exchemist

That’s something I never knew.

Those were both dark chocolate products, though, weren’t they?

Butyric acid smells like vomit. Why anyone would add that to chocolate beats me.

There is quite a bit of good British food in fact, but we still live with the hangover of our postwar austerity, which for decades caused us to lose faith and fail to do justice to it. These days you can eat better in London than in many capital cities. But it’s true that provincial standards of cooking are rather uneven, shall we say. You are dead right about British industrial milk chocolate, though. Most Continentals wouldn’t consider it chocolate at all, adulterated as it is by non cocoa fats etc. I believe Cadbury’s Dairy Milk no longer qualifies at chocolate under EU rules - not enough cocoa-derived content.

Ha. I have a niece who has just moved to Tobermory, from Tiree. I have not visited since the move.

I love the fact it was discovered in a plastic recycling plant in Japan, having apparently evolved there. One in the eye for the creationists! Maybe that's what we need to do more of: search carefully in polluted environments to see what handy microbes may have developed to make use of our junk. Microscopic wombles, in fact.

OK, I see Cornelius went through a number of instars, migrating from aviation compressors to refrigeration equipment and thence to food handling. So out of the serious compressor business for several decades by the look of it. Now part of Marmon Food Service Technology (owned by Berkshire Hathaway). However I see there are still some of these ex B52 compressors for sale on EBay as military surplus. Other people also seem to use them for SCUBA by the look of it. (I'd be a bit nervous about using them for breathing air quality applications myself, but that's another story.) But none of this helps you, I realise.

Yes, for posting what they considered pseudoscience. At least here nobody has accused you of that.

Are there bugs that digest microplastics?

Yeah I think a lot of this is hype. They still don't have a way to make a commercial quantum computer and the technical problems are formidable.

I presume the advantage is that if these materials escape containment they do less damage. In normal use, capturing microplastics etc, I imagine the precipitated flocculant must be extracted and incinerated or something, to destroy said microplastics.

Just out of interest, what is the make and model?

But it was you that got banned from the astronomy forum, was it not? Perhaps a bit of self-reflection?............just a thought...........

Recreating sub-assemblies, or simulated similar sub-assemblies, is certainly one method of discovery and is in fact done, for instance in the case of bi-lipid membranes: https://en.wikipedia.org/wiki/Model_lipid_bilayer But that is far from recreating a living organism synthetically, of course. You clearly understand a fair bit about the biochemical components of life, so I am not sure why you then descend into wild-arsed-guesses (WAGs) involving QM and relativity. This is what is known as "quantum woo". It is not science and is frankly painful to read for anyone who understands science. There is no reason whatsoever to think life somehow magically bridges the gap between QM and relativity. That gap in theory is a question of fundamental physics. The biochemistry of life does not suggest any fundamental gap in theory. Relativity in particular is quite irrelevant to living organisms. (Quantum theory of course is relevant, as it is the basis of all chemistry, so there's nothing new in that.) Please drop the crap about hidden dimensions. This is more woo and has nothing to contribute to a study of the mechanisms of life. Abiogenesis is a uniquely complex problem to solve, no doubt of it, but that does not mean it requires new physics or woolly mathematical speculations. Existing physics, chemistry and biology seem able to handle the issues involved perfectly satisfactorily. Boring though it may seem, it just requires a lot of patient work, using existing science. Great strides are being made all the time, but it is a long road.

At least with wine you can just have the one glass which, even with jet lag, shouldn't do much damage. Spirits, or worse, a session in a bar, would be pretty ghastly though. I got into the habit of indicating before the trip that, if we were all going out one evening, could we please do that after the visitors from London had a couple of days to adjust, if there was a time difference.

Ah yes, I know UK universities often host conferences, usually in the summer when the students are away, to get some value out of the unoccupied facilities. The accommodation can be a bit spartan, but it’s a good idea.

My son graduated from there this summer. What took you to St. Andrews?

I hardly drink Scotch these days but one of my favourites is Bowmore: an Islay malt, peaty enough to remind me of climbing the munros, but not in-your-face phenolic like Laphroaig.

Er yes, probably. One suspects they banned you because they felt you were not talking good science.

Reset? What do you mean by that?

Do you really think posting this adds to your credibility?

I'm not a cosmologist but I should have thought the temperature of the black body radiation from the Surface of Last Scattering could be worked out from the CMBR and the degree of cosmological redshift since then.

Also Norway. I recall being given a bottle by a group of Norwegian shipping line customers to whom I gave a tour of our oil blending plant when I was production manager there. The problem for me was that possession of alcohol on a refinery site was a matter of instant dismissal. They should never have been allowed in with it. I decided not to make a scene, accepted the gift courteously and - and got it off site pronto in my car when I drove home. This was what the Norwegian called Linie (pronounced like "linear") Aquavit, meaning it has gone round the world by ship to mature, crossing the equator, i.e. the line. So that's why a shipping line would give it as a gift. But I think this is a lot closer to vodka than to whisky (or even whiskey). Certainly the taste was, um, not that great.

Yes that's very familiar, but the interesting thing to a chemist is the deep connection between refractive index and the absorption and emission of EM radiation, through the polarisability of the medium and how close the light frequency is to an absorption band. For instance my understanding is that the reason why blue light is bent more than red in glass is because there is an absorption in the UV, so blue light experiences more refraction than red, as it is closer to the resonant frequency at which real absorption will occur. From this point of view it is a bit unsatisfactory to stick entirely to a classical picture, as absorption is quintessentially a quantum phenomenon. I suppose one could envisage a fleeting pseudo-absorption followed by almost instant stimulated pseudo-emission. That would avoid the scattering issue that would arise if true absorption were to occur, as then spontaneous emission in random directions would be expected, as @KJW points out. So one would picture photons progressing at c, but in stop-start fashion, through the medium. In the trampoline analogy, you put your foot down and the surface gives, preventing forward motion, but then it rebounds, giving your input energy back and sending you on your way after a brief delay. (I realise such analogies can't be pushed too far, but it is handy to be able explain the phenomenon is a way that gives non-experts some idea of the process.)

Yes this expresses how I like to think of it. I have sometimes used the analogy of running on a trampoline, whereby you put energy into undulation of the surface, lending it energy and getting it back a bit later, but the net effect being that it makes it slower to run. This type of wave-based explanation accounts for the reduced phase velocity. However, while it avoids claiming there is actual absorption and re-emission (and thus the scattering problem), what I struggle with is how to show this is consistent with the speed of photons under these conditions still being c. I am aware that (again in wave terms) the group velocity and the signal velocity will differ from the phase velocity in a polarisable medium, but I have yet to see any source claim that either of these corresponds to the velocity of the photons, or that either of these velocities remains equal to c within the medium. How would you describe how it is that photons still travel at c in a polarisable medium, in spite of all this going on?