You said: "Keep in mind that the firestorm is caused by heat which travels in a stright line.
Actually the firestorm occurs after the heat from the blast is absorbed, not at the blast. It occurs when there is such a substantial fire ongoing in a city that hurricane force winds develop to keep the fire burning. This firestorm will, of course, be unstoppable once it has started and continue until it consumes all fuel in the area. A comparable effect is the strong winds seen over forest fires.
You said: 3. The tsunami might not even be that high. Remember, much of the water will flash to steam.
If the heat flux is high enough, very little heat will actually be transmitted to the water. This is because the initial steam around the blast will insulate the rest of the water from the fireball. Compare this to fully heating a pan on the oven and tossing on butter. The butter very slowly melts because of the superhot film layer insulates it. With a lower heat flux (a lower temperature of the frying pan) the butter would melt without forming this layer. The reality of this is that it might lower the energy transmitted to the water because it would let the fireball escape into the atmosphere from the water (but I'm not sure).
You said: "3. If you did have a nuke, I think I'd prefer it be set off underwater. Bad news for longshoremen, but taking it to the observation deck of the Sears Tower would be a lot worse."
I'm not really sure about this. When atomic bomb tests were conducted in Operation Crossroads, the underwater test (Baker) destroyed more staged Navy ships and caused much greater radioactive contamination of those ships than did the airborne test (Able). It should be noted that the Able shot was off target by about 1000 to 2000 ft, but this probably didn't account for the greater destruction and radioactive contamination.
I think the big concept is that in an airshot, a significant fraction of the energy is lost by being released up into the atmosphere or reflected off the ground into the atmosphere, while in an underwater shot much less energy will be lost. If the shot were to attack a city it could probably be safely assumed that the resultant tsunami would cause more damage than the weapon released in the air. Additionally the radioactive contamination would be far reaching. But of course this is no easy feat to do.
You said: "U-238 is barely radioactive, with a halflife of about 4500 million years. U-235 on the other hand is way more radioactive"
Nuclear types like to measure radioactivity in what is known as activity: A=(lambda)*N, (lambda)= (ln 2)/ t1/2, where is the decay constant, N is the concentration, and t1/2 is the half-life.
What this means is that activity is inversely proportional to half-life. So in order to have a highly radioactive sample with a long half-life you must have a high concentration of it. It doesn't work this way with U-235. It has a 713,000,000 year half-life. Doing a quick calculation you will find that even a pure large sample of U-235 (subcritical of course) would have very low activity.
You said: "The history of nuclear power so far, however, doesn't leave one optimistic."
What metric are you using to say that nuclear power has historically been unsafe? The number of deaths caused per MWh produced? Deaths or injuries per reactor-hour of operation? Average deaths per year at a given plant?
Really, compare these metrics to that of any other power distribution plant and you will see historically, even with the huge publicized disasters like Chernobyl and TMI, that no other large scale power producer even compares in safety to nuclear power.
You said: "of course humans also dectect phermerones with their noses. why wouldn't they if other mammals do? i know science is about being skeptical and all, but is it that big of a jump and illogical to expect that humans detect phermerones by smelling?"
Scientists believe that pherormones are suppressed in humans. One point of evidence cited is that about the time that homonids developed color vision, a pheromonal pathway gene mutated and became unusable. One item of speculation from that is that color vision gives advantages of finding mates from a distance rather than close up as would be required when recieving pheromones. This would make the need for pheromonal pathways much less important (so much less important that subsequent mutation didn't affect survival). Additionally, many other mammals don't have color vision and tend to be much more receptive to pheromones than humans.
You said: "Was it also proven by this tv show that the cause of the ocean gas was completely unrelated to any kind of impacts?
For the future, link to or provide details of any sort of discovery claims, lest they be dismissed out of hand."
Reminds me of an article in Nature (Wood, W. T., et al. Nature 420, 656-660 (2002)) that discussed how methane in seafloor deposits is released to the oceans. One of the points discussed was that as seawater temperature rises, the base of gas hydrate stability rises. What this means is that some of the methane trapped under the seafloor in solid methane hydrate turns instead into methane gas due to the increase in temperature. This release of gas in turn will increase the pressure near the seafloor, and if close enough to the surface, or near a fault that allows a gas chimney to form, it can be released to the ocean (perhaps like a valve until the pressure subsided). Obviously this would be amplifying if it occured on a large scale since methane is a powerful greenhouse gas.
One possible method for being on a large enough scale would be catastrophic seafloor failure (maybe an earthquake or meteorite) where a large amount of initial methane is released. This, of course, could allow the amplifying reaction to occur with methane deposits far remote from the source of impact potentially leading to a global warming effect.
You said: "(Of course then, you have to wonder why the US lags behind some other countries in science education....)"
You have to be really careful to say exactly what you mean when you make general statements like this. While it is true that US K-12 (or in particular 8-12) science education falls behind much of Europe, that is not true for college education or other types of education not normally considered (thinktanks, museums, libraries, private education, etc.,). You can't always compare one countries science education against another because they use different methods of implementation in their education process. For example, some countries give a test in about the 8th grade. Depending on the student's score, he or she is trained in vocational or scientific disciplines for the equivalent of his or her high school period. These vocational students are not tested for science when compared against other countries.
You said: "You're just proving the point I am making."
In order to have a proof you have to have 3 things: 1. A mutual understanding of words, symbols, and their meanings, 2. Agreement on axioms that require no further justification, and 3. Agreement on when one statement follows logically from another.
I think is extremely obvious that you do not give any of those in your argument. Prefer the word 'demonstrating' to 'proving'. The idea of a proof really loses its meaning (both legal and scientific) when people use it informally to justify biased arguments.
If you're like me and your base units are TeV, Mparsecs, and fortnights, you'll find the values to be 1.98*10^13 TeV*Mparsec/fortnight^2 and 4.78*10^13 TeV*Mparsec/fortnight^2. Hope this helps.
You said: This is absolute rubbish, a different system of quantification should be used when referring to binary powers, as the borrowing of those from SI is clearly misleading.
There is a system that isn't used by many people. For example, it uses kibibyte for 2^10 bytes and mebibyte for 2^20 bytes (and so on).
You said: "Actually, I'm not against nuclear power on principle, but it is a huge risk, not so much for waste, but that it easily segues into nuclear weapons."
The genie is out of the bottle and isn't going back in. Its not really rational for us to stop using nuclear power for electricity and research because other countries are independently developing WMD with it.
You said: "Canadian reactors use weapons grade plutonium and uranium, rather than whatever it is that other reactors use (which is how India and Pakistan got their hands on nuclear material -- from nuclear reactors bought from Canada). I remember there was a big fuss during the Clinton administration, because the plutonium and uranamium from a number of decomissioned nuclear weapons was going to be shipped to Canada, and people on both sides of the border weren't too keen on that."
Canadian reactors are not initially fueled with plutonium. They are just not highly enriched (where the fraction of the isotope U-235, which occurs 0.7% naturally, is increased). The consequence of this is that in order to have a self-sustaining chain reaction (criticality), the neutron flux must be higher. This is because the Candu reactor uses slow-fission which utilizes U-235 as a fuel and not U-238. In order for the core to remain critical (where on average one neutron from a fission event goes on to cause another fission vice being absorbed by another nucleus or escaping the boundary of the core) it has to be very large size and have a very high neutron flux (as compared to a more enriched core which could be smaller and have a lower neutron flux and stay critical).
One consequence of a core with a very high neutron flux is that U-238 can absorb a neutron (which is helped because the core utilizes slow fission unlike a nuclear bomb), become U-239, undergo 2 beta decays and form Pu-239. Pu-239 can also undergo fission like U-235 and be used as a fuel (odd numbered atomic mass numbers of very heavy elements will undergo slow fission but even numbers will not). This is one of the reasons why natural uranium and thorium (which would produce U-233) could potentially create more fuel over time in the reactor (as the U-235 is depleted). Since it is much easier to make a nuclear bomb from plutonium than the brute force method of seperating U-235 from natural uranium this is obviously a potential threat for nuclear weapons poliferation around the world if these reactors are sold.
You asked: "So -- as far as environmentally friendliness is concerned, how do the different types of reactors stack up?"
When you think about environmental friendliness there is short term safety (immediate event of casuality) and long term (groundwater and storage of waste) concerns.
In the short term the major concerns are preventing the reactor from breaking and spilling its fission fragments (which is the VERY highly radioactive waste in a reactor compared to everything else which is relatively lowly radioactive), and if it does break, by containing it. Preventing the reactor from breaking is pretty much controlled by good engineering practice of operating it and by competent design. If we've learned anything from the Chernobyl accident, the least of which is that *only* the people who are trained to operate and know the most about the reactor should be allowed to do any test (or any operation for that matter). Once management steps in and decides that they know how to operate the reactor better than the operators themselves, there is a serious problem. Containment is much simpler. You put up several barriers to prevent radioactive fission gasses from escaping. The final one, the most obvious one, is the cement dome that covers nuclear power plants. But other methods of containment are also useful, such as the pebble bed design where each fuel particle is encased in a ceramic sphere that can contain all fission product gases ever produced by that particle. In the worst case accident the particle will not melt or lose any of its ability to hold the gasses. Future reactors will be much safer due to designs like this (in fact the NRC has rated some as requiring "no evacuations under any accident condition", meaning that they don't think a meltdown can occur).
For long term concerns, continuous sampling and monitoring as well as storage of radioactive waste are the concerns. As long as there is
I find it interesting that they determined an estimate of the total mass of all the matter in the Universe before they figured out how many stars there are. You'd think they'd come up with the number of stars first, and then base the mass estimate on that.
IIRC, the mass of the universe was determined as follows:
1. Since the amount of deuterium formed in the Big Bang Nucleosynthesis is directly proportional to the density of matter, the density of the Universe can be determined by looking at very old hydrogen gas clouds (ones where the hydrogen to deuterium ratio is the same as that of the Big Bang Nucleosynthesis) that haven't been burned in stars. In particular, the method used was using a powerful quasar to be able to see such a cloud. The amount of deuterium can be determined by spectral analysis. 2. Experiments have been done that show how cool nucleons have to be to be able to form atoms (in particular helium and deuterium). The universe has been cooling since it formed so the time that the Big Bang Nucleosynthesis occurred after the Big Bang can be determined (for deuterium I think it was about 4 minutes). 3. Assuming that all forces have negligable affect on the distribution of matter during the first few minutes after the Big Bang (due to the incredible temperatures), and that the universe expanded uniformly in a sphere (COBE has shown that this is not entirely true...but it is very close) at the speed of light in all directions (I'm not entirely sure how inflation theory affects this), the volume of the universe at the time of Big Bang Nucleosynthesis can be determined. Now the mass of normal matter can be determined. 4. Since galaxies should follow Kepler's Laws of planetary motion, but don't (i.e. many parts of a galaxy rotate at about the same radial velocity at different radial positions not equidistant from the galactic nucleus) something has to account for the discrepancy. The current theory is that about another 90% of the galactic mass exists in a dark matter halo around the galaxy.
You are absolutely right. What many people fail to recognize is that there are different levels of radioactivity. If a radionuclide has a long half life it will be less radioactive in the short term. In particular, U-235 and 238 with hundreds of million year half lives (U-238 in the billions) will have very low radioactivity compared to a fission product which may have a fraction of a second half-life. If you don't start up the reactor until it is safely in orbit, then there will be no fission products, and even if it did burn up in the atmosphere, it would have too low radioactivity to even notice.
if our simulator were bound to a similar sort of physics as our own:
There may be no stable enough platform to make such computations. Ever. If, in order to simulate our planet's homelife, you'd need a planet full of future computers simulating at 1/10,000th time (they might need to simulate much much slower), there may be no intelligence in a universe like our own that will ever have the capabilities to dedicate that sort of resources for the amount of time that would be required.
In order to simulate a universe you have to have a more complex universe. At a minimum you have to take into account the mass, velocity, and positions of every particle unless you decide to make gross simplifications (limits on observation, the definition of particles inside a black holes event horizon, etc.). To put the data into a framework that can be used for simulation would require a universe larger than the one simulated.
As far as resource management, a meta-universe may have a greatly exagerated speed of light and atoms (if they exist as defined in our physics) may be many times smaller, making the potential abilities of computers (and quantum computers (or another similar meta-universe physics construct)) much faster.
But then again, all points don't necessarily need to be simulated. Our perception is based on what our memory tells us is the past. It is as difficult to touch the past as it is to touch the future. As long as you simulate one time point, you have suceeded in your simulation because all the people in your simulation have memories and believe that they are continuing in a linear time. They believe that what their memories tell them happened 1 second ago even though it was never simulated. If you decide to run a simulation that reverses time it would have no affect on perception of time since it is based on the past. Even though you may grow from an adult into a child (in the time of the computer), at every time data point you think that you are growing into an adult.
There's no way processor speed can continue at its current pace to that point. It would have to be nearly infinately fast to simulate all the 10000000000000000000000000000000000's of atoms i can see right now
They don't necessarily have to be that fast. Its not like there is a time limit since they are defining time. Even if they took 10000 sec to simulate 1 sec, it would not alter our perception since it is only based on the past. It will still be 1 sec to us.
And why not assume that they did some simplifications? Why should we assume that the universe that we exist in the the one that the simulators run? It could be much different and the laws of physics different as well. It may be able to run simulations of huge amounts of atoms because that may be a trivial amount of processing time to a much more complex universe.
Yes this is all assuming that there isn't a meta-matrix in which the matrix is run. It seems pretty obvious to me that that is what the last scene was trying to portray in a subtle way.
And if there is a meta-matrix, what prevents having a meta-meta-matrix and so on? Its really impossible to speculate the age of the matrix based on this information.
1. With the vast majority of energy demand in industry, it would hardly help even if every single person on the planet diconnected from the grid.
2. Economics will not allow alternative energy due to the fact that it produces too little power and costs too much when it is send over distribution lines to connect to the grid. It will be able to supply point sources but not an industrial site 500km away.
3. In order to power the 60MWe factory that I mentioned in my previous post, at 10% effeiciency (including the inverter), given that 1.34KW of radiation are incident on the atmosphere per square meter of which 50% will be absorbed or reflected by the atmosphere, an area of roughly 1 square km is needed! Imagine the size of the battery if it were to diconnect from the electrical grid completely (for cloudy days)!
No matter how much you hope and 'walk the walk' it will not change the fact solar power will not be able to meet the growing world energy demand. It is ingenious for some devices (like calculators) but I don't think it should be used on top of houses. The dc from the cells will have to become ac through an inverter. This inverter will be in continuous use so it will need some sort of cooling (probably ambient air flow through fins). If this cooling is blocked a fire could happen. Additionally you have two options: remain connected to the grid or use a battery on rainy days. If you use a battery there is obviously the concern over a large battery maintenance and periodic replacement as well as hazards of the battery itself (for example if you had rainwater which has any amount of chlorides--possibly from the ground--you would have chlorine gas produced as well as a high energy electrical fire that you could not diconnect). Large batteries just are not as simple as car batteries.
If you remain connected to the grid you could sell back additional power right? Well there are two obvious problems, paralleling with the grid and producing smooth 60Hz. Paralleling a power source is a risky move. If you don't do it correctly and the incoming and running are out of phase the differential voltage across your breaker (up to twice the running or incoming if you parallel 180 degrees out of phase) can fry your breaker and other operational equipment. Smooth 60Hz vs. rough inverter 60Hz is a little less known problem. An inverter can only really produce DC voltages that change to follow a sinusoidal type waveform. But not continuously--it does it in steps. So once you parallel you have the smooth 60Hz that comes from a rotating machine with the rough 60Hz from the inverter. Depending upon the quality of your inverter the diferential voltages from the smooth 60Hz to the steped DC will cause current surges to and from the source. This in turn by itself may overrate your distribution complex to your house and cause an electrical fire.
Now while I am trained in electronics and electric motors, generators, and power distribution systems (as part of my job) and I could operate all of the above mentioned with safety, I don't believe the average homeowner could. People seem to be confident about burning down their houses without the above mentioned complexities. They really don't need these additional options to kill themselves or burn down their houses regardless of whether it might save the world 10% of its energy demand.
If we could get one million more people to actually BUY and install some of the stuff that is available now, it would really help
I doubt it.
An average household uses about 2KWe of power. With a houshold size of 4 in a town of 30,000 (my hometown) this yields about 15MWe of power. One industrial plant in my hometown (it makes silicon wafers) uses 60MWe. All in all, my hometown uses over 200MWe of power.
Even if everyone decided to have electrical power cut off from their homes it would dent (and only dent) the enormous demand due to industrial sites. The number of these sites is more likely to increase rather than decrease over time FAR outstretching the demand that homeowners might be able to counter.
Energy demand isn't that simple, some of the factors:
1. Any fuel derived from petroleum reserves is becoming more scarce and it emits greenhouse gases among other toxic byproducts. 2. Solar cells have abysmal efficiency and are made through very toxic processes 3. Hydroelectric power is affected by the fact that there are only so many rivers you can dam and once you dam them you have to deal with the ecological consequences. 4. Coal is obviously a greenhouse gas emitter and very toxic. 5. Nuclear plants have phenomenally large insurance costs and questions about long term storage of high level radioactive waste 6. Alternative sources have yet to be designed so that they can be scaled up to the level of 100's or more MWe so that they would be effective in an electrical grid (Let me put it this way: they can support point sources of power but when you try to send it over lines 100 km away the electrical losses may well exceed 40%. This is obviously not cost effective). 7. Wind power suffers from the above electrical losses.
There is no One True Power Source that people can use. It has to be a combination of the above factors taking into account the pros and cons (IMHO it should be nuclear and alternative sources (not including solar) using gasoline plants as peaking plants).
It depends on the design. Most boats are designed with the 'V' shape so that very little of the energy is transferred to the wake of the boat. This makes them very efficient for travelling on the surface.
When you are talking about a submarine there are 2 designs. There are the diesel boats (i.e. similar to WW II subs) and there are nuclear boats. The diesel boats had the 'V' shape since they had to spend a great deal of their time on the surface and this is a much more efficient way to transit (after all a diesel submarine is pretty much just a surface ship that can occasionally submerge for short periods of time). The nuclear submarines have the 'O' shapes since they have no real need to surface except for return to port and an O shape is more efficient submerged (minimizes surface area and can keep a better balance). When a nuclear submarine is on the surface it takes a major speed hit because a significant amount of energy used for propulsion is transfered to the wake (since it doesn't have the 'V' shape). Therefore a nuclear submarine will travel faster submerged.
So a diesel submarine should be almost as efficient as a surface ship, but a nuclear submarine will be less efficient (but will travel faster than diesel subs due to raw power).
You said: "It's one thing I hate about Mozilla (why can't they use the native menus and widgets?) -- though I use Mozilla exclusively, I still feel a lot of time was wasted implementing their own text box (that still doesn't work quite right), menus, etc...
This was discussed extensively in the design of Mozilla. The reason native UI's aren't used is that in order to be standards compliant, the widgets had to differ from the functionality offered by the standard OS' widgets. If they used the same widgets with the different functionality it would mislead users who expect (and rightly so) that the same looking widget should act the same. It wasn't just so they could create XUL and make the browser completely skinable. That wasn't even a consideration.
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Just a couple of minor points:
You said: "Keep in mind that the firestorm is caused by heat which travels in a stright line.
Actually the firestorm occurs after the heat from the blast is absorbed, not at the blast. It occurs when there is such a substantial fire ongoing in a city that hurricane force winds develop to keep the fire burning. This firestorm will, of course, be unstoppable once it has started and continue until it consumes all fuel in the area. A comparable effect is the strong winds seen over forest fires.
You said: 3. The tsunami might not even be that high. Remember, much of the water will flash to steam.
If the heat flux is high enough, very little heat will actually be transmitted to the water. This is because the initial steam around the blast will insulate the rest of the water from the fireball. Compare this to fully heating a pan on the oven and tossing on butter. The butter very slowly melts because of the superhot film layer insulates it. With a lower heat flux (a lower temperature of the frying pan) the butter would melt without forming this layer. The reality of this is that it might lower the energy transmitted to the water because it would let the fireball escape into the atmosphere from the water (but I'm not sure).
You said: "3. If you did have a nuke, I think I'd prefer it be set off underwater. Bad news for longshoremen, but taking it to the observation deck of the Sears Tower would be a lot worse."
I'm not really sure about this. When atomic bomb tests were conducted in Operation Crossroads, the underwater test (Baker) destroyed more staged Navy ships and caused much greater radioactive contamination of those ships than did the airborne test (Able). It should be noted that the Able shot was off target by about 1000 to 2000 ft, but this probably didn't account for the greater destruction and radioactive contamination.
I think the big concept is that in an airshot, a significant fraction of the energy is lost by being released up into the atmosphere or reflected off the ground into the atmosphere, while in an underwater shot much less energy will be lost. If the shot were to attack a city it could probably be safely assumed that the resultant tsunami would cause more damage than the weapon released in the air. Additionally the radioactive contamination would be far reaching. But of course this is no easy feat to do.
You said: "U-238 is barely radioactive, with a halflife of about 4500 million years. U-235 on the other hand is way more radioactive"
Nuclear types like to measure radioactivity in what is known as activity:
A=(lambda)*N,
(lambda)= (ln 2)/ t1/2,
where is the decay constant, N is the concentration, and t1/2 is the half-life.
What this means is that activity is inversely proportional to half-life. So in order to have a highly radioactive sample with a long half-life you must have a high concentration of it. It doesn't work this way with U-235. It has a 713,000,000 year half-life. Doing a quick calculation you will find that even a pure large sample of U-235 (subcritical of course) would have very low activity.
You said: "The history of nuclear power so far, however, doesn't leave one optimistic."
What metric are you using to say that nuclear power has historically been unsafe? The number of deaths caused per MWh produced? Deaths or injuries per reactor-hour of operation? Average deaths per year at a given plant?
Really, compare these metrics to that of any other power distribution plant and you will see historically, even with the huge publicized disasters like Chernobyl and TMI, that no other large scale power producer even compares in safety to nuclear power.
But since we're on the topic of nuclear power safety history, the website The History of Nuclear Power Safety is an excellent resource.
You said: "of course humans also dectect phermerones with their noses. why wouldn't they if other mammals do? i know science is about being skeptical and all, but is it that big of a jump and illogical to expect that humans detect phermerones by smelling?"
Scientists believe that pherormones are suppressed in humans. One point of evidence cited is that about the time that homonids developed color vision, a pheromonal pathway gene mutated and became unusable. One item of speculation from that is that color vision gives advantages of finding mates from a distance rather than close up as would be required when recieving pheromones. This would make the need for pheromonal pathways much less important (so much less important that subsequent mutation didn't affect survival). Additionally, many other mammals don't have color vision and tend to be much more receptive to pheromones than humans.
You said: "Was it also proven by this tv show that the cause of the ocean gas was completely unrelated to any kind of impacts?
For the future, link to or provide details of any sort of discovery claims, lest they be dismissed out of hand."
Reminds me of an article in Nature (Wood, W. T., et al. Nature 420, 656-660 (2002)) that discussed how methane in seafloor deposits is released to the oceans. One of the points discussed was that as seawater temperature rises, the base of gas hydrate stability rises. What this means is that some of the methane trapped under the seafloor in solid methane hydrate turns instead into methane gas due to the increase in temperature. This release of gas in turn will increase the pressure near the seafloor, and if close enough to the surface, or near a fault that allows a gas chimney to form, it can be released to the ocean (perhaps like a valve until the pressure subsided). Obviously this would be amplifying if it occured on a large scale since methane is a powerful greenhouse gas.
One possible method for being on a large enough scale would be catastrophic seafloor failure (maybe an earthquake or meteorite) where a large amount of initial methane is released. This, of course, could allow the amplifying reaction to occur with methane deposits far remote from the source of impact potentially leading to a global warming effect.
You said: "(Of course then, you have to wonder why the US lags behind some other countries in science education....)"
You have to be really careful to say exactly what you mean when you make general statements like this. While it is true that US K-12 (or in particular 8-12) science education falls behind much of Europe, that is not true for college education or other types of education not normally considered (thinktanks, museums, libraries, private education, etc.,). You can't always compare one countries science education against another because they use different methods of implementation in their education process. For example, some countries give a test in about the 8th grade. Depending on the student's score, he or she is trained in vocational or scientific disciplines for the equivalent of his or her high school period. These vocational students are not tested for science when compared against other countries.
You said: "You're just proving the point I am making."
In order to have a proof you have to have 3 things:
1. A mutual understanding of words, symbols, and their meanings,
2. Agreement on axioms that require no further justification, and
3. Agreement on when one statement follows logically from another.
I think is extremely obvious that you do not give any of those in your argument. Prefer the word 'demonstrating' to 'proving'. The idea of a proof really loses its meaning (both legal and scientific) when people use it informally to justify biased arguments.
You said: "Einstein was born in 1879 and moved to America in 1931 at the age of 52."
Actually it was 1932. He was so proud of his german heritage that he gave up his citizenship twice. He became a US citizen in 1940.
If you're like me and your base units are TeV, Mparsecs, and fortnights, you'll find the values to be 1.98*10^13 TeV*Mparsec/fortnight^2 and 4.78*10^13 TeV*Mparsec/fortnight^2. Hope this helps.
You said: This is absolute rubbish, a different system of quantification should be used when referring to binary powers, as the borrowing of those from SI is clearly misleading.
There is a system that isn't used by many people. For example, it uses kibibyte for 2^10 bytes and mebibyte for 2^20 bytes (and so on).
You said: "Actually, I'm not against nuclear power on principle, but it is a huge risk, not so much for waste, but that it easily segues into nuclear weapons."
The genie is out of the bottle and isn't going back in. Its not really rational for us to stop using nuclear power for electricity and research because other countries are independently developing WMD with it.
You said: "Canadian reactors use weapons grade plutonium and uranium, rather than whatever it is that other reactors use (which is how India and Pakistan got their hands on nuclear material -- from nuclear reactors bought from Canada). I remember there was a big fuss during the Clinton administration, because the plutonium and uranamium from a number of decomissioned nuclear weapons was going to be shipped to Canada, and people on both sides of the border weren't too keen on that."
Canadian reactors are not initially fueled with plutonium. They are just not highly enriched (where the fraction of the isotope U-235, which occurs 0.7% naturally, is increased). The consequence of this is that in order to have a self-sustaining chain reaction (criticality), the neutron flux must be higher. This is because the Candu reactor uses slow-fission which utilizes U-235 as a fuel and not U-238. In order for the core to remain critical (where on average one neutron from a fission event goes on to cause another fission vice being absorbed by another nucleus or escaping the boundary of the core) it has to be very large size and have a very high neutron flux (as compared to a more enriched core which could be smaller and have a lower neutron flux and stay critical).
One consequence of a core with a very high neutron flux is that U-238 can absorb a neutron (which is helped because the core utilizes slow fission unlike a nuclear bomb), become U-239, undergo 2 beta decays and form Pu-239. Pu-239 can also undergo fission like U-235 and be used as a fuel (odd numbered atomic mass numbers of very heavy elements will undergo slow fission but even numbers will not). This is one of the reasons why natural uranium and thorium (which would produce U-233) could potentially create more fuel over time in the reactor (as the U-235 is depleted). Since it is much easier to make a nuclear bomb from plutonium than the brute force method of seperating U-235 from natural uranium this is obviously a potential threat for nuclear weapons poliferation around the world if these reactors are sold.
You asked: "So -- as far as environmentally friendliness is concerned, how do the different types of reactors stack up?"
When you think about environmental friendliness there is short term safety (immediate event of casuality) and long term (groundwater and storage of waste) concerns.
In the short term the major concerns are preventing the reactor from breaking and spilling its fission fragments (which is the VERY highly radioactive waste in a reactor compared to everything else which is relatively lowly radioactive), and if it does break, by containing it. Preventing the reactor from breaking is pretty much controlled by good engineering practice of operating it and by competent design. If we've learned anything from the Chernobyl accident, the least of which is that *only* the people who are trained to operate and know the most about the reactor should be allowed to do any test (or any operation for that matter). Once management steps in and decides that they know how to operate the reactor better than the operators themselves, there is a serious problem. Containment is much simpler. You put up several barriers to prevent radioactive fission gasses from escaping. The final one, the most obvious one, is the cement dome that covers nuclear power plants. But other methods of containment are also useful, such as the pebble bed design where each fuel particle is encased in a ceramic sphere that can contain all fission product gases ever produced by that particle. In the worst case accident the particle will not melt or lose any of its ability to hold the gasses. Future reactors will be much safer due to designs like this (in fact the NRC has rated some as requiring "no evacuations under any accident condition", meaning that they don't think a meltdown can occur).
For long term concerns, continuous sampling and monitoring as well as storage of radioactive waste are the concerns. As long as there is
1. Since the amount of deuterium formed in the Big Bang Nucleosynthesis is directly proportional to the density of matter, the density of the Universe can be determined by looking at very old hydrogen gas clouds (ones where the hydrogen to deuterium ratio is the same as that of the Big Bang Nucleosynthesis) that haven't been burned in stars. In particular, the method used was using a powerful quasar to be able to see such a cloud. The amount of deuterium can be determined by spectral analysis.
2. Experiments have been done that show how cool nucleons have to be to be able to form atoms (in particular helium and deuterium). The universe has been cooling since it formed so the time that the Big Bang Nucleosynthesis occurred after the Big Bang can be determined (for deuterium I think it was about 4 minutes).
3. Assuming that all forces have negligable affect on the distribution of matter during the first few minutes after the Big Bang (due to the incredible temperatures), and that the universe expanded uniformly in a sphere (COBE has shown that this is not entirely true...but it is very close) at the speed of light in all directions (I'm not entirely sure how inflation theory affects this), the volume of the universe at the time of Big Bang Nucleosynthesis can be determined. Now the mass of normal matter can be determined.
4. Since galaxies should follow Kepler's Laws of planetary motion, but don't (i.e. many parts of a galaxy rotate at about the same radial velocity at different radial positions not equidistant from the galactic nucleus) something has to account for the discrepancy. The current theory is that about another 90% of the galactic mass exists in a dark matter halo around the galaxy.
If I had points I'd mod you up.
You are absolutely right. What many people fail to recognize is that there are different levels of radioactivity. If a radionuclide has a long half life it will be less radioactive in the short term. In particular, U-235 and 238 with hundreds of million year half lives (U-238 in the billions) will have very low radioactivity compared to a fission product which may have a fraction of a second half-life. If you don't start up the reactor until it is safely in orbit, then there will be no fission products, and even if it did burn up in the atmosphere, it would have too low radioactivity to even notice.
As far as resource management, a meta-universe may have a greatly exagerated speed of light and atoms (if they exist as defined in our physics) may be many times smaller, making the potential abilities of computers (and quantum computers (or another similar meta-universe physics construct)) much faster.
But then again, all points don't necessarily need to be simulated. Our perception is based on what our memory tells us is the past. It is as difficult to touch the past as it is to touch the future. As long as you simulate one time point, you have suceeded in your simulation because all the people in your simulation have memories and believe that they are continuing in a linear time. They believe that what their memories tell them happened 1 second ago even though it was never simulated. If you decide to run a simulation that reverses time it would have no affect on perception of time since it is based on the past. Even though you may grow from an adult into a child (in the time of the computer), at every time data point you think that you are growing into an adult.
And why not assume that they did some simplifications? Why should we assume that the universe that we exist in the the one that the simulators run? It could be much different and the laws of physics different as well. It may be able to run simulations of huge amounts of atoms because that may be a trivial amount of processing time to a much more complex universe.
Yes this is all assuming that there isn't a meta-matrix in which the matrix is run. It seems pretty obvious to me that that is what the last scene was trying to portray in a subtle way.
And if there is a meta-matrix, what prevents having a meta-meta-matrix and so on? Its really impossible to speculate the age of the matrix based on this information.
You completely missed my points:
1. With the vast majority of energy demand in industry, it would hardly help even if every single person on the planet diconnected from the grid.
2. Economics will not allow alternative energy due to the fact that it produces too little power and costs too much when it is send over distribution lines to connect to the grid. It will be able to supply point sources but not an industrial site 500km away.
3. In order to power the 60MWe factory that I mentioned in my previous post, at 10% effeiciency (including the inverter), given that 1.34KW of radiation are incident on the atmosphere per square meter of which 50% will be absorbed or reflected by the atmosphere, an area of roughly 1 square km is needed! Imagine the size of the battery if it were to diconnect from the electrical grid completely (for cloudy days)!
No matter how much you hope and 'walk the walk' it will not change the fact solar power will not be able to meet the growing world energy demand. It is ingenious for some devices (like calculators) but I don't think it should be used on top of houses. The dc from the cells will have to become ac through an inverter. This inverter will be in continuous use so it will need some sort of cooling (probably ambient air flow through fins). If this cooling is blocked a fire could happen. Additionally you have two options: remain connected to the grid or use a battery on rainy days. If you use a battery there is obviously the concern over a large battery maintenance and periodic replacement as well as hazards of the battery itself (for example if you had rainwater which has any amount of chlorides--possibly from the ground--you would have chlorine gas produced as well as a high energy electrical fire that you could not diconnect). Large batteries just are not as simple as car batteries.
If you remain connected to the grid you could sell back additional power right? Well there are two obvious problems, paralleling with the grid and producing smooth 60Hz. Paralleling a power source is a risky move. If you don't do it correctly and the incoming and running are out of phase the differential voltage across your breaker (up to twice the running or incoming if you parallel 180 degrees out of phase) can fry your breaker and other operational equipment. Smooth 60Hz vs. rough inverter 60Hz is a little less known problem. An inverter can only really produce DC voltages that change to follow a sinusoidal type waveform. But not continuously--it does it in steps. So once you parallel you have the smooth 60Hz that comes from a rotating machine with the rough 60Hz from the inverter. Depending upon the quality of your inverter the diferential voltages from the smooth 60Hz to the steped DC will cause current surges to and from the source. This in turn by itself may overrate your distribution complex to your house and cause an electrical fire.
Now while I am trained in electronics and electric motors, generators, and power distribution systems (as part of my job) and I could operate all of the above mentioned with safety, I don't believe the average homeowner could. People seem to be confident about burning down their houses without the above mentioned complexities. They really don't need these additional options to kill themselves or burn down their houses regardless of whether it might save the world 10% of its energy demand.
An average household uses about 2KWe of power. With a houshold size of 4 in a town of 30,000 (my hometown) this yields about 15MWe of power. One industrial plant in my hometown (it makes silicon wafers) uses 60MWe. All in all, my hometown uses over 200MWe of power.
Even if everyone decided to have electrical power cut off from their homes it would dent (and only dent) the enormous demand due to industrial sites. The number of these sites is more likely to increase rather than decrease over time FAR outstretching the demand that homeowners might be able to counter.
Energy demand isn't that simple, some of the factors:
1. Any fuel derived from petroleum reserves is becoming more scarce and it emits greenhouse gases among other toxic byproducts.
2. Solar cells have abysmal efficiency and are made through very toxic processes
3. Hydroelectric power is affected by the fact that there are only so many rivers you can dam and once you dam them you have to deal with the ecological consequences.
4. Coal is obviously a greenhouse gas emitter and very toxic.
5. Nuclear plants have phenomenally large insurance costs and questions about long term storage of high level radioactive waste
6. Alternative sources have yet to be designed so that they can be scaled up to the level of 100's or more MWe so that they would be effective in an electrical grid (Let me put it this way: they can support point sources of power but when you try to send it over lines 100 km away the electrical losses may well exceed 40%. This is obviously not cost effective).
7. Wind power suffers from the above electrical losses.
There is no One True Power Source that people can use. It has to be a combination of the above factors taking into account the pros and cons (IMHO it should be nuclear and alternative sources (not including solar) using gasoline plants as peaking plants).
Actually, the kitchen sink is right here.
Reminds me of the story of the Turtle. Very similar tactic, only over 200 years ago.
It depends on the design. Most boats are designed with the 'V' shape so that very little of the energy is transferred to the wake of the boat. This makes them very efficient for travelling on the surface.
When you are talking about a submarine there are 2 designs. There are the diesel boats (i.e. similar to WW II subs) and there are nuclear boats. The diesel boats had the 'V' shape since they had to spend a great deal of their time on the surface and this is a much more efficient way to transit (after all a diesel submarine is pretty much just a surface ship that can occasionally submerge for short periods of time). The nuclear submarines have the 'O' shapes since they have no real need to surface except for return to port and an O shape is more efficient submerged (minimizes surface area and can keep a better balance). When a nuclear submarine is on the surface it takes a major speed hit because a significant amount of energy used for propulsion is transfered to the wake (since it doesn't have the 'V' shape). Therefore a nuclear submarine will travel faster submerged.
So a diesel submarine should be almost as efficient as a surface ship, but a nuclear submarine will be less efficient (but will travel faster than diesel subs due to raw power).
You said: "It's one thing I hate about Mozilla (why can't they use the native menus and widgets?) -- though I use Mozilla exclusively, I still feel a lot of time was wasted implementing their own text box (that still doesn't work quite right), menus, etc...
This was discussed extensively in the design of Mozilla. The reason native UI's aren't used is that in order to be standards compliant, the widgets had to differ from the functionality offered by the standard OS' widgets. If they used the same widgets with the different functionality it would mislead users who expect (and rightly so) that the same looking widget should act the same. It wasn't just so they could create XUL and make the browser completely skinable. That wasn't even a consideration.
You said: "Well, I suppose when Bush wins in 2004 and we all move to Australia, we'll have to run our file-sharing apps via carrier pidgeon."
Fortunately they'll be prepared. There is a protocol: RFC 1149 and a sucessful test by a LUG in Norway.