exchemist

Hmm, not sure what FAG ductwork means in a US context😳. Does this mean a ducted warm air system is common in the US, rather than hot water radiators? I think @studiot is the person with experience of transitioning to a heat pump system. I explored it a bit but was told there wasn't a big enough heat pump for a house like mine so I'd need a supplemental boiler on top, at which point I gave it up. I was also given conflicting advice about whether a heat pump could work with the existing radiators, which are designed for a gas-fired hot water system. Some said yes, but others said that heat pumps put out heat at a lower temperature (in order to stay efficient) so bigger radiators are needed. That for me would be the kiss of death as I have about 20 of them spread across 3 floors. Also I've been told the system needs to run all day, not just run on a timer for periods when the house is occupied. Everyone says heat pumps work well with underfloor heating pipes, but that is really suitable for new builds, not retrofitting to a Victorian place like mine. The steam (haha) seems to have gone out of the UK government's earlier talk of encouraging a switch to heat pumps. It may be that age of our housing stock makes it too hard to implement for many people. But for new houses it ought to be mandatory - and I think it will be in a few years' time.

Yes, electricity is typically 4 x the cost of gas in the UK. This is historically understandable, due to the far greater infrastructure needed to generate and distribute electricity and of course the fact that a lot of it is generated with an efficiency of <50% from fossil fuel. However what seems criminal nowadays is that the development of renewable generation, and the investment this necessitates in the distribution network, is all loaded onto electricity bills, while the legacy fossil fuel we are all trying to reduce dependence on incurs none of these costs. It's a political hot potato of course, as in the UK most people use gas for heating and we can't have elderly poor people freezing to death in their homes because they can't pay the gas bill. But I feel we really do need to start cross-subsidising since at the moment all the incentives are to retain the old gas boiler.

This is not about virtual particles though. It is standard undergraduate level chemical QM, involving bog-standard quantum systems, like vibrating chemical bonds or electronic states in atoms and molecules. As I said previously, although the idea of zero point energy often gets popularly associated with the energy of the vacuum, virtual particles popping in and out of existence and that weird QFT stuff, it is actually quite general to all kinds of mundane quantum system. Here's a simplified diagram of the energy well of a chemical bond between 2 atoms. The vibrational energy this system can have is restricted to certain quantised values, E₀ , E₁, E₂ etc. Notice that E₀ is not at the bottom of the well. That means there is still some kinetic energy left in the ground state - it is still vibrating a bit, in effect. You can't get that bit of energy out because it is already in the lowest allowed state. That is zero point energy, which the molecule will still have even at absolute zero. (The animation about the photon is just to point out if it doesn't have the correct energy it can't excite the vibration to the next level up. This is not important for the present discussion, it was just on the first decent diagram I found to copy.)

UK energy costs are ~6p/kWh for gas and ~25p/kWh for electricity: https://energyguide.org.uk/average-cost-gas-kwh/ https://energyguide.org.uk/average-cost-electricity-kwh-uk/ So I suppose someone in the UK with a house like mine but no gas supply could end up paying £8k/yr which would be £670/month. But that’s still nowhere near the case in the BBC article.

These videos are all crap, because of the lack of supporting explanation of what exactly we are seeing. As far as I can see from a quick internet search, there are no bioluminescent lizards. However if the lizard is being illuminated by a UV lamp, it could be fluorescing. But with no explanation, it could be anything, or just faked up for internet clickbait.

I agree with others there is something odd about these numbers. I live a large 3 storey Victorian house in London, with poor insulation. My energy costs (gas and electricity) are of the order of £2.5-3k/yr * . It seems amazing that this person spends that every 2 months. Does she live in a mansion? Or in a flimsy wooden hut in Alaska? It is also very odd that the bill is said to have tripled. What kind of energy utility can get away with tripling energy bills? It's absurd. Is this perhaps some computer error that hit the headlines and the BBC has credulously picked it up without questioning it? *~30,000kWh, of which ~28,000kWh gas and ~ 2,000 kWh electricity.

I'm not sure what you mean by "sub-quantum". The ground state is just the bottom rung of the energy ladder for every quantised system. For instance the electron in the 1s orbital of the H atom is in the ground state, with a residual kinetic and potential energy that cannot be reduced. The ground vibrational state of a diatomic molecule still has residual kinetic and potential energy that cannot be reduced. And so on. There is sometimes a misconception that ZPE applies only to the vacuum. Vacuum ZPE is indeed a somewhat mysterious feature of quantum field theory. However ZPE itself is far more general and applies to everything quantised, in principle. (Though as it happens the ground rotational state of a diatomic molecule has no zero point energy, because of how the maths works out for quantised rotation).

The point is that the energy of the ground state (the zero point energy) cannot contribute to temperature, as there is no lower state and therefore this energy can never be extracted. It is the energy that still remains AT absolute zero. Absolute zero, remember, is just the lowest temperature you can get, i.e. there is no lower temperature. Lowering the temperature of a system in which every degree of freedom was in the ground state would require extracting heat from it - which would mean getting it to a state lower in energy than the ground state - a contradiction in terms. So the residual energy of the ground state has nothing to do with why you can't get to absolute zero. That's simply a matter of not being able, in practice, to extract 100% of the extractable energy (which is the energy of states above the ground state).

Thermal shock I expect, from differential heating in the atmosphere. The skin must reach thousands of C deg, while the inside is still cold from outer space. Thanks for the explanation about how they know what to pick up.

If these are people just picking them up, one would think there must be some visible feature or something detectable by a hand-held device like a magnet. Maybe it is just the mineralogy that indicates they are "erratics".

Reports today of Venezuelan paramilitaries search for Americans. Somehow I think it will be a while before oil majors start investing. Last time round they got their assets expropriated by the Venezuelan government. I gather that happened to Exxon twice. An analyst was quoted a few days ago as saying: “Exxon and Shell are not going to invest……without physical security, legal certainty and a competitive fiscal framework”. How, I wonder, is Trump going to achieve that, just by holding a gun to Delcy Rodriguez's head? But maybe instead the idea is for some consortium, led by, let's say, ooh, I don't know, Jared "Kerchingg!" Kushner (just to pluck one name out of the air ) , to put up some funds for smaller US operators to take the risk, watch the stock price climb - and then dump the shares before it all goes tits up.

How did they determine these were meteorites? Are they iron or something?

Yes. Though often I think the effect of a drug is found before the mechanism is established. So it is not a clean process of looking for the molecule to alter and then making a drug to do so. Certainly with older drugs like aspirin, the effect was known long before the biochemistry by which it works was understood. But the essential point is that biochemical molecules in the body often do several different things, so affecting them can have more than one consequence. Or else, as with @TheVat 's example of chemotherapy for cancer, the aim is to disrupt the process of cell division which is very fast and out of control in cancer. So it disproportionately disrupts the growth of the cancer cells, but with the side effect that it also disrupts the cells that are dividing normally and generally makes the patient feel ill. Basically the patient is being poisoned, but with a poison that hurts the cancer cells worse than everything else. So you give a course of treatment, during which patient feels iller and iller from the side effects - and then have a pause to allow the normal cells to recover from the attack, before repeating the process. It can be pretty exhausting for the patient but, you hope, it kills off the tumour(s).

I'm not sure a science forum is the best place to ask what idiots think. Why not ask them, if you are curious? I feel sure the USA has masses of social media channels where such idiots hold the stage. But no doubt there are loads of different garbled reasons and each idiot will seize on the one that appeals to his particular preoccupations and/or his particular reason for hating experts. (I think it rather unlikely many of them will be able to talk about the actual mechanism by which mRNA vaccines work, as you are doing.)

But there is nothing extreme about heat death. It's just about temperature evening out. So mild conditions, well within the scope of current theory. In fact, it is their very mildness that removes all capacity for dynamic change.

I can't immediately see why quantum mechanics would cease to apply in a heat death scenario.

Here is an example: aspirin: https://en.wikipedia.org/wiki/Mechanism_of_action_of_aspirin If you read that, you will see that it inhibits the production of things called prostaglandins, which have more than one role in the body, two of them being a role in the body’s inflammatory response and a role in blood clotting. So if you take aspirin for inflammation, you will also bleed more if a blood vessel is broken. That’s a side effect, especially gastro-intestinal bleeding , which can be an issue if you take a lot of aspirin. However that also means aspirin can be used to prevent unwanted blood clotting, e.g. in heart attacks. This is typical of the way many drugs work. They alter something in the biochemistry of the body, which gives one desired effect, but often they have other consequences as well, which may or may not be a problem depending on what is and also on the condition of the patient.

At absolute zero there is still energy in the ground states of many quantum mechanical systems. Some of this energy is kinetic energy, so one could say it is associated with “motion”. However, as @swansont points out, you can’t define a path along which these QM entities move, so it is not motion in the classical sense. This residual energy of the ground state does not contribute to temperature, which is why it is called “zero point energy”.

That's very kind of you. I think, though, you will find that a large part of the reason many of us post on these forums is for the pleasure of spreading knowledge of science - and learning from one another, in the areas where are not expert, or have simply forgotten. So people like you are pushing at an open door. (It's the people who come with a fixed agenda and don't listen that are the annoying ones.😄)

I presume the latter point is that the droplets evaporate, leaving a tiny dry nucleus of virus particles, which can drift in the air more easily. There is also, at least in climates like that of the UK, the issue of less sunlight in winter months (shorter days, more cloud cover) which reduces the sterilising effect of UV sunlight. I think we all became far more aware of these factors during the Covid pandemic. Certainly I knew nothing of the reasons until then. As for A/C, my experience in Dubai in the 1980s was that people caught colds in summer, presumably as a result of having all the windows shut and breathing recirculated air. There was also a theory about the shock to the body of moving between an external temperature of 40C with 95% humidity and a low humidity indoor temperature of <20C. But I have never seen that substantiated.

Yes quite right, being in a hurry I chose my words clumsily. What I had in mind is that the sine wave repeats its wave pattern indefinitely, whereas the Gaussian is just the one bump.

The Financial Times is in no doubt that we are in the midst of a stock market bubble, largely based around AI and crapto. I gather 35% of US stock value is now in AI tech companies - with no profitability in sight. It's a question of when, not whether, it bursts and what happens then. Nobody thinks it would usher in a new Great Depression, but a lot of people will get burnt. It's like those cartoons in which you run off a cliff and are fine until you look down. Some people are trying hard not to look down ,but soon one of them will.

The curve is the Normal Distribution or Gaussian. You can find various version of the equation for this here: https://en.wikipedia.org/wiki/Normal_distribution It is not a sine wave though, which is the shape of a simple wave, as is evident by the fact that it does not continue indefinitely, like the graph of Sin x. I am not aware of an opposite, but I’m not a mathematician. It has been Christmas. People have had other things to do than answer queries on internet forums. I have spent the day taking the decorations off the Christmas tree, getting it outside for collection with the help of my son (it is a 9ft tree) and making a galette des Rois, which is the French tradition at Epiphany (today). That will conclude the festivities for another season. To your question, infra red photons are just about everywhere, as they are emitted by bodies above absolute zero. Being infra red, they are not visible and so might be described as “dark”. Photons are not a medium. They are disturbances in a sort of immaterial medium, the medium being the electromagnetic field.

One of my brothers emailed me today with a Star Trek clip from “The Squire of Gothos” episode. Trump at times reminds one of an overgrown child, playing with adult things. There’s a bit of a “Come along now, Junior” feeling about his antics. Just wish I could wake up from the nightmare. Apparently Trump thinks there are “Islamic radicals” in Venezuela. https://www.theguardian.com/world/2026/jan/04/venezuela-trump-rubio-republicans Really?

Now that is really interesting. Have Trump's henchmen done their homework, one wonders. Actually, almost certainly not, given the low calibre of these goons. It would be funny if she rises to the occasion, tells them to get stuffed and mobilises the country to boot the Americans out. The parallel with Ukraine would be just about perfect.