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Ken Fabian

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Ken Fabian last won the day on February 15

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    Climate Science: Climate Politics: Energy technologies: Human Evolution

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  1. If you want to make arguments to support these assertions you are welcome, but stating them doesn't make them true. In my experience pretty much only staunch doubt, deny, delay opponents of addressing global warming seem chronically unable to update what they are sure they know about climate science or climate policy or options for doing something, like renewable energy. Around 3/4 of all new electricity generation being added around the world is now solar and wind, on their merits, as commercial decisions - not out of deep commitment to zero emissions (although the possibility of emissions accountability emerging in the future does figure into investment decisions) but because of this - .
  2. Sure, with fictional propulsion systems the impediments don't look so overwhelming. Reality is not so easy. Not that I would expect chemical propellants to be the favored choice apart from the initial launch - I would be looking at solar electric/arc-jets using asteroid water for reaction mass (or something like), ie something with barest minimum of consumables sourced from Earth. Whilst examples of electric arc-jets do exist that is not the same as large scale, long lasting versions with proven extreme reliability suitable for such a job; every part of such a mining project would be bespoke.
  3. I have no fear of corporate tyranny in space because space lacks opportunities for profitable enterprise. It is only in fiction that there are opportunities that are worth the effort. Space companies milking the taxpayer funded agencies is a depressingly ordinary kind of bad behavior. Unless there is something I am missing, something big, it looks like if we take away the taxpayer funding there is no self funding commercial opportunity in space exploration or any space activities that don't directly service Earth customers. I don't count transporting astronauts to and from the ISS - or the ISS itself - as self funding. No space tourism venture comes close to recovering costs, let alone makes a profit. If anyone can point to anything we do in space apart from ground sensing and communications satellite services that earns income from Earth customers and can be self funding I'd be interested. Asteroid mining, in potential, is the best I can see and even that appears to be far short of viable. For unashamedly taxpayer funded ambitions in space I think meteor defense is as good as it gets - far reaching enough to support ongoing space R&D with big ambitions, with multi-nation participation, that might end up opening up and spinning off something commercially self funding, but will be worthwhile even if doesn't.
  4. I expect the rate of success for self made wealth from initial poverty is very low compared to those starting from even modest (well short of "wealthy") inheritances - or just with families that can afford to be loan guarantors. "Just try hard and you will succeed" works much better for those with existing resources to draw upon - including being able to try again if not succeeding first time around more readily too.
  5. I prefer to have the video contents summarised for discussion - if I watch every one that gets suggested to me there would not be enough hours. I don't doubt that, given enough funding, aerospace companies will attempt Mars sample return missions, with reasonable expectations (but no guarantee) of success. But I expect it to continue to be easier and more cost effective to send remote operated robotic equipment to Mars to analyze mineral samples than bring samples back. If something of exceptional interest worthy of the kinds of study that can only be done on Earth gets found then the case could be made for a sample return mission. The knowledge is what is valuable although no doubt the samples would have collector value. Not sure the extent to which Mars colony hype influences exploration priorities but it seems to be explicit in objectives for many Mars missions.
  6. I think it is an oversimplification - or at least the quoted bit without the context and explanation of what that means could be misconstrued. Yes, some individual critter was a common ancestor of both baboons and humans, but it was not their only ancestor (or even only pair of ancestors). Their progeny would be a lot more like the parents and parent population than like baboons or humans and I would expect generations of "common ancestors" for each to coexist and for some of (and possibly all of) their progeny to also be common ancestors of both later lines. A whole lot of evolution would be still to come, including some cause for divergence into separate populations.
  7. Human consciousness seems to be a predictive machine, anticipating the present out of near-past perceptions. Observations are never truly in the present yet it all seems to work. And maybe revisiting observations after actually makes for greater clarity.
  8. As for restricting home computers (the OP) - the deaths of innocent victims from AI are hypothetical, and even more hypothetical from home computers. Deaths of innocent victims from misuse of assault rifles are not hypothetical. Not sure many home computers can even support the kinds of AI that can (hypothetically) be dangerous; AI as a tool used nefariously by military and intelligence services (including by despotic regimes) seems more likely to me than rogue AI. But assault rifles are designed for one purpose - injuring, maiming and killing people. I'd prefer that power to use such force be in the hands of trained people who understand proportional and appropriate responses as well as operate within the rule of law. (Which I would want to be the case for government agencies using AI as well). In functioning democracies with rule of law armed citizens rising up to support and protect their government and institutions when attacked by enemies, including insurrectionists makes more sense than as a standing tool, just in case, FOR insurrectionists. Without an existing, credible threat and absence of military capability to face it there seems no good cause for a standing armed populace. No government as better - Libertarianism - is delusional; the solution to bad governance is better governance, not absence of governance - and a lot of nations with high levels of personal freedom have made their institutions, like independent courts, their bulwarks against tyranny. From outside the USA it looks like the day the armed populace there rises up will be the nation's ruination - those weapons are for use against other Americans and the designation of "enemy of America" for those with different politics, religion, ideals as promoted through free speech and voting will be self serving justification at best. The historic Revolution may be the aberration, where the winners did not put themselves above the rule of law - eventually - once those who supported the King were ousted, or summarily executed, or had their property taken or were forced to flee (to Canada). The kinds of insurrection the US faces now doesn't look legitimate in any sense, and unlikely to result in greater freedom or prosperity even if it succeeds.
  9. You could, but that wouldn't have the horsepower of a gasoline vehicle. Not correct; a gasoline vehicle might have greater range than an EV but weight for weight the power of electric motors beat ICE easily by a huge margin. If the vehicle has to carry oxygen as well as fuel an ICE won't have much range either. And if you have to bring the fuel AND the oxygen (or oxidant) from Earth then EV's running off solar power looks like the better choice every time. Somewhere like the moon might manage with direct solar power for 2 weeks out of 4; large lightweight solar wings in vacuum would not even present serious stability problems without wind - but may need shock absorbing stabilisers for rough ground. Or unfold and unfurl them when stopped to charge batteries. Traveling by lunar night would probably present other problems besides energy storage - scheduling to avoid it may be more practical.
  10. All interesting, if disappointing. Does it mean this - "Demonstration of resonant tunneling effects in metal-double-insulator-metal (MI2M) diodes" (a demonstration of an optical rectenna in IR) only works because the source is in phase? Would not work otherwise? I suppose that means it was in phase but I don't know. "Linearly polarized" ? "Modulated by a 3320A function generator"? Polarized to a specific axis? It is all beyond my paygrade - but my surmise that it had to do with the heat emissions of the receiver overlapping with it's tuning seems wrong as well.
  11. I don't know why Dr Novack thinks it but I think it because I think the photons interacting with an antenna don't add (all of) their energy as heat to the antenna, some energy making electrical potential. Some gets converted to electrical energy and carried away. It may initially be at thermal equilibrium but it isn't a closed system. Note, I don't think this as a certainty - I don't know enough. But if the antenna can't absorb IR because the temperature of the antenna makes it radiate IR - not the antenna transmitting IR because that takes electricity from somewhere else, but the materials radiating it in the normal way things that are warm radiate - then, yes, it is at thermal equilibrium and an IR rectenna cannot work. I had thought that interaction between EMR and an antenna was independent of antenna temperature but that was most likely ignorance - most working antenna aren't tuned to the band the antenna normally radiates in.
  12. @sethoflagos I understand that antennae work as transmitters and receivers (but little real understanding of how they work). I am simply looking at energy flows. Antennae do turn EMR - if only narrow bands of it - into electricity and that energy is not being absorbed into the substance of the receiver. Simply, the energy that is diverted away isn't turned into heat in the receiver. In an otherwise closed system it has a leak; there will be loss of energy, ie cooling. Are you (or Kirchoff) saying an antenna won't work if the substance of an antenna radiates within the band it is tuned to - that IR emissions (specifically) are too close in wavelength to the receiver and prevent it working? This may indeed be the case - ie there isn't any flow of energy away as electricity in a rectenna tuned to the bands that materials radiate heat because it doesn't work. But at shorter or longer wavelengths - outside the IR - they will? Yet my understanding is optical rectennae have been shown to work - albeit at very low conversion efficiencies; at just what wavelengths, at what temperatures and under what conditions I don't know.
  13. Thanks Sethoflagos. I admit I still can't say I understand. Seems to me the materials of an antennae will get warmed by what the antenna doesn't turn into electricity - but a warmer antenna should work at similar efficiency as a cold one, it not being a thermal phenomena; unlike an ordinary material less energy/heat is added to the material of an IR antenna than the total energy received and absorbed by it. I still think diverting it away as electricity diverts energy away from the combined emitter + receiver and should result in loss of energy within them, ie cooling.
  14. I admit I am still unclear on this. Won't the receiver in this case only gain heat from what is not converted to electricity and will radiate back less than reaches it? Seems to me the rate of absorption by the antennae is independent of temperature of the antennae. A cooling emitter - radiating away some of it's energy, yes - but a cooling receiver too (?), diverting what reaches it to electricity instead of raising it's temperature (and radiating it back). Again, adding to efficiency?? I recall one of the suggested possible uses for Optical Rectenna is surface coatings on walls for cooling rooms, an alternative to A/C - "waste" heat turned to electricity as a bonus.
  15. Off the top of my head I don't think that is correct. I think IR intensity of the emitter is purely temperature dependent but is not dependent on a difference in temperature - ie is independent of the temperature of the receiver. Except maybe will be receiving IR or conducted heat back - which, if the receiver is heated by the process would counter intuitively increase the efficiency... ?? Doesn't sound correct, but... @sethoflagos Any thoughts on this?
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