Ken Fabian

My source - Sanchez and McInnes - were looking at blocking the amount estimated to be needed - about 1.7% of sunlight. As much mass as Three Gorges Dam, but in space. I suppose the grand space dreamers will suggest we "just" mine the moon or asteroids. I didn't see any estimates of how long the hardware would last or how much ongoing maintenance; given how speculative it is that might look like a minor detail. I think that without extraordinary advances in space capabilities (and even then) this isn't a climate solution we can use.

For L1 positioning most of the light pressure may be compensated for by placement closer to the Sun - ie Sunward of L1. I hadn't considered that. I don't think that will work for anything in low orbit - and it would still not be stable near L1, ie still requires the means to align and move, but with less fuel. Doing a bit of reading reveals that it is hypothetically possible to have some active control over the relative dimming regionally as well as tropics vs poles - via paired occulting discs (iiuc) and that ability to move and align. I wasn't aware of that. These issues are a long way from solved and it still leaves us with ocean pH change - maybe more so if space shades are used as the excuse to allow ongoing and unconstrained emissions. Those aside we are still talking about (according to that source) about 107 - 108 metric tons for the array itself. The array will not be the entirety of what needs to be launched. So far there has been around 20,000 metric tons total launched into space - with much of that to low orbits and expected to return to Earth as orbits degrade. At US$1m per ton to launch 10's and 100's of millions of tons gets extremely expensive - and still extremely expensive even if we see costs reduced by another order of magnitude, ie US$1,000,000,000,000 - $10,000,000,000,000 . I don't think it is possible to grow space launch capabilities that much or in time for it to be much help on our climate problem, especially for a major project that doesn't generate any income directly. Aside from the technical matters... who pays for it?

No unpowered objects will stay where they are put; the light pressure and solar wind will blow the foil away. Any mirrors/shades in space need to be able to do station keeping - ie move about with drives to keep them in place and aligned. There will be more mass than just foil. My understanding is these approaches also are likely to result in regional climate changes above and beyond simply being overall cooler. If emissions continue the ocean pH impacts will not be resolved. I don't think there are any "just do x" solutions that are better or cheaper or quicker or easier or more compelling than a primary solution of "just build an an abundance of clean energy". I suppose it has value to explore the feasibility of all options but not at the expense of the options we already have or are close to viability. My impression is that the space based ones are championed principally by the grand space dreamers for whom greatly expanding space capabilities and getting lots of humans into space - often with the express intention of being able to leave Earth and it's problems behind - are their priority. It won't go well to abuse and misuse the legitimate concerns about climate change to advance quite different goals and ambitions.

I think Hydrogen's greatest downside is it is difficult to store. That includes being bulky compared to other kinds of rocket fuel. It is challenging to use when all the infrastructure is on Earth and most of it gets used within minutes of launch; producing Hydrogen on Mars and using it for launching return journeys for example would be a lot more difficult. As would any long range missions, where the storage duration becomes an issue. I don't know if carbonaceous asteroid material could be used to produce hydrocarbon liquid fuels - it seems likely it could.

I like the idea of an intelligent, tool using octopoidal form, which would, of course, have to differ in many ways to octopuses as we know them. Evolve from an octopus or evolve differently, from a common cephalapod ancestor? Convergent evolution in the ocean of a distant exoplanet, that bear resemblance in form to octopuses? They wouldn't be octopuses.

I don't think we can assume that if German Greens had just supported nuclear then EnergieWende and emissions reductions would be more successful and more advanced. We can decry the historic and ideological baggage that makes most Environmentalist orgs anti-nuclear and free market capitalists anti-climate action; both left nuclear hanging in the breeze just when the winds of change blew through. But I believe it was the latter that was pivotal; it wouldn't have been up to Greens except mainstream politics handed the issue, the podium, the microphone to them. I am cynical enough to think wind and solar got mainstream support over nuclear because they were expected to make no difference. In an alt-history timeline Greens divided on nuclear may well have led to overall weaker action on climate and clean energy; certainly the German coal and gas interests would have taken advantage of internal disagreement, without supporting nuclear. Reduced early support for wind and solar - EnergieWende being a driving force for making them globally mainstream - could easily have been a consequence, leaving us all further behind at this point. Greens expect longer term RE growth to displace the gas as well as the nuclear; I am not prepared to declare they were or are wrong to make RE their focus and distrust nuclear and the "just use nuclear" arguments. Germany is a major industrial nation and despite the economic alarmist fear of being economically ruined by RE, it has grown whilst significantly reducing both emissions intensity and total emissions. Even after nuclear closures (past the short term reverberations) Germany's economy has grown and emissions have gone down. The leadership has changed so we will need to see how they proceed. To establish itself as a primary clean energy option nuclear now it needs those low cost, fast to build, ultra safe modular nuclear power plants - but they are decades overdue and look unlikely to ever be low cost - perhaps they are not so simple and easy and reliable and safe as the optimistic advocates like to make out. I suggest that whilst support from "green" advocacy might help nuclear it isn't essential; the essential support base nuclear absolutely has to have is still supporting fossil fuels and opposing the shift to clean energy. In any encounter with a nuclear supporter I put the odds above even that they will dispute the validity of climate science; with friends like that... Above even for the commenters at sites like atomicinsights.com - I suspect that thread of climate science denial running through nuclear advocacy is there in Germany too, despite appearances that climate science denial is not widespread there.

Given plastic waste can be turned into liquid hydrocarbons and those can be used as rocket fuel - yes. It doesn't look like an efficient means of either reducing plastic pollution or producing rocket fuel. Ultimately we need to shift to recyclable/decomposable plastics and make rocket fuels using low emissions methods.

In the sense that extremists imposing their will on everyone else - veganism would be a hindrance. But I think true of pretty much every kind of extreme ideology that is uncompromising. The best outcomes look to be in the compromises - the reduced meat eating for health, supply chains that are more environmentally sustainable, minimising animal suffering . I haven't been impressed enough to want to learn more - I rarely eat meat because I don't like it much and I don't like cruel animal husbandry but I eat eggs and milk products regularly. I don't think food proscriptions work - and I am personally familiar with a common human failing; knowing better but doing it anyway. I don't know much about the practicalities of proposed Vegan food production and have tended to be tolerant of Vegan activism that exposes cruel farming practices and promotes eating plant based diets, without any in-depth understanding of their deeper beliefs and aims. Studiot makes a good point that it isn't possible to grow food naturally and exclude animal life. I am more familiar with Permaculture ideas, that use animals and incorporates them systematically. I once heard a then unknown Bill Mollison speak about incorporating chickens into gardening systems around the time the first Permaculture books were published; the final tally of potential useful functions was impressive, as were the practical means of designing gardens, pens and runs to support those uses. It all seemed very practical - a synthesis of existing ideas being the principle "out of the box" idea. He didn't strike me as unthinking and uncompromising (although there are now Permaculture extremists too) and use of the products of science and industry were not rejected - their use was minimised but not excluded. I agree with Peterkin that Vegans are not a major influence; even the promoting of plant based foods doesn't depend on them.

You sure you want to derail the thread with a German nuclear vs renewables sidetrack? In answer to the question, no, I think that is oversimplistic - it may play some part in short term demand driven volatility but there is too much else going on, including Russia playing games with supply availability. How much German supply comes via long term contracts at fixed prices and how much is vulnerable to short term variability? How well did they anticipate Covid would impact economic activity - declines and rebounds - as well as anticipate how nuclear closures would affect demand? How well does Germany manage gas reserves? Gas prices have been and are very volatile all around the world quite independently of German policy to phase out of nuclear - which is a tiny portion of global demand. My hope is they will double down on renewables as a response to price volatility and gas market games as well as continue to push ahead with a transition away from fossil fuels, but I don't know how post-Merkel Germany will manage Energiewende into the longer term. On the face of it, I would have favored keeping the nuclear plants for their working life, for the low emissions, but my understanding of the in's and out's of German energy and climate politics is limited. But I do think failure of large parts of German politics to fight for nuclear is down to the same kinds of apathy and hostility to strong climate policies we see everywhere - handing the issue to others in "you care so much, you fix it" style, whilst supporting coal and gas. "Not like that" isn't alternative policy. So far the alarmist economic doomist fears of renewable energy have failed to eventuate although short term volatility still gets treated like evidence of fundamental failure. Germany is still the biggest and most successful industrial nation of Europe.

I still think overcoming vulnerabilities and limitations is what intelligence does best - I think the intelligence and problem solving capability matters much more than any baseline of physical abilities, although without some ability to hold and manipulate things tools would be more difficult. But I hesitate to say impossible. Co-opting other creatures? We make structures like hedges out of living things, we use other animals to utilize resources we can't use directly and make them into usable things. I don't see the short life span of octopi - or their marine nature - as nearly as much of an impediment as being mostly solitary and lacking language is. With language the lessons learned by an individual can be passed on to others - to youngsters of the next generation. No individual human can hold all knowledge - and our own example shows it is not necessary. Individual intelligences that are not social? Even that seems possible to me - but may require the long lifespan and mutability/adaptability of form might help. Octopi probably wouldn't find land as intimidating as some other marine creatures - some do go from rock pool to rock pool across dry land when seeking food. A species that cannot hold a spear or throw anything may still be able to make traps. I suspect I would be in serious trouble if I had to hunt live prey by throwing things at them but I think I would be capable of making traps. We are not adapted to live in space - yet we go there. We use fire - and are not adapted to handle it or survive it.

We only have one example of intelligence capable of the kinds of technology we have - we don't know enough to even suggest a tech using intelligence having that form is more or less capable or likely. Or appreciate the kinds of technologies we don't have and may not recognise. We do have examples of other physical forms finding, making and using tools as well as cooperating on tasks individuals are incapable of. Even, I suggest, examples of animals that engage in reasoning and problem solving. I suspect strong human prejudices on what form intelligent aliens might take - and perhaps an unhealthy measure of self deception about our innate superiority. I see no basis to conclude that plants are unlikely evolve intelligence or evolve movement - there are venus fly traps and other exceptions and just using time lapse gives a whole different perspective on plants and movement. Going by the human example I see no basis to conclude that, having crossed interstellar space, aliens are unlikely to be hostile. We can't even be assured that if humans achieved such a feat, that we would not covet the target world and it's resource or that humans would never do xenocide. I think if we are honest we will concede that humans are quite capable of such things - and of finding justifications before, during and after. Or, where justifications seem inadequate - scapegoats. We may even be predisposed to doing such things. I am not sure we would recognise some kinds of intelligent aliens and I think we would be capable of wiping them out just by mistake by simply failing to recognise them as intelligent. And should any intelligent aliens take violent exception to human presence in their territory - on the basis that doing so is justified as self defense. If a child is caught and killed by an intelligent carnivorous plant on it's own world would humans refrain from retribution? We ARE the consummate nest raiders but we won't tolerate anything that raids our nests; any onworld human presence that has committed itself to survival by colonisation will be capable of wiping out alien species to assure that survival.

I don't think there is a "human resemblance evolutionary process" and there are no known advanced intelligent aliens that have that form. It seems like rank anthropomorphising to presume it is superior or even necessary - if that is what that prejudice is. Whilst hands with opposable thumbs at the ends of upper arms of visually capable bipeds appear a very good way to make and use tools (to humans) I don't see it is a requirement; birds build complex nests with beaks and even manipulate tools and Octopuses ('pi?) can do it with suction cup fitted tentacles. But I suspect that physical capabilities are amongst the least essential - mental and communicative abilities can work around a lot of physical limitations, including by making teamwork possible. One beak to hold the work piece, another to steady the anvil and two more to work the hammer? Isn't much of human success a result of tools and techniques that work around the physical limitations of individuals? Might that ability to work around physical limitations be a crucial marker of an "intelligent" tool using species? Where is the lower threshold for physical abilities? When starting off a lower base the achievements look greater, not less.

What top physicists? What great ideas? Human "evolution" is biology although I expect colloquial English can apply it loosely enough to encompass evolution of knowledge (including physics). Any physicist who has something worth publishing will be able to do so - or else bring it into the public domain and be in a position to promote and defend it. Lots of crackpot and occasionally a sound idea gets attention outside of peer review publication and institutions that do science; it rarely takes other top level scientists to identify the crackpots but the sound ideas DO get noticed, often getting the support and backing of "established" scientists - claims otherwise being scurrilous (and mostly by the crackpots who don't take to their mistakes being corrected). Evidence of a scientist's ability to publish and promote and discuss being suppressed would attract attention - science is built around documentation that is widely disseminated. So far no evidence has been presented.

It sound like if running continuously there would be waste heat equivalent to a coal or gas power plant. In addition to the cooling at the coal or gas plants or other sources of it's electricity. It doesn't run continuously. The info around the cooling isn't prominent but (from Wikipedia, without much detail) it sounds like ITER has water based cooling, from a closed system joined to a separate cooling system via heat exchangers, with one conventional cooling tower plus cooling ponds. Water is piped in and discharges back to a major river. It wasn't clear if there is air cooling as well, like refrigerators and A/C might use. Now, if only the waste heat could be harvested... but if it could do that effectively and efficiently we probably won't need fusion power plants.

With conventional exoplanets, that transit their parent star, yes. Wandering "free" planets, no. I don't think that determining atmospheres of 'free' planets - of any planets using it's IR detectors - is what Webb is expected to do but it is expected to detect more such planets with other instruments. The Webb telescope is expected to be able to get spectral data from light passing through the planet's atmosphere during transits across their parent star - the more conventional "exoplanet". Free planets might be more problematic for atmosphere detection than planets that don't transit their Primary. I don't know if it will ever become possible to use more distant starlight passing through planetary atmosphere in a similar way - maybe not, given how weak the light source would be. A Nitrogen and Oxygen atmosphere would almost certainly be considered a product of life, as would other atmospheric indicators. Not sure what the specific characteristics of earlier (pre-oxygen) Earth atmosphere's would be, but there would be indicators of life amongst them.

It seems to me the issues are solvable. Emergency services can have big on site batteries to charge EV's and mobile battery packs that can be taken to the site of emergencies. Whilst keeping them always well charged just in case will limit other everyday use it doesn't rule it out entirely; big batteries might still be used for grid and onsite purposes whilst staying above a set reserve charge level. Here in Australia, with high levels of rooftop solar local "islanding" looks feasible - not just a way to keep emergency services operating but keeping whole areas with power by isolating them from failures of the larger grid.

I think angels were an illusion some people saw, that other people refused to admit they could not see, for fear of religious persecution. My understanding (could be wrong) is that representations - drawings, paintings - were prohibited amongst Jews and later Christian images of them would have had to be approved by the Church. I don't recall any that looked like the description in (by?) Ezekial but I'm not well versed in iconography.

The active ingredient?

Since it isn't possible to put the equivalent of compression wrapping around our heads to keep down excess blood and fluid perhaps anti-compression wrapping of the rest makes a kind of sense.

For the first time in 12 years tourists are in orbit (?). But I find little to be excited about - it doesn't come out as a demonstration of how great space is, rather it is a demonstration of the wealth and resources and capabilities Earth has - to be able to do something so extravagantly self-indulgent.

Using wind, water turbines and solar panels... as components of a fusion power plant to turn fusion energy into electricity? I did miss that. My initial comment wasn't a response to any other comments, just my thoughts. I have Li-Iron-Phosphate batteries at home - more expensive than not having them, but not by much. One more halving of battery costs and nothing will be the same. So far not a lot of grid scale storage but one very large pumped hydro project is proceeding and there is a lot more investment in batteries than anyone expected. AEMO's most recent 20 year Integrated system plan, if adopted, would reach close to 95% RE (electricity, with a lot of EV and other extra demand) by 2040. Storage is a big part of that but as AEMO sees it there are other things that can and are being done that reduce the amount of storage, that help lesser amounts of it go further. Not my intention to derail the discussion of fusion. My sensitivities around blanket disparagement of renewable energy got triggered, wrongly in this case - but I also think the larger context cannot be avoided and shouldn't. The Why of ongoing development of fusion immediately opens the discussion up to options apart from fusion, if just to compare. Fusion is worthy of ongoing efforts but so are many other technologies. One would be low cost, ultra safe, mass manufactured modular nuclear power plants - the much hyped SMR... if we'd had those back when climate emerged as a global issue things may have played out differently - something that can be built fast and deliver emissions reductions and political benefits within political timeframes - but they seem as perpetually far off as fusion, always another decade, maybe, more funding needed and not likely to be cheap. Throwing support behind wind and solar hasn't ended up a mistake.

If fusion is so extremely difficult to do at all, doing lots of it reliably at low cost seems a long way off. There is no way we can factor fusion into our clean energy ambitions. Sitting here using solar energy right now (at night btw), I'm inclined to disagree. The Australian Electricity Market Operator believes RE, even without dramatic tech advances, can run most of Australia's energy intensive economy with high reliability and do it with less costs than coal power. Take away wind and solar and there isn't a clean energy transition.

More serious penalties should be reserved for actual instances of infecting other people through their failures to follow community health advice - which I think counts as causing significant harm. I am not advocating jail as the principle penalty for refusing to wash hands or vaccinate but it needs to be made clear that it endangers public safety. I think assurances of public health and safety are a prerequisite for freedom of movement.

If refusing vaccination, masks, handwashing etc as advised to minimise the risks to others is some kind of inalienable human right it is news to me, but if we are to grant that right I think those of us doing the right thing should have a complementary right to hold them legally accountable if we get sick with Covid as a result and sue them for damages. I've had to work with anti-vaxxers and they are dangerous idiots full of contradictory conspiratorial BS who are not simply arguing for personal liberty or only putting their own health on the line; the risks are also to others - even those vaccinated are still at risk (vaccination isn't 100% effective) and there are people who legitimately should not be vaccinated for medical reasons who are endangered. One thing to claim they would rather die than get vaccinated or obey health orders - another for them to be okay that other people to die because they refuse to get vaccinated. I don't think known risks to public health should be off limits for regulation - which I think is the view of a large majority around here; pandering to the extremists is a bad idea.

Whilst nations that can afford it work hard at vaccination of their own populations they appear reluctant to support global vaccination efforts in a big way - not at the scales necessary. New variants are one of the consequences of that parochialism. And whilst developers of vaccines deserve and require a financial return I don't think we can afford ordinary patent rights having precedence over maximising production and distribution; government involvement and support for those R&D efforts has been substantial but could be structured differently to assure the developers recoup or are subsidised for costs without making independent manufacture under license expensive and difficult. Cynically, it seems to be in the interests of Big Pharma to widely distribute such vaccines even with minimal profit - more people who survive Covid will be more ongoing customers for their other drugs - which can be a lot more profitable.