4. The Maxwell Equations I believe. But I'll have to leave it to someone else to guide you through the niceties of those.
  5. Then how would light manage to traverse deep space where it's interactions with matter particles are exceedingly rare? Are you proposing the resurrection of the luminiferous aether?
  6. Good! Now compare and contrast with your assertion in the OP So why are you assigning a physical size to photons? Forget the transmission medium, that's irrelevant to the topic. Both light and sound propagate outward as expanding spherical disturbances in their respective fields. At this level, they have no meaningful physical size, but they carry a certain amount of energy that extends over a certain sphere of influence. Where apparent conflicts begin is when we consider the transfer of an individual packet of light energy between an emitting particle and an absorbing particle. How does a specific accurately directed packet of energy 'condense' from a diffuse spherical wave? This is one of the central mysteries of quantum mechanics. The quantum world is a strange one and most of its workings seem to play out not in our observable material universe, but in a complex space we can never directly observe. All we can say with any certainty is that the transfer is observed to occur. The image we see maybe of an emitter firing a 'billiard ball' of energy at an absorber. But is this really a full and true reflection of actual events? I wouldn't put money on it.
  7. Your post evaded answering my question by introducing diversionary anthropocentric observer dependent contingencies. Ideas like these (Schrodinger's Cat is a typical example) strike me as being solipsistic, which I see as leading the unwary towards... well, I've already told you where I believe that bus terminates. No more than a friendly warning. So no, I wasn't insulting you. However, even if the ears are deaf, the bottle is still full of sound.
  8. I put quite a bit of thought into asking you a question that I thought might help you break free of a misleading mental picture (trap) that I was also (and occasionally still am) prone to falling into. It is a bit disappointing therefore that instead of answering my question after due consideration, you treated me to a spontaneous party political broadcast on behalf of the solipsist party. Good luck with that one. Planet Narcissus can be a pretty lonely place to inhabit.
  9. You seem to be equating the physical size of a particle with the sphere of influence it may exert on a field. What would you say was the physical size of a soprano's high C? Is it the size of a large concert hall? ... The sound of a strong soprano can certainly fill one. Or is it just the air molecules inside the Albert Hall jiggling around in a slightly more ordered pattern than normal?
  10. There are many mechanisms through which evolution may occur, but let's take the simplest A virus can undergo an inheritable point mutation of a single nucleotide base in its genome, altering its protein expression in a manner that effects either positively or negatively the new strain's fitness for survival. A fruitfly can undergo an inheritable point mutation of a single nucleotide base in its genome, altering its protein expression in a manner that effects either positively or negatively the new strain's fitness for survival. Darwinian evolution is totally indifferent to where you pin your arbitrary classification of 'life'. It simply identifies any parent-offspring relationship and acts on it without any prejudice whatsoever. Virus, fruitfly, prion particle, or humanity, it's all grist to the mill. You seem to be pretty upset by this concept (all capitals, thirteen exclamation marks, negative reps and complaints to management upset apparently). Perhaps it's time to ask yourself whether the object that you're clutching onto for dear life is a lifebelt or a lead weight.
  11. So you're quite happy to accept that dead things can be subject to Darwinian evolution but living things cannot? Really?
  12. Over the last couple of years, earth's entire population has witnessed and observed the real-time evolution of coronavirus.
  13. What is your understanding of the word 'machine'? Stars are machines. In that they convert mass into electromagnetic radiation. And yet they seem to self assemble from merely a locally higher than average abundance of hydrogen. No apparent intervention by any 'designer' here.
  14. There seems to have been some progress there too. Quoting from https://www.cambridge.org/core/journals/quarterly-reviews-of-biophysics/article/nucleic-acids-function-and-potential-for-abiogenesis/842529B9BDAD6E86F7919827725C1931
  15. Just how excited ought we be about these recently published results? Craig A. Jerome, Hyo-Joong Kim, Stephen J. Mojzsis, Steven A. Benner, and Elisa Biondi.Astrobiology.ahead of print http://doi.org/10.1089/ast.2022.0027
  16. I'm so sorry, Genady, I missed this last post of yours. So for the maximum we get the Legrangian function L(x1, x2 ... xn, k) = -x1.ln(x1) -x2.ln(x2) ... -xn.ln(xn) - k.(x1 +x2 ... +xn -1) The partial derivatives for all xi = -(ln(xi) +k +1) and therefore are zero at -ln(xi) = k+1 or xi = e^(-k-1) The partial derivative wrt k is zero for the constraint condition x1 +x2 ... +xn = 1 Hence n.e^(-k-1) = 1 which solves to k = ln(n) -1 Hence xi = 1/n and ln(xi) = -ln(n) Hence max value of original function = n.(1/n.ln(n)) = ln(n) And you were not wrong! Thankyou so much for putting a new string on my mathematical bow. I think I'll go away now and quietly try this method out on a few other functions.
  17. Important to point out that this does not exclude there being a significant iridium content in the sample. Merely that the iridescent surface coating has other causes. Much of the world's accessible iridium reserves are in sulphide minerals, including pyrite, associated with some very particular geological structures. But in the absence of any information from the OP as to exactly where the sample came from or what other minerals and rock types it was associated with, the anomalous x-ray fluorescence data will probably remain just that. We have nothing else to go on.
  18. Interesting article! It's easier to see the common threads when a good mix of examples are explained in a single source.
  19. Pyrite is unstable in air, and frequently accumulates a tarnish of goethite - a hydrated Fe III oxide. Goethite is quite well known (in the jewellery trade and elsewhere) for the iridescence that can develop in the right conditions.
  20. Have a look at https://en.wikipedia.org/wiki/Crystal_growth, particularly the section entitled 'Non-uniform lateral growth'. I believe that will help explain the regular stepped edges you can see.
  21. Not really my field of expertise here! Not even sure what the question is. But if the query is the strong zigzag features, my first guess would be crystal twinning. Iron pyrites (if that's what the samples are) does have an interesting form in the iron cross twin (example below). Erode an oblique cross-section through that and you might find a similar surface. The 'pyritohedra' form can also generate some exotic angles.
  22. You are absolutely right that most of the water involved is absorbed during the alteration of forsterite the magnesium component of olivine. And olivine is mostly forsterite. But there is always >~8% fayalite in olivine, so in that sense there is always hydrogen produced during serpentisation. I'm just paraphrasing the commonly held understanding of the process eg (from https://en.wikipedia.org/wiki/Serpentinite) Yes, some intriguing ideas here. Most of the quoted research is dated recently and some seems to be a bit dismissive of the standard sequence of metamorphic grades and facies that I'm familiar with from a different century(!) If they are suggesting that the slab is subducting so quickly that the water content (whatever its form) is unable to rise fast enough to escape being dragged down, then I'd be more than interested to know what form it actually is in. Some exotic new hydrated mineralogy would be fascinating. Free water even more so. Unfortunately the authors do not say. I'm not suggesting these ideas are impossible, and in support, the material returned deeply emplaced at constructive plate margins (typically gabbro) always has a bit of hydrated material in it in the form of 2-3% hornblende. So there must be some water content deep down. It's one of the standard equilibrium shifts for eclogite facies metamorphism which I simply accept as read. I guess it must be 2-3 GPa or so. But your point is well taken. It's the sort of question I ask myself, and I wish I could get my hands on the thermodynamic data for these materials to plot out the relevant phase equilibria for the benefit of both of us. It's got to be out there somewhere,
  23. Me too. I'm no more than a hobby geologist but it has been a somewhat obsessive fascination since I was about 8! (a very long time ago) One observation that strongly colours my view of this topic is that it must square with not only the surface geology we see around us, but also a very long term gradual trend of oxidation from the global reducing conditions of the earliest times due to photosynthesis. The banded iron formations around the world record oxygen fugacity being controlled by the oxidation of oceanic Fe II to Fe III in the Archean. And to this day, there is still an iron oxidation front controlling oxygen fugacity - called the FMQ (fayalite-magnetite-quartz) redox buffer - now deep within the earth's crust. 3Fe2SiO4 + O2 = 2Fe3O4 + 3SiO2 Compare this with @exchemist's serpentisation reaction 1a) 3Fe2SiO4 + 2H2O → 2Fe3O4 + 3SiO2 + 2H2 ... which can proceed when FMQ has exhausted all the free silica in its environment, and water becomes the favoured source of oxygen. I'm all too aware that this picture is simplistic in the extreme, and maybe the second reaction is not favoured at some key limiting temperature, but it does raise a question in my mind about the stability of water in the low silica reducing environments found at depth. Or perhaps I'm completely off-track, and the ocean is busy converting the lower mantle to topaz!
  24. But eventually this reaction reverses as the high pressure form of serpentine (antigorite) breaks down at ~600 C into forsterite, enstatite and water.
  25. But Ca(OH)2 (and the more relevant Mg form, brucite) thermally decompose, releasing their water while still at only modest depth. For water to get beyond say 100 km depth, it has to find its way into a high density mineral that is stable at the elevated temperatures found down there. All the likely candidates I can think of are hydrogen depleted.
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