Ken Fabian

@MigL The sorts that consume planets and stars may better suit being the Great Enemy of SF and fantasy storytelling than shining examples to emulate. Whilst natural physical phenomena seem amenable to a sound understanding without needing to go and see everything (do we need to visit a black hole to understand it?) biology seems to be the phenomena most likely to surprise - and it will be a rare example that announces itself so freely as humans have been doing. Curiosity seems saner motivation than colonising and traveling between stars may be better to have transporting observation and communications technologies and knowledge as primary intention than live crews. As some SF character would say, aliens are alien. Biology throws up some really odd things, but I do think a species that sought unconstrained expansion would not be comfortable neighbors. @TheVat A serious societal collapse would be hard to fully recover from even without gaining an aversion to advanced technologies. I think the dependence on the things taken for granted may be more critical than the things that are hard - without them the hard becomes impossible. Advanced technological self sufficiency in isolation, without global trade seems difficult. A wealthy economy without the easy, never before exploited mineral ores - high dependence instead on recycling from landfills and abandoned cites, when, with all our capabilities we still find recycling our wastes back to virgin quality materials mostly uneconomic - would be difficult to achieve. We rely a lot on natural soils and the foods from un-irrigated dryland agriculture, the least cost sorts; without them I think many kinds of technologies - products of economies with resources to spare - would be harder again.

@TheVat Getting a bit off topic here, but an nteresting discussion. Civilisations that cannot ever have enough or be enough don't sound healthy to me. Whilst I too like more (something built into our biology? Defense against hard times?) my idea of adequacy and sufficiency is relatively modest - extravagant compared to someone a century ago, yes, or even compared to the current global average but forever striving for more and more, into perpetuity? It doesn't appeal that much. An EV and some more solar to power it is something I would like, yet getting that wish fulfilled would reduce my energy consumption. Good food - fresh baked sourdough included - good company, interesting and fulfilling work and hobbies, music, art, garden, nature... feeling economically secure and safe with accessible healthcare... Sure, lots of people do want muscle cars and monster trucks and homes with twice as many (designer) bathrooms as residents and no limits but I'm not convinced such consumerism is a natural and unavoidable condition, let alone healthy or even, ultimately, is able to provide genuine deep gratification. The epitome of civilisation? I don't think so. Living sustainably within closed systems - which elevates energy efficiency above gross consumption - seems an unavoidable challenge for any intelligent species and succeeding doesn't look like inadequate ambition to me. On the contrary it looks like critical measure of technological advancement to my mind. And I'm inclined to be philosophical about mortality, both individually and for our species. @MigL Like with fission and fusion I think using anti-matter for energy means more 'dry mass' and that will undercut some of the gains. Undercut all the gains, unless the ratio of 'tank' to antimatter is vastly improved. It sounds like another of those hypothetically possible but practically impossible things. Suitable for speculative thought experiment style fiction, not for a tangible goal to commit to.

Red Shift explained! To me the Kardashev Scale has always sounded like something for an SF character to say in an infodump. I'm not convinced any sane civilisation would be that insatiable and it sucks as a measure of a civilisation's technological advancement.

Well, they weren't choosing a multi-generation journey in a leaky boat and they could go back if they could hold out until a suitable sailing ship visited - just go back poorer maybe. Not to nothing. And they did have a known destination that had the qualities that made going there a reasonable choice - where the air is sweet and fresh water falls from the sky onto forests that could provide shelter and fuel (the single most consumed product would have been firewood) and goods for trading and soils that could grow crops, waters that can be fished and used for transportation. Where they possessed superior weapons to the indigenous inhabitants. Whilst they would expect to alter their new environment to their requirements it was not terraforming. I don't think Euro-colonialism can tell us anything useful about interstellar travel.

@studiot I would read the topic as specific to intelligent aliens doing it on purpose. Enlarging the scope to non-sentient life I would not say known types of spores surviving such a trip is impossible - just may be impossible. I would say we don't know. It seems like something we might be able to determine. I didn't look very hard but none jumped out that comprehensively studied it. Spores are known to be very hardy but that is a relative term; we are talking about thousands of years and possibly as much as millions at extreme cold temperatures. Moss spores successfully propagated from ISS hull residues managed a couple of years in LEO conditions but the temperatures, cold as they got, were nothing near what interstellar space would present. How will cosmic ray exposure affect them? Small packages will be less shielded and get more exposure. But wouldn't high energy particles hitting the surrounding material have a cascading effect? Given enough time would radioactive decay within the spores cause significant damage? Would the radioactive decay within the packaging material affect the spores? And there is the atmospheric entry - faster speeds reduce time in interstellar space but make it hit harder and burn hotter in atmosphere and on impact. Bigger objects offering more protection are harder to accelerate to interstellar speeds. Possibly the nature of the packaging will make a difference - some material might shed away in a controlled way to dissipate the extreme heat. Can life spread that way? I think we don't know enough to say. ====== As a variant possibility - might a rogue planet with sufficient internal heat to sustain liquid water for millions/billions of year carry life across interstellar distances and much shorter distance/duration exchanges from meteorite impacts within a solar system during a fly-by passage cross contaminate them?

Perhaps not impossible in an absolute sense but so difficult as to be impossible in practice. Alien visitations. like interstellar colonialism almost always assumes 'magic' grade technology. And whilst the Clarke observation that sufficiently advanced technologies look like magic I do think we are circling in on a complete understand of the physics of the universe - and we are not finding room for FTL. The gaps in understanding where such possibilities may still exist seem more likely to close than to open. Even the mass advantages of fission and fusion over chemical rockets comes up against the need for a lot of reaction mass - whilst likely to require greater 'dry' mass as hardware. The gains, significant as they can be are likely to still be far short of fixing the problem. Boosting a whole asteroid doesn't fix the fuel and resources problem, it makes it worse by increasing the total mass that has to be accelerated. I think leapfrogging between deep space objects, building an economy capable of refitting and resupplying, over and over again for thousands of generations is the most feasible, yet, again, I think that would be unachievable in practice. If such economies were possible there would be no need to go onwards towards other stars - it would take indoctrination to sustain the goal. Without knowing the composition of such interstellar bodies we don't know if stone and nickel-iron will be easy to find; not non-existent but exceptionally rare or deep within icy objects. If it is possible to build an advanced industrial economy amidst the resource scarcity between stars there is likely to be dependence on robotics and virtual expertise and the sum of human knowledge; societies and economies large enough to support a sufficiency of humans with high level expertise to have deep and comprehensive understanding of the technologies and systems they depend on is going to be difficult. It does seem like there is high potential for ongoing loss of capabilities.

Reversible ground source heat pumps do seem to offer advantages, where the gains are independent of a narrower measure of efficiency of the gross heat flows in and out of the underground thermal mass. How energy efficient can total operation get if eg, air source heat pumps are used through Summer to charge up the thermal mass as well as using heat pumps to extract it in Winter and boost the delivered temperatures? A quick search didn't turn up real world examples with numbers and I'm not sure I could do hypothetical calculations. (I note that for large buildings with borehole ground source heating and cooling they often have to include external cooling to prevent underground heat accumulating above ideal working temperature range.) I've also read of trials (I posted somewhere) of conversion of a gas pipe network to district heating - where those pipes may run close to sewage pipes that shed waste heat into the ground, achieving (if I remember) COP above 5. I think we will also see more and better heat pumps for direct supply of industrial heat. The best currently manage up to 200 C (but I think those rely on waste heat rather than air or ground source).

Not sure 'free' is possible. Our PV + battery fitted home uses almost no electricity from the grid - and sends more than twice what we use to the grid - but we paid for the hardware and will face replacement costs down the track. Too cheap for profitable commercial investment suggest that 'socialising' - treating energy supply as a government provided essential service - could be appropriate. I can envisage roofing manufacturers including some kind of cheap and easy PV coating as a no-extra-cost inducement but even so called plug and play doesn't quite cover all that is involved in installing it with the associated wiring and hardware.

As one of the most staunchly Republican US states, how much would an 'anything but renewables' energy choice be a necessary condition for government support for such a massive project in Utah, despite of - even because of - so much energy in Utah already coming from solar and wind ? How much is the massive energy demand of AI seen as a spanner in the spokes of renewable energy growth - an opportunity to shift away from that course - by people who don't really know much or care about AI? My cynicism - full disclosure here - runs very deep.

Here in Australia it is an offense - hands-free (bluetooth with on-the-steering wheel or verbal switching) is fine but holding the phone isn't. It does make sense. The danger isn't so much the talking part, but more from locating a ringing phone, looking to see who the caller is, finding the 'answer' option or conversely, the process of making a call out. Those do require a lot of attention and looking at the phone. >>Considering all the recent discussions about AI lying to us to satisfy its programming, how should we consider evidence of wrongdoing provided by AI ? For the topic itself I am more concerned for AI as 'expert witness' than for faking of evidence; it could become problematic (more so with news media than courts) but I think identifying fake images or documents may be less so (probably using a form of AI?) than assessing the competence of AI giving expert testimony. I don't know whether how cross examination might work. One AI 'expert opinion' seems insufficient for a court but the same 'testimony' across several different, independent AI's may be seen as sufficient - whilst differing testimony would see it rejected.

This did make me think about utilising that kind of expansion and contraction to make a solar powered 'motor - pushing pistons on an axle - perhaps for water pumping. I think it could be made to work (and someone probably has); I just don't think it would work very well. The versatility of electricity and effectiveness of PV seem to do these things very well already, yet are still a long way from the learning curve topping out. The hardware is not for home workshops but innovative ways of putting the components together can be.

They are slaters here in Australia. I haven't encountered any that roll up but haven't looked hard. No response from Ulrich so far. Given how easy to find information about evolution of tetrapods I am not convinced the OP was sincere...

I typed "Why are reptiles, birds and mammals four limbed?" into a search engine and got abundant references to Tetrapods and their evolution. Amongst those near the top were links to explanations of why that body plan is so prevalent and has persisted so strongly. I find it odd that you have not found and read any of those. Lots of links and references from a simple search to the fact that most species of extant fish are not tetrapods, despite the four fins if you don't count the tail form is very common. But six fins and tail are common too. Most living fish are 'ray finned' and are not tetrapods. Early tetrapods 'fish' (fish being a body style rather than a taxonomic category) were 'lobe finned'. Lungfish and Coelacanths are examples of 'lobe finned' fish more closely related to tetrapods - but aren't descended from them.

Should be useful for science fiction writers who are wanting to make their stories sound credible.

Hydrofoils ran regular services on Sydney Harbour for a couple of decades, up into the 1980's I think, ultimately replaced with catamarans. I think there were a few collisions with floating debris, that didn't stop the service, but I don't know to the extent that played in choosing the catamarans to replace them. Seems to me a high speed catamaran - any vessel at any speed - would be at risk too. Hydrofoils may be the better at lowering their working surface area to reduce drag and maximise speed but catamarans do well too. Hovercraft have the least of all I suppose but they have other problems.

I learned that hydrofoil boats are not only faster with smoother ride, they use less energy. But I also learned that their use is limited where there are things in the water, like floating logs washed down rivers or animals like whales and dolphins. Will we get better radar/sonar to navigate those shifting hazards? And drones come to my mind as a way to track the hazards. https://cleantechnica.com/2026/04/15/fast-hydrofoils-floating-logs-canadas-ferry-electrification-challenge/

I do think that batteries are going to do a lot more and sooner than most people think. Here there are almost more battery projects than solar and wind ones, with them becoming a ubiquitous inclusion in new wind and solar farms. They will give a huge boost solar and wind by increasing their effectiveness and reduce reliance on gas peaking plants (which have a price setting/price inflating role around here even without oil and gas supply crises) but also provide (already providing) solutions to grid chokepoints and (with grid forming inverters) giving voltage/frequency instability/system strength and provide quick and convenient and versatile solutions to inadequacies within the grid, often in spite of relative costs compared to grid upgrades. I think quick and convenient as short term fix in the face of planning indecision and uncertainty will continue work in their favour - and become a long term fixture. Lots of EV's in the system are potentially grid stabilising and decentralising too, especially with proliferation of charger fitted parking spaces at workplaces (which may have rooftop solar too), shopping centres and street parking; a plugged in EV being potentially a lot more than a passive load. And when a lot of EV's charge elsewhere during the day and plug into homes at night they will cut down the evening peak loads. I do think lot of overnight low cost power and EV charging like that has been a consequence of coal plants. And convenience. That won't persist and may depend on wind for overnight charging to remain dominant - or just convenience. People appear willing to pay quite a bit extra for convenience and if charger fitted parking is commonplace, especially if it is wireless and hands free, that will be able to take advantage of and better utilise daytime solar.

Whilst cherry blossoms in Japan by themselves are more a regional indicator than global similar records within horticulture with a variety of species - spring budding, flowering, Autumn leaf falls etc - showing that same warming trend around the world. We are not short of clear indicators of a major climate shift being in progress, just short on commitments to doing much about it. I think that if solar/wind/batteries had failed to break the cost barrier and begin to scale we would be in a much worse position, with much less progress on decarbonising energy. Arguing about nuclear, doing it at inadequate scales, with higher levels of 'but decarbonising transport is too hard and our industry is essential to the economy' (without battery EV's)?

We should be using PPE for every kind of timber and it seems like a case of some being worse than others but no wood dust being benign, even without timber preservatives or sealers. Around here the much prized but now rare Australian Red Cedar is known as a particularly bad one to breathe, as is Camphor Laurel (that smells nice), which was introduced here and in some areas has become a seriously invasive pest. There are others of concern. Use of silica coatings does seem to present heightened health risks and even use of air filtration for the workspace won't eliminate all dusts.

The Common Law system seems somewhat similar - not a written out set of laws (although Common Law rulings often lead to legislated laws) but legal precedents from past cases (initially cases without precedents) that can be revised case by case in the face of changing arguments and new evidence.

Whilst some jazz has made it into my listening it hasn't been the largest part so I still get some surprises encountering Jazz greats I wasn't aware of. I acquired a copy of a Monty Alexander album "Threesome" and was blown away especially by the bassist. Long time jazz fans most likely all know of (the late) Niels-Henning Ørsted Pedersen but he was a surprise to me. This guy just playing normally comes off as showing off, an Art Tatum of the double bass. Not necessarily my first choice for easy listening for enjoyment but well worth it for the jawdropping virtuosity... (couldn't find vids of him with Monty Alexander, did find astonishing classical bass solo but have included a jazz one with Oscar Peterson) -

An exception to my mostly live music videos has been viewing animations of biochemistry processes, eg this one for mitosis and the kinetichore -

I don't watch many internet videos - don't watch much TV or movies, I prefer reading or messing about with a guitar or wasting time on internet forums in free time - but occasionally will watch some music videos, usually of the live performances sort. Links to which may better belong in a 'what are you listening to?' thread. Most recently some Oliver Mtukudzi (a Zimbabwe muso I heard by accident and found I liked) and some Yes, that I've had a renewed enthusiasm for lately -

A brain having some ECG measurable activity and being conscious seem very different to me. How much of a brain's function is devoted to consciousness? Which may depend on how we define it.

Where I am when both (all?) participants are near in age and both 'underage' that is treated differently to someone adult/older and someone who is underage. 16 years is considered 'able to consent' and above 18 is legally adult - enough of a difference to make 'near in age' an uncertain defense where one is legally adult. Which is not to say boys of similar age can't be using coercion; I've encountered claims that the greatest risk of sexual assaults are from others who are also underage, which seems likely to be true. I think the ability of some older men (mostly men but not exclusively) to lure and persuade the young and inexperienced should not be underestimated. The extent to which their mixed feelings, including sexual curiosity can be manipulated and appearance of consent contrived should not be underestimated. As an aside I made the mistake of reading some of Marquis de Sade's writings - causing abandonment of any absolute 'burning books is wrong' principles, that was a book deserving of banning and burning imo; I could not read more than a couple of chapters - truly sickening - but amongst what I did skim over was a character renowned for his ability to turn innocent underage virgins into 'willing' sex slaves. I suspect it was a book that inspired some accomplished abusers.