sethoflagos

... so some say. I'm in no position to defend the concept at a deep technical level, however, others are and do so. Admitting the advanced wave solutions seems to offer neat solutions to some otherwise seemingly intractable phenomena such as EPR. Perhaps more pertinently, the apparent and 'unlikely' flatness of our universe just shouts 'negative feedback - asymptotic approach' to me. Okay, that sense implies some sort of retrocausal effect. It's a tough call, but I'd sooner trust to Feynman's gut feel than the dim designer of the OT.

Perhaps in the sense that the time evolution of the universe is 'just' thermodynamics. However, it's apparent preference for universes similar to ours, amenable to the evolution of life without appeal to either the anthropic principle or a 'creator', seems a valid enough point.

As I understand it (I may not), Feynman-Wheeler absorber theory postulates that every emitter is coupled to a future absorber. If this is the case, then it introduces an interesting aspect to the teleological argument: that there exists in the (possibly far distant) future, sufficient, and sufficiently diverse structures to provide all necessary absorbers. This suggests that the past is influenced by the consequences of its state and dynamics on its future evolution.

Just a poorly worded afterthought. I intended to say that in the absence of a ram pump or equivalent, the only driving force to hand is the velocity head of the source. On the other hand a ram pump could use a waste flow head drop of a metre, say, to generate surge pulses of up to 15 bar or so albeit for a much lower flowrate.

Yes, I'm well aware of how ram pumps work. But there was no ram pump in the system described, and therefore no means of channeling the input kinetic energy preferentially into the vertical output stream.

The 'logic' seems to be that running water out of a sealed header tank creates a partial vacuum (true so far) that can be used to suck up water from a lower elevation than the discharge. Seconded. Just another PM dream. As for the ram pump idea, if the incoming velocity head was higher than the required lift, the flow would climb the bank of it's own accord.

I'm sure some supermarkets must stock it, but I don't recall seeing peanut butter in Nigeria. It's very much a US product. Here, processed peanuts yield peanut oil and the dry product kuli-kuli which is mixed with various peppers to yield our signature barbeque spice mix suya. Peanut oil and suya pepper have a pretty well indefinite unrefrigerated shelf life even in our climate.

And yet despite being one of the master race, you ended up in your sixties shuffling round Walmart wondering who's fault it was you were still at the bottom of the heap. Oh dear, how sad. Time for you to head back to your cold lonely pond and crawl beneath your stone I think.

This has been tested in South African courts. In what I consider to show a remarkably conciliatory attitude, the San and associated peoples stated that they didn't object to the term 'Bushman' providing it was framed in a positive context. Obviously our racist little troll falls way short of that requirement.

I SO want your dream to be realised as a dung beetle in elephant country. A nice little lesson in humility though I'm sure it would be lost on you.

Why do you pick on Africans? Their impact on climate change has been negligible in comparison to those accustomed to riding in modern air-conditioned automobiles.

So how do you propose persuading 2 billion women of child-bearing age that your material and spiritual comforts require the vast majority of them to forego parenthood for the next fifty years? Friendly and reasonable discussion?

Yes, it's not long out of the nest. Difficult ID until you're familiar with them. They're so very different to the adult form.

This one is a bit younger, but has still lost the yellow gape. The OP bird maybe barely fledged. Assuming it's N America or Europe

I had no issues with your post. Guess I must have missed something.

For me it has to be David Attenborough. I find his series as fascinating and awe-inspiring now as I did as a child. For YouTube, the group of channels put out by the profs and associates at Nottingham University seem very well curated and pitched at an accessible level. Professor Poliakoff on the Periodic Videos chemistry channel is particularly entertaining. Associated channels are Sixty Symbols (physics) and Numberphile (maths).

The articles themselves can often be problematic, but publications given in the references at the bottom of the page can be more helpful.

At time of writing, I was thinking of 'the ether'. We may be on a surer footing with space-time (when we get around to understanding what space and time really are). It helps keep a foot on the ground perhaps. These days I find myself drawn more to an instrumental point of view even outside of the work environment. 'Shut up and calculate' is maybe the ultimate Ockham.

Quite. We might even extend this to a system of mutually consistent interacting theories forming a coherent body of understanding. Yes, but here's the rub. If some critical property of the territory is unmeasurable, then the idea runs into falsifiability problems. Duhem-Quine extend this by questioning whether or not the territory itself is merely an abstraction created by the body of understanding of which the proposed theory is a part. An unstated assumption if you like. Perhaps this goes too far, but since Duhem was a sound thermodynamicist, I think he's worth a mention.

'True' in the limited sense that certain measurable inputs may lead to certain predictable and measurable outputs without known contradiction. Perhaps that is enough. It says very little about the muddle in the middle though. One only needs to consider the many interpretations of QM. Is one of them true in an absolute sense? For the sake of our sanity, it may be as well to think so. But don't bet the house on it.

Indeed. If the common thread of these 'rip' sounds is that they are the combination of many small pressure discontinuities (as I think they are) then their acoustic spectrum will include a large high frequency component anyway.

Wouldn't 'tiny parts' have tiny vibrational wavelengths? Have you noticed how tearing paper, undoing Velcro, and electrical arcs all sound remarkably similar?

I'm struggling a little to recollect beer mediated musings from 30-odd years ago, so please bear with me. Am I correct in understanding your last point as CPT symmetry reversal is not a physically realisable phase change in contrast to say electroweak symmetry breaking or recombination?

Probably the wrong word to choose. 'Pointlike' may be better. Suggesting that an instantaneous 'now' of zero duration doesn't exist. So a unit of Planck time, say, wouldn't have any clearly definable start or endpoint.

More of a dual-universe speculation. Perhaps one way out of the t=0 conundrum is to drop the idea of absolute time at these scales in favour of a sequence of time intervals, one of which happens to span t=0. A form of quantisation if you will. The surface of that cell should have no associated infinities, but half of the boundary surface is time-reversed and that (the point you raise) would need to be addressed. It's probably complete tosh, but the idea of two universes being spawned in opposite time directions has a pleasing symmetry to me.