exchemist

It would generate energy, yes, but very little. What this device would do is displace a volume of water equal to the area of the pipe x the tidal range, once every 12hrs, so it would be a sort of very slow pump. To extract energy from the tides, you are far better off to use a place where a natural restriction, say the entrance to a bay, causes a significant tidal current and then use a turbine of some kind. That way, you exploit the tidal displacement of an entire bay's worth of water volume every cycle.

It seems to me a lot of this is old gnus.

OK, I see what you are saying, but if that were a valid explanation for the cosmological red shift, then presumably GR would be false and would predict results contrary to observation in other respects. Is that the case? Or can you somehow preserve GR AND this idea at the same time?

Re your last line, I think you may be confusing motion through space with expansion of the metric.

As far as I'm aware, we don't have a theory for that. As quarks are the most elementary unit of matter we know of, I doubt that we have anything on which to base any speculations as to whether or not they might be decomposable into something "more" fundamental. Though I'd be interested if any physicists have anything to add on that.

People theorise about "quark matter", I think, viz. a form of degenerate matter in which neutrons lose their identity and one has just quarks. But I know nothing about this. I gather we don't know enough about the strong force to model it very well.

You mean, what would we see if the laws of physics were not what they are? Surely that would depend on what they were instead, wouldn't it?

Energy is a property of a physical system of some sort. It is not "stuff": you can't have a jug of energy. So it becomes pretty hard to see how a singularity can have energy. It would have to be a system, and that would prevent it being a singularity.

I have not altered the meaning of what you wrote in any way. Whereas your cutting the part of my sentence which actually already addresses the point you go on to make, does alter its meaning.

Do you really think nobody would notice this "resource consumption" and take steps to limit it?

My actual sentence, part of which you have snipped out of the whole, thereby altering its meaning, was : " If the foetus has the normal complement of chromosomes and the mother has no problems in the pregnancy, it would seem there are no issues for the child, once it is born. " Down's syndrome involves an extra copy of all or part of chromosome 21.

All these issues seem to relate either to chromosomal abnormalities or to the process of pregnancy itself. If the foetus has the normal complement of chromosomes and the mother has no problems in the pregnancy, it would seem there are no issues for the child, once it is born.

Well yes, sure, if it is literally zero, but equally one can say density has no physical meaning if one has a zero-sized lump of material. What I suppose I mean is it that has physical meaning if instead one considers, let us say, an arbitrarily small volume of space close to the nucleus. What I'm rather more interested in, though, as I don't have the physics to know the answer to this, and I hope you might, is whether one can legitimately speak of an s-electron passing through the nucleus. I am not sure whether any of the interactions operating in the nucleus would prohibit this. Do you know?

I'm not sure I agree. It seems to me that the concentration of a dissolved chemical substance, or the strength of a magnetic field - or indeed the density of a material - has a physical meaning, regardless of what volume one considers.

Yes, I've got Roslin's book. What you say is trivially true, if your 0.001th percentile does indeed generate waste exponentially. But that nicely illustrates how naive (a polite way of saying "wrong") it is to model just about anything on the basis of a pure exponential - a point Roslin makes repeatedly. Nothing works like that. In the case of resource consumption, it is obvious that as a resource becomes more scarce, it becomes more costly and the incentive to substitute it with something else - or to stop the activity entirely- grows. So very quickly you get a departure from exponential behaviour. In the case of fossil fuel consumption, we do not see anything like exponential growth. We are still seeing growth, true, but it is linear or plateauing. So please put aside these exponential extrapolations. They almost invariably give wrong predictions. Just about their only use is to show people what would happen if nothing were done to prevent a runaway exponential.

Isn't that just tantamount to saying that a sphere of zero radius contains zero volume, so the chance of the electron being there is zero, the non-zero probability density function notwithstanding?

Bitcoin is just the latest IT fad, followed by a handful of nerdy and greedy people. It already looks doomed, because of its absurd energy consumption, cf. the recent reverse ferret by Elon Musk (now that he has made a tidy profit, no doubt). If Bitcoin doesn't fix this, it will get shut down. By governments. Human society has lots of ways of preventing runaway exponentials. Population growth is another. All the indications are it will stabilise, because as people get more prosperous they delay having children and want to focus more attention on a small number of them. More and more countries are now worrying about ageing or even falling populations, China included. Climate change and pollution are far more pressing concerns than bloody bitcoin*. * Once memorably described by Warren Buffet as "rat poison, squared".

Ah, I may have misinterpreted what you were looking for in terms of physical significance. Let me try another angle. You may have come across the problem with the original Rutherford-Bohr model of the atom that it can't account for why a supposedly orbiting electron does not emit radiation, lose kinetic energy and fall into the nucleus. In a sense you can view the s-orbitals as the QM version of exactly that scenario. Electrons in s orbitals have zero angular momentum, so they can't be said, in any sense, to be "orbiting " the nucleus. Instead, it is as if they continually fall towards it - even through it perhaps - and come out the other side. Being QM entities (Uncertainty Principle and all that), one cannot say they follow any defined trajectory of course, but the overall sense is of being able to touch the nucleus, rather as if they fall into it. Whereas p, d, f, etc orbitals have 1,2, 3 etc units of angular momentum and, lo and behold, all have a node at the nucleus, which is more consistent with some kind of "orbiting" motion, even though again, being QM entities, they have no defined trajectory. So I'be tempted to say the physical significance of non-zero ψ at the nucleus is a reflection of the absence of orbital angular momentum.

I don't believe there are any simple exponential processes that are relevant to this issue. Almost everything proves to be self-limiting in some way, eventually. (And actually, I've never understood the Fermi paradox. It seems to me that, given that in space travel all the numbers are awful, any intelligent race of aliens would work out that embarking on interstellar travel at all is a pointless exercise, and consequently signalling to the void is equally pointless.)

To build a bit on what @swansonthas said, yes it does have profound significance in chemistry. Because the s orbital wave function has no node at the nucleus, it implies that the electron spends some of its time up close to the nucleus. This means that, in multi-electron atoms, the s electrons are exposed to the full nuclear charge more than electrons in p , d or f orbitals, which are more "shielded" from the full nuclear charge by the electrons in shells closer in. S-orbitals are said to "penetrate" the cloud of electrons surrounding the nucleus more than the others. As one goes up* the Periodic Table, the increasing nuclear charge progressively pulls in the s orbitals and lowers their energy more than it does for the others. This is the reason why the Periodic Table has the shape it does. It results in s orbitals having lower energy than p, d or f orbitals of the same shell. This even happens to such a degree in the 4th row that at potassium, the 4s has lower energy than 3d. This is why the first row of the transition elements (d block) appears after K and Ca. It is only then that the 3d has come down in energy enough to be filled, in preference to 4p. *This concept of progressively filling subshells with electrons as the nuclear charge increases from one element to the next is known as the Aufbauprinzip (= building up principle).

While everything you have said is illuminating (to me, anyway), it presupposes an already high degree of order in living things, viz. a system of heredity, mediated by codes of bases on a long molecule. So it seems to me it can't address the fundamental argument in the (creationist) claim recited in the OP. Though I suppose it does address the issue of the probabilities involved in how more complex life arises from simple life through variation (and selection), once an RNA or DNA type replication system is up and running.

The latter: https://mecadi.com/en/literature_tools/encyclopedia/categorial/Elastomer_Thermoset/Acrylic-nitrile-Butadiene-Rubber_Buna-N_NBR

That strikes me as a rather penetrating question. +1. The answer, I think, must be that for Ca++ to pinch an electron from O-- would involve it getting a lot bigger, because the electron would have to go into the next shell (4s), which is at a greater distance from the nucleus than the 3s and 3p subshells, which are already full in Ca++. As I mentioned in an earlier post, Ca++ and O-- are of similar size and can pack efficiently. A larger Ca+ ion would pack less efficiently. The larger size would push the neighbouring ions apart, reducing the strength of the ionic bonding and leading to a higher energy state overall for the crystal. In other words, it would reduce the so-called "lattice energy".

This question is too general to be answerable as it stands. There are plenty of solvents for resins of various sorts, depending on the resin. Raw linseed oil seems a rather peculiar choice in the first place.

No.