exchemist

The Beer-Lambert law seems to have been formulated in 1913. Apart from that I can't think of any c.20th "laws", offhand. I'm speculating, but I suspect the notion of "laws" went out of fashion along with the "classical" absolute and deterministic worldview of science, which Einstein, Heisenberg et al threw out of the window in the first two decades of the c.20th. Most "laws" seem to be named after the person that formulated them - and to be broken in practice.

I thought this happened over a week ago and the police had closed the case. Later note: I'm wrong it was over a month ago. And nothing was found:https://www.latimes.com/california/story/2023-06-09/las-vegas-police-investigate-reports-of-alien-sightings Can you provide a reference to the claim of a large round depression?

And the police found what, exactly, when they investigated?

Time dilation? The observed increase in half life of unstable particles, at velocities relative to the observer that are a significant fraction of the speed of light. Atmospheric muons are one well-known instance. Regarding mass, the best example is probably the observed mass defect in nuclear fission, which is accounted for by E=mc². "Mass increase" is, so I understand, not a concept used that much nowadays, since mass is generally taken nowadays to mean rest mass, which does not increase. One tends instead to use the full formula, E² = (mc²)² + (pc)², in which there is a momentum term (p). Length contraction is harder, admittedly. I struggle to think of a good example, save in the sense that, when time dilation is observed, one must have a corresponding length contraction from the viewpoint of the other reference frame. Perhaps one of the physicists here can come up with a more direct example. None of this is a matter of "faith". The observations are the observations. If you consider SR is wrong, it is up to you to show what better, i.e. correct in your view, explanation can successfully account for the observations.

Because relativity works, so your supposed logical objections, however clever you imagine them to be, are beside the point. All this sound and fury about the logic behind it, faulty or not, is so much wasted breath if the theory accurately predicts what we should be able to observe. And it does. Many theories in science have arisen from conjectures or faulty reasoning. For instance Sadi Carnot's insights into thermodynamics, which we use to this day, were based on the supposed flow of a heat-transmitting substance called "caloric", which was later shown to be non-existent. But the laws of thermodynamics work. So we use them. Obsessing about supposed logical defects of a theory is irrelevant compared to the true test of a theory, which is via observation. I asked you a while back on this thread if you had an alternative model that also accounts for these observations. There has been no response.

The critical point for CO2 seems to be at ~30C and at a pressure of ~74bar. So you will not have any liquid above that temperature. At 20C, say, the minimum pressure to keep it liquid is about 65bar. Phase diagram here: https://www.engineeringtoolbox.com/CO2-carbon-dioxide-properties-d_2017.html#phases So I suppose if you are supplied with a "liquid CO2" cylinder, it must have a pressure when full of 70bar or so. But it won't take much of a drop in pressure before what you have is a gas, at which point the degree to which the smaller cylinder is "filled" will just be a function of the total volume of both cylinders, when you equalise the pressure between the two. At least, that's how I read the phase diagram.

How is it, then, that observation (e.g. the operation of particle accelerators, the mass defect in nuclear physics, atmospheric muon lifetimes, and things like that) are in agreement with SR? After all, in science it is observation that is the test of a hypothesis. Do you have an alternative model that correctly accounts for the observations? P.S. You're not an electrical engineer by any chance, are you? Something about you is a bit familiar.

The brightness of the cloud obscuring the sun will be generally greater than that of the sky or blue-coloured objects, so most of the light falling on the paper will still be white, even if there is a cloud preventing direct sunlight from reaching it. Consider: you can gaze at a blue sky far from the sun without discomfort, whereas looking at a cloud in front of the sun often involves screwing up your eyes. I suppose that, if the cloud were very dark (which it would never actually be in an otherwise blue sky, but never mind) then most of the light reaching the paper would be blue and it would consequently appear blueish.

Our local dump ( in London) has a separate section for electrical items. But I don’t know where they send it.

Can you summarise this error?

Yes, that article mentions that an overpotential is needed, which increases the degree of ionisation from its equilibrium value, thus speeding up the electrolysis.

On the contrary, I think we should be looking at both approaches. They should not be seen as mutually exclusive alternatives. It seems to me we need all the help we can get, from any method that proves viable. Since the transition from fossil fuel will take at least a couple of decades to complete, we ought to pay some attention to what happens to the CO2 that the legacy uses will be producing over that time. But this particular idea is not intended for that and would almost certainly not be suitable.

Yeah, it’s not for making a breathable atmosphere though, it’s as oxidiser for rocket fuel for the return journey. But in any case you can capture the oxygen separately at the anode and release the CO to the Martian atmosphere at the cathode.

This is rather clever. It relies on certain metal oxides acting as conductors for oxide (O²⁻) ions in the solid state at high temperature. At 800C, CO2 is reduced at a porous, nickel-based cathode, to CO and O²⁻, the ions travelling, by means of ion vacancies in doped zirconium oxide, to the anode, where they give up 2 electrons and combine into O2. Details here: https://en.wikipedia.org/wiki/Mars_Oxygen_ISRU_Experiment Neat, but indeed requires electrical energy to accomplish and generates carbon monoxide. As @John Cuthber points out, that would have to be disproportionated into C and CO2 in a further step, before it could be applied terrestrially. There are probably easier ways to convert CO2 to solids here on Earth, most of them biological and making use of sunlight rather than electricity.

Because those are the common forms of radiation emitted in radioactive decay. So they were the first to be given names, before it was even known that only gamma rays are actually EM radiation, the others being particles.

Well actually I think that’s a bit of a non-story. All it says is we don’t have recycling capacity yet. But that’s to be expected, since the panels installed over the last decade won’t need replacing for another 15 years. Nobody is going to invest in a plant that will sit idle for years.

I can’t see offhand why someone couldn’t make an engine with such a cycle for demonstration purposes, though like you I can’t find any examples of it having been done. It does seem, though, that such an engine would probably work rather slowly and so might not be a very practical source of mechanical work. One would need insulating shutters to alternately expose and shut off the working fluid from hot and cold sinks (assuming a cylinder whose walls had negligible heat capacity) and then let pseudo-adiabatic expansion and compression occur in between. Or something. You’d have thought some enterprising soul at Imperial College or MIT - or perhaps at one of the Grandes Ecoles in Paris - might have given it a go.

I didn't watch it all. The guy's accent is so strong it's a real challenge to understand him. What do you think he is proposing, then? A rule of thumb is it's the amps that kill you not the volts. A battery sounds dangerous to me as it can store a lot of charge, i.e. can supply a lot of amps in a short space of time. A van der Graaf generator on the other hand supplies a high voltage but only stores a tiny amount of charge.

At the risk of being thought racist, I would NOT trust a video from the Indian subcontinent showing somebody putting a screwdriver into an electric socket. When I was in Dubai we were constantly stopping people from that part of the world from doing dangerous things with electricity. Their safety culture around it seemed non-existent. You can safely send sparks between people if you have a van de Graaf generator, but don’t even think of doing anything involving mains electricity.

Many Englishmen get through a litre or more of tea each day, of course. But not in one go.

And in fact at that temperature it makes bugger all difference whether you use C or K.

What you calculate is the integral. Have you looked at the example I gave you a link for? That shows you how you do the calculation.

I find the graphical representation of this the most helpful in understanding it. If you plot f(x) against x as a curve, f(x)dx - i.e. f(x) times the infinitesimal length dx along the x axis - is an infinitesimally thin vertical strip of area under the curve at the value x. If you add up a series of such strips you get a block of area under the curve. That is what integration does: it gives you the area under the curve representing the function, between two points on the x axis. The integral sign, ∫ , indicates a sum of these infinitely thin strips, adding up to a finite value for the area. Here is one example: https://www.bbc.co.uk/bitesize/guides/zq3ggk7/revision/1 This basic idea spins off into a host of applications, all over natural science and engineering.

Wouldn’t such a drive mean the laws of physics can change with time, though? In which case Noether’s theorem would not apply any more.

No it isn't. N14 can react with a neutron to generate C14 plus a proton. That is how C14 is generated in the atmosphere from the effect of cosmic rays. So your bomb is going to convert nitrogen into carbon, which will probably eventually form CO2 with some of the oxygen in the air. So it seems to me that - aside from all the other issues with this preposterous idea - your bomb is going to increase the CO2 in the atmosphere rather than decrease it.