Ken Fabian

Farid, are you trying to be a topologist? Anyway it is your premise that the circle gets changed into a square - and that means (and therefore proves) the circle undergoes change. It is you that keeps telling us it is changed - should I be apologising for believing you?

Farid - Leaving aside the logical inconsistency in proposing that changing something (B is changed into A) doesn't change it (B is unchanged from A) - perhaps the totality of matter and energy in the universe can be considered unchanged but the arrangements of them definitely does get changed. Even the separateness of material objects gets a bit blurry at smaller scales; sublimation and erosion and chemical changes of surface material will be going on constantly, exchanging substance with the air and water they are immersed in. An object (or drawing) that we would agree is "square" will turn out to have no straight lines or perfect corners at nano-scales - and will be changing in it's fine details over time. Was it ever truly "square"? Depends on how you define "square". What did come to mind - not quite sure it strictly applies - is the old joke about topologists; topologists cannot tell the difference between a donut and the cup their coffee is in. As topology defines them they have the same shape. (As they would - iiuc - consider a circle and square to be the same kind of thing). It seems to me that appropriate definitions definitely do matter - and failing to get them correct leads to mistakes.

I'm not sure that would be the case; yes you can push a big mass and it will keep moving, but you need to push against something to start and stop that big mass. Having gravity and friction are actually very helpful to moving and processing stuff - I think doing useful work in microgravity will be more difficult, not less because of their absence. And of all the processing steps for mining and refining most materials, the moving stuff around part is likely to be the least energy intensive part of the whole exercise. I would expect a lot of energy intensive processing just to make (and recycle) the raw ingredients needed for metal refining. I am presuming energy will be some kind of fusion power - ie fusion that is simple enough that a small colony with limited economic and industrial capabilities can build and operate reliably, entirely with local skills and resources - no small step for getting that I am thinking. Fission is technically easier but fissionable elements are not abundant and will probably be mostly contained at very low concentrations within nickel-iron - and 'minimal amounts of energy' looks unlikely to be sufficient to refine it; energy costs of making energy using fission look like a serious issue in such conditions. I've thought the 'stepping stone' approach is the most reasonable of the various virtually impossible ways we might use to get people to another star - if truly self-sufficient colonies capable of spawning new self-sufficient colonies can be successful using asteroid/comet materials, and each new colony is in the direction of a target star, then potentially, eventually, some distant descendants might get there. But except for the very last of that long line, the stepping stones will only be a step to another stepping stone; the people involved aren't going to that star - and if their lifestyle works they don't need to - so keeping society wide commitment to that far, far distant end goal may prove difficult to sustain for the thousands of generations needed. I suggest the urge to find new territory - a primitive urge - underlies the sense of attraction people have for other stars and other worlds, but given the multi-generational nature of the goal, that is really not going to be sufficient to expect whole populations to repeatedly make economic sacrifices for something they will not see. That urge to up stakes and hit the road when things get tough in search of some place better is too vague and non-specific as a motivation, and is not (I think) sufficient for circumstances where you have the ability to make the 'someplace better' yourself, even if from such dismal and difficult raw material as asteroids and comets. Having worked hard and made some comfort and security - if you have successfully built someplace better and the way forward involves sacrificing that hard won security and comfort for starting all over again - that commitment to the far off end goal will be hard to keep going.

No, we do not agree. In any case, surely genes only directly determine RNA sequences. And not all of those RNA's are used to pattern proteins from. I provided images of working examples of combinations of RNA and proteins. RNA's have enormous biochemical potential - able to bring proteins together as a catalyst for example, as well as combine directly with them, as well as provide the pattern for making those proteins. If you are seeking better understanding then sticking to the belief that DNA only determines proteins when it has been pointed out clearly and repeatedly that is not the case is not a good start. And you still haven't told us your reasoning for concluding that DNA doesn't contain enough information - just repeated that conclusion. Not a good example perhaps. On consideration, all species share so much DNA that the total is not going to include enormously more than one species has. However I still absolutely depend on the DNA of other species, including for molecules my own body and cells can make. And my mother provided the ovum with all the cellular 'machinery' and epigenetic triggers, patterned from her DNA - which I may well have good copies of, for later. I'm not convinced a design specification exists, or more correctly that it is an appropriate conceptual framework for describing what is happening - the structures and their form look like an emergent outcome, not a specification.That may be arguing semantics. But I suspect this whole thread is about semantics.

DanielBoyd - it isn't just one individual's DNA involved in this - from edible plants and animals to gut flora, an individual's DNA operates with access to - making use of - the biochemical products of a complex biological community, based around more DNA than any discreet, single organism ever contains. My DNA doesn't have to have the combinations that will make every component that goes into assembling me. I don't need the DNA combinations for getting cells to make gluten for example, that I need; DNA of plants have those. I think the ability of DNA - of individual, parents and associated species - to determine which specific molecules are made (including molecules that, when put together will assemble into more complex biochemical structures) hasn't been actually been shown to require more DNA than is present. You really need to move beyond claiming there is not enough information to quantifying what is available compared to what is required. I think you need to be showing much more of the reasoning you are using for seeing a cell structure like eg a microtubule and a molecular motor and concluding DNA can't have determined the precise molecules used - which includes those that are downstream products made by structures that were made from DNA determined parts. Of course there is no 'design' specification in that DNA - that has always been just an analogy; the cascading, branching, interacting flow of biochemical processes that is Life only need for the resultant biochemical structures to work, not for the DNA to contain any descriptions of the end results.

PS Just clarifying my answer above - the fluid coolant would collect heat from that (probably Lithium) 'jacket' that surrounds the containment chamber.

My (limited) understanding mostly they intend heating of some kind of fluid coolant, probably water, and using that directly or indirectly for steam power generation as the means of using the energy from fusion. Neutrons are captured by a surrounding jacket, heating it. Lithium has been proposed for such a jacket because the process should convert some into Tritium, that can pass back to the working plasma as more fuel. Direct energy capture has been proposed as another means of extracting the energy - a kind of magneto-hydrodynamic process, using the flow of fast charged particles in a magnetic field. I'm not expecting any great results any time soon - and anything that is that hard to do at all is going to be difficult to optimise into a reliable and low cost form of energy generation. Worth trying I think - but so are other possible energy solutions that don't get nearly the levels of attention, support and funding that fusion does - some that look far more suitable to mass manufacture and worldwide everyday use (like a favourite of mine is optical rectennas that could work a bit like PV but should able to utilise IR, including from atmospheric back radiation and ground heat - ie would work at night. Or utilise low grade heat from waste heat or ground heat storage).

I've tried to imagine how electro-magnets might be used for tensile strength in some kind of chain - substituting for physical material strength. Hard to imagine it could be as strong as, well, chain but I don't really know how well they might work and what theoretical as well as practical limits would apply. Some things like that have made their way into SF - "The Moon Goddess and The Son" (Kingsbury?) had a mass driver system in orbit made of strung out sections that could concertina as it caught and launched stuff. Vague recollections of a laser up the butt type system (or was it another mass driver) for the launch from Earth in the same novel, that might rate as an example of external energy displacing onboard fuel. They may be technically feasible - but otherwise not. Or, more optimistically, not yet. I raised the issue of limits to physical material strength as a hard limit we aren't going to be able to push past - and maybe there are technologies and applications that can work around them, but I suspect the applications will be very limited - and have limits of their own. It doesn't make me change my view that science and engineering are not on a path of endless unlimited development.

Endy - the video is a bit long; can you summarise the main points for us? I would note that the material strengths we are getting in laboratories are truly impressive - a lot of opportunity still for engineering advancement to flow through into the structures and products we use. Still a lot of room on that S-curve, even from my more pessimistic pov - and my thinking that we are getting closer to where the trend flattens off than where it is still accelerating. I see us facing some serious problems with the course our civilisation is taking and our inability to incorporate knowledge and foresight into our decision making - we have vulnerabilities that can be helped by appropriate engineering; that looks like a different kind of focus than a less nuanced view of "progress", which seems almost to treat it like it is a natural law at play. Mismanagement - social and economic - look more capable of delivering us problems that resist any good intentions, and can reduce the growth in our capabilities and take them backwards; we are not so smart that we cannot mess things up so badly that our capability for R&D is reduced or lost. I think we will need to be increasingly cognizant of unintended consequences; are they going to be environmentally benign, sustainable and recyclable materials? How much energy required to make them and safely dispose of them? I would be alarmed at lighter than air construction materials for example - wind blown litter is already a problem, but having chunks of crashed aircraft floating about could take litter to a whole higher level, literally. And, of course, are the most advanced materials economically viable? There are a whole lot of considerations that can put limits on applications - it is not only about the physical properties we want but about about social and environmental consequences.

It seems quite common to believe that there are no limits - that progress is exponential (or some form of limitless growth). There are limits and I think recognising and understanding them is important. I think we are already quite a way along that S-curve - that a more complete understanding of physical laws is not going to be greatly different to what we know now and resolving the last questions (eg reconciling gravity with quantum mechanics or understanding the nature of dark matter) won't necessarily present us with great engineering opportunities - and may well close off some long running hopes that exist because real limits are not recognised and understood.. I think the strongest materials that can be made are not likely to be enormously better than what we can make in labs now and those may never be candidates for cheap and mass produced - limits of binding forces within molecules will be a hard limit that no amount of research will overcome. Just persisting and trying harder in the face of them can be a recipe for wasting precious resources. Testing those limits to be sure of them is one thing but operating on the basis that they can be overcome isn't, and even the opportunities for spin offs will have limits. Optimising - taking us closer to those limits, especially with respect to real world considerations (economics again) - will be a kind of ongoing development process, but could well end up with more focus on doing the same things better than on finding new things. SpaceX for example is optimising existing rocket technology and reducing its costs, not so much inventing new kinds, much as Mr Musk might wish for such possibilities. We can make supersonic passenger aircraft but we don't - the economic limits flow on from an understanding of aerodynamics that inform us that supersonic aircraft will be much more energy hungry the faster you push them and components will work under extreme conditions that make for choices between more expensive materials or ongoing maintenance costs. Or both. Or for not doing it. Can we engineer something better? Musk sees the possibilities for transport via vacuum tubes and I can too - but there are limits there also, in and on an Earth that can shake and deform as well as those pesky economic considerations. Perhaps the future of aircraft will not be faster - it hasn't been for several decades now - but will end up slower, driven by a need for hyper-efficiency. Perhaps solar powered airships. Progress, but not quite in the way people imagine. Where we are on the S-curve is a question - I do see areas where we will see a lot of progress but some of our economically important ones are - I think - nearing the top of their S-curve.

Well, my point is those new discoveries do become harder to find as the true nature of our universe becomes well understood and the limitations of materials and processes are approached - it is just assumption, and I think it is a weak one, that there will always be more. Especially that fundamental understandings of the nature of reality can't be achieved or relied on and can be readily overturned. History, seen from the steep part of the bigger overall S-curve (that is the product of all those individual S-curves) only makes it look like there will always be more - but I think it is an illusion. The supply of what we do not know is ultimately diminished by what we do know and the more confident we are about what we know, the less room there is for surprises. Knowledge may grow fractally and get more refined and nuanced in many fields but still come up against hard limits based on fundamental physical properties of spacetime, matter and energy.

I am one of those rain on the parade types in this; I think knowledge and technological capability - science and engineering - will follow more of an S-curve that tops out rather than exponential that doesn't. We can improve heat resistance or strength or hardness and may discover new materials to do those better - but real limits to how heat resistant, how hard or strong are being approached, that no amount of research will overcome. The steep part of that curve can be exciting and from there (here) it can seem like its continuance is inevitable, yet it isn't a natural law; fail to invest in research and it stops, but if research produces diminishing returns the funding stops. I don't think we will so much reach a cut off point where nothing truly new can be discovered or done as them becoming more difficult to find or make and less revolutionary, and with economic viability more difficult to extract when we do find or make them. There are already things we are capable of doing but don't for the negative economics of them. We may well find that research itself reaches the point of negative economics.

I don't see how you come to that conclusion. Of course they do not rely solely on proteins - Not only proteins; RNA transcribed from DNA also gets used directly in some remarkable molecular machines, such as ribosomes - like a molecular scaffolding that can assemble different proteins together into more complex arrangements than proteins alone -

I think that is diffusion - the molecular motions diffusion rely upon are thermally driven - Brownian motion iirc. I admit I am a bit vague on the physical mechanisms that make diffusion work, whereby the same kind of molecule seems to be 'repelled' by close proximity but are not affected by presence of other kinds of molecules. Of course there are physical structures that can aid movement - eg microtubules within cells that molecular motors can use to move an attached vesicle or carry signalling molecules- Just for the sheer wonder of it - an animation of a molecular motor hauling a vesicle along a micro-tubule -

Seems like there is a crossover period during the earliest stages of fertilisation where the new DNA operates within structures it had no part in making. The egg and the cell 'machinery' it contains came before the new mix of X's and Y's and is a product of parental DNA. That 'new' DNA only functions (at first) within existing biological structures of other's making - it doesn't make them it'self. Not sure to what extent epigenetic guidance and triggering is provided via the ova a sperm - but expect that those will be at work. At some later stage it will make those for kickstarting the next generation I think that is more like what it actually is - and naming it 'genetic design' always was potentially misleading. Analogy breaks down. The shape of a body part is the consequence of the self-assembly - no specifications for it's shape exist, but as processes of cell divisions and differentiation and growth occur, that shape is where the growth limits are reached. If it doesn't work the individual is in trouble and is unlikely to survive to reproduce - but the evolutionary process has left us with the ones that work. Picking just one point out of the many - I would expect diffusion to be a principle means for getting specific molecules to the right place within a cell - the 'right place' will be taking up those molecules and concentrations will be lower around there, so molecules will flow from where they are higher concentration to lower. Over such short distances, diffusion will have a strong affect. It would require a minimum concentration of those molecules - more than end up being used, with lots left over, to be recycled into other things.

DanielBoyd - you are not going to get much joy (from people rushing to agree with you) by claiming the mainstream science based understanding of DNA's role is so wrong as to be unworkable. Not here anyway, and especially not objections based on some personal insight into theoretical constraints that somehow make what is happening in your body right now impossible.You've dropped a whole lot of arguments all together on us, each capable of inducing people with varying degrees of understanding of it to disagree with you. Seems like the objections you have are mostly those of incredulity - your not understanding how DNA could perform a particular function seems to be taken to be evidence that it cannot. I suggest that analogies, as useful as they can be to aid understanding, can be misleading and suggest something that can be shown to occur is not possible; DNA is not a blueprint or design as we usually think of them but the parts life is made of - even to individuals and different species as well as specialised cells and organs - are made of multifunctional components; they share more in common than they have differences. Perhaps DNA and associated biochemistry is akin to recipe (which you do mention) or perhaps a string of coded instructions, with a lot of "if-then" branches but it not a recipe either. I don't think every biochemical step along the way is anywhere close to being understood - and for abiogenesis and early evolution, may never be known with certainty - but currently some of the questions you ask (differently framed) are on the way to getting answered. If you are not seeing divine intervention, do you have any better alternatives for how living biochemistry does what it does? Or are you saying that not only do you not know, it is not possible for anyone to know?

Less winter frosts here are getting hard to ignore - the longer term average is (was) about 40 frosty mornings a year and we have been getting fewer than 10 over recent winters, 2 so far this winter. Highly variable from year to year but when winter temperatures - both minimums and maximums - are breaking records in an upward direction it is hard to ignore. Those extra cold mornings, with a 'hard' frost are becoming quite rare. This has real significance; frost vulnerable perennial weeds that were previously held in check are becoming rampant, adding a burden of time and costs for weed control. Winter heatwaves - not necessarily 'hot' but much warmer than usual - have limited the opportunities for safe cool weather hazard reduction fires through the past several winters; burning off grass and leaf litter in order to reduce hot season fire intensity is becoming more difficult to do without risk of escaping past firebreaks. It used to be common to have cool overnight conditions slow and stop fires. Now we cannot rely on that and must be more vigilant and have more equipment and manpower to do the same job.

Yet lots of homosexual people - identifying as gay - do have children. Some may find it impossible to have hetero sex but I think the majority find, perhaps using some imagination, that they can want to have children and can perform the required act. No homosexual gene, perhaps, but they still have a lot more than zero chance of replicating and even if there were a 'gay' gene unless it has a much more reliable effect that prevents hetero sex it is not going to be selected out of the gene pool, and either way homosexuality will persist. I can envisage circumstances where there are a shortage of available mates - alpha males laying claim to multiple women for example is likely to have been commonplace. Outlets for sexual urges in such circumstance, that are not socially disruptive - avoiding fights and injuries - aid the reproductive success rate of the whole group, and more so when they are useful contributors to group survival. In 'selfish gene' style, the childless will share most of their genes with most of the group; aiding their nieces and nephews and cousins along the way will ensure the genes they share will continue.

I think at heart it is a hard nosed and short sighted business decision. A widespread desire by business owners and operators and broader commercial and industrial interests to not be held responsible and accountable for anything climate related is at the core of climate science denial - which I think is effect not cause; climate responsibility denial requires some kind of justification and denying the science is true is the most basic kind. Framing those who advocate for climate action as extremists with anti-capitalist ideological agendas and solutions as incompatible with free market democracy and prosperity have been powerful messages and the understandable concerns of political environmentalists and their being loud and standing tall on the issue - whilst the mainstream 'leadership' has avoided strong commitment of any kind but to the status-quo - made it easier to make that 'led by extremists' fear appear credible to the uninformed. I think this desire to avoid responsibility and accountability and ultimately to avoid liability flows downward through their companies to their employees, as fear for job security and lower pay - potent near term fears that tend to override any longer term concerns - and upwards to politicians and political parties as business leaders and associations lobby them hard to keep an enduring amnesty and de-facto subsidy on the externalised costs of emissions. Given how solid the science is, it takes something extraordinary to get people to distrust it, so framing it as about free market democracy versus extremist socialist ideology and prosperity vs poverty with so much pre-existing strong feeling and innate support for the former allowed them to bypass that trust in science by using alarmist fears. It has been extraordinarily successful. Pro- business politicians and parties (which tend to include all centrist as well as conservative right ones) put aside their greater obligations of trust and responsibility to their nations as a whole in order to act as advocates for those narrower interests - and those interests have developed a variety of techniques for inducing and influencing politicians, government policy and community opinion. PR, Advertising, Strategic Donations, Tactical Lawfare, Post politics career inducements, Lobbying and Tankthink are all used ruthlessly and with only minimal regard for the truth or ethics. The validity of the decades of science based expert advice governments have commissioned and received barely enters into their decision making.

It is not erring on the side of exaggeration to take those IPCC reports - and the numerous studies and reports that are summarised and referenced within them - very seriously. And those are consistently telling us that it is very serious and the consequences highly likely to take the world into dangerous territory ie more towards the 'alarmist' end of media reporting and climate advocacy; the proper balance is not between those who are saying it is serious and dangerous and those who say it isn't but between serious and dangerous and more serious and more dangerous. What the media says and what advocates say may or may not mirror that. 12 years to "save the Earth" or 12 years to stay below CO2 levels beyond which avoiding more serious and irreversible climate consequences becomes unavoidable? I'm not sure 'save the Earth' in this context is even truly exaggeration - losing the Earth as we know it and large parts of the remnant ecosystems still surviving looks highly likely, whilst interpreting it as 'no more Earth' certainly is exaggeration. But it looks like that claim it is alarmist exaggeration is as likely or more likely to be made as a criticism of those saying things like that than be the meaning intended. Certainly at the politcal advocacy level being succinct and impactful will continue to have priority over being precise - but those expert reports and studies are the bottom line here - not what advocates say or the slogans they use.

I have similar opinions on this. I'm not sure what the minumum population would need to be but, yes, self-sufficiency requires a colony to be a working, advanced, industrial economy with a large population - likely more advanced than any nation we have on Earth. It needs thousands of technical specialties to support such a technology dependent economy - and I think the availability of resources will be a serious problem; every bit of equipment for mining and refining on Mars will be an exercise in serious innovation, even if the full range of mineral resources such an economy needs are even available as usable ore bodies. And I see advanced, high tech innovation as a luxury that only successful economies - Earth economies - can support. An economy where absolutely everything is very expensive and every activity is more difficult than anything we deal with on Earth is an economy that is in trouble - and whilst AI may help, robotics are another layer of advanced technological requirements that a remote colony will struggle to support and sustain - I don't see robotics so much reducing the technology requirements but increasing the requirements for technology to be developed and supplied by Earth. Unless we are talking about AI - rather than humans - colonising Mars. Can such an economy exist independently - and safely - on Mars? I'm doubtful but suppose it is probably possible. The biggest problem I see is that there is no sound economic underpinnings for the long process of such a colony's establishment - that between getting a base on the surface (or under it) and establishing mines and factories and farms and all the supporting infrastructure there are accumulating cost but an absence of means to repay the enormous Earthside investments needed in any form of material trade.

Yes, the anthropogenic part is our responsibility. Seems to me the very susceptibility of our world's climate system to change is why adding lots of CO2 (our most abundant waste product by far) can cause a significant climate shift - it would take a climate system that resists change for it to not matter. et pet - whether or not some glaciers survive or the world still subject to future glacial periods does not change the seriousness of the climate changes we are inducing. Like the susceptibility to change, the extent of uncertainty about how it will play it is not a basis for complacency. Rather it is cause to be very concerned for unforeseen or unlikely consequences

Some glaciers will still be glaciers. Some will be in deep valleys at high latitudes that never get direct sunlight - and would take more warming than we are expecting to melt. A bit like 'ice free Arctic Ocean' will still have some ice in inlets that never see the sun ("ice free" being a term that includes the presence of such ice). Predictions from leading glaciologists and specialist science agencies (rather than secondary re-interpretations and media reports) of how rapidly global warming causes glaciers to retreat and when they ultimately stop being glaciers have never been precise and have included a lot of clearly stated uncertainty. And considering a 'worst case' scenario will always give a very different answer to 'most likely' - and worst case outcomes are more likely to get the attention once the discussion moves outside the realms of experts talking with experts.

It is an interesting question - the extent to which competing new technologies are bought out in order to prevent their use rather than to fully develop and commercialise them. Good ideas can be lost because of that as well as to inadequate funding and various forms of mismanagement. I once naively thought patent law was for making inventions and innovations widely available to others, with royalties ensuring a means for the inventors to be justly rewarded where it happens. It appear to be used more to prevent others using them - despite the potential for earnings from others succeeding at perfecting and commercialising them. It does appear that patents are for the big players - that without financial and legal resources the smaller players cannot defend against their theft of intellectual property.

Externet - I don't think it it works like that - the overall braking force aligns with the road surface, where the tires contact the road - not through the centre of gravity. Applying the brakes applies a torque between those tire/road contact points, which are lower than the centre of gravity, and the rest of the vehicle. All of the vehicle mass is above the line of braking force. That torque from the brakes will try and rotate the vehicle around the axles - but because of the rigidity of the body the combined result is a single torque lifting the load from the rear wheels and transferring it to the front - effectively the front tire/road contact points become the pivot point. As that happens the braking ability of the front brakes is increased and the rear brakes is reduced. (As MigL points out, they have the means to balance the difference between front and rear brakes - less braking to the rear, so the rear wheels don't lock up). Having the centre of gravity lower than the axles does reduce that tendency of the torque from braking to force the vehicle nose down, by placing it closer to the road surface and the line of braking force, but does not eliminate it.