Ken Fabian

With zero friction a flywheel should keep spinning indefinitely - but when you draw any energy from it, eg by using it to power an electrical generator, it will slow down. You won't evade the laws of thermodynamics.

My knowledge of the underlying theory is surely weak, however I note the original post posited a simple DC circuit, without transformers. Energy crossing between coils isn't the same thing. If electrons don't shift around then how does energy in a DC circuit flow? Or AC without any moving of electrons back and forth? How do capacitors work if there is no accumulation (or absence) of electrons? I will have a view of the video - although I'd prefer the OP had a summary of what it says.

Off the top of my head (and without watching the video)... leaving aside resistance across such a distance, ie with superconductivity, and absence of electromagnetic fields (the solar system having them) I would expect the initial wave of current flow to proceed at C. An electron doesn't have to travel the full length before there is a current. It should be a bit like water in a primed hose (with water already along it's length) where the flow doesn't begin when the water entering at one end reaches the other end, but begins when the pressure change does (in that case, at the speed of sound). When that pressure wave (is that correct terminology?) reaches the end the water nearest that end flows out first.

Just saying I think flat earth "theory" is pure nonsense. I don't feel any need to justify why I think mainstream science has it right. Moving on...

A disappointing OP. Seriously? Do you use roads? Water supply? Have you or your family received taxpayer funded education? Health services? Do you receive benefits from taxpayer funded Defense services? Law and order? Financial systems that protect property rights and investments? Even if you feel confident you can afford to pay for all the services you need yourself you are doing so in a nation with a functioning government; all that confidence won't do you any good in a nation without one. I am constantly amazed that people cannot see the advantages to them of other people - neighbors, fellow workers, employees for example - being educated and healthy or of having their basic needs met. Don't you want others to avoid dire poverty and desperation and prevent entrenched social inequalities that are breeding grounds for crime, militant protest and revolution? Can't you see any value to you from social stability that basic welfare to others provides. Even the lazy opportunists ultimately aren't winners, even where welfare programs give them some benefit of doubt. Their children, if not them, need basic needs met - and it is worthwhile to offer education, to provide as much opportunity for as many as possible to become productive, with wider benefits than to them alone. I think it is wrong to conclude that free enterprise competition always does things best - or that governments would be better run by successful business people, like a business. A nation is not a business and even the standout business successes don't represent the totality of business efficiency; whilst the inefficient and failed companies and the human toll of their failures don't appear on a winning company's books they are on the nation's books. There is no 'firing' the unproductive citizens to make the nation's books look better. Surely the economic framework that makes such business success possible at all are in large part down to taxpayer funded governments programs and services. The reality is that many nations do many important and essential services better than competitive private enterprise can eg the UK and many other nations do health care using taxation much more cost effectively than US commercial medicine and insurance does it. Their successes should be appreciated more. It is always a case of vigilance and to do government better and to prevent or eliminate corruption - but there are places in the world where you won't have to pay taxes for anything and governments are powerless to make you. They are as far from utopias as it is possible to imagine.

Convection from the tropics doesn't carry air to the poles, just to mid-latitudes - with global warming causing the Hadley cells to expand to higher latitudes, something of concern here in Australia, as Hadley cells are associated with the high pressure systems that bring dry weather and push hot air from Australia's inland to the coast and are making the dry zones bigger. Not sure if enough warming could cause merging of Ferrel and Hadley cells or otherwise change this basic pattern of air circulation - messing with the climate has consequences -

The changes to the climate and weather patterns from global warming will have a bigger impact on winds, local and global average, than the atmospheric impacts of wind farms.

Usage defines words and ultimately trumps any prior dictionary definitions. Even the compilers of dictionaries must bow to common usage - ie even 'standard' and agreed meanings of words get revised (usually by adding a numbered alt definition) according to how people actually use them in practice. If you are engaging in discussions and debates about atheism you need to accept that there are no absolute rules about word usage and if what someone means is not explicit or apparent from context you should ask for clarity. I am not sure it serves any purpose to argue over those differences when it is usually easy to work out what is actually meant so you can argue about that. A bit like how I think arguing about calling anthopogenic climate change "global warming" or "climate change" for common usage is a distraction from what is important and serves no real purpose. .

I too have had bad experiences with Microsoft, eg having to buy a new copy of Windows because the reinstall option went missing from the harddrive - "talk to manufacturer - your original may have been 100% legal but no, you cannot download a copy". Out of manufacturer warranty of course - although I may have had a case, since a previous warranty repair appeared responsible for the missing hidden partition. But I wanted it going again asap. Only to go through the entire new install (with no going back) and near the very end - "Hardware not compatible with this version". Don't know which was worse - paying for that copy or the time wasted.

My first thought was something to do with technical drawing - reminded me of parts from an antique compass or parallel rule, but brass parts were in all kinds of tools and instruments. I have a jar full of odd brass screws, including knurled knob types like shown (but without the other bit), with original purposes unknown. Perhaps paper binding (like externet mentioned) or for mounting worksheets on a drawing board. Just guessing - I have no idea.

I think he merely baits his opponents - usually well below his rhetorical weight - with a keen sense of what buttons to press and coming off as sane and reasonable in comparison to what his trolling stirs up. When I listened to him discussing climate issues - issues I do follow keenly - the accurate content and evidence of actual understanding just wasn't there. From very misleading "facts" to outright wrong. And as Politically Correct in his own way with those talking points as any Left Warrior's conformity of Left rhetoric; you'd have thought getting worked up about climate change at all was Left idiocy - backed by using the wrong talking points of Right idiots. Any sense this was someone who really knows what he's talking about or should be listened to as a great intellect - or at all - was gone.

In my experience it isn't usually the trees that burn or that are the principle hazard, it is leaf litter and undergrowth (that will include seedling/sapling trees); it takes the right (wrong?) conditions for forest canopy fires, ie trees to burn. Reducing the undergrowth reduces opportunities for fires to find their way into canopies (laddering), although if conditions are severe enough they can do it regardless and (with Australian and I suspect SW USA vegetation) readily cross large gaps in canopy. They can also burn across areas where hazard reduction fires have been recently done. Early European explorer accounts of the area I live in cited very large, mature trees with grassy areas underneath, but these were not natural; they were the consequence of centuries of humans using fire as land management tool. After 2 centuries of tree harvesting and clearing the numbers of trees is greater, but they are smaller and with denser undergrowth. Thinning of larger trees is probably not going to help and that is what I think of for "thinning"; others might think of it undergrowth removal I suppose. Short term removal of trees leaves a load of dead tree tops unless those get cleaned up, which makes the exercise more difficult. Longer term the breaks in forest canopies from tree harvesting become areas of maximum undergrowth. Hazard reduction burning is done in large part because physical removal is not viable - too much of it and too much of it inaccessible. When drought has been ongoing the opportunities to do that hazard reduction burning safely is reduced. And warmer temperatures also reduce those safe opportunities. I think raised dewpoint temperatures are critical in that; the old style light it and leave it "burning off" by Australian farmers that aped Aboriginal practices relied heavily on cool overnight conditions laying down natural fire retardant - dew and frost - that meant the fires reliably (mostly) went out by themselves. With global warming there will be less of those opportunities, ie more vigilance, labour and equipment to be safe.

No, it is closer to 1/3 making most of the global warming; it isn't a direct relationship. Rather it is a direct relationship between total fossil fuel use and climate change - and fossil fuel use can be avoided. From original thread, not copied over -

I think using zero emissions energy decouples global warming from population. Not entirely but the biggest part of it. Population matters but I think global warming is not an unavoidable consequence of high population - and it is unhelpful as well as wrong to presume it. Unhelpful because believing it true means believing there is no solution that doesn't involve significant population reduction and there aren't any nice ways that can happen quickly and even the ways to do it as a global priority by controlling birth rates still risk crossing over into crimes against humanity territory. Unhelpful because it supports the argument that the cure will be - must be - worse than the disease and committing - really committing - to fixing the problem must lead to global tyranny that regulates fertility. But it is an avoidable consequence of high population and committing - really committing - to fixing the climate problem can accommodate the natural human urge and desire to have children and climate policy can butt out of people's family lives. There will be issues arising from high populations and continued population growth but they don't have to be climate issues. A high population using clean energy can make less emissions and global warming than a low population using dirty energy and (as others have noted) education, access to medical services and contraceptives have proven effective at reducing birth rates - even within communities with religious prohibitions against them - so economic development that is based around clean energy looks like a win-win.

Maybe I'm a bit sensitive - I'd encountered people making the "cure worse than problem" argument citing renewable waste recently. As an argument for not making and selling and using things that are in demand citing future waste obviously doesn't work very well anyway - and their position ultimately depended on presuming climate impacts from fossil fuels to be exaggerated. Sigh. Even so I think too few people, even reasonably well informed ones, realise just how much problem waste fossil fuel use produces - and it is worth highlighting how much less the total volumes using renewable energy can be expected to make. Dealing with waste too often has come as an afterthought, or perhaps as and after the waste problems present themselves. I would expect manufacturing wastes at large scale to present as a problem quite quickly and safe disposal becomes a working necessity, with relatively few high volume sources making it hard to ignore. End use waste becoming the user's problem presents less directly or immediately. RE will be at scales that are off the scale if they are to work for 10 billion people, so yes we will need to deal with the wastes responsibly. I see building an abundance of clean energy as the best thing we can do and it surprises and astonishes me that wind and solar have emerged as a cost effective action - such that we can and are using them in serious volumes. If renewable Hydrogen is to have a significant role it requires that clean energy growth and more, so committing to more solar and wind right now makes sense. And this appears to be happening and is cause for cautious optimism that, despite appearances, that we can make a real difference. From 1.7% of global electricity in 2010 Wind and Solar have grown to 8.7% of a larger total in 2020; by any measure that is extraordinary growth, but I think we ain't seen nothing yet, because crossing a crucial tipping point on costs (in most places during that decade) has not fully flowed through. How much energy storage can grow is a question but batteries are emerging as serious contributors. I note that about 20 times more electricity supply batteries (grid and domestic) have been built in Australia since 2016 than predictions at the time. Power companies that previously assumed a growing role for gas as backup are choosing to use batteries and are questioning those plans. Ongoing R&D and support for pilot programs for many other contributing technologies and options is essential because Wind and Solar can't do it all. Hydrogen is one. Energy storage of all kinds is another - battery R&D has gained it's own momentum and high levels of commercial funding. So is growing interconnections across ever wider electricity grids something I think worthwhile - whether it is Africa to Europe, Australian to SE Asia (SunCable tm) or the UK linked to Iceland hydrothermal power (due for completion soon?).

But I don't think it is that good a point, which is why I urge you - and urge Studiot too btw - not to buy into the alarmist fears of renewable energy wastes. Maybe the big bold heading "a serious waste problem" was a copy and paste, not you warning of the dangers of committing to renewable energy - but I think it deserved some qualifications, if only to make clear your opinion. I don't necessarily follow links, but I was aware of that study on battery waste in Australia and see it as evidence the problems with waste are not being ignored. And maybe the strength of my response was less about you and more about the widespread use of those alarmist fears to undercut confidence in committing to clean energy. We probably agree on more than we disagree; just more likely to get exchanges of views where we disagree. It seems to me we have passed the point where weighing up our future options is the best use of our resources - we have options that work, if imperfectly, and pathways that are clear for the near term, even if less clear for the longer term. (A general observation, not specific to any posts). Battery electric looks like the current best option for transport but any commitment to it doesn't lock us into anything we cannot change; it looks flexible to me and that flexibility looks more important than waiting on a clear and unambiguous overarching "plan". If Hydrogen does emerge as cost effective for transport that will be good but holding out on commitment to low emissions transport whilst we wait for it will squander the opportunities we have now.

"True costs" of batteries... compared to what? The whole climate issue is about including true costs that otherwise don't get counted. Replacement costs vs the utility? I think Li-ion is doing well on that scale and battery tech is still a work in progress. My understanding is that most of the earliest Tesla's still have the original batteries and most can expect a longer working life with less maintenance than ICE drivetrains. But I don't expect Li-ion to stay the same or to be the only viable chemistry. It is disappointing that you aren't putting those numbers into perspective. I think there is a strong thread of alarmist fear about the resource requirements and wastes of renewable energy that is being encouraged by opponents of climate accountability and supporters of fossil fuels and I don't think it is warranted; I urge you not to buy into it. It is not that there are not problem wastes from RE but that the problem wastes from fossil fuel burning are so, so, so abundant as well as intractable. Australia makes 12.5 million tons a year of serious problem waste in the form of coal ash - 125x expected battery waste in a heavily RE and battery dependent 2036 - and 4,000 times as much CO2 as that. Neither waste is amenable to recycling - I am not convinced including fly ash in concrete can be scaled sufficiently, nor that it won't leave an enduring legacy of heavy metals contaminated concrete. CCS (with 2-3 tons of CO2 for each ton of FF burned) can't scale up and is just Greenwash. There is recognition of the need for solutions to RE waste - and supporters of fossil fuels won't stop reminding us. Renewable energy industry overall tends to accept the need to develop recycling/safe disposal and appears open to inclusion of pre-payment for disposal in initial purchase. I don't think recycling/safe disposal is even possible for fossil fuels wastes but the industry fiercely opposes any accountability. I would note that EV and large scale batteries are very unlikely to enter ordinary waste streams and it is small consumer item batteries that are a fire risk. No vehicle recycler is going to be stupid enough to put them in the crusher (well, let's hope not) and no ordinary landfill will accept them. We will deal with the wastes - that will be in much reduced volumes compared to FF's and, foreseeing the issues, will probably do so better at it than we've handled problem wastes in the past.

I do think Hydrogen has intrinsic and intractable issues around efficiency in some of the steps. We have losses from electrolysis, losses from storage energy requirements, inefficient burning, inefficient fuel cells. If we include a step to and step back using ammonia we get two more conversions that will have losses. Hypothetically a lot of energy from compressing and condensing can be recovered but in practice is not so easy. The on-site production and storage for industrial applications are able to avoid high pressure storage but transport fuel and transportable fuel requires it. It is the industrial uses that are crucial, without ready alternatives that look the easiest to do and the uses like transport that are more difficult and include inefficiencies that cannot be avoided do have alternatives.

If they were "little things" - rather than turned way up past 11 - I could look past the overly dramatic tone. The DeGrasse Tyson "Cosmos" was like that. And I might look past it if the content was up to my grade - which isn't claiming my knowledge is exceptional, just that of an interested adult. Like Peterkin says, for the target audience it probably works well. I am not the target audience. I enjoyed watching "SolarMax" for example - a doco on solar science and the solar cycle. I got my Sagan in book form mostly - and yes, a great science educator. Attenborough is good too, although I am not a fan of presenters pretending to see the CGI reconstructions of extinct animals; it isn't the CGI that looks fake, just the presenter's pretense. Again a matter of tastes perhaps. People hold up Gravity as being very realistic but it made serious mistakes that undid my perceptions of it being realistic - you can't tow another spacesuited person like towing a boat on a line... ie wobbling around behind them; if they tried that they would end spinning around each other at the ends of their tether, probably in both senses of the phrase. Better to lash their suits together and move as a single mass. No reason not to do it like that; it could've offered opportunities for lewd innuendo depending on the position, except that the moviemakers didn't seek good information about how one suit with jets could be used to do a rescue. And spotting a space station and boosting in that direction wouldn't work either; the suits needed some kind of course planning software and again there was no reason not to have done it that way, with opportunity for explanation for why you can't just aim and boost. But for the ignorance and misunderstandings and lack of research of the film makers. For sure I was enthused during my youth by science fiction as well as the Moon Landing and space exploration that was going on at the time but the more I know the less likely I think these space programs will be stepping stones to making the grand space dreams - the fiction - come true. The universe and solar system are awesome and those kinds of entertainment probably did prompt the enjoyment I get in learning more about them. If it encourages people to do science, I think it is positive but if it merely encourages unrealistic fantasies about space and new iterations of science fiction based on science fiction I am not so sure.

I remain somewhat skeptical of the hype and cynically think that choosing H2 on the big things like transport is most popular within industries that do those things because it means Delay. There are good reasons to pursue renewable Hydrogen for some critical applications but too many other applications aren't going to work until and unless a low cost supply chain is established - that not yet being an inevitability and for which there are other, more immediately available options. Building the abundance of clean energy needs to be the priority; it doesn't depend on H2 but H2 depends on it. Heat pumps using clean electricity look much better for building heating in most locations - with energy efficiencies above unity that no alternatives can match; in most climates that can be air source aka reverse cycle A/C that can be retrofitted. Ground source heat pumps are easier with new construction - as is district heating and energy efficient building design - but worth doing even as retrofits. Heat pumps offer a superior and potentially total heating solution whereas adding H2 to gas and convert later to 100% H2 option kicks the emissions can down the road. Not necessarily a wasted effort to add H2 to existing gas where efforts continue to replace it but it isn't a solution. Lots of steel processing can already use electric arc furnaces and other electricity based processes. The smelting part is still crucial but is not the largest part of steel making; the total demand for Hydrogen for that is significant but not likely to be enormous. The long range trucking, shipping and air travel applications sound good but I'm not convinced the substance is there; the industries like it in direct proportion to how long it is likely to take. Trucks and shipping can do battery electric for short/medium range right now. I'd like to see more done with swappable batteries for trucks - and there are serious attempts to try that. Rail, including for freight, maybe even especially for freight, seems well placed to use a combination of direct electric and battery electric - battery electric rail isn't even a new thing, just previously a niche thing. Freight trains often make a lot of stops or spend a lot of time in sidings, where batteries can be recharged - or dedicated battery wagons could be shunted in and out, or stretches of electrified track can allow recharging without stopping and steep ascents/descents can be electrified. Transportable H2 might benefit from conversion to ammonia and back again but Hydrogen already has serious energy efficiency problems - losses at the electrolyser, losses when burned for heat (then heat to electricity) or losses when used with fuel cells. Converting to ammonia and back again will add more losses into that chain. I had thought gas power plants that can convert to H2 might be feasible with on-site electrolysers and low pressure storage - but being able to run the electrolysers intermittently is currently not cost effective, even with very low (otherwise surplus) electricity. The kinds of applied science that can develop better electrolysers can also develop better batteries (and supercapacitors); battery storage isn't a stationary target and still has room for significant improvements. Around here we are getting large scale batteries as much because system planners are kicking decarbonisation down the road as because of deep planning - smallish amounts can smooth the RE output and respond rapidly to sudden system needs and put back the need for bigger and more enduring investments that are likely to face rising emissions reductions requirements. Predictions of less than a decade ago for a few MWh of grid connected batteries by now are being exceeded by around 20x.

I'd put documentary above SF - they at least attempt (the ones I'm tempted by) to be factual, but I find I struggle to keep watching the doco's too; the last time I tried the overly dramatic background music and awestruck narration was just too much. And I was familiar with most of the content, so not much that was new. SF unfortunately presents a fantasy vision of Humans in Space that references the F of other SF far more than it references S. They get so much so wrong that I can't look past the mistakes. Whether back in my youth, when a space monster blocked the air intakes of the ship of Lost in Space - the Robinsons were going to asphyxiate (even then we thought it was stupid) - or my failed attempt to watch "Expanse", that others consider very good. Having the SF standard tyrannical and corrupt UN running Earth badly in Expanse was mildly irritating but I know most people who like SF will be Americans who have been taught to dislike and distrust the UN, so it hits their buttons (but annoy me) and there is an independent and powerful Mars (colonising Mars is inevitable, right?); these are the kind of tropes that get used to suit viewer tastes I don't share. But it was the water shortage on Ceres that lost me. Seriously? They are a major mining operation but they don't know you can heat carbonaceous chondrite material and get water? And don't they do recycling? There are some SF writers (of novels) that I enjoy a lot but very little of TV or cinema SF can grab me; it is the ones that don't take themselves seriously, that are unashamedly fantasy or comedy or both that are most likely to appeal to me.

Just asking. Isn't Au (gold) a precious metal? It is good to see progress on better electrolyzers and I hope it flows through to renewable Hydrogen production. It won't become widely used without better electrolyzers. I see iron smelting and chemical feedstocks as the uses of most significance. I am less optimistic for H2 as transport fuel and as transportable fuel; iron production and chemical feedstocks can operate with on-site production and storage at low(er) pressure and therefore cheaper than bringing it from somewhere else. Battery electric looks better for vehicles - overall much higher energy efficiencies and piggy backs onto existing energy distribution networks. Hydrogen as transport fuel needs economy wide infrastructure built from zero. One more halving of battery costs will make existing type EV's unstoppable. One more doubling of energy density will make EV's unstoppable - and open up aviation to battery electric. Achieve both and it is game over for fossil fuels. Hydrogen won't be in that game. I'm cynical and think that, important as clean iron smelting and fertiliser production is too much is being made of Hydrogen - and the reason it has such widespread political support is that it can't do much any time soon. Those looking for empty gestures to follow up their empty gestures on zero emission targets like renewable Hydrogen sometime in the future, but so does the fossil fuel industry, that currently make most Hydrogen like it; it uses empty gestures on Carbon Capture and Storage to justify competing (with aid of subsidies from sympathetic politicians) against emerging clean Hydrogen and other clean energy.

The more sophisticated the technology becomes the less likely that any repairs in flight by non-specialists will be possible. Reliability is the key, not repairability. Having a pilot along in an automated space vehicle because some passengers feel safer becomes a question of psychology and behavior of the passengers. The solution for the passengers will be confronting and overcoming fears of automated/remote flight control rather than the solution being the company's via the inclusion of an unnecessary pilot that will eat up payload and profitability whilst being unlikely to be able to save anyone.

And I think there is nothing inevitable about it, nor see that space tourism, even as some kind of interim step, will deliver overall benefits to humanity. If you don't want people to argue about other issues around space tourism in this thread you need to avoid including big picture opinions that others can legitimately disagree with.

Beecee, SpaceX demonstrated that crew are not necessary to fly a rocket carrying passengers, as is routinely done for rockets that don't carry passengers. Why aren't you celebrating this as a success? Actually this made me recall The Right Stuff, where the rocket scientists were planning pilot-less rockets but there were objections. Mostly around public perceptions - test pilots who actually get to fly them made for better PR than sending chimpanzees. Or scientists. Or pilots that had nothing to do. I don't know if that reflected the actual arguments that led to having pilots and giving them some controls to operate - as well as a viewport. But it does seem like it was always a choice, not a necessity. It may not be pilots or engineers that space tourist flights cannot do without - it could be the flight attendants.