$7/month for a 10 KW service has to be compared to $0.11/kw-hr for Arizona electricity, scaled out to the actual energy consumed by the household. If I am paying $150/month for electricity and drop that to zero, netting $143 doesn't increase the amortization schedule for the hardware by an enormous amount. Is it reasonable? Hard to say. Charging the consumer SOMETHING for the use of the lines isn't crazy. I pay $15/month just to have power turned on to a cabin I hardly ever use and that consumes no electricity at all. But it is cheaper than having the power turned on and off when I do use it.
FWIW, I agree with you completely, sir, and I don't even "believe" that AGW is likely to be catastrophic or that CO_2 is intrinsically bad (I actually have pretty good reasons for my beliefs, but not worth the flame wars asserting them entail). Solar power SHOULD come into its own when it is cost effective. Indeed, it is the capitalist way. In the case of power, though, since power companies are hardly capitalist enterprises -- they are publicly sanctioned local monopolies and nearly completely protected from anything like actual competition -- it is entirely within the rights of the same commonwealth that gave them the monopoly to require them to run the damn meter backwards for people that put energy back into the system by whatever means. It is POSSIBLY OK for them to add in a "tax" of some sort and pay back the added power at a SMALL discount, since the consumer is using company resources to effectively redistribute their energy surplus on lines maintained by the company. But then, they are also helping the company load balance and avoid building new generation facilities, so it isn't even clear that should be the case.
I myself already have replaced my windows, my roof, added in a double layer of high-R insulation in the attic, replaced all of the old furnaces and AC units with uber-high-efficiency units and use tankless gas hot water (which leaves a bit to be desired, actually). My energy costs are so low there isn't a lot leftover to pay off an investment in solar out of reduced cost of purchased electricity (one of the paradoxes of this is that your amortization scheme depends on how much you pay out, and conservation measures elsewhere actually increase amortization to where the advantage of PV solar once again is marginal to lose-a-little).
Still, I expect to PROBABLY bite the bullet and do rooftop solar in the next 2-4 years, sooner if hardware gets cheaper faster (reducing the amortization schedule). For the electric utilities, though, solar is already a no brainer win and they are building their own solar farms just because if I can break even or win a bit at full retail costs for solar, they can probably double my payback via economy of scale in solar farms. That may be why they are opposing the buyback option -- they can make more money making solar on their own than reselling solar energy you made and sold back to them at cost. In fact, they don't MAKE any money on the latter.
Obviously not. My physics Ph.D. is just an accident.
It is equally interesting that you completely avoid the point I was making, which is that we cannot successfully predict the climate using general circulation models. But I suppose if you know any physics or mathematics you already know this. You certainly know how to argue on the basis of logical fallacies. My statement that we are not able to predict the extent of any warming caused by CO_2 and are very, very far from being able to show that it is or will be a bad thing does not, in fact, equate to stating that there is no such thing as the greenhouse effect or that increasing CO_2 should not cause a logarithmic increase in average surface temperature. Outside of that, it is a simple matter of fact that -- if you bother to actually look at e.g. figure 9.8a of AR5 -- the GCMs do an absolutely terrible job of either predicting or hindcasting the climate outside of the reference period where they were dynamically tuned to match it.
Some other facts. One cannot observationally separate natural versus forced warming in a dynamical nonlinear chaotic open system like the Earth. The error bars in our knowledge of past climate state are far larger than are acknowledged to the public (when error bars are published at all -- as a general rule a simple line graph is drawn as if it is "true") and IMO the error bars on things like HadCRUT4 -- which are only a factor of 2 larger in 1850 than they are in 2014 -- are completely absurd. And the GCMs, BTW, are basically just dressed up weather models, run forward in time on an absurdly coarse (compared to the Kolmogorov scale) spatiotemporal grid, some 36 orders of magnitude short of where they would need to be to be able to semi-reliably actually integrate out the models from known initial conditions, if we knew the initial conditions. They are limited not by design (only) but by the simple fact that we cannot afford to build a computer network capable of solving the problem.
But hey, I probably don't know anything about mathematics or statistics or computational modeling or large scale computation either. So feel free to dismiss my opinion because you don't agree with it on the basis of my presumed incompetence. After all, anybody that doesn't agree with you must be ignorant or stupid or being paid off or holding a vested interest or -- pick your favorite fallacy and have at it.
In the meantime, by all means support research into ways to irreversibly change the climate system even more than it may or may not have been changed already. What can go wrong?
I think it would have a substantial ripple effect. TFA isn't about possession, it is about using a "lethal weapon" in a drug-related crime. If you subtract out the pot, you also take away the right to search people who happen to visibly be smoking pot and your odds of catching them for secondary offenses go way down. Sadly we wouldn't make a dent in the petty crime committed to support a drug addiction (as pot is not addictive and not so expensive most people feel compelled to steal in order to afford it) but it is a good first step in that direction as well.
And even 20% fewer lawyers is a good thing. With luck we might even make it 25 or 30% fewer. So far I've spent $20K or very near that defending my sons from silly possession charges, almost all of it going to lawyers.
We've had traffic signal LEDs for a while, but AFAIK no overhead street lights. I'm not sure they are bright enough to meet their "standard" or whatever.
I'm just quoting over the counter prices I see in my grocery store or local hardware store. So far Duke power hasn't offered any killer deals on them (although they do periodically with CFs, but I'm already using CFs throughout the house). Also, I need/want 100W equivalent brightness and the best Harris-Teeter can do is 60W equivalent for around $25-30. Online Cree bulbs (Cree is right down the road and some of my ex-students work there) are around $24 for 100 W equivalent, Eco-bulbs around $23, save a bit if you buy in bulk.
That's a lot of money for a single bulb. Yes, they claim 25,000 hours. Yes, the bulbs haven't existed for any reasonable fraction of that much time so we have no idea how long they'll last. My garage has a whole bag of CFs that are rated for 8000 hours and didn't make it to 3000.
Where do you live? Someplace either very enlightened or broke, I imagine. Mostly enlightened if they are buying LED lamps, which are not cheap.
But hey, when I visit Charlottesville, it has these lovely 1 meter wide bike lanes on most of the streets near UVA. I'm so jealous. Durham just painted a line on the side of existing streets that sequesters anywhere from 0 to 40 or 50 cm and call that a "bike lane". On my own ride into campus there is a place where it goes from 40 cm to 0 cm under an overpass at one of the two busiest traffic points on the entire route. Several people are badly injured or killed every year riding bikes in Durham (including, a couple of years ago, Seth Vidal, the principle developer of YUM and a good friend of mine) -- I wonder why?
These are the steps we should take long before we try uber-expensive and risky measures like mucking around with either atmospheric chemistry or space blankets in the sky or even massive (and hence expensive) rail projects. They make sense even if AGW is nonsense or sensible but not a real threat or even beneficial. It's a lot healthier for me to ride a bike into work -- or would be if it weren't for the substantial risk of injury along the route and the fact that I'd have to ride down a mile of country road with an inadequate bike lane during rush hour in the dark because of the silly time shift. Bike lanes, losing most of the street lights and regulating commercial light pollution after hours, and some clever use of electronics to control crime instead of light. They make sense even if Lockheed-Martin does have commercial fusion (as they claim that they will) within five years.
What's the point of putting anyone in prison for weed ever? If the states would just get around to legalizing it completely, no more BB-gun crime in your area! Prisons would empty! Lawyers would starve! All of these are good things.
And one day we will. As my son points out, every year, lots of Old People (tm) die. At some point enough of them who learned about the evils of pot from William Randolph Hearst and Anslinger via vehicles like "Reefer Madness" will have died, and the simple fact that states that have legalized it de facto or de jure aren't imploding in an orgy of drug-fuelled crime will be persuasive even to those that think that it is not necessarily good for you to smoke pot. And on that day, every single person who lost their freedom, their health, their wealth, and their future not because of the chemical effects of pot but because we made it illegal and created a world where breaking any law, just or not, is dangerous will cry out to the sky:
Yeah, and did you notice that nobody -- nobody at all -- is calling for street lights to be turned off for good. Everybody's worried about burning coal, wasting energy, making resistance heating electric hot water heaters illegal as of this year (sheesh!). They want us to turn off the lights in our houses, they want us to spend $20-30 on LED bulbs because incandescents use too much energy -- but the streets are lit outside of my door with enormous halogen bulbs that burn all night even when there are no human eyes open to see their light. Empty parking lots blaze with halogen and mercury and neon. Cities string Christmas lights by the thousands along miles of road once a year. We pay for all of it, and yeah, it means that we can't see the sky particularly well even living on the rural edge of the city with deer in our back yard.
As a species, we're scared of the dark. We don't even consider turning off all of this completely wasted light (and saving some serious power, instantly) because then bad things would come out from under the bed and get us.
We're not even completely incorrect in this belief. One of the bad things is us and we are indeed scary as shit.
However, for far, far less than it would cost to loft crap into upper atmosphere or orbit, for far less than it would cost to even "commission research into" eventually lofting crap into orbit, we could start to actually use smart technology we already have and e.g. make street lights motion sensitive, or control crime (the usual excuse for having them, since "to prevent irrational fear of monsters" isn't an easy political sell for all of its truth) by actual robocop monitoring, looking for crime and not just putting up lights to nominally scare it off.
One could go down a rather long list of petty vanities that cost comparatively huge amounts of energy that we routinely pay for -- and waste. Billboards. Streetlights. The pointless annual time shift. Trucks vs trains. The utter lack of functional, safe, bicycle lanes in almost all the communities in the US. Electric cars. Living in borderline desert regions instead of water-rich temperate regions just because cheap, plentiful energy and long range importation of water makes it possible if unwise (as California and Las Vegas and the southwest in general may learn any year now).
Personally, I think that the evidence for catastrophic anthropogenic climate change is all but nonexistent -- it is a simple matter of fact that the changes in climate from the mid-1600's to the present, whatever their cause, have been almost entirely beneficial and in any event are utterly lost in the noise of normal daily and annual variation (overall warming from that entire period is around 1 C, an a signal too small for people to even notice against the noise). If someone truly "believes" in it, however, in spite of the fact that the models that predict it suck and the IPCC itself in the third annual report admitted that the problem of predicting the climate was basically unsolvable so that it is no surprise that the models suck -- let's start by turning off not the lights in my house, where I live and use the light, but outside where all it does is help the deer find the best hastas and roses from my garden to eat late at night.
Seriously. We have a perfect understanding of the climate. We can predict to a tenth of a degree what the weather will be two weeks or two hundred years from now anywhere on Earth. We fully understand what triggers ice ages and can hindcast the climate of the entire Pliestocene, quantitatively. Our knowledge of solar dynamics is almost perfect, so we can confidently predict the state of the sun well into the future. Our measurements of atmosphere, ocean, and land are complete so that we know the entire state of the ocean (for example) well enough to predict with complete accuracy its future evolution given any possible variation of solar input. Finally, we are perfectly capable of predicting the future course of human affairs -- global population, the distribution of that population, land use -- and can predict already precisely when we will make critical scientific and technological breakthroughs (like thermonuclear fusion or widespread LFTR fission or storage batteries that don't suck or high temperature high current superconductors) . Our knowledge of the interior of the Earth itself is at last nearly complete, so we can predict to the day when Yellowstone or other supervolcanoes will wake up and erupt continuously for ten or twenty thousand years. Finally, once we create an orbital cloud of atomic sodium (or whatever) into space, it will be easy to remove it or rearrange it if it turns out to do something completely different than we expect, such as trigger snowball earth or act in its own right like a layer of greenhouse gas between the Earth and 3 K infinity.
Oh, wait, those are all things we don't have, and can't do, and don't know. And I absolutely shudder to think of the price tag, both in dollars and in joules.
I swear, common sense is a lost art.
Let's go back to discussing orbital solar cells as a solution to both energy production and screening. Adding 64 MJ/kg (times a thousand or so) to the cost of solar cells by lofting them into orbit and giving world governments potential access to an orbital superweapon just to get to 1370 W/m^2 sunlight is sheer economic brilliance compared to this one. Oh, wait! Maybe we can combine the two! We can mortgage the next 100 years of human productivity to pay for it, no problem! It's not like we have anything else to do, like ending world poverty, preventing antibiotic resistant malaria from breaking out into a worldwide pandemic, embracing rational thought at the expense of the not-great world religions, and coping with leftover hypernationalism and colonialism from the cold war. So sure, let's do it! Solar cells AND making Earth a ringed or stratospheric smog laden planet!
That works amazingly well for me, actually... In fact, I like the "moron point" add-on for so very many things. So many it would be difficult to make a list...
So do stone-cold sober drivers. So do old people. So do young people. So do drivers who are high, but who also had a few beers. The reason god invented statistical analysis was so that we could stop using anecdotal reports of "knowledge" as if they were fact.
That said, pot is like alcohol in one important respect, and that is that one can have a lot or a little THC on board, and then, there are different cannibinoids with different action on the brain, and since the THC tests are comparatively insensitive to both concentration and type compared to blood alcohol tests it isn't so easy to build a table that extracts the risk associated with driving while doing bong hits of resin-saturated buds every few miles compared to driving having smoked part of a joint of everyday weed two hours earlier. You remain THC positive for days after smoking, but are at (possibly) increased risk for at most hours, where with alcohol one metabolizes roughly 1 drink/hour (perhaps a bit less if you get a lot of alcohol on board instead of a little) and can remain at increased risk for six or more hours if you drink heavily at a party.
However, TFA (which I actually read, as the subject interests me) basically showed that across all categories of pot use, there is a very small, statistically insignificant increase in risk of accident. They noted a number of studies that show decreased risk for moderate pot intake -- the theory here being that stoned people know that they are stoned and drive extra-carefully and end up safer than your average cell-phone-toting, conversation distracted, overworked and stressed out driver. This may well be cancelling out part of the increased risk associated with drivers doing hits while they drive. But designing a study to reveal this sort of thing would be challenging and in some sense isn't useful. Common sense suggests that it is dumb to do bong hits while driving at high speed down an interstate, especially while washing it down with a cold beer on the side, just as common sense suggests that it is dumb to drive without a seat belt or while texting or while fumbling with a music player or when one is really sleepy. Some (many) people, myself included, have done one or more of these things at one point or another in their lives.
The evidence, however, supports at most the citation of individuals caught driving WHILE smoking weed, not people who have THC in their bloodstream. That's the whole point of the study. Unless/until we have better tests that can easily detect the quantity and type of THC in your brain and studies based on those tests that are sensitive to and demonstrate the increased risk you assert is there based on anecdotal evidence (and sure, common sense) for some specific levels of concentration, the risk based on the mere presence of THC in the blood is substantially less than the risk associated with drinking a single beer. Field sobriety tests measuring actual intoxication are going to be more valuable than "just" the presence of THC.
That's right, I like to include Nitrogen and Phosphorus and Uranium in my beer. None of this wussy carbon, oxygen and hydrogen. You know you've been drinking when you drink molten thorium fluoride salts.
Oh, you mean from hydrogen and carbon dioxide only...
Ah, that makes a lot more sense. So it was set up to basically do a reverse greenhouse -- reflect sunlight with very high albedo (not strongly absorbed because the non-humid atmosphere is largely transparent to sunlight) but emit on its own in bands that are counterposed to the greenhouse gas bands. That I can believe, I think. No second law violation because it is stuck between two reservoirs, one at 6000 K (sunlight), one at 3 K (space) and in thermal contact and quasi-equilibrium with a third (its environment). Interesting.
So during the day it would absorb less heat from the sun, and would radiate what it did absorb away in a comparatively narrow band. There are still some heat flow issues -- in order to be in dynamic equilibrium via heat loss through the smaller window, it has to get hotter than it would the same as an ordinary material with outgoing radiation merely blocked and reradiated down in the greenhouse bands, but it is decoupled from those bands instead of being in balance with them.
One does have to wonder what happens to greenhouse radiation incident on the material from above. It can't be absorbed because of Kirchoff's Law. So it must be reflected too?
No problem with resonant fluorescence or colored objects and so on. It's the notion of something being in thermal equilibrium with (say) 300 K but radiating only at a single frequency being a more efficient cooler. That's basically a picture of a thermal refrigeration laser (at least, if one puts the optically active material in between two mirrors). It requires a very peculiar quantum structure and as I said, one has to worry about detailed balance because the ordinary bouncing of internal thermal energy has to keep the resonant level "pumped" without itself radiating. It is metaphorically very close to a nanoscale Maxwell gate that only lets molecules through if they are warmer, or cooler, than equilibrium so that a gas spontaneously separates into hotter/cooler volumes, although as you say technically it might not violate the 2nd law by cooling to a reservoir at 3 K bypassing the material in between and hence enable a perpetual motion machine of the 1st kind. Odd to say the least.
I don't remember it on/. but I'll look around. Usually I catch anything of interest in optics but sometimes topics cycle fast enough in my feed that I don't see them before they breeze on through. However, if the time frame is "very recent" that helps. I suppose I can see what google can turn up. Thanks.
I'm not disbelieving, but given the nature of thermodynamics and radiation, I'm not believing until I read the paper(s) and see some evidence that it works. There's the detailed balance issue.
Then one can look at the cost-benefit. If it is cheap, it absorbs heat and radiates it away in a single channel, and you can make roof tiles or roadway surface out of it, it might make some sort of difference. Sadly, this is what I'm having trouble with because with a single sharpish frequency one is dangerously close to a Maxwell Demon, take "heat" and radiate it away as a single frequency.
And when the day comes that we can build general purpose robots, your obvious retort #2 will be apropos, although even then one will have to compare the operational efficiency and cost-benefit of a really, really good firefighting robot that is designed and "hardened" to be ideal for fires vs a slender, athletic, wide-hipped robot with highly flammable rubber padding in strategic places and a variety of special "attachments" that happen to include an appendage that can spray whipped cream or class B fire fighting foam.
I'd argue that the latter might be more appropriate for the home, not so good for a navy ship.
You'd also really like the AI to be pretty well debugged so that you don't get an inappropriate response if you mutter "Oh baby, I just burn for you..." at an inopportune moment.
Because they already have that, and it is boring? Because robotics are cool and fundable even where they are pointless and useless? Because the people that approved it have watched too many WW II movies? Because automated fire suppression systems might be vulnerable to damage elsewhere, requiring some system capable of dynamically bypassing nearly arbitrary intermediate zones of damage by archaic means like "fire hoses" in order to deliver fire suppression? Maybe a bit of all of these?
One can certainly imagine a scenario where a cruise missile or torpedo or even a shell strikes a ship in such a way that it knocks out most built in systems in some zone and sets that zone on fire, at which point sending humans in to fight the fire puts them at high risk and not sending humans in to fight the fire might put them at even greater risk from a sinking ship. At that point sending in a robot (humanoid or not) instead could be a lifesaver.
One is reminded of any number of science fiction stories, though, by Asimov and others. Building a humanoid robot for this purpose seems incredibly stupid. One doesn't want a robot to run a vacuum cleaner as if it is a metal version of a french maid. One wants a robot that is a vacuum cleaner, or a vacuum cleaner that happens to be a robot. Take vacuum cleaner. Add mechanism for moving. Add mechanism for navigating. Add minimal hardware needed to perform standard operational maintenance (that is, dump the dirt and clean filters). Add judgement/programming (or not, make it remote operated by humans sitting in a chair somewhere by remote control). In the end, one is more likely to end up with R2D2 with a carpet-sweeping vacuum base and "arms" that ARE extensible, manipulable tubes with nozzle(s) than with anything that looks like C3PO pushing a Dyson. And ditto for fire-fighting, only even more so.
OK, so we have multiple cosmi (space-time continua) embedded in a higher dimensional universe. I'm totally down with that and have written an entire SF novel based on the premise. Those cosmi (as the plural of cosmos) have a coupling. I'm good with that. But that means that "neighboring" cosmi will exist in a coherent bundle, and one will have to get quite distant from "this" brane to find a brane with substantial drift in its general mass distribution.
This is simple statistical mechanics, by the way -- if most brane-to-brane transitions occur in places where there is chuck of mass in one cosmos and none in another cosmos, there will be steady diffusion from the high mass concentration to the low one. This would lead to egregious and painful violation of mass-energy conservation as my foot in this cosmos diffuses into a vacuum in many, many others, because after all, the mass density of any cosmos at all is nearly zero with a hard, hard vacuum nearly everywhere.
This is overwhelming evidence that this sort of brane to brane, cosmos to cosmos transition does NOT happen in a universe in which the cosmi are equidistant and randomly organized. The only way that those transitions are possible at all is if there is a metric in the higher dimensional universe and if neighboring cosmi have ALMOST identical mass distributions and if transitions are only likely as pair exchanges between neighboring cosmi (note the requirement for pair exchanges is also a rather hard one or else one would observe a cumulative violation of conservation of mass in random-walk style that would be impossible to miss and that people have looked for, unless the transitions were VERY unlikely, or became very unlikely as a function of the intercosmos metric separation to increasingly different cosmi.
Note well that these constraints mean that no matter what, they aren't going to "bypass" a shield with a neutron flux, because there are going to be no nearby cosmi/branes in which the shield does not exist.
Note well in addition the response to those who suggest that this might be a way of viewing tunnelling. It is indeed -- the alternative cosmi are one of the POSSIBLE (I don't say plausible) interpretations of path integral formulations of quantum mechanics, integrated out. But in this case you STILL won't get tunneling through a barrier centimeters thick.
So this is a pointless experiment. One might as well just look for egregious violations of mass-energy conservation in everyday experiments, because if there is any substantive probability of mass energy departing our own spacetime cosmos and appearing in another "nearby" one, it would happen all the time and all mass concentrations would diffuse out into a multicosmo heat death.
Gravitation is an excellent possibility as the coupling between branes/cosmi -- one would guess that the "dimpling" of one spacetime dimples all of the neighboring ones on all sides (however many "sides" there are:-). The dimples probably don't have to precisely correspond, but they are likely to have to approximately correspond to minimize almost any sort of coupling across the sheets that permits a transition to occur in the first place.
In that part of the universe that is visible. We have no idea how much of the universe is beyond the ~14 billion light year visible boundary, only that it very likely extends at least many times as far beyond.
We absolutely do not know if there are more non-simply connected, non-interacting universes, because by definition you can't get there from here and cannot see them in any way -- but that does not mean that they do not exist, nor does it mean that they do. It means that we do not know if they exist because we have no evidence for their existence. We absolutely do not know if there are more coupled universes -- universes that one might be able to reach -- with independent space-time, because whatever coupling there might be between them, it is weak.
Finally, we do not know even in the simplest case that the many worlds quantum theorists hypothesize whether or not the bundle of universes is coherent, so that there are indeed lots of "nearby" universes with alternate-me as part of a coherent quantum bundle of me embedded in a coherent quantum bundle of universes that is semi-classical in evolution but knit together (entangled) with many little quantum jumps at the planck scale, or if you prefer the macroscopic cosmological hypothesis (which is pretty much completely without empirical foundation or any likelihood of obtaining any) of universes bubbling up in some sort of overarching ether with coupling constants that vary (without any explanation of how they might vary, or what sort of space of possible values bounds or does not boud the variation, or the physics that couples them with meta-coupling constants -- do you get the feeling that this is just mathematical science fiction, because it is -- we do not have any evidence that one single one more of these hypothetical universes exist.
It's like planets. Before 1990 there were lots of theories for planetary formation, and science fiction writers had been writing stories involving planets around other stars, usually with highly evolved life, just taking it for granted that they exist. But nobody had ever seen one, so that the statement "there is a planet within 100 LY of Earth with highly evolved life" was at best a scientific hypothesis unsupported by any evidence, but really was a complex form of science fiction because science had no way of sensibly bounding the probability that such a statement is true and there are a near-infinity of possibly true statements and we quite rightly give little credence to almost all of them without evidence and a really, really good reason to think that they might be true in the physics.
Today we have built instrumentation that permits us to "see" these "alternate universes" -- very crudely, but even that is improving over time as we build still-better instrumentation -- and we have at least some idea of what the density of planets of at least a certain size is in our immediate vicinity, much as we built the Hertzsprung-Russell diagram from parallax observations of nearby stars. We therefore have some small empirical basis for a model of planetary density around third generation stars (that probably doesn't extend into specialized environments, e.g. globular clusters). At the same time we are learning, somewhat painfully, lots of things about planetary chemistry and planetary ecology from observations within our own solar system and MIGHT -- as soon as we can sensibly measure some of the gross signatures of these things with even BETTER instrumentation -- soon get an idea of whether or not it is at all probable that there be highly evolved life within 100 LY. By an idea, of course I mean some statement of probability based on observations that has some statistical significance, as opposed to a statement built on top of a teetering tower of Bayesian priors 2/3 of which have no observational basis at all, none of which can be improved by recomputation of posterior probabilities based on observations within some restricted set.
We know no such thing. We make conditional inferences, and part of what they are conditional on is our incomplete understanding of field theory. We don't even know if there is truly dark matter and/or dark energy, or what they are or how they work. Our understanding of the big bang/inflation extends back (again, rather conditionally since any number of field theory variations would completely alter it) to 13.8 bya but is extremely fuzzy given that we can't "see" events any earlier than the end of the Great Dark. All we have is a lower bound on the size of the Universe associated with the homogeneity of the CMB and estimates (which vary according to one's beliefs concerning DM/DE) as to whether the visible part of the universe is open or closed.
That's at the macroscopic level. At the microscopic level we are many orders of magnitude short of the Planck scale and do not even know how to reconcile quantum theory and gravity. But don't let that stop you from asserting certain knowledge just because you read something somewhere that was stated as truth without bothering to add all of the conditionals.
Unless they exist in a loop. Then there is no first. Then one can scale the loop up to infinity.
There are many rooms in Hilbert's Grand Hotel, and even though nobody ever brings cigars in through the front door, there is always a fresh cigar waiting in your room every morning.
Unless and until there is a glitch in the matrix, there isn't any really good reason to think we are a simulation in some sort of meta-universe, and some excellent information-theoretic reasons to think that we aren't. The estimates of "probability" here are completely meaningless because the Bayesian priors are utterly disconnected from any possibility of proof. If this, that, and the other thing are all true, then we are probably a simulation. If there are multiple universes at all (whatever that even means) and if we make a small mountain of assumptions about the rules that govern them (all unprovable) then there is no you in any of them, unless of course the distribution of universes isn't uniform or defies the odds and there is. If wishes were horses, beggars would ride. If pigs had wings, they could fly.
The only sad thing is that people are even pretending that this is science. You have it pegged -- it is science fantasy written by a cynical but very funny philosopher to mock human frailty when it comes to making absurd arguments without evidence.
Why is it that they don't understand the meaning of the term "evidence" applied to "all the Universes that inflation creates" as if we actually have evidence that it creates more than a single one?
a) We have no evidence that even one "parallel universe" exists.
b) If "parallel universes" do exist, we don't really know what that means or what the overarching physical laws are that govern them, their distribution, their number because -- wait for it -- we have no evidence that even one parallel universe exists.
c) So somebody makes up a theory that takes an interpretation of quantum mechanics (which does exist, or at least for which there is actual evidence), extends it by fiat to describe one particular possible way that -- subject to a mountain of unprovable assumptions -- parallel universes might exist, and assumes that we know enough to be able to do the quantum statistical mechanics of the multiverse and determine whether or not they are infinite in number and whether the infinity is aleph null or aleph prime or whatever, and then makes a pronouncement that they cannot possibly justify because (oh my gosh) we have no evidence that even one parallel universe exists and hence we have no observational basis for determining their statistical distribution or the statistical distribution of some meta-universal dynamics.
Once upon a time science actually was based on observations. Well, actually, once upon a time it was all Platonic Forms, bullshit philosophy, but then the human race supposedly grew up just a little bit during the Enlightenment. Apparently we are now taking a giant step for mankind -- backwards.
Next stop, the Star Wars universe and the Tolkein universe. I'm not in them, but they sure are fun to read about as fiction, pending a glitch in the matrix...
The computation goes as follows. The issue, as several people have pointed out, is that it is current across the heart that causes defibrillation (basically interrupting the heart's natural rhythm so that it pulses chaotically), not a matter of cooking the person (which will also work, BTW, but isn't the most common cause of electrical shock deaths). It isn't even the case that more current is always worse -- there appears to be a range of currents that are more toxic than others. A brief explanation of this is here:
The maximally toxic range of currents across the thorax is empirically 0.1 to 0.2 amps. Below that it isn't enough to defibrillate, above that the heart muscle clamps all the way which means that when the current is removed it is actually more likely that it can with help or will on its own restore a normal rhythm.
The internal resistance of the human body once you introduce probes through the comparatively insulating skin is around 100 ohms. A 9V battery across ~100 ohms makes a thoracic current of roughly 0.1 amp, right at the start of the maximally fatal range. The Darwin above was given because an idiot didn't believe this and stuck probes through his skin to "prove" that it wasn't so.
Personally I've experienced shocks from 12 V car batteries when screwing around with them on rainy nights with salt water on my hands. That's another good way of reducing skin resistance. I didn't take the hit across the torso, but it was every bit as painful as a 110V shock through dry skin -- more so, actually -- and caused my muscles to contract like lightning.
None of this is actually news -- it has been known as long as there has been electricity, because people have been killing themselves accidentally with electricity just that long. My scout leader 50 years ago worked for GE (as an inventor, actually -- one of the people who invented the photodiode controlled light). He taught me that long ago to ground one finger and then brush another finger of the same hand against any possible hot wire so that you find out with a jolt across your hand, not through your torso. Hand to foot, hand to hand, not so good. People used to kill themselves all the time touching hot electrical switches while standing in wet feet on bathroom floors before ground fault circuits were invented and mandated by code.
None of which has much to do with TFA, but it is good to know if you work at all with electricity. Physicists need to know it just to be able to teach it to their students so THEY don't kill themselves accidentally one day. It isn't the voltage that kills you, it's the current, and it doesn't take much current to do the job (or much voltage to create a fatal current).
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$7/month for a 10 KW service has to be compared to $0.11/kw-hr for Arizona electricity, scaled out to the actual energy consumed by the household. If I am paying $150/month for electricity and drop that to zero, netting $143 doesn't increase the amortization schedule for the hardware by an enormous amount. Is it reasonable? Hard to say. Charging the consumer SOMETHING for the use of the lines isn't crazy. I pay $15/month just to have power turned on to a cabin I hardly ever use and that consumes no electricity at all. But it is cheaper than having the power turned on and off when I do use it.
rgb
FWIW, I agree with you completely, sir, and I don't even "believe" that AGW is likely to be catastrophic or that CO_2 is intrinsically bad (I actually have pretty good reasons for my beliefs, but not worth the flame wars asserting them entail). Solar power SHOULD come into its own when it is cost effective. Indeed, it is the capitalist way. In the case of power, though, since power companies are hardly capitalist enterprises -- they are publicly sanctioned local monopolies and nearly completely protected from anything like actual competition -- it is entirely within the rights of the same commonwealth that gave them the monopoly to require them to run the damn meter backwards for people that put energy back into the system by whatever means. It is POSSIBLY OK for them to add in a "tax" of some sort and pay back the added power at a SMALL discount, since the consumer is using company resources to effectively redistribute their energy surplus on lines maintained by the company. But then, they are also helping the company load balance and avoid building new generation facilities, so it isn't even clear that should be the case.
I myself already have replaced my windows, my roof, added in a double layer of high-R insulation in the attic, replaced all of the old furnaces and AC units with uber-high-efficiency units and use tankless gas hot water (which leaves a bit to be desired, actually). My energy costs are so low there isn't a lot leftover to pay off an investment in solar out of reduced cost of purchased electricity (one of the paradoxes of this is that your amortization scheme depends on how much you pay out, and conservation measures elsewhere actually increase amortization to where the advantage of PV solar once again is marginal to lose-a-little).
Still, I expect to PROBABLY bite the bullet and do rooftop solar in the next 2-4 years, sooner if hardware gets cheaper faster (reducing the amortization schedule). For the electric utilities, though, solar is already a no brainer win and they are building their own solar farms just because if I can break even or win a bit at full retail costs for solar, they can probably double my payback via economy of scale in solar farms. That may be why they are opposing the buyback option -- they can make more money making solar on their own than reselling solar energy you made and sold back to them at cost. In fact, they don't MAKE any money on the latter.
rgb
Obviously not. My physics Ph.D. is just an accident.
It is equally interesting that you completely avoid the point I was making, which is that we cannot successfully predict the climate using general circulation models. But I suppose if you know any physics or mathematics you already know this. You certainly know how to argue on the basis of logical fallacies. My statement that we are not able to predict the extent of any warming caused by CO_2 and are very, very far from being able to show that it is or will be a bad thing does not, in fact, equate to stating that there is no such thing as the greenhouse effect or that increasing CO_2 should not cause a logarithmic increase in average surface temperature. Outside of that, it is a simple matter of fact that -- if you bother to actually look at e.g. figure 9.8a of AR5 -- the GCMs do an absolutely terrible job of either predicting or hindcasting the climate outside of the reference period where they were dynamically tuned to match it.
Some other facts. One cannot observationally separate natural versus forced warming in a dynamical nonlinear chaotic open system like the Earth. The error bars in our knowledge of past climate state are far larger than are acknowledged to the public (when error bars are published at all -- as a general rule a simple line graph is drawn as if it is "true") and IMO the error bars on things like HadCRUT4 -- which are only a factor of 2 larger in 1850 than they are in 2014 -- are completely absurd. And the GCMs, BTW, are basically just dressed up weather models, run forward in time on an absurdly coarse (compared to the Kolmogorov scale) spatiotemporal grid, some 36 orders of magnitude short of where they would need to be to be able to semi-reliably actually integrate out the models from known initial conditions, if we knew the initial conditions. They are limited not by design (only) but by the simple fact that we cannot afford to build a computer network capable of solving the problem.
But hey, I probably don't know anything about mathematics or statistics or computational modeling or large scale computation either. So feel free to dismiss my opinion because you don't agree with it on the basis of my presumed incompetence. After all, anybody that doesn't agree with you must be ignorant or stupid or being paid off or holding a vested interest or -- pick your favorite fallacy and have at it.
In the meantime, by all means support research into ways to irreversibly change the climate system even more than it may or may not have been changed already. What can go wrong?
rgb
http://en.wikipedia.org/wiki/U...
I think it would have a substantial ripple effect. TFA isn't about possession, it is about using a "lethal weapon" in a drug-related crime. If you subtract out the pot, you also take away the right to search people who happen to visibly be smoking pot and your odds of catching them for secondary offenses go way down. Sadly we wouldn't make a dent in the petty crime committed to support a drug addiction (as pot is not addictive and not so expensive most people feel compelled to steal in order to afford it) but it is a good first step in that direction as well.
And even 20% fewer lawyers is a good thing. With luck we might even make it 25 or 30% fewer. So far I've spent $20K or very near that defending my sons from silly possession charges, almost all of it going to lawyers.
rgb
We've had traffic signal LEDs for a while, but AFAIK no overhead street lights. I'm not sure they are bright enough to meet their "standard" or whatever.
I'm just quoting over the counter prices I see in my grocery store or local hardware store. So far Duke power hasn't offered any killer deals on them (although they do periodically with CFs, but I'm already using CFs throughout the house). Also, I need/want 100W equivalent brightness and the best Harris-Teeter can do is 60W equivalent for around $25-30. Online Cree bulbs (Cree is right down the road and some of my ex-students work there) are around $24 for 100 W equivalent, Eco-bulbs around $23, save a bit if you buy in bulk.
That's a lot of money for a single bulb. Yes, they claim 25,000 hours. Yes, the bulbs haven't existed for any reasonable fraction of that much time so we have no idea how long they'll last. My garage has a whole bag of CFs that are rated for 8000 hours and didn't make it to 3000.
rgb
Including me...;-) But we are what, 0.001% of the total population? Not exactly a plurality to be taken seriously.
rgb
Where do you live? Someplace either very enlightened or broke, I imagine. Mostly enlightened if they are buying LED lamps, which are not cheap.
But hey, when I visit Charlottesville, it has these lovely 1 meter wide bike lanes on most of the streets near UVA. I'm so jealous. Durham just painted a line on the side of existing streets that sequesters anywhere from 0 to 40 or 50 cm and call that a "bike lane". On my own ride into campus there is a place where it goes from 40 cm to 0 cm under an overpass at one of the two busiest traffic points on the entire route. Several people are badly injured or killed every year riding bikes in Durham (including, a couple of years ago, Seth Vidal, the principle developer of YUM and a good friend of mine) -- I wonder why?
These are the steps we should take long before we try uber-expensive and risky measures like mucking around with either atmospheric chemistry or space blankets in the sky or even massive (and hence expensive) rail projects. They make sense even if AGW is nonsense or sensible but not a real threat or even beneficial. It's a lot healthier for me to ride a bike into work -- or would be if it weren't for the substantial risk of injury along the route and the fact that I'd have to ride down a mile of country road with an inadequate bike lane during rush hour in the dark because of the silly time shift. Bike lanes, losing most of the street lights and regulating commercial light pollution after hours, and some clever use of electronics to control crime instead of light. They make sense even if Lockheed-Martin does have commercial fusion (as they claim that they will) within five years.
rgb
What's the point of putting anyone in prison for weed ever? If the states would just get around to legalizing it completely, no more BB-gun crime in your area! Prisons would empty! Lawyers would starve! All of these are good things.
And one day we will. As my son points out, every year, lots of Old People (tm) die. At some point enough of them who learned about the evils of pot from William Randolph Hearst and Anslinger via vehicles like "Reefer Madness" will have died, and the simple fact that states that have legalized it de facto or de jure aren't imploding in an orgy of drug-fuelled crime will be persuasive even to those that think that it is not necessarily good for you to smoke pot. And on that day, every single person who lost their freedom, their health, their wealth, and their future not because of the chemical effects of pot but because we made it illegal and created a world where breaking any law, just or not, is dangerous will cry out to the sky:
Why?
Yeah, and did you notice that nobody -- nobody at all -- is calling for street lights to be turned off for good. Everybody's worried about burning coal, wasting energy, making resistance heating electric hot water heaters illegal as of this year (sheesh!). They want us to turn off the lights in our houses, they want us to spend $20-30 on LED bulbs because incandescents use too much energy -- but the streets are lit outside of my door with enormous halogen bulbs that burn all night even when there are no human eyes open to see their light. Empty parking lots blaze with halogen and mercury and neon. Cities string Christmas lights by the thousands along miles of road once a year. We pay for all of it, and yeah, it means that we can't see the sky particularly well even living on the rural edge of the city with deer in our back yard.
As a species, we're scared of the dark. We don't even consider turning off all of this completely wasted light (and saving some serious power, instantly) because then bad things would come out from under the bed and get us.
We're not even completely incorrect in this belief. One of the bad things is us and we are indeed scary as shit.
However, for far, far less than it would cost to loft crap into upper atmosphere or orbit, for far less than it would cost to even "commission research into" eventually lofting crap into orbit, we could start to actually use smart technology we already have and e.g. make street lights motion sensitive, or control crime (the usual excuse for having them, since "to prevent irrational fear of monsters" isn't an easy political sell for all of its truth) by actual robocop monitoring, looking for crime and not just putting up lights to nominally scare it off.
One could go down a rather long list of petty vanities that cost comparatively huge amounts of energy that we routinely pay for -- and waste. Billboards. Streetlights. The pointless annual time shift. Trucks vs trains. The utter lack of functional, safe, bicycle lanes in almost all the communities in the US. Electric cars. Living in borderline desert regions instead of water-rich temperate regions just because cheap, plentiful energy and long range importation of water makes it possible if unwise (as California and Las Vegas and the southwest in general may learn any year now).
Personally, I think that the evidence for catastrophic anthropogenic climate change is all but nonexistent -- it is a simple matter of fact that the changes in climate from the mid-1600's to the present, whatever their cause, have been almost entirely beneficial and in any event are utterly lost in the noise of normal daily and annual variation (overall warming from that entire period is around 1 C, an a signal too small for people to even notice against the noise). If someone truly "believes" in it, however, in spite of the fact that the models that predict it suck and the IPCC itself in the third annual report admitted that the problem of predicting the climate was basically unsolvable so that it is no surprise that the models suck -- let's start by turning off not the lights in my house, where I live and use the light, but outside where all it does is help the deer find the best hastas and roses from my garden to eat late at night.
rgb
Seriously. We have a perfect understanding of the climate. We can predict to a tenth of a degree what the weather will be two weeks or two hundred years from now anywhere on Earth. We fully understand what triggers ice ages and can hindcast the climate of the entire Pliestocene, quantitatively. Our knowledge of solar dynamics is almost perfect, so we can confidently predict the state of the sun well into the future. Our measurements of atmosphere, ocean, and land are complete so that we know the entire state of the ocean (for example) well enough to predict with complete accuracy its future evolution given any possible variation of solar input. Finally, we are perfectly capable of predicting the future course of human affairs -- global population, the distribution of that population, land use -- and can predict already precisely when we will make critical scientific and technological breakthroughs (like thermonuclear fusion or widespread LFTR fission or storage batteries that don't suck or high temperature high current superconductors) . Our knowledge of the interior of the Earth itself is at last nearly complete, so we can predict to the day when Yellowstone or other supervolcanoes will wake up and erupt continuously for ten or twenty thousand years. Finally, once we create an orbital cloud of atomic sodium (or whatever) into space, it will be easy to remove it or rearrange it if it turns out to do something completely different than we expect, such as trigger snowball earth or act in its own right like a layer of greenhouse gas between the Earth and 3 K infinity.
Oh, wait, those are all things we don't have, and can't do, and don't know. And I absolutely shudder to think of the price tag, both in dollars and in joules.
I swear, common sense is a lost art.
Let's go back to discussing orbital solar cells as a solution to both energy production and screening. Adding 64 MJ/kg (times a thousand or so) to the cost of solar cells by lofting them into orbit and giving world governments potential access to an orbital superweapon just to get to 1370 W/m^2 sunlight is sheer economic brilliance compared to this one. Oh, wait! Maybe we can combine the two! We can mortgage the next 100 years of human productivity to pay for it, no problem! It's not like we have anything else to do, like ending world poverty, preventing antibiotic resistant malaria from breaking out into a worldwide pandemic, embracing rational thought at the expense of the not-great world religions, and coping with leftover hypernationalism and colonialism from the cold war. So sure, let's do it! Solar cells AND making Earth a ringed or stratospheric smog laden planet!
What could go wrong!
rgb
That works amazingly well for me, actually...
In fact, I like the "moron point" add-on for so very many things. So many it would be difficult to make a list...
So do stone-cold sober drivers. So do old people. So do young people. So do drivers who are high, but who also had a few beers. The reason god invented statistical analysis was so that we could stop using anecdotal reports of "knowledge" as if they were fact.
That said, pot is like alcohol in one important respect, and that is that one can have a lot or a little THC on board, and then, there are different cannibinoids with different action on the brain, and since the THC tests are comparatively insensitive to both concentration and type compared to blood alcohol tests it isn't so easy to build a table that extracts the risk associated with driving while doing
bong hits of resin-saturated buds every few miles compared to driving having smoked part of a joint of everyday weed two hours earlier. You remain THC positive for days after smoking, but are at (possibly) increased risk for at most hours, where with alcohol one metabolizes roughly 1 drink/hour (perhaps a bit less if you get a lot of alcohol on board instead of a little) and can remain at increased risk for six or more hours if you drink heavily at a party.
However, TFA (which I actually read, as the subject interests me) basically showed that across all categories of pot use, there is a very small, statistically insignificant increase in risk of accident. They noted a number of studies that show decreased risk for moderate pot intake -- the theory here being that stoned people know that they are stoned and drive extra-carefully and end up safer than your average cell-phone-toting, conversation distracted, overworked and stressed out driver. This may well be cancelling out part of the increased risk associated with drivers doing hits while they drive. But designing a study to reveal this sort of thing would be challenging and in some sense isn't useful. Common sense suggests that it is dumb to do bong hits while driving at high speed down an interstate, especially while washing it down with a cold beer on the side, just as common sense suggests that it is dumb to drive without a seat belt or while texting or while fumbling with a music player or when one is really sleepy. Some (many) people, myself included, have done one or more of these things at one point or another in their lives.
The evidence, however, supports at most the citation of individuals caught driving WHILE smoking weed, not people who have THC in their bloodstream. That's the whole point of the study. Unless/until we have better tests that can easily detect the quantity and type of THC in your brain and studies based on those tests that are sensitive to and demonstrate the increased risk you assert is there based on anecdotal evidence (and sure, common sense) for some specific levels of concentration, the risk based on the mere presence of THC in the blood is substantially less than the risk associated with drinking a single beer. Field sobriety tests measuring actual intoxication are going to be more valuable than "just" the presence of THC.
rgb
That's right, I like to include Nitrogen and Phosphorus and Uranium in my beer. None of this wussy carbon, oxygen and hydrogen. You know you've been drinking when you drink molten thorium fluoride salts.
Oh, you mean from hydrogen and carbon dioxide only...
Never mind.
Ah, that makes a lot more sense. So it was set up to basically do a reverse greenhouse -- reflect sunlight with very high albedo (not strongly absorbed because the non-humid atmosphere is largely transparent to sunlight) but emit on its own in bands that are counterposed to the greenhouse gas bands. That I can believe, I think. No second law violation because it is stuck between two reservoirs, one at 6000 K (sunlight), one at 3 K (space) and in thermal contact and quasi-equilibrium with a third (its environment). Interesting.
So during the day it would absorb less heat from the sun, and would radiate what it did absorb away in a comparatively narrow band. There are still some heat flow issues -- in order to be in dynamic equilibrium via heat loss through the smaller window, it has to get hotter than it would the same as an ordinary material with outgoing radiation merely blocked and reradiated down in the greenhouse bands, but it is decoupled from those bands instead of being in balance with them.
One does have to wonder what happens to greenhouse radiation incident on the material from above. It can't be absorbed because of Kirchoff's Law. So it must be reflected too?
rgb
No problem with resonant fluorescence or colored objects and so on. It's the notion of something being in thermal equilibrium with (say) 300 K but radiating only at a single frequency being a more efficient cooler. That's basically a picture of a thermal refrigeration laser (at least, if one puts the optically active material in between two mirrors). It requires a very peculiar quantum structure and as I said, one has to worry about detailed balance because the ordinary bouncing of internal thermal energy has to keep the resonant level "pumped" without itself radiating. It is metaphorically very close to a nanoscale Maxwell gate that only lets molecules through if they are warmer, or cooler, than equilibrium so that a gas spontaneously separates into hotter/cooler volumes, although as you say technically it might not violate the 2nd law by cooling to a reservoir at 3 K bypassing the material in between and hence enable a perpetual motion machine of the 1st kind. Odd to say the least.
I don't remember it on /. but I'll look around. Usually I catch anything of interest in optics but sometimes topics cycle fast enough in my feed that I don't see them before they breeze on through. However, if the time frame is "very recent" that helps. I suppose I can see what google can turn up. Thanks.
rgb
Reference (to the new meta-material)?
I'm not disbelieving, but given the nature of thermodynamics and radiation, I'm not believing until I read the paper(s) and see some evidence that it works. There's the detailed balance issue.
Then one can look at the cost-benefit. If it is cheap, it absorbs heat and radiates it away in a single channel, and you can make roof tiles or roadway surface out of it, it might make some sort of difference. Sadly, this is what I'm having trouble with because with a single sharpish frequency one is dangerously close to a Maxwell Demon, take "heat" and radiate it away as a single frequency.
rgb
And when the day comes that we can build general purpose robots, your obvious retort #2 will be apropos, although even then one will have to compare the operational efficiency and cost-benefit of a really, really good firefighting robot that is designed and "hardened" to be ideal for fires vs a slender, athletic, wide-hipped robot with highly flammable rubber padding in strategic places and a variety of special "attachments" that happen to include an appendage that can spray whipped cream or class B fire fighting foam.
I'd argue that the latter might be more appropriate for the home, not so good for a navy ship.
You'd also really like the AI to be pretty well debugged so that you don't get an inappropriate response if you mutter "Oh baby, I just burn for you..." at an inopportune moment.
rgb
Because they already have that, and it is boring? Because robotics are cool and fundable even where they are pointless and useless? Because the people that approved it have watched too many WW II movies? Because automated fire suppression systems might be vulnerable to damage elsewhere, requiring some system capable of dynamically bypassing nearly arbitrary intermediate zones of damage by archaic means like "fire hoses" in order to deliver fire suppression? Maybe a bit of all of these?
One can certainly imagine a scenario where a cruise missile or torpedo or even a shell strikes a ship in such a way that it knocks out most built in systems in some zone and sets that zone on fire, at which point sending humans in to fight the fire puts them at high risk and not sending humans in to fight the fire might put them at even greater risk from a sinking ship. At that point sending in a robot (humanoid or not) instead could be a lifesaver.
One is reminded of any number of science fiction stories, though, by Asimov and others. Building a humanoid robot for this purpose seems incredibly stupid. One doesn't want a robot to run a vacuum cleaner as if it is a metal version of a french maid. One wants a robot that is a vacuum cleaner, or a vacuum cleaner that happens to be a robot. Take vacuum cleaner. Add mechanism for moving. Add mechanism for navigating. Add minimal hardware needed to perform standard operational maintenance (that is, dump the dirt and clean filters). Add judgement/programming (or not, make it remote operated by humans sitting in a chair somewhere by remote control). In the end, one is more likely to end up with R2D2 with a carpet-sweeping vacuum base and "arms" that ARE extensible, manipulable tubes with nozzle(s) than with anything that looks like C3PO pushing a Dyson. And ditto for fire-fighting, only even more so.
rgb
OK, so we have multiple cosmi (space-time continua) embedded in a higher dimensional universe. I'm totally down with that and have written an entire SF novel based on the premise. Those cosmi (as the plural of cosmos) have a coupling. I'm good with that. But that means that "neighboring" cosmi will exist in a coherent bundle, and one will have to get quite distant from "this" brane to find a brane with substantial drift in its general mass distribution.
This is simple statistical mechanics, by the way -- if most brane-to-brane transitions occur in places where there is chuck of mass in one cosmos and none in another cosmos, there will be steady diffusion from the high mass concentration to the low one. This would lead to egregious and painful violation of mass-energy conservation as my foot in this cosmos diffuses into a vacuum in many, many others, because after all, the mass density of any cosmos at all is nearly zero with a hard, hard vacuum nearly everywhere.
This is overwhelming evidence that this sort of brane to brane, cosmos to cosmos transition does NOT happen in a universe in which the cosmi are equidistant and randomly organized. The only way that those transitions are possible at all is if there is a metric in the higher dimensional universe and if neighboring cosmi have ALMOST identical mass distributions and if transitions are only likely as pair exchanges between neighboring cosmi (note the requirement for pair exchanges is also a rather hard one or else one would observe a cumulative violation of conservation of mass in random-walk style that would be impossible to miss and that people have looked for, unless the transitions were VERY unlikely, or became very unlikely as a function of the intercosmos metric separation to increasingly different cosmi.
Note well that these constraints mean that no matter what, they aren't going to "bypass" a shield with a neutron flux, because there are going to be no nearby cosmi/branes in which the shield does not exist.
Note well in addition the response to those who suggest that this might be a way of viewing tunnelling. It is indeed -- the alternative cosmi are one of the POSSIBLE (I don't say plausible) interpretations of path integral formulations of quantum mechanics, integrated out. But in this case you STILL won't get tunneling through a barrier centimeters thick.
So this is a pointless experiment. One might as well just look for egregious violations of mass-energy conservation in everyday experiments, because if there is any substantive probability of mass energy departing our own spacetime cosmos and appearing in another "nearby" one, it would happen all the time and all mass concentrations would diffuse out into a multicosmo heat death.
Gravitation is an excellent possibility as the coupling between branes/cosmi -- one would guess that the "dimpling" of one spacetime dimples all of the neighboring ones on all sides (however many "sides" there are:-). The dimples probably don't have to precisely correspond, but they are likely to have to approximately correspond to minimize almost any sort of coupling across the sheets that permits a transition to occur in the first place.
rgb
In that part of the universe that is visible. We have no idea how much of the universe is beyond the ~14 billion light year visible boundary, only that it very likely extends at least many times as far beyond.
We absolutely do not know if there are more non-simply connected, non-interacting universes, because by definition you can't get there from here and cannot see them in any way -- but that does not mean that they do not exist, nor does it mean that they do. It means that we do not know if they exist because we have no evidence for their existence. We absolutely do not know if there are more coupled universes -- universes that one might be able to reach -- with independent space-time, because whatever coupling there might be between them, it is weak.
Finally, we do not know even in the simplest case that the many worlds quantum theorists hypothesize whether or not the bundle of universes is coherent, so that there are indeed lots of "nearby" universes with alternate-me as part of a coherent quantum bundle of me embedded in a coherent quantum bundle of universes that is semi-classical in evolution but knit together (entangled) with many little quantum jumps at the planck scale, or if you prefer the macroscopic cosmological hypothesis (which is pretty much completely without empirical foundation or any likelihood of obtaining any) of universes bubbling up in some sort of overarching ether with coupling constants that vary (without any explanation of how they might vary, or what sort of space of possible values bounds or does not boud the variation, or the physics that couples them with meta-coupling constants -- do you get the feeling that this is just mathematical science fiction, because it is -- we do not have any evidence that one single one more of these hypothetical universes exist.
It's like planets. Before 1990 there were lots of theories for planetary formation, and science fiction writers had been writing stories involving planets around other stars, usually with highly evolved life, just taking it for granted that they exist. But nobody had ever seen one, so that the statement "there is a planet within 100 LY of Earth with highly evolved life" was at best a scientific hypothesis unsupported by any evidence, but really was a complex form of science fiction because science had no way of sensibly bounding the probability that such a statement is true and there are a near-infinity of possibly true statements and we quite rightly give little credence to almost all of them without evidence and a really, really good reason to think that they might be true in the physics.
Today we have built instrumentation that permits us to "see" these "alternate universes" -- very crudely, but even that is improving over time as we build still-better instrumentation -- and we have at least some idea of what the density of planets of at least a certain size is in our immediate vicinity, much as we built the Hertzsprung-Russell diagram from parallax observations of nearby stars. We therefore have some small empirical basis for a model of planetary density around third generation stars (that probably doesn't extend into specialized environments, e.g. globular clusters). At the same time we are learning, somewhat painfully, lots of things about planetary chemistry and planetary ecology from observations within our own solar system and MIGHT -- as soon as we can sensibly measure some of the gross signatures of these things with even BETTER instrumentation -- soon get an idea of whether or not it is at all probable that there be highly evolved life within 100 LY. By an idea, of course I mean some statement of probability based on observations that has some statistical significance, as opposed to a statement built on top of a teetering tower of Bayesian priors 2/3 of which have no observational basis at all, none of which can be improved by recomputation of posterior probabilities based on observations within some restricted set.
A si
We know no such thing. We make conditional inferences, and part of what they are conditional on is our incomplete understanding of field theory. We don't even know if there is truly dark matter and/or dark energy, or what they are or how they work. Our understanding of the big bang/inflation extends back (again, rather conditionally since any number of field theory variations would completely alter it) to 13.8 bya but is extremely fuzzy given that we can't "see" events any earlier than the end of the Great Dark. All we have is a lower bound on the size of the Universe associated with the homogeneity of the CMB and estimates (which vary according to one's beliefs concerning DM/DE) as to whether the visible part of the universe is open or closed.
That's at the macroscopic level. At the microscopic level we are many orders of magnitude short of the Planck scale and do not even know how to reconcile quantum theory and gravity. But don't let that stop you from asserting certain knowledge just because you read something somewhere that was stated as truth without bothering to add all of the conditionals.
rgb
Unless they exist in a loop. Then there is no first. Then one can scale the loop up to infinity.
There are many rooms in Hilbert's Grand Hotel, and even though nobody ever brings cigars in through the front door, there is always a fresh cigar waiting in your room every morning.
Unless and until there is a glitch in the matrix, there isn't any really good reason to think we are a simulation in some sort of meta-universe, and some excellent information-theoretic reasons to think that we aren't. The estimates of "probability" here are completely meaningless because the Bayesian priors are utterly disconnected from any possibility of proof. If this, that, and the other thing are all true, then we are probably a simulation. If there are multiple universes at all (whatever that even means) and if we make a small mountain of assumptions about the rules that govern them (all unprovable) then there is no you in any of them, unless of course the distribution of universes isn't uniform or defies the odds and there is. If wishes were horses, beggars would ride. If pigs had wings, they could fly.
The only sad thing is that people are even pretending that this is science. You have it pegged -- it is science fantasy written by a cynical but very funny philosopher to mock human frailty when it comes to making absurd arguments without evidence.
rgb
Why is it that they don't understand the meaning of the term "evidence" applied to "all the Universes that inflation creates" as if we actually have evidence that it creates more than a single one?
Seriously.
a) We have no evidence that even one "parallel universe" exists.
b) If "parallel universes" do exist, we don't really know what that means or what the overarching physical laws are that govern them, their distribution, their number because -- wait for it -- we have no evidence that even one parallel universe exists.
c) So somebody makes up a theory that takes an interpretation of quantum mechanics (which does exist, or at least for which there is actual evidence), extends it by fiat to describe one particular possible way that -- subject to a mountain of unprovable assumptions -- parallel universes might exist, and assumes that we know enough to be able to do the quantum statistical mechanics of the multiverse and determine whether or not they are infinite in number and whether the infinity is aleph null or aleph prime or whatever, and then makes a pronouncement that they cannot possibly justify because (oh my gosh) we have no evidence that even one parallel universe exists and hence we have no observational basis for determining their statistical distribution or the statistical distribution of some meta-universal dynamics .
Once upon a time science actually was based on observations. Well, actually, once upon a time it was all Platonic Forms, bullshit philosophy, but then the human race supposedly grew up just a little bit during the Enlightenment. Apparently we are now taking a giant step for mankind -- backwards.
Next stop, the Star Wars universe and the Tolkein universe. I'm not in them, but they sure are fun to read about as fiction, pending a glitch in the matrix...
rgb
Actually, you can kill yourself with a single 9 V battery -- or the 12 V battery of your car. One man did:
http://darwinawards.com/darwin...
The computation goes as follows. The issue, as several people have pointed out, is that it is current across the heart that causes defibrillation (basically interrupting the heart's natural rhythm so that it pulses chaotically), not a matter of cooking the person (which will also work, BTW, but isn't the most common cause of electrical shock deaths). It isn't even the case that more current is always worse -- there appears to be a range of currents that are more toxic than others. A brief explanation of this is here:
https://www.physics.ohio-state...
The maximally toxic range of currents across the thorax is empirically 0.1 to 0.2 amps. Below that it isn't enough to defibrillate, above that the heart muscle clamps all the way which means that when the current is removed it is actually more likely that it can with help or will on its own restore a normal rhythm.
The internal resistance of the human body once you introduce probes through the comparatively insulating skin is around 100 ohms. A 9V battery across ~100 ohms makes a thoracic current of roughly 0.1 amp, right at the start of the maximally fatal range. The Darwin above was given because an idiot didn't believe this and stuck probes through his skin to "prove" that it wasn't so.
Personally I've experienced shocks from 12 V car batteries when screwing around with them on rainy nights with salt water on my hands. That's another good way of reducing skin resistance. I didn't take the hit across the torso, but it was every bit as painful as a 110V shock through dry skin -- more so, actually -- and caused my muscles to contract like lightning.
None of this is actually news -- it has been known as long as there has been electricity, because people have been killing themselves accidentally with electricity just that long. My scout leader 50 years ago worked for GE (as an inventor, actually -- one of the people who invented the photodiode controlled light). He taught me that long ago to ground one finger and then brush another finger of the same hand against any possible hot wire so that you find out with a jolt across your hand, not through your torso. Hand to foot, hand to hand, not so good. People used to kill themselves all the time touching hot electrical switches while standing in wet feet on bathroom floors before ground fault circuits were invented and mandated by code.
None of which has much to do with TFA, but it is good to know if you work at all with electricity. Physicists need to know it just to be able to teach it to their students so THEY don't kill themselves accidentally one day. It isn't the voltage that kills you, it's the current, and it doesn't take much current to do the job (or much voltage to create a fatal current).