By your retarded reasoning somebody who never used much of our resources to begin with is less responsible that a greedy fuck who now "only" uses 10 times as much as he should, simply because he made a modest effort to control an even more reckless behaviour in his past.
I guess those people in India are more responsible for the problem, despite emitting an order of magnitude less, simply because the US went from "really fucking bad" to "still really bad, but not quite as horrific as before" ? Yea, darn those people who think they should not be making more sacrifices and give up clean drinking water when us in teh west had to consider actually walking for short trips instead of driving...
This is nothing new. Many battery technologies can last for decades. It's only the Cobalt based lithium ones that have the abysmal 2-3 year shelf-life.
Ni-Iron batteries have demonstrated more than 50 year life, with no noticeable degradation following deep discharge. LiFePO has demonstrated less than 20% capacity loss over 15 years and many thousands of cycles. Ni-Hydrogen has been in service without maintenance on satellites for many many years. The batteries on the Hubble went 19 years without servicing. Lead-Acid requires a bit of servicing and maintenance, but they can also last more than a decade when properly cared for.
Now when it comes to energy storage to deal with renewables the problem is the shear amount of energy storage needed as well as energy lost to inefficiency. The technology exists, but the cost would be prohibitive.
Explain to me how whatever we come up with won't provide an evolutionary pressure when misused, and become worthless after the bacteria evolves...
There are limits to what evolution can achieve. No bacteria will survive pressure cooking at 300 C in concentrated sodium hydroxide as an example.
There's also the possibility of eradicating a disease before it can evolve into something you cannot treat. Smallpox will never become resistant to the vaccine, because we eradicated it. It cannot evolve if it doesn't exist.
It would of course be naive to assume we will easily eradicate all disease causing bacteria , but even with the problems we have with antibiotic resistance, modern medicine has brought down the number of people suffering and dyeing from bacterial infections dramatically. In fact, the main reason Tuberculosis has not been eradicated is that many countries fail at supplying adequate healthcare to their people.
It has a snowball's chance in hell of happening this way, but in principle this could be implemented well.
You'd put a small tax on telecommunications and use it to support artists and musicians. That way you wouldn't need the copyright garbage, music and art would be financed through taxes, and it could be freely distributed across the entire world.
Of course, in reality corruption will see it end up lining the pockets of a handful of people, the oppressive copyright laws would remain, and the government will use the funding as a means to bully "content providers" into doing their bidding.
The high temperature makes the fissile nuclei move fast, increasing the relative speed of the neutrons and therefore reducing the rate of the reaction
It's actually WAY cooler than that. It cannot really be explained in a few sentences, but if you can be bothered I've tried to explain:
Doppler broadening refers to the Doppler effect causing U-238 nuclei to "see" a wider range of neutron energies due to an effect not to different from the doppler effect. The heating doesn't actually change the neutron energies all too much, but it causes different U-238 atoms to "see" different neutron energies, greatly increasing the probability of resonance absorption. All materials, including the non-fissile U-238 in reactors, absorb neutrons exceptionally well at certain energies. These "peaks" in graph of the probability of absorption occur mostly in the intermediate energy range. This is also the reason why a moderator helps so much. You let the neutrons slow down in a medium with low neutron capture probability, thereby allowing them to avoid the high probability of absorption in the intermediate energy range. If you did not use a moderator, but simply piled a bunch of uranium together, then the neutrons would make many collisions with U-238 as they are slowing down, and the resonance absorption peaks in the intermediate energy range would waste most of the neutrons.
So basically the idea is that you form the uranium into small pellets, rods or grains, and embed them into a moderator. The neutrons will escape the uranium , bounce around inside the moderator until their energy is low, and then eventually strike the uranium fuel again, only this time they are much more likely to collide with a nucleus ( slow particles have a larger wavelength ), and since their energy is too low for resonance absorption, the fission/capture ratio is much better.
Now, when the reactor heats up the U-238 atoms will vibrate quicker (that's what heat is ). Since motion is relative this means that from the point of view of the U-238 nuclei , the energy at which it absorbs neutrons exceptionally well is different. Since there are many U-238 nuclei in the reactor, and since they don't all have the same energy, the heating has the consequence of broadening the range of energies at which neutrons are absorbed very well.
As a consequence, heating has the effect of increasing the chance that neutrons will be absorbed in U-238 without causing fission. This is not due to changes in the neutron spectrum or the physical properties of the materials. It occurs because different U-238 nuclei "see" a different distribution of neutron energies, and so a wider range of neutron energies are absorbed very easily.
This effect occurs in all reactors, but it is less pronounced in fast reactors, since the high fissile content tend to cause the neutrons to split a fissile nucleus before they have had a chance to slow down much. This is part of the reason why it's more difficult to make a fast reactor stable. A more important reason is that the fast fission tends to produce more prompt neutrons per fission, and thus the delayed neutron fraction is lower.
Many non-military targets such as Kyoto were considered but in the end they decided that they should at least make some effort to claim they were attacking ports and manufacturing.
Hiroshima was not the primary target. It was chosen because of favourable weather conditions. They picked a city to annihilate based on where the sun was shining...
So somehow MAD worked for decades between the US and the USSR, but suddenly that is invalid just because you want to do things differently this time?
There were multiple close calls, and on a few occasions the decision not to fire off the full scale retaliation was down to a very small number of people. Furthermore, it has not prevented various military conflicts between India and Pakistan.
B) I think PETA are a bunch of self-promoting idiots whose campaigns are more often than not counterproductive
C) The campaigns they had portraying women as pieces of meat are downright offensive, and have caused them to fall out with many organisations that would otherwise have been sympathetic to animal welfare. In particular a lot of women's rights organisations despise them for it.
D) If you think this campaign is something , read up about their uses of photography of Auschwitz victims. I kid you not, these people figured it was a good idea to use pictures of burning corpses fresh out of nazi gas chambers as part of a political campaign. Now even if you do think the way the meat industry treats animals is comparable to concentration camps, any remotely sober person ought to realize that a stunt like that is only going to stir up a lot of anger and hurt.
I hate Teflon pans, you have to cuddle them like a fragile little creature or they get scratched. In comparison you can scrub the cast iron ones with steel wool or even sand blaster them ( yes really ) and all it takes to get them back to pristine condition afterwards is a drop of veg oil.
Specifically, one wonders about the environmental impact--how hard must this stuff be *to clean* when it gets stuck on something, for example? If we put it on a hundred million bottles a year, how will that impact the environment?
Slippery doesn't mean it is hard. Notice how teflon is fairly non-stick, but you can still scratch it quite easily with any metal utensil. In the same way I kinda suspect you will be able to just scrub this stuff away. It is also likely to be sensitive to temperature and some chemicals.
It is REALLY hard to make a material which will resist corrosion from alkaline solutions as well as acid, heat , scratching , fracture and so on all at the same time. People that design satellites, space probes or nuclear reactors additionally have to deal with intense radiation that can alter the chemical properties.
Then there is photo-damage. Many organic materials degrade under exposure to sunlight. You got oxidation to worry about, redox reactions with salts and other ionic compounds. If the material is porous then small molecules can diffuse into it and weaken it from the inside.
Basically you will not be able to make a material I cannot find a way to dissolve or destroy. Granted, if you put something quite tough onto a very sensitive fabric, I may not be able to get rid of it without destroying the cloth. There's no need for super-slippery materials for this however. Just rub some used motor oil into your clothes and they are pretty much permanently ruined.
What do you think happens when we get honey? we squish bees and the sweet stuff comes out?
Yes, that does happen. See there is no way to tell the bees "hey I'm going to remove this huge wafer of your home now, will you stay out of the way so you don't get hurt?" so in practice it is almost unavoidable to crush a number of them when you take the honey from the hive. Beyond that it depends a lot on how the bees are kept. There is the individual beekeeper that takes care of his bees and interferes minimally with them. Then there is the industrial production which often involves frequently "replacing" the queen or even the entire hive, as well as shipping hives around as a product to be used for pollination.
Now, granted that it is not at all clear that bees are even capable of suffering in the same way vertebrates do, so many people argue there is no ethical issues with hurting bees (or other insects ) anyways, but that is quite a different argument than pretending that collecting honey is harmless to the bees.
I should add, that my "for the sake of argument" of 10^20 is an EXTREMELY conservative estimate. In practice the IPv6 address space has an amount of addresses that is greater than the number of stars in the universe.
People underestimate the address space in IPv6 when they make remarks like this.
In principle IPv6 could hold more than 10^38 addresses. Now due to structuring and various reservations and so on there is considerably fewer. So for the sake of argument, let's say it is "only" 10^20. That's still enough that for every present IPv4 address you could add an entire internet and still have addresses left over.
What this means is that even if ISPs were incredibly wasteful and basically trashed 99.9% of the address space due to bad practices, you'd still have millions of addresses for every person in the world.
The industry can't see an arms-race when it's staring them in the face.
This will escalate until file-sharing is done over invite-only darknets. Best of luck filtering fully encrypted data streams that make a jump or two across national borders. A DNS blacklist is one thing, but forcing ISPs to engage in highly costly traffic analysis is something they will fight tooth and nail.
Climate science is considerably more complex than rocket engines, ballistics, and even the fluid dynamics of re-entry. So I guess you are correct, it's not rocket science.
It is nothing more scary than to make a really grim joke about war and suffering , only to realise there are people who not only think you're serious, but they agree with you.
don't actually exist. virtual particles are just mathematical simplicities. They are only a *model* of how physics works. Even in the name- they are "virtual" because they are just mathematical abstractions. nothing more.
The electric field started out as a model of how charges interact, then he noticed that waves in the electromagnetic field would produce energy transfer at a speed that was the same as that of light.
Einstein's theory of relativity was just a model of how gravity works, a gravitational field was just a mathematical tool for predicting the motions of objects, and black holes were mathematical curiosities that probably did not exist in reality. Today we have observed binary star systems gradually changing their orbits as they lose energy due to gravity waves. Frame dragging of space itself surrounding the earth has been empirically measured in satellites, and several black holes have been found by astronomers.
Quantum mechanical wave functions were models for how elementary particles work, and the Dirac equation predicted negative energy solutions, suggesting each particle had a double of opposite charge. A few years latter the positron was discovered.
Circulation in fluid dynamics is a mathematical quantity used in predicting the flow of fluids. As it happens it cannot simply disappear without viscosity, leading to the concept of vortex tubes, the most famous example of which is a tornado.
Perhaps the greatest prejudice to new ideas is however found in mathematics. Whenever new numbers have been discovered, how have we named them? Negative, irrational , imaginary... As it happens complex numbers are inherent to the laws of quantum mechanics. You would have a very hard time trying to explain why matter sticks together without them.
But, going about intentionally ripping space/time, getting into dark matter and whatnot, without actually having grasped and totally measured the presence, effects and mechanics of what we already discovered in regard to these, is dangerous.
Yep, we're playing with fire. And as we all know, humans were better off without fire.
And we feel good about letting Europeans man the switch?
See the thing is, after having had our continent torn asunder by two world wars, a couple of genocides, decades of Soviet occupation of the eastern block, followed by being dragged into a hornet nest in Iraq following faulty US intelligence, most people over here are so fed up with the whole war thing that we only agreed to help the Libyans deal with Gaddafi after he started using the air-force to bomb innocent protesters.
However, if you prefer I guess we could put the device in Texas. Then they can use it to guard the double layered, 10 foot tall , lethally electrified, barbed wire fence Herman Cain was talking about. Don't worry though, Rick Perry will have the keys.
Not quite. A reactor fuelled with natural uranium will start producing Pu-239 from neutron capture in U-238. In order to get it good enough for weapons use it must not be present in the reactor for too long because that will cause a build-up of Pu-238 , Pu-240 and Pu-241 that is very difficult to separate from Pu-239 ( the bomb stuff ). These isotopes , and Pu-238 in particular, are very troublesome for making nuclear weapons since they produce a lot of heat and spontaneous neutron emission. For modern high-burnup spent fuel it is likely that the heat would cause vital bomb components to deform or even melt if you tried to use it.
The solution for a bomb maker is to refuel teh reactor frequently, thus getting the Pu-239 before more troublesome isotopes have formed in quantity. I believe the GP is mistaking the CANDU reactor's ability to refuel while it is running for being easy to refuel frequently. In reality the CANFLEX refuelling system is quite slow, and not really suitable for making bomb material.
Now of course you CAN make bomb material using a CANDU reactor, just run the reactor for a brief period of time and then replace all teh fuel. This is true for any reactor that is fuelled by natural or slightly enriched uranium. However, CANDU is not much more suitable for this than many other reactors. The British Magnox design is as an example known to have been used in the British as well as North Korean nuclear programs, while CANDU has as far as I know never been used in any bomb program.
There's a world of difference between a Paedophile and somebody taking advantage of or raping children. That you appear to be using the two interchangeably leads me to suspect you assume the vast majority of Paedophiles are poised to hurt children in one way or another. It's about as stupid as assuming guilt when a man is accused of rape.
So better make that four designs - one conventional, on thorium, one that can be converted from conventional to thorium, and one breeder. Cover all the bases.
Sounds like you want a CANDU reactor.
They can run on natural Uranium,slightly enriched Uranium , MOX , U-233/Thorium , and for the case of Thorium and U-233 they can be run in a self-sufficient breeder mode.
Personally I'm somewhat sceptical to thorium however. Margins on neutron economy are so tight that reprocessing would have to be done frequently to get a positive breeding ratio. In the case of molten salt reactors they even suggested doing it continuously while the plant is running. Since reprocessing is expensive and adds considerably to the cost of the electricity, you want to minimize the need for it and exploit economies of scale to the full extent. The Plutonium/U238 in a fast neutron spectrum will likely perform better due to the much better neutron economy. Plutonium produces nearly 3 neutrons per fission in a fast spectrum , and the fission/capture ratios in non-fissile nuclei is much better for fast neutrons.
Thorium is a stupid move. You'd have to start the darn things on reprocessed plutonium anyway, so you may as well go with fast breeders ( The reprocessing step is the major obstacle at the moment ).
Now while there may be some safety advantages with using molten salts as coolant, there is no reason why you could not do that in a fast neutron spectrum with plutonium and uranium. In fact, the latter would probably be easier since you could use much more common and less corrosive salts, like NaCl , MgCl or ZrCl , whereas the thorium versions would use Lithium and Beryllium fluorides.
The GGPs post is fine as far as the wording is concerned, though he is wrong about the physics. It's not tricky to achieve criticality. It's more that you need a very efficient compression to ensure the fissile material reaches an optimal configuration before the reaction starts.
"Prompt criticality" is a property of the nuclear reaction inside an assembly of material, not a type of explosion. It refers to whether the chain reaction is self-sustaining without the contribution of delayed neutrons. It says nothing about how powerful an explosion will be, or how high a yield a nuclear weapon may have. It is not difficult to achieve, and even just dropping two suitably sized pieces of fissile material onto each other could produce a prompt-critical reaction.
Now, the reason a weapon may produce a very poor yield if the compression is inefficient is not because it doesn't become prompt critical , but rather because the explosion will blow the bomb apart before the reaction has produced very much energy. In particular, a poor compression could cause the chain reaction to begin before the fissile material is in an optimal configuration.
People sometimes try to make some distinction between a "thermal" or "nuclear" explosion, usually while discussing the Chernobyl disaster, but there is no such distinction as far as the physics is concerned. The amount of energy released in a nuclear explosion depends almost entirely on what neutron multiplication factor can be achieved, as well as how long the material is kept together before the explosion blows it apart. A nuclear fission bomb achieves the high explosive yield for basically two reasons:
1) The high enrichment and fusion-boosting allows the multiplication factor to become very large, 3-4 or even greater.
2) The fissile material has been accelerated inwards by powerful explosives, giving a lot of momentum that has to be overcome before the pressure blows the bomb apart.
Note that we to this day do not know whether the Chernobyl reactor went prompt critical or not. It may well be the case that it simply overheated to the point that the piping could not sustain the pressure from the steam, but given the design of the reactor it is also very possible it reached prompt criticality. In either case the explosion was very much a nuclear explosion in the sense that it was driven by the heat released from a nuclear chain reaction. It is of course not possible for a chain reaction that is not prompt-critical to produce an explosive yield of several kilotons, but that is mostly because it would be too slow to produce much energy before the thing blows itself apart. For the same reason it is not sufficient for a chain reaction to be prompt critical in order for it to produce a substantial yield. The neutron multiplication factor must also be large enough, and the material must be kept together for a long enough time. That is why a reactor could never produce an explosion similar in power to a nuclear bomb. It simply doesn't have a high enough multiplication factor. In fact, it will likely be very close to 1.
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By your retarded reasoning somebody who never used much of our resources to begin with is less responsible that a greedy fuck who now "only" uses 10 times as much as he should, simply because he made a modest effort to control an even more reckless behaviour in his past.
I guess those people in India are more responsible for the problem, despite emitting an order of magnitude less, simply because the US went from "really fucking bad" to "still really bad, but not quite as horrific as before" ? Yea, darn those people who think they should not be making more sacrifices and give up clean drinking water when us in teh west had to consider actually walking for short trips instead of driving...
This is nothing new. Many battery technologies can last for decades. It's only the Cobalt based lithium ones that have the abysmal 2-3 year shelf-life.
Ni-Iron batteries have demonstrated more than 50 year life, with no noticeable degradation following deep discharge.
LiFePO has demonstrated less than 20% capacity loss over 15 years and many thousands of cycles.
Ni-Hydrogen has been in service without maintenance on satellites for many many years. The batteries on the Hubble went 19 years without servicing.
Lead-Acid requires a bit of servicing and maintenance, but they can also last more than a decade when properly cared for.
Now when it comes to energy storage to deal with renewables the problem is the shear amount of energy storage needed as well as energy lost to inefficiency. The technology exists, but the cost would be prohibitive.
There are limits to what evolution can achieve. No bacteria will survive pressure cooking at 300 C in concentrated sodium hydroxide as an example.
There's also the possibility of eradicating a disease before it can evolve into something you cannot treat. Smallpox will never become resistant to the vaccine, because we eradicated it. It cannot evolve if it doesn't exist.
It would of course be naive to assume we will easily eradicate all disease causing bacteria , but even with the problems we have with antibiotic resistance, modern medicine has brought down the number of people suffering and dyeing from bacterial infections dramatically. In fact, the main reason Tuberculosis has not been eradicated is that many countries fail at supplying adequate healthcare to their people.
It has a snowball's chance in hell of happening this way, but in principle this could be implemented well.
You'd put a small tax on telecommunications and use it to support artists and musicians. That way you wouldn't need the copyright garbage, music and art would be financed through taxes, and it could be freely distributed across the entire world.
Of course, in reality corruption will see it end up lining the pockets of a handful of people, the oppressive copyright laws would remain, and the government will use the funding as a means to bully "content providers" into doing their bidding.
Probably because it is intended for pornography , and sex is more than that.
It's actually WAY cooler than that. It cannot really be explained in a few sentences, but if you can be bothered I've tried to explain:
Doppler broadening refers to the Doppler effect causing U-238 nuclei to "see" a wider range of neutron energies due to an effect not to different from the doppler effect. The heating doesn't actually change the neutron energies all too much, but it causes different U-238 atoms to "see" different neutron energies, greatly increasing the probability of resonance absorption. All materials, including the non-fissile U-238 in reactors, absorb neutrons exceptionally well at certain energies. These "peaks" in graph of the probability of absorption occur mostly in the intermediate energy range. This is also the reason why a moderator helps so much. You let the neutrons slow down in a medium with low neutron capture probability, thereby allowing them to avoid the high probability of absorption in the intermediate energy range. If you did not use a moderator, but simply piled a bunch of uranium together, then the neutrons would make many collisions with U-238 as they are slowing down, and the resonance absorption peaks in the intermediate energy range would waste most of the neutrons.
So basically the idea is that you form the uranium into small pellets, rods or grains, and embed them into a moderator. The neutrons will escape the uranium , bounce around inside the moderator until their energy is low, and then eventually strike the uranium fuel again, only this time they are much more likely to collide with a nucleus ( slow particles have a larger wavelength ), and since their energy is too low for resonance absorption, the fission/capture ratio is much better.
Now, when the reactor heats up the U-238 atoms will vibrate quicker (that's what heat is ). Since motion is relative this means that from the point of view of the U-238 nuclei , the energy at which it absorbs neutrons exceptionally well is different. Since there are many U-238 nuclei in the reactor, and since they don't all have the same energy, the heating has the consequence of broadening the range of energies at which neutrons are absorbed very well.
As a consequence, heating has the effect of increasing the chance that neutrons will be absorbed in U-238 without causing fission. This is not due to changes in the neutron spectrum or the physical properties of the materials. It occurs because different U-238 nuclei "see" a different distribution of neutron energies, and so a wider range of neutron energies are absorbed very easily.
This effect occurs in all reactors, but it is less pronounced in fast reactors, since the high fissile content tend to cause the neutrons to split a fissile nucleus before they have had a chance to slow down much. This is part of the reason why it's more difficult to make a fast reactor stable. A more important reason is that the fast fission tends to produce more prompt neutrons per fission, and thus the delayed neutron fraction is lower.
Hiroshima was not the primary target. It was chosen because of favourable weather conditions. They picked a city to annihilate based on where the sun was shining...
There were multiple close calls, and on a few occasions the decision not to fire off the full scale retaliation was down to a very small number of people. Furthermore, it has not prevented various military conflicts between India and Pakistan.
Or to put it another way:
http://www.youtube.com/watch?v=uk37TD_08eA
Couple of things:
A) I'm a vegan for ethical reasons
B) I think PETA are a bunch of self-promoting idiots whose campaigns are more often than not counterproductive
C) The campaigns they had portraying women as pieces of meat are downright offensive, and have caused them to fall out with many organisations that would otherwise have been sympathetic to animal welfare. In particular a lot of women's rights organisations despise them for it.
D) If you think this campaign is something , read up about their uses of photography of Auschwitz victims. I kid you not, these people figured it was a good idea to use pictures of burning corpses fresh out of nazi gas chambers as part of a political campaign. Now even if you do think the way the meat industry treats animals is comparable to concentration camps, any remotely sober person ought to realize that a stunt like that is only going to stir up a lot of anger and hurt.
Take a good ol regular steel pan,
Better yet, cast iron.
I hate Teflon pans, you have to cuddle them like a fragile little creature or they get scratched. In comparison you can scrub the cast iron ones with steel wool or even sand blaster them ( yes really ) and all it takes to get them back to pristine condition afterwards is a drop of veg oil.
Slippery doesn't mean it is hard. Notice how teflon is fairly non-stick, but you can still scratch it quite easily with any metal utensil. In the same way I kinda suspect you will be able to just scrub this stuff away. It is also likely to be sensitive to temperature and some chemicals.
It is REALLY hard to make a material which will resist corrosion from alkaline solutions as well as acid, heat , scratching , fracture and so on all at the same time. People that design satellites, space probes or nuclear reactors additionally have to deal with intense radiation that can alter the chemical properties.
Then there is photo-damage. Many organic materials degrade under exposure to sunlight. You got oxidation to worry about, redox reactions with salts and other ionic compounds. If the material is porous then small molecules can diffuse into it and weaken it from the inside.
Basically you will not be able to make a material I cannot find a way to dissolve or destroy. Granted, if you put something quite tough onto a very sensitive fabric, I may not be able to get rid of it without destroying the cloth. There's no need for super-slippery materials for this however. Just rub some used motor oil into your clothes and they are pretty much permanently ruined.
Yes, that does happen. See there is no way to tell the bees "hey I'm going to remove this huge wafer of your home now, will you stay out of the way so you don't get hurt?" so in practice it is almost unavoidable to crush a number of them when you take the honey from the hive. Beyond that it depends a lot on how the bees are kept. There is the individual beekeeper that takes care of his bees and interferes minimally with them. Then there is the industrial production which often involves frequently "replacing" the queen or even the entire hive, as well as shipping hives around as a product to be used for pollination.
Now, granted that it is not at all clear that bees are even capable of suffering in the same way vertebrates do, so many people argue there is no ethical issues with hurting bees (or other insects ) anyways, but that is quite a different argument than pretending that collecting honey is harmless to the bees.
I should add, that my "for the sake of argument" of 10^20 is an EXTREMELY conservative estimate. In practice the IPv6 address space has an amount of addresses that is greater than the number of stars in the universe.
People underestimate the address space in IPv6 when they make remarks like this.
In principle IPv6 could hold more than 10^38 addresses. Now due to structuring and various reservations and so on there is considerably fewer. So for the sake of argument, let's say it is "only" 10^20. That's still enough that for every present IPv4 address you could add an entire internet and still have addresses left over.
What this means is that even if ISPs were incredibly wasteful and basically trashed 99.9% of the address space due to bad practices, you'd still have millions of addresses for every person in the world.
The industry can't see an arms-race when it's staring them in the face.
This will escalate until file-sharing is done over invite-only darknets. Best
of luck filtering fully encrypted data streams that make a jump or two
across national borders. A DNS blacklist is one thing, but forcing ISPs to
engage in highly costly traffic analysis is something they will fight tooth and nail.
Climate science is considerably more complex than rocket engines, ballistics, and even the fluid dynamics of re-entry. So I guess you are correct, it's not rocket science.
It is nothing more scary than to make a really grim joke about war and suffering , only to realise there are people who not only think you're serious, but they agree with you.
The electric field started out as a model of how charges interact, then he noticed that waves in the electromagnetic field would produce energy transfer at a speed that was the same as that of light.
Einstein's theory of relativity was just a model of how gravity works, a gravitational field was just a mathematical tool for predicting the motions of objects, and black holes were mathematical curiosities that probably did not exist in reality. Today we have observed binary star systems gradually changing their orbits as they lose energy due to gravity waves. Frame dragging of space itself surrounding the earth has been empirically measured in satellites, and several black holes have been found by astronomers.
Quantum mechanical wave functions were models for how elementary particles work, and the Dirac equation predicted negative energy solutions, suggesting each particle had a double of opposite charge. A few years latter the positron was discovered.
Circulation in fluid dynamics is a mathematical quantity used in predicting the flow of fluids. As it happens it cannot simply disappear without viscosity, leading to the concept of vortex tubes, the most famous example of which is a tornado.
Perhaps the greatest prejudice to new ideas is however found in mathematics. Whenever new numbers have been discovered, how have we named them? Negative, irrational , imaginary ... As it happens complex numbers are inherent to the laws of quantum mechanics. You would have a very hard time trying to explain why matter sticks together without them.
Yep, we're playing with fire. And as we all know, humans were better off without fire.
See the thing is, after having had our continent torn asunder by two world wars, a couple of genocides, decades of Soviet occupation of the eastern block, followed by being dragged into a hornet nest in Iraq following faulty US intelligence, most people over here are so fed up with the whole war thing that we only agreed to help the Libyans deal with Gaddafi after he started using the air-force to bomb innocent protesters.
However, if you prefer I guess we could put the device in Texas. Then they can use it to guard the double layered, 10 foot tall , lethally electrified, barbed wire fence Herman Cain was talking about. Don't worry though, Rick Perry will have the keys.
Not quite. A reactor fuelled with natural uranium will start producing Pu-239 from neutron capture in U-238. In order to get it good enough for weapons use it must not be present in the reactor for too long because that will cause a build-up of Pu-238 , Pu-240 and Pu-241 that is very difficult to separate from Pu-239 ( the bomb stuff ). These isotopes , and Pu-238 in particular, are very troublesome for making nuclear weapons since they produce a lot of heat and spontaneous neutron emission. For modern high-burnup spent fuel it is likely that the heat would cause vital bomb components to deform or even melt if you tried to use it.
The solution for a bomb maker is to refuel teh reactor frequently, thus getting the Pu-239 before more troublesome isotopes have formed in quantity. I believe the GP is mistaking the CANDU reactor's ability to refuel while it is running for being easy to refuel frequently. In reality the CANFLEX refuelling system is quite slow, and not really suitable for making bomb material.
Now of course you CAN make bomb material using a CANDU reactor, just run the reactor for a brief period of time and then replace all teh fuel. This is true for any reactor that is fuelled by natural or slightly enriched uranium. However, CANDU is not much more suitable for this than many other reactors. The British Magnox design is as an example known to have been used in the British as well as North Korean nuclear programs, while CANDU has as far as I know never been used in any bomb program.
There's a world of difference between a Paedophile and somebody taking advantage of or raping children. That you appear to be using the two interchangeably leads me to suspect you assume the vast majority of Paedophiles are poised to hurt children in one way or another. It's about as stupid as assuming guilt when a man is accused of rape.
Sounds like you want a CANDU reactor.
They can run on natural Uranium,slightly enriched Uranium , MOX , U-233/Thorium , and for the case of Thorium and U-233 they can be run in a self-sufficient breeder mode.
Personally I'm somewhat sceptical to thorium however. Margins on neutron economy are so tight that reprocessing would have to be done frequently to get a positive breeding ratio. In the case of molten salt reactors they even suggested doing it continuously while the plant is running. Since reprocessing is expensive and adds considerably to the cost of the electricity, you want to minimize the need for it and exploit economies of scale to the full extent. The Plutonium/U238 in a fast neutron spectrum will likely perform better due to the much better neutron economy. Plutonium produces nearly 3 neutrons per fission in a fast spectrum , and the fission/capture ratios in non-fissile nuclei is much better for fast neutrons.
Thorium is a stupid move. You'd have to start the darn things on reprocessed plutonium anyway, so you may as well go with fast breeders ( The reprocessing step is the major obstacle at the moment ).
Now while there may be some safety advantages with using molten salts as coolant, there is no reason why you could not do that in a fast neutron spectrum with plutonium and uranium. In fact, the latter would probably be easier since you could use much more common and less corrosive salts, like NaCl , MgCl or ZrCl , whereas the thorium versions would use Lithium and Beryllium fluorides.
The GGPs post is fine as far as the wording is concerned, though he is wrong about the physics. It's not tricky to achieve criticality. It's more that you need a very efficient compression to ensure the fissile material reaches an optimal configuration before the reaction starts.
"Prompt criticality" is a property of the nuclear reaction inside an assembly of material, not a type of explosion. It refers to whether the chain reaction is self-sustaining without the contribution of delayed neutrons. It says nothing about how powerful an explosion will be, or how high a yield a nuclear weapon may have. It is not difficult to achieve, and even just dropping two suitably sized pieces of fissile material onto each other could produce a prompt-critical reaction.
Now, the reason a weapon may produce a very poor yield if the compression is inefficient is not because it doesn't become prompt critical , but rather because the explosion will blow the bomb apart before the reaction has produced very much energy. In particular, a poor compression could cause the chain reaction to begin before the fissile material is in an optimal configuration.
People sometimes try to make some distinction between a "thermal" or "nuclear" explosion, usually while discussing the Chernobyl disaster, but there is no such distinction as far as the physics is concerned. The amount of energy released in a nuclear explosion depends almost entirely on what neutron multiplication factor can be achieved, as well as how long the material is kept together before the explosion blows it apart. A nuclear fission bomb achieves the high explosive yield for basically two reasons:
1) The high enrichment and fusion-boosting allows the multiplication factor to become very large, 3-4 or even greater.
2) The fissile material has been accelerated inwards by powerful explosives, giving a lot of momentum that has to be overcome before the pressure blows the bomb apart.
Note that we to this day do not know whether the Chernobyl reactor went prompt critical or not. It may well be the case that it simply overheated to the point that the piping could not sustain the pressure from the steam, but given the design of the reactor it is also very possible it reached prompt criticality. In either case the explosion was very much a nuclear explosion in the sense that it was driven by the heat released from a nuclear chain reaction. It is of course not possible for a chain reaction that is not prompt-critical to produce an explosive yield of several kilotons, but that is mostly because it would be too slow to produce much energy before the thing blows itself apart. For the same reason it is not sufficient for a chain reaction to be prompt critical in order for it to produce a substantial yield. The neutron multiplication factor must also be large enough, and the material must be kept together for a long enough time. That is why a reactor could never produce an explosion similar in power to a nuclear bomb. It simply doesn't have a high enough multiplication factor. In fact, it will likely be very close to 1.