exchemist

Hmph. I don't trust anything emanating from Greenpeace. I know for a fact that they are happy to misrepresent the truth for publicity purposes cf. Brent Spar. They are also one of the prime actors seeking to blame the fossil fuel industry for our carbon-intensive lifestyle, a deeply hypocritical exercise in blame shifting to a suitable "other" we can settle back and safely hate, as we carry on driving our petrol cars, heating our homes with gas and whining about the price of "gasoline". Oil and gas companies are willing to do CCS because they know how to do it and have the depleted reservoirs to hand. Secondary extraction is not intrinsic to the economics. But it is not cheap, that's true enough. When I was at Shell we had a pilot project to do this for the UK government about 20years ago, but they pulled out after we had spent $1m on it. No secondary recovery featured in that. It's not greenwashing, it is real and it might help to bridge the gap during the technology transition. However I would always be worried that CO2 buried in this way might somehow find its way back to the surface over time, so I wouldn't want to see it become a major component of the moves to carbon neutrality.

Hmm, interesting to look at it this way. A cargo ship may burn of the order of 50mt/day of RFO, 85% of which is carbon. So roughly speaking it will produce 150mt/day CO2, generating over 300mt/day of limestone! There's going to have to be an awful lot of both quicklime and limestone on this ship for a voyage from Singapore to Antwerp.

https://www.theguardian.com/environment/2025/jun/26/global-shipping-emissions-invention-clean-up-cargo-fleets-net-zero The idea here is to use quicklime (Calcium oxide, CaO) to absorb CO2 from the exhaust of ship engines, generating calcium carbonate (CaCO3, limestone, chalk etc). And they speak of using renewable energy to power the kilns that generate the quicklime. But, er, the kilns generate CaO by driving off CO2 from calcium carbonate. So all you've done with this proposed technology is move your CO2 from the ship to the shore; you still now need to dispose of it, somehow. I don't see in the article where this issue is addressed. Does anyone know more about this? Is this idea designed to work in conjunction with CCS, perhaps, i.e. disposing of the CO2 in depleted oil and gas fields? If so I suppose it could have a role as a bridging technology, before shipping is converted to ammonia or something. But then CCS is yet to prove itself, so a number of imponderables here.

Yes I think you and Degrasse Tyson raise a good point. All this "simulation" talk we seem to get does look to me very much like a fad caused by the new domination of our lives by IT-based products and services. Speaking as someone who never saw "The Matrix" and who has no social media presence (apart from 2 science forums), I have never understood what the fuss is about or seen any point in it.

According to this: https://en.wikipedia.org/wiki/Humanzee. there have been reports, at various points, of attempts to produce a human-chimpanzee hybrid. However none of them seems to have ever been confirmed. So its does not look to me as if there is any evidence of whether or not such a hybrid would be viable. Obviously the ethical issues involved would preclude such attempts in any civilised society. And the notion of "using" a human being with Down's Syndrome to try it is especially repugnant, as well as having no scientific foundation that I can see. People with Down's Syndrome have an extra copy of chromosome 21. This does not make their genetic make-up more like that of a chimpanzee: in fact rather the contrary, as it is fusion of the apes' chromosomes 12 and 13 that leads to the reduced number in humans, nothing to do with no. 21. So I should have thought having an extra no. 21 would make a person more dissimilar to a chimp, not more like one.

What I’m getting at is you can’t have an orbit at a latitude of, say, 40 deg North of the equator. It would have to be one that went from 40deg N to 40deg S and back in the course of one revolution. That’s because every orbit has to be centred on the centre of the Earth, at that is what gravity pulls towards. So if you had one like that and another that was equatorial, they would intersect at 2 points per revolution. So they would have to be at different altitudes to avoid colliding.

OK I see. I think the difficulty with putting dust into an Earth orbit will be that you could only put the dust into one narrow band, e.g. around the equator, since to cover different latitudes would need a series of different orbital paths that would clash, unless you had a complex system with different orbits at different altitudes. I'm not sure what orbital dynamics would do to an orbiting dust cloud. One might think that small differences in speed of individual particles would eventually make it unstable, but this is not my field so I don't know if this would actually be a problem.

I’m not quite clear whether you are proposing to introduce graphene powder into the upper atmosphere or into space. If the former it won’t stay there, due to atmospheric mixing and eventual precipitation. If the latter, i.e. into space, you would need to establish an orbiting dust cloud in effect, surrounding the sun, at some radius from it. That would need a lot of powder, it seems to me, and a lot of energy to give the dust the right orbital speed.

As the Financial Times observed in a piece by their Washington correspondent, Trump is, for all his macho bluster, in fact just following Netanyahu's game plan. It was Netanyahu who blew up Trump's Iran diplomacy and Netanyahu who talked him into a strike with the bunker buster bombs. Netanyahu is in the driving seat here.

They have always been rational actors, as far as I can see. It seems to me all this "existential threat" stuff is just part of the relentless diet of Islamophobia fed to the US public by the Israel Lobby (of which this "Middle East Forum", referred to in the OP, is a part.).

What mathematicians do you have in mind?

Which is to say in places where the roads remain at the service of the people, rather than being the exclusive preserve of motor vehicles.

Hmm, I have little time for Nagel on the issue of consciousness, I'm afraid. I'm with Massimo Pigliucci: https://philosophynow.org/issues/99/What_Hard_Problem And I do not see that there is huge problem to solve with QM. But then, my training is in natural science. QM is a model that works extraordinarily well. It has never been faulted in its predictions. I find it preposterous to build an interpretation of QM that elevates the activity of the conscious brain to some mystical entity, able to affect how nature works. (As a chemist, I am used to distinguishing between "reality" and the models of reality we use in science to predict how nature will behave. In chemistry we quite commonly have more than one model for a given scenario and choose the one appropriate to the task, without troubling ourselves unduly about what is "really" going on. That's because chemistry is complex and messy, so if we got hung up on such pedantry we would never accomplish anything. We use QM all the time in chemistry and it works just fine. I suppose what I'm saying amounts to a "shut up and calculate" approach to the question. 🙂 )

"The Confessions of Felix Krull, Confidence Man", Thomas Mann. Surprisingly funny in places. Also quite modern in its matter-of-fact portrayal of the voile et vapeur sexuality of the protagonist.

I read recently that one of the difficulties cited by US developers of robocars, when implementing them in the UK, is that the number of "jaywalkers" is said to be 7 times as high as in the USA. What these nerds don't seem to have clocked yet is that there is no such thing as "jaywalking" in the UK. Pedestrians are allowed to cross the street anywhere, at any time - and do. They should get their technology fit for London, Manchester or Glasgow and then it will work in Austin, TX.

What evidence do you have that "the sites were empty"? It's not easy to just move a nuclear fuel enrichment facility.

Rovelli would say we have to give up the implicit assumption that entities have a concrete existence in between interactions. They have potential existence only, described by the wave function, until the next interaction makes them concrete once more.

You raise an interesting point with the cost angle. It could be that a decision to reconstitute the nuclear programme, with the concomitant economic sacrifices demanded of Iran's people, might cause the downfall of the hardliners among the Serious Beards. This unprovoked attack will strengthen, not weaken, national unity, but the strategy they adopt in response could be a trickier path for them to navigate. However the notion of "regime change", referred to by Netanyahu, strikes me as pretty delusional - and probably is not meant seriously. Iran is a medium-sized industrial power of 90m people with an entire constitutional system. It's not just some one-man dictatorship, or S. American style military junta.

Interesting. I looked up Henry Stapp, of whom I had never heard. He seems to be an eccentric whose ideas about wave function collapse are dismissed by mainstream interpretations: https://en.wikipedia.org/wiki/Consciousness_causes_collapse. He further seems to embrace Cartesian duality, treating "the mind" as an entity distinct from the brain, or indeed the physical world more generally. This a very dubious notion. While not exactly woo, it seems to be indeed a mystical view, perhaps like some of Wigner's early ideas, which he later repudiated. I don't think you will get much support for ideas based on consciousness in the science community. Personally, I am attracted by Rovelli's relational interpretation of QM, in which there is no one wave function for a system, but one that depends on the informational "frame of reference", as it were, for the observer. Thus, for instance, Schrödinger's Cat is both alive and dead to the world outside the box , with a wave function that describes that condition, but to the world inside the box the cat is definitely one or the other, with a wave function appropriate to whichever definite state applies.

This, again, is an extraordinarily stupid argument. Utter waste of time even to engage with it.

Tragic for the scientists, but frankly I struggle to sympathise with Israel about this.

Actually I think the HUP is a different issue from the wave function collapse one. The former is to do with pairs of conjugate variables being Fourier transforms of each other, whereas wave function collapse is the replacement of probability ranges of potential values of properties being replaced by actual ones when an interaction occurs. My understanding is HUP relates to simultaneous definition of pairs of properties, whereas collapse may pertain to a single property alone.

Perhaps you should ask the forum admin whether there is a time limit on the posting history that is stored. (I joined after 2011 so I can't check it using my own posting history, I'm afraid.)

Yet your idea seems - to me at least - to be based on a misunderstanding about the role, or rather the lack of it, of the conscious observer in QM. I outlined this earlier, and you have yet to respond on this point. It would appear fairly crucial to resolve.

This is too stupid to argue with.