What? Do you have a citation, anything at all, to suggest that an elevated train is "fairly easy to isolate from an earthquake"? That is really astounding!
So what? Every mass transit system on the planet loses money. Transport does not by itself generate wealth, rather it is a net drain on the economy. At best it only facilitate economic development. Travelling from A to B costs money, energy and resources and the only way to make a net economic gain is if by travelling to point B, you can do something useful at the end.
By comparison, how much money does the US interstate system make every year? Isn't it some huge negative number that dwarfs the Amtrak budget? I don't believe your claim that it makes money through gas taxes. To measure that properly, you can only count the additional revenue from the extra gas that is spent because the interstate system exists; gas that would have been used anyway, even if the interstate was not there, doesn't count. Nor does vague "net economic contribution" estimates, that include many things other than the direct transport infrastructure and running costs (unless of course you find a similar comparison for the railway network, so we can compare apples with apples).
As will no doubt be pointed out to you at length, that is an urban myth. Also, they don't and never did use graphite pencils in space. Graphite is a conductor - can you imagine what would happen if you had graphite dust floating around a spacecraft?
Good point. I'm not from the USA, so I converted it with google from celsius, for the benefit of the Yankees;-) Not sure how I managed to mess it up, obviously 75 fahrenheit is not that warm!
The 3K temperature comes from the background radiation in `empty' space (mostly photons, but longer wavelengths than visible light). If you are close to a star like the sun, you clearly get a lot more radiating heat than that. Satelites, for example, have heat shields to protect them from getting too hot and melting. Similarly, the surface of the moon that is in direct sunlight gets quite warm, about 75 degrees Fahrenheit (about 125 degrees C, so above the boiling point of water, if it was at standard pressure).
No, this is excellent news, should have been done years ago. The problem with Telstra is that, as well as being a front-end retailer and ISP, they own all of the back-end infrastructure. Despite regulations that are supposed to allow access by other providers to the back-end infrastructure, Telstra have always managed to find a way to charge more for other companies to use the infrastructure than it costs themselves, giving Telstra (ISP) an unfair advantage over other ISP's.
Now, the retail end of Telstra (the part that would presumably keep the brand name) will need to compete on a level playing field with the other telcos for a share of the wholesale bandwidth. There is no reason for there to be any kind of special relationship between the separated arms of (former) Telstra, anyway there are plenty of existing laws (eg, price fixing!) to discourage that.
I don't agree that "people don't know better" than use Telstra. That might have been true for the first decade after deregulation, but no longer. Telstra is universally loathed in Australia, and people who still use it tend to only do so because in some markets (but by no means all) they are the cheapest.
I have no agenda in HR 3200. I'm not even American, I don't care at all what your healthcare system is. I do find the level of political debate in the US to be rather low, and I find the paranoia about universal healthcare (that works quite well in every other industrialized nation) to be bizarre, but that is for the USA to sort out, not me.
I have no idea whether the US regulations are available online, but the regulations themselves surely are published in some form. Typically, every year the revised regulations are published and available for lawyers, police etc to obtain. The system you imagine, where there is no such document, would be completely impractical, as you acknowledge. That is why it isn't done! Yes, there surely are much better tools that legislators could use to evaluate legislation (context highlighted diffs including the original and revised regulations etc), but the debate over legislation is rarely about details like that. If you want a software analogy, the legislative debates are like a meeting with the upper management about the features of the software. Details of the actual source code won't be discussed, except to ensure that the programmers (drafters of the legislation) are doing their job to correctly implement the requirements.
Is this article a troll? Yes, I can see the utility in comparing legislation with software, although I was hoping for something a bit more than superficial analogies. But if the comparison is any use at all, then it will apply to legislation as a whole, so why choose one particular piece of current and controversial legislation to discuss? Surely the fact that it is both current and controversial is only a distraction from the main thesis, of comparing legislation with software? I suspect that the author has an agenda, of trashing the legislation. He also makes a rather fundamental misunderstanding, in his haste to criticize HR 3200. The 'spaghetti coding' is because he isn't looking at the source program itself, what he is looking at is a diff, between the existing regulation and the proposed amended regulation. That is a rather critical difference that invalidates 90% of his analysis.
compare the diagrams of an electric and magnetic dipole field. One of these is not like the other, it's easier to see in diagram then my attempt to describe in words.
No, they are the same: just that the diagram of the electric dipole has the two charges separated by some distance, whereas they are next to each other in the lower diagram. If you move the charges together, the top diagram turns into the bottom diagram (well, and flip the direction of the arrows too - that is of no consequence). If you made a dipole out of two separated magnetic monopoles (or a bar magnet!) rather than a single fundamental dipole, you would get field lines exactly like the top diagram.
You're thinking of a diode, not a capacitor.
No idea what you are talking about here. I didn't mention (or intend to mention) either a diode or a capacitor. I was referring to the well-known phenomena where the electric field inside a conductor is zero. See, for example, http://www.glenbrook.k12.il.us/gbssci/phys/Class/estatics/u8l4d.html : "One characteristic of a conductor at electrostatic equilibrium is that the electric field anywhere beneath the surface of a charged conductor is zero"
I think you are a bit confused, in a dipole all the field lines emerge at one end and terminate at the other end. The exact shape of the field lines depends only on the shape of the magnet or electric dipole, in principle any magnetic dipole configuration can be exactly reproduced with an electric dipole and vice versa.
If you make an electric dipole by charging opposite ends of a conductor, then you will get zero field inside the conductor. This is because the charges inside the conductor are free to move, so if there was a field within it they would accelerate and it isn't a stable configuration. The net effect of this is that charges migrate to the surface, creating a field that exactly negates the dipole field within the conductor. You can view this as an additional field that is pointing in the opposite direction, which is perhaps where you got your idea from. But it isn't an effect that you can use to produce useful work, simply that the net field inside the conductor is zero, the field lines don't travel in the opposite direction. A similar effect will always happen when you put a conductor in an electric field.
wouldn't a monopole just start moving and never stop until it exits the universe?
In principle, YES! Imagine the gravitational field lines radiating away from the Earth. If there were no other masses in the universe to bend the field lines, then ALL of them would go on forever.
Presumably you understand electric field lines, and gravitational field lines, and how they terminate at charges and masses respectively. Why is it so hard to visualize the field lines of a magnetic monopole? They work in exactly the same way.
how does a magnetic field line just stop somewhere and not continue on its way around to the other side of a magnet?
By having a non-zero divergence. Just like Gauss' law divergence D = rho (charge density), we have divergence B = rho_m (density of magnetic monopoles).
You should do some more research, anarchyboy is right, there is no theoretical reason (aside from never having observed them) why magnetic monopoles cannot exist.
What this work shows is that they can exist, although it is not in the 'real world', but as effective particles in a solid state system. The mechanism will be similar to spin-charge separation that occurs in 1D systems, whereby the degrees of freedom of a particle separate into independently moving constituents. In this case, it will be the north and south poles of a dipole that become effectively independent and behave as distinct particles.
This doesn't mean that monopoles must be able to exist in a vacuum, possibly (probably?) they cannot, but the reason why will be due to the properties of the vacuum, not any fundamental restriction on monopoles.
I agree with the general sentiment, but there is an important caveat. One single measurement on a reliable apparatus is worth any number of dubious measurements on dodgy equipment. My point (which I didn't make very well) is that the distance to the target is not necessarily a factor in judging the reliability of the results. I am a professional physicist, I trust their result, but I also am pretty sure (I would say 'believe', but I don't want anyone to get the wrong impression that my 'beliefs' are not subject to reversal, as demanded by compelling evidence) that there is an explanation that doesn't require rewriting any of the fundamental laws of physics. It may well require rewriting some of the 'rules of thumb' that astrophysicists use to judge what to expect from their measurements, but if science teaches us anything, it is that 'intuition' and 'rules of thumb' are not a good guide to telling us the secrets of how the world works.
(By the way, if the ultimate explanation does require rewriting some laws of physics, I would be very happy - but it would need very compelling evidence, and in particular, the requirement that any changes to the laws of physics don't affect what we observe every day on the Earth is a very severe constraint on how they could be modified. The current arguments about what new physics look like affect either very tiny length scales [string theory], or very large length scales [modifications to relativity etc], neither of which have any consequence for ordinary life, and are not measurable without equipment at the forefront of technology.)
It implies no such thing. Given the evidence, I would suggest that by far the most likely explanation is something that the authors of paper themselves suggest; something has happened since to knock a planet into a close orbit of the star. There are many explanations that don't require a modification of orbital mechanics (pretty much any modification that is big enough to produce this planet with no external influence, would give an effect that is observable within out solar system), why assume that such a modification is required? The slashdot headline is inflammatory, it is a "puzzle" (the article headline), not "impossible" (the slashdot headline).
Hmm, I was trying to find a good analogy. This isn't a good one. I was thinking about a prototype jet, and why would one belive that it should fly on its first test flight. Experiments have experimental error. But any researcher who is worth their salt has some idea of how large that error is. Basically, you are accusing the researchers of incompetence. Have you ever used binoculars? Why do you trust what you see, if you haven't been there to see it yourself?
Why do you think physicists need to visit a planet to be able to make reliable measurements about them? I would expect that they can have confidence in their measuring equipment in the same way that you can have confidence that the sun will rise in the morning. After all, you have never been there, how can you know anything about how it works?
That is where most of the rest of the (developed) world disagrees with you. Almost all medical problems happen by chance, to some unlucky person whose dice comes up the wrong way. Why should someone be forced into bankruptcy, or left die of some treatable disease, for something they have no control over? Let me put it another way: suppose that tomorrow you are diagnosed with some rare but treatable form of cancer. Unfortunately the treatment costs one million dollars, and your medical insurance (if you have any) refuses to pay. The cancer is rare enough that, spread across the whole population, the cost of treating all cases per year is rather small. Do you think you should be given the treatment? If so, who should pay?
It is a common argument, "I'm not going to get sick, why should I have to pay for everone else's healthcare?". It works just fine, right up until the moment where you do get sick.
Heh, that is funny! But antigravity itself may or may not be possible - physics as it stands could probably accommodate it without too much modification. Perpetual motion is in a different class entirely, so it was a bad example for trying to show the supposed scientific orthodoxy conspiracy.
If I were to claim that I invented a machine that produced more energy than I put in, would I get a fair hearing?
Yes, you would get a "fair" hearing. Exactly as "fair" as you would expect for claiming to have invented a machine that violates a cherished principle of physics, one that has withstood every theoretical and experimental test that humanity has been able to throw at it in the last 500+ years.
The history of science is littered with once-cherished theories that have been invalidated. So, it is certainly not impossible. But if you are going to propose a device for perpetual motion you need extraordinary evidence, both experimental and theoretical. I can't put it any better than Wikipedia:
The conservation laws are particularly robust. Noether's theorem states that any conservation law can be derived from a corresponding continuous symmetry. In other words, so long as the laws of physics (not simply the current understanding of them, but the actual laws, which may still be undiscovered) and the various physical constants remain invariant over time so long as the laws of the universe are fixed then the conservation laws must be true, in the sense that they follow from the presupposition using mathematical logic. To put it the other way around: if perpetual motion or "overunity" machines were possible, then most of what we believe to be true about physics, mathematics, or both would have to be false.
Generations of people believe(d) that Freud could practically read minds because he was the expert, right?
Got a citation for that? Who believed that? I might believe some fraction of the unwashed masses beleved that (and possibly still do), but no real expert would claim that "Freud could practically read minds".
That is almost entirely wrong. The overwhelming historical difference between different peoples is one of technology, and ensuing positive feedback effects. It took thousands of years to develop farming (for example), and once you have farming, then it is possible to develop cities, schools, and civilization. How quickly (or even if) a society develops technologies depends primarily on environmental factors, not intelligence per se. The stone age, for example, began about 2.5 million years ago and only culminated in the development of farming on around 7000BC. If the rate of technological progress on another continent was only 1% different, then they would not yet have discovered farming! That doesn't imply anything about intelligence, just that very small changes can have big effect.
It would be interesting to put the AC parent poster in the wilds with no equipment, and see how quickly he/she develops some descent farming tools (as a precursor to rediscovering the microchip;-)
Slashdot Mirror
Umm, the Nobel prizes are not all announced at the same time. The Medicine prize was announced yesterday. The Physics prize was announced today.
What? Do you have a citation, anything at all, to suggest that an elevated train is "fairly easy to isolate from an earthquake"? That is really astounding!
So what? Every mass transit system on the planet loses money. Transport does not by itself generate wealth, rather it is a net drain on the economy. At best it only facilitate economic development. Travelling from A to B costs money, energy and resources and the only way to make a net economic gain is if by travelling to point B, you can do something useful at the end.
By comparison, how much money does the US interstate system make every year? Isn't it some huge negative number that dwarfs the Amtrak budget? I don't believe your claim that it makes money through gas taxes. To measure that properly, you can only count the additional revenue from the extra gas that is spent because the interstate system exists; gas that would have been used anyway, even if the interstate was not there, doesn't count. Nor does vague "net economic contribution" estimates, that include many things other than the direct transport infrastructure and running costs (unless of course you find a similar comparison for the railway network, so we can compare apples with apples).
As will no doubt be pointed out to you at length, that is an urban myth. Also, they don't and never did use graphite pencils in space. Graphite is a conductor - can you imagine what would happen if you had graphite dust floating around a spacecraft?
Good point. I'm not from the USA, so I converted it with google from celsius, for the benefit of the Yankees ;-) Not sure how I managed to mess it up, obviously 75 fahrenheit is not that warm!
The 3K temperature comes from the background radiation in `empty' space (mostly photons, but longer wavelengths than visible light). If you are close to a star like the sun, you clearly get a lot more radiating heat than that. Satelites, for example, have heat shields to protect them from getting too hot and melting. Similarly, the surface of the moon that is in direct sunlight gets quite warm, about 75 degrees Fahrenheit (about 125 degrees C, so above the boiling point of water, if it was at standard pressure).
No, this is excellent news, should have been done years ago. The problem with Telstra is that, as well as being a front-end retailer and ISP, they own all of the back-end infrastructure. Despite regulations that are supposed to allow access by other providers to the back-end infrastructure, Telstra have always managed to find a way to charge more for other companies to use the infrastructure than it costs themselves, giving Telstra (ISP) an unfair advantage over other ISP's.
Now, the retail end of Telstra (the part that would presumably keep the brand name) will need to compete on a level playing field with the other telcos for a share of the wholesale bandwidth. There is no reason for there to be any kind of special relationship between the separated arms of (former) Telstra, anyway there are plenty of existing laws (eg, price fixing!) to discourage that.
I don't agree that "people don't know better" than use Telstra. That might have been true for the first decade after deregulation, but no longer. Telstra is universally loathed in Australia, and people who still use it tend to only do so because in some markets (but by no means all) they are the cheapest.
I have no idea whether the US regulations are available online, but the regulations themselves surely are published in some form. Typically, every year the revised regulations are published and available for lawyers, police etc to obtain. The system you imagine, where there is no such document, would be completely impractical, as you acknowledge. That is why it isn't done! Yes, there surely are much better tools that legislators could use to evaluate legislation (context highlighted diffs including the original and revised regulations etc), but the debate over legislation is rarely about details like that. If you want a software analogy, the legislative debates are like a meeting with the upper management about the features of the software. Details of the actual source code won't be discussed, except to ensure that the programmers (drafters of the legislation) are doing their job to correctly implement the requirements.
Is this article a troll? Yes, I can see the utility in comparing legislation with software, although I was hoping for something a bit more than superficial analogies. But if the comparison is any use at all, then it will apply to legislation as a whole, so why choose one particular piece of current and controversial legislation to discuss? Surely the fact that it is both current and controversial is only a distraction from the main thesis, of comparing legislation with software? I suspect that the author has an agenda, of trashing the legislation. He also makes a rather fundamental misunderstanding, in his haste to criticize HR 3200. The 'spaghetti coding' is because he isn't looking at the source program itself, what he is looking at is a diff, between the existing regulation and the proposed amended regulation. That is a rather critical difference that invalidates 90% of his analysis.
No, they are the same: just that the diagram of the electric dipole has the two charges separated by some distance, whereas they are next to each other in the lower diagram. If you move the charges together, the top diagram turns into the bottom diagram (well, and flip the direction of the arrows too - that is of no consequence). If you made a dipole out of two separated magnetic monopoles (or a bar magnet!) rather than a single fundamental dipole, you would get field lines exactly like the top diagram.
No idea what you are talking about here. I didn't mention (or intend to mention) either a diode or a capacitor. I was referring to the well-known phenomena where the electric field inside a conductor is zero. See, for example, http://www.glenbrook.k12.il.us/gbssci/phys/Class/estatics/u8l4d.html : "One characteristic of a conductor at electrostatic equilibrium is that the electric field anywhere beneath the surface of a charged conductor is zero"
I think you are a bit confused, in a dipole all the field lines emerge at one end and terminate at the other end. The exact shape of the field lines depends only on the shape of the magnet or electric dipole, in principle any magnetic dipole configuration can be exactly reproduced with an electric dipole and vice versa.
If you make an electric dipole by charging opposite ends of a conductor, then you will get zero field inside the conductor. This is because the charges inside the conductor are free to move, so if there was a field within it they would accelerate and it isn't a stable configuration. The net effect of this is that charges migrate to the surface, creating a field that exactly negates the dipole field within the conductor. You can view this as an additional field that is pointing in the opposite direction, which is perhaps where you got your idea from. But it isn't an effect that you can use to produce useful work, simply that the net field inside the conductor is zero, the field lines don't travel in the opposite direction. A similar effect will always happen when you put a conductor in an electric field.
Can you explain further why you think that a monopole implies perpetual motion?
In principle, YES! Imagine the gravitational field lines radiating away from the Earth. If there were no other masses in the universe to bend the field lines, then ALL of them would go on forever.
Presumably you understand electric field lines, and gravitational field lines, and how they terminate at charges and masses respectively. Why is it so hard to visualize the field lines of a magnetic monopole? They work in exactly the same way.
By having a non-zero divergence. Just like Gauss' law divergence D = rho (charge density), we have divergence B = rho_m (density of magnetic monopoles).
You should do some more research, anarchyboy is right, there is no theoretical reason (aside from never having observed them) why magnetic monopoles cannot exist.
What this work shows is that they can exist, although it is not in the 'real world', but as effective particles in a solid state system. The mechanism will be similar to spin-charge separation that occurs in 1D systems, whereby the degrees of freedom of a particle separate into independently moving constituents. In this case, it will be the north and south poles of a dipole that become effectively independent and behave as distinct particles.
This doesn't mean that monopoles must be able to exist in a vacuum, possibly (probably?) they cannot, but the reason why will be due to the properties of the vacuum, not any fundamental restriction on monopoles.
I agree with the general sentiment, but there is an important caveat. One single measurement on a reliable apparatus is worth any number of dubious measurements on dodgy equipment. My point (which I didn't make very well) is that the distance to the target is not necessarily a factor in judging the reliability of the results. I am a professional physicist, I trust their result, but I also am pretty sure (I would say 'believe', but I don't want anyone to get the wrong impression that my 'beliefs' are not subject to reversal, as demanded by compelling evidence) that there is an explanation that doesn't require rewriting any of the fundamental laws of physics. It may well require rewriting some of the 'rules of thumb' that astrophysicists use to judge what to expect from their measurements, but if science teaches us anything, it is that 'intuition' and 'rules of thumb' are not a good guide to telling us the secrets of how the world works.
(By the way, if the ultimate explanation does require rewriting some laws of physics, I would be very happy - but it would need very compelling evidence, and in particular, the requirement that any changes to the laws of physics don't affect what we observe every day on the Earth is a very severe constraint on how they could be modified. The current arguments about what new physics look like affect either very tiny length scales [string theory], or very large length scales [modifications to relativity etc], neither of which have any consequence for ordinary life, and are not measurable without equipment at the forefront of technology.)
It implies no such thing. Given the evidence, I would suggest that by far the most likely explanation is something that the authors of paper themselves suggest; something has happened since to knock a planet into a close orbit of the star. There are many explanations that don't require a modification of orbital mechanics (pretty much any modification that is big enough to produce this planet with no external influence, would give an effect that is observable within out solar system), why assume that such a modification is required? The slashdot headline is inflammatory, it is a "puzzle" (the article headline), not "impossible" (the slashdot headline).
Hmm, I was trying to find a good analogy. This isn't a good one. I was thinking about a prototype jet, and why would one belive that it should fly on its first test flight. Experiments have experimental error. But any researcher who is worth their salt has some idea of how large that error is. Basically, you are accusing the researchers of incompetence. Have you ever used binoculars? Why do you trust what you see, if you haven't been there to see it yourself?
Why do you think physicists need to visit a planet to be able to make reliable measurements about them? I would expect that they can have confidence in their measuring equipment in the same way that you can have confidence that the sun will rise in the morning. After all, you have never been there, how can you know anything about how it works?
That is where most of the rest of the (developed) world disagrees with you. Almost all medical problems happen by chance, to some unlucky person whose dice comes up the wrong way. Why should someone be forced into bankruptcy, or left die of some treatable disease, for something they have no control over? Let me put it another way: suppose that tomorrow you are diagnosed with some rare but treatable form of cancer. Unfortunately the treatment costs one million dollars, and your medical insurance (if you have any) refuses to pay. The cancer is rare enough that, spread across the whole population, the cost of treating all cases per year is rather small. Do you think you should be given the treatment? If so, who should pay?
It is a common argument, "I'm not going to get sick, why should I have to pay for everone else's healthcare?". It works just fine, right up until the moment where you do get sick.
You should RTFA. Most of it is about exactly those issues, of managing the address space.
Heh, that is funny! But antigravity itself may or may not be possible - physics as it stands could probably accommodate it without too much modification. Perpetual motion is in a different class entirely, so it was a bad example for trying to show the supposed scientific orthodoxy conspiracy.
Yes, you would get a "fair" hearing. Exactly as "fair" as you would expect for claiming to have invented a machine that violates a cherished principle of physics, one that has withstood every theoretical and experimental test that humanity has been able to throw at it in the last 500+ years.
The history of science is littered with once-cherished theories that have been invalidated. So, it is certainly not impossible. But if you are going to propose a device for perpetual motion you need extraordinary evidence, both experimental and theoretical. I can't put it any better than Wikipedia:
Got a citation for that? Who believed that? I might believe some fraction of the unwashed masses beleved that (and possibly still do), but no real expert would claim that "Freud could practically read minds".
That is almost entirely wrong. The overwhelming historical difference between different peoples is one of technology, and ensuing positive feedback effects. It took thousands of years to develop farming (for example), and once you have farming, then it is possible to develop cities, schools, and civilization. How quickly (or even if) a society develops technologies depends primarily on environmental factors, not intelligence per se. The stone age, for example, began about 2.5 million years ago and only culminated in the development of farming on around 7000BC. If the rate of technological progress on another continent was only 1% different, then they would not yet have discovered farming! That doesn't imply anything about intelligence, just that very small changes can have big effect.
It would be interesting to put the AC parent poster in the wilds with no equipment, and see how quickly he/she develops some descent farming tools (as a precursor to rediscovering the microchip ;-)