exchemist

It seems you don't have anything to discuss on the forum at the moment, then. See you around, perhaps.

Where have you addressed the thermodynamic objection to the existence of these hypothetical things.

This seems to be due to the media being almost entirely owned by business corporations, who at the end of the day have no guiding star other than making money.

It would in my view be pointless. There is no issue I can think of where the people of the world would be well enough informed to make a good decision. The essence of representative democracy is to choose governments and legislators that people trust to make those decisions for them, having first informed themselves on the issues in question. “Do you want to live in a peaceful world or not?” Is a fairly empty question, unless accompanied by a lot of context.

I’m not sure what you mean by “debate” here. Do you mean attack? Or challenge? That would make sense from the context, but it’s not how I understand the term. Surely one debates a proposition of some kind. What would the proposition be here?

I was interested to learn of the protective, UV-absorbing properties of dissolved iron in the oceans before the Great Oxygenation Event. Fe II salts being more soluble than Fe III (less liable to precipitate as hydroxides) would have provided some protection in the photosynthetic zone. It also seems modern cyanobacteria contain scytonemin https://en.wikipedia.org/wiki/Scytonemin which acts as a UV-absorbing pigment. The evolution of this fairly early on would have helped. There were a couple of threads on this some months ago, I think, if you are interested. One on lichens, if I remember right.

Yes this is a science forum and what you have written here is meaningless nonsense, not science or anything remotely like it. I suggest you may be better off finding somewhere else for your effusions. You won’t last long here at this rate.

It doesn’t quack. These are heterocyclic compounds containing nitrogen, thought to be formed inorganically in deep space on cold bodies containing carbon and ammonia. They are not evidence of life elsewhere.

Oh I agree it seems most improbable that our planet is the only one in the cosmos with life. However there have been no signs of life in meteorites, so far as I am aware. There been signs of certain building blocks of our biochemistry (precursors of nucleotide bases) which could explain how they came to be available on earth, but that’s about it, at least according to what I have read.

I grew up eating meat and still do, but the vegetarian dishes I like are not fake meat, they are dishes in their own right, from a proper culinary tradition. Things like cheese soufflé, mushroom or cauliflower risotto, dhal of various kinds, grilled Mediterranean vegetables, caponata, lentil and vegetable soup, pasta with broccoli or fried courgettes, and so on. I suspect eating a meat substitute just makes one pine for the real thing, rather than being a satisfying alternative. But if my son’s girlfriend sticks around, I’ll be doing more of this, so I’ll see how I get on. One slight issue is that cheese becomes more important, and many of the AOP cheeses in Europe have to be made with animal rennet rather the synthetic version. It’s a bit silly, as chemically it is the same, but the traditionalists won’t allow it. One can get a synthetic rennet “parmesan” (thank God) but can’t call it that. There is one stilton (Colston Basset) that uses it and some quite good modern artisanal English cheeses like Wigmore, but the gold standard French and Italian ones all still need animal rennet to qualify as the real thing. I’m on a learning curve with all this, thanks to this rather strict but otherwise sweet Scottish lass my son has teamed up with.

Yes I’ve always thought it silly to produce fake meat instead of using the whole cuisines out there that are based on vegetables, such as Indian and much of Italian (delicious aubergine ravioli last night, here in Syracuse). Vegetarianism is certainly growing among the Gen Zs like my son and his girlfriend, and they don’t go in for fake meat.

Not according to the report I previously read about it in the Guardian. As @swansont points out there may be a bit of journalistic exaggeration of what NASA is actually claiming though, so perhaps I’m being unfair.

I’m getting a bit cynical about NASA’s claims over this. Inorganic processes could be responsible for what they’ve found. But they need the interest to keep the funding.

???

I'll look out for them. Ortygia, Agrigento, Piazza Armerina, and maybe Selinunte, will be on the list. (My son read Ancient History so these places will be of interest to him.)

Yes Archimedes lived in Syracuse. (Where I shall be in fact, 24hrs from now, for 5 days holiday with my son.) Re N Hemisphere ice loss, could it be something to do with the transport of warm water in the Gulf Stream/N. Atlantic Drift?

Good morning Mr President. So you did send Epstein a birthday greeting, with your signature serving as the pubic hair on a woman's torso. How witty and tasteful of you!

Yes, more or less what I was also trying to say. Like you, I'm chary of the word "random" in this context. It's more a matter of dispersion (of energy), I think.

I don't know how this NCERT material is compiled, but I suspect it will be by various authors contributing different sections on a pro bono basis. What may happen, I imagine, is an author may not know exactly what has been taught elsewhere in other modules and hence what level of knowledge to assume in the student. That might explain this rather ham-fisted attempt to teach integral calculus, sitting in the middle of a piece of physics. It does make it hard for @HbWhi5F , so I sympathise with his or her difficulties with some of this. I don't think these questions are homework, by the way. They read to me like attempts by a student to understand the (not always clearly explained) text.

Yes I quite like your analogy, though I think it needs a fair bit of explanation for our 6th form scholar. Entropy, or rather entropy change, which is what we are talking about in this instance, is notoriously tricky to visualise at the molecular level. Your point, I presume, is that the increase in "diversity", when heat is to supplied to molecules that are mostly initially in the ground state, is greater than if they are already busy cascading among numerous thermally excited states before the extra heat is added.

There is only one now as experienced from our frame of reference, since we are unable to occupy the frame of reference of anywhere else. Speaking about “now” in relation to astronomically distant objects is a fairly useless exercise, as there is no way to experience it. And if they happen to move at relativistic speeds, relative to us, it gets worse because their clocks as seen by us run slow.

Sure. What is your problem?

I'm not sure why you think it is saying it takes more energy when done in finite steps. I don't think the text is saying that. What is giving you that impression? This whole business about finite steps is because when you compress the gas in the cylinder, the pressure goes up. It is to show you that you can't just multiply the pressure at the start by the volume change, or you will get the wrong answer for the work done (too low). The pressure is a function of volume, i.e. p is p(V). So as I said before you need to calculate this as an integral: W = - ∫p(V) dV. If you have studied calculus, you will know that integration is the limiting case of adding up a number of steps, each with a different value of the quantity. (Again as I said previously, I personally think it is mistake on the part of the writer of this text to try to teach integral calculus as a sidebar to a discussion of the gas laws. It's just confusing - and, lo and behold, you have got confused! Some simple calculus is something you need to know to do physics at this level anyway.) But luckily for us chemists, a lot of the time we only need to consider PV work in the context of lab experiments done under ambient atmospheric pressure. Under these conditions the volume changes during a chemical reaction occur under constant pressure, so we can calculate PV work, e.g. to work out enthalpy changes, just on the basis of volume change, without needing to do an integration, i.e. we can say ΔH = ΔU + PΔV. (That would not be true if we were reacting gases, in a vacuum line or something.)

It's not to do with the speed at which heat is supplied though. There is no time dependence in dQ(rev)/T= dS. So I would say it is closer to 1 than 2. Transferring heat at a lower temperature results in it being distributed in more different ways within the substance.

Ah, thanks, so this is the Indian government school material that goes up to class 12 in the final year of secondary education. So you are in your penultimate year of secondary school then. That is useful background to your series of questions.