Scientists also care about where an equation is valid. G=8piT is great - describes gravity everywhere (in classical GR). Unfortunately it is so for insolvable and ferociously difficult to simulate in the general case. Scientists are happy to find simpler versions of equations that are valid under a limited set of conditions. To a significant extent, science is the art of approximation.
If the universe contained areas of matter and areas of antimatter, you would see annihilation radiation at the boundaries. I think (not completely sure) that would be detectable for a wide variety of different sized regions. As another poster points out, it would be difficult to explain such a separation without introducing new physics.
An airplane that can be driven would be great - if there were no other disadvantages. The problem is that aircraft are already such optimized designs that you take a big performance hit when you modify them for road use. You end up with something that is a mediocre airplane and a mediocre car. If you look at the specs, the "useful load" is 430 pounds. Useful load includes fuel (30 pounds an hour). This means you can barely carry 2 average sized adults. For such a low speed aircraft (100 Kts) it needs a lot of runway (1700' to 50' obstacle clearance). These are all worse performance numbers than an ancient Cessna 172.
Flying also isn't as simple as just driving onto the runway and taking off. Most pilots insist on doing a pre-flight inspection of the plane and some amount of flight planning. In principal you can get a sport pilot license in 20 hours, but in practice few pilots are comfortable doing cross country trips until they have > 100 hours.
Maintenance may also be an issue - do you need a certified mechanic to do anything to your car / plane? That would make its road use very expensive.
We give police guns, but don't allow them to randomly shoot people on the streets (it happens but is very rare). It is possible to control law enforcement - but I agree that it can be difficult.
I think there are a couple of reasons we haven't seen this yet (as far as I know). DNA evidence is most useful in violent crimes (doesn't help much with securities fraud). I expect violent crimes are in general perpetrated by less educated and less sophisticated criminals. (of course there are exceptions). Also, DNA evidence so far is mostly used as a back-up to other evidence. If it becomes more important I think we will see more faking / framing.
Same argument applies to cell phone tracking. As this is used more by law enforcement I expect we will see various hacks on cell phones to mis-report locations, or to appear as a different phone.
I don't think the important issue is whether the data is collected, but how it can be used. For example if law enforcement can try to match a sample from a crime scene against EVERY person in their database, you need a really low rate of false positives. Nationwide there are probably something like a million crimes committed each year (just guessing from the prison population). If you can match each against 300 million people in a database, that gives you 3x10^14 chances to make a mistake. We can't expect perfect justice, but even with a 1 in a 10 BILLION error rate, that is 30,000 false positives per year. Some of those will have enough other (weak) evidence to get convictions. Yet what jury wouldn't be convinced by a (true) claim that the chance of a false match is "only" one in 10 billion?
Also, once the data exists, is (should?) the government be required to check everyone in prison against DNA evidence if it exists? Personally I think this is very desirable, but it would be very expensive.
Also can the DNA evidence be used to predict tendencies to crime. This isn't practical yet, but we might in the future detect genetic markers that have correlation with types of criminal behaviour. Is it fair to say in court that the accused "has genetic markers that indicate a propensity to violence"?
The final problem is that once DNA evidence is very common use, as the poster above mentions criminals will start to plane evidence. Murder someone - plant a few hairs that you collected from someone else. Framing someone becomes much easier.
Juries need to understand that the existence of DNA evidence at a crime scene only shows that....the person's DNA was at the crime scene - it doesn't say the person was there, or that they committed the crime.
Many of these arguments apply to various other high tech information gathering.
Though I might have put it more politely, I agree to some extent. How many deaths a year do we have from terrorism? Is that number really big enough to justify giving up some of our rights?
On the other hand, we already consider rights to be a trade off against security. Most people support allowing some forms of surveillance with a court order. Laws haven't kept up with improving technology, so there isn't really a black and white "this violates our rights and that does not".
I don't have serious objections to collecting information to stop terrorism. what I object to is using that information to stop other crimes. We already accept the idea that our military is given different tools than our police: We don't give the police attack helicopters, grenade launchers and nukes. By the same sort of argument, I don't mind the military having extensive surveillance technology to stop international terrorism, but I DO object to that technology or information obtained from it being used to stop other crimes like copyright violations.
Class IV is serious. Not only can a direct hit or specular reflection blind you, but you can get eye damage from a diffuse reflection. That means that if you point it at a sheet of paper and stare at the paper, the spot can do damage. This happens faster than you can blink.
I used to work with class IV lasers in my lab - required goggles, interlocks, and vast amounts of paper work. Set my shirt on fire once with a similarly powered laser.
I think its OK for these to be available to the public but they should require some form of licensing and training of the sort used for firearms. Because of its range and lack of traceability, I think this is every bit as dangerous as a gun.
I don't even want to suggest in an open forum the sort of things you could do with this to cause serious injury and death - but if you have some imagination you can figure out what I might be thinking of.
Tianamen Square was a difficult situation - handled disastrously badly. Thousands of protesters had occupied the center of the city - there were no coherent demands with extremists of various sorts pushing for conflicting agendas. Sending in the army was the WRONG thing to do - but its not clear what is the right thing. Thailand recently found itself in a similar situation and didn't do a whole lot better at solving it.
I've been to China recently and it doesn't "feel" oppressive - people there are willing to discuss and criticize the government. I believe that North Korea is a whole different level of oppressive.
Not saying China is good, but they aren't that bad.
Its actually not easy to put a price tag on ITER. I was just at a conference in Kyoto where I heard a talk from one of the project directors on this. The various national contributions to the project are "in kind". This means that each country agrees to supply some part of the ITER - say a magnet coil. Then the cost of producing the coil within that country is at the whim of internal politics, and international exchange rate fluctuations. Some countries may decide to spend additional money to increase their ability to produce similar products (superconducting magnets for example) - then do you count that extra expense or not?
In any event ITER is something on the order of $10B. Whether that is a lot or not depends on your perspective. Its not very big compared to health-care costs, or projected global warming costs. Its probably similar to what the gulf oil spill will cost BP.
Will it give us usable fusion energy? I think its a long shot - but maybe a gamble that is worth taking. We don't have a lot of attractive options for long term future energy production.
This can extend to the way people behave. People with fuel efficient cars tend to drive in a more fuel efficient fashion, trying to get 50mpg rather than just 45 because 50 sounds impressive. People with inefficient cars don't really worry if they are getting 12 or 16, doesn't seem like much of a difference - but of course it is.
It seems unfortunate that to have secure code you need to use a pre-release version. There is a need for a secure, but not feature-rich document format - I don't need dancing bears.
Only reading documents from "trusted" sources doesn't work - those sources may have been compromised.
Its not so clear that this has much military application. Its unlikely to be stealthy at that speed - aerodynamic heating will make it very obvious in IR. I suspect the efficiency isn't very good, and it needs a rocket for initial launch. I'm sure there are some cases where it would be preferable to a spy satellite, but I think the us has stopped using SR-71s because those cases are pretty rare.
I'd love to have scramjet technology for launch vehicles, but so far they seem to be single Mach number designs, so the don't work for that either.
My feeling is that there is a sort of technological no-mans-land between ~Mach 3 and sub-orbital trajectories.
I'm happy to see the research continue (I also love fast planes), but it really isn't clear how it would be used.
I think there are 2 independent issues: Lack of competition and usage dependent pricing.
Lack of competition will continue to produce problems, but is somewhat difficult to solve.
Usage dependent pricing actually seems like a good idea: it removes the incentive for companies to block bit-torrent and the like. If the pricing system is fair, then the low volume users will not need to pay to support the high volume users or vice-versa. I understand the argument about adds, but I think most volume probably comes from large scale downloading, not web-browsing.
For a lot of applications, speed isn't the limit, development time is. I use Matlab a lot (I'm an accelerator physicist), and most of the time the programs run almost instantly on a modern computer. I'm mostly interested in a language that lets me develop quickly. I almost never use integers so the lack of 64 bit integer arithmetic isn't a problem - didn't even know about the lack until seeing this.
I've tried Scilab, Octave and Python for this sort of use, but I've found Matlab best meets my requirements - but of course depending on the the application, different languages will be superior.
They may not want simple physical resources, but rather the technological resources of a planetary civilization. They may not be impressed with our overall level of technology, but there may still be some things we know how to do well. For example maybe we are unusually good at making silicon chips. That could be a minor niche market for an alien civilization, but still worth sending a cargo ship every few hundred years.
A really advanced civilization might even subtly manipulate our civilization until a significant fraction of all our engineering and production capacity went into making this niche product.
They could enforce it by requiring ISPs to check that the computer has a working copy of the spyware. There would the usual hacking war against this, but with regular updates to the spyware it would be too much effort for the majority of users to fight. Add criminal penalties if you are found to have a computer without the spyware and the the MPAA wins.
Companies could get exemptions. (You can pay a $100K "licensing" fee for your organization to not need the scanning software.
I'm worried that this could be sold on some sort of "protect the children" / "stop child porn" / "prevent terrorism" argument.
Would they dare? I've seen a lot of things recently that are beyond the limit of what I thought people would dare.
Anyone know at what density the ash is a hazard? This is the first large scale grounding of commercial aircraft due to a volcanic eruption that I can remember. Wikipedia lists an all engine out on a 747 in 1982 but maybe there are more cases.
Volcanic ash above some concentration is certainly a hazard, but this seems like a lot of airspace for a modest eruption.
The moon missions were a long time ago - but its not clear that we have progressed much with technology needed for aerospace. The basic technology hasn't changed, launch costs aren't that different. It was hard then, and its still hard now. Mars is a lot harder. We could do it if we wanted to, but we aren't willing to put in the require effort, or take the required risks. Its not that I think Obama's plan is fundamentally flawed, but when he talks about a mars mission in the 2030s, it sounds like another of the every 10 years "lets go to mars" talk, never followed by any action. I think I will likely live to see the day when no living man has been beyond 1000 miles from earth.
Maybe China will do it - they have the will and are willing to take the risks. Not the flag I'd most like to see flying over a mars base though. Not what I imagined when I watched the first moon landing 2 generations ago.
Exploring and colonizing space doesn't have a point - it IS the point.
There are 2 different issues here. One is whether the government's definition of child porn makes sense. Personally I think that including drawings makes it unreasonable. The second is whether the wikipedia images meet the government's definition - I think they probably do.
The way to change the first problem is through political action / voting. If you think it is unreasonable to send someone to prison for looking at a DRAWING of a naked child, write your congress person.
The second is a different issue. On line as well as off line organizations should follow the law - or engage in specific legal challenges.
Like most people with well thought out reasonable opinions, you don't do well in revolutions. I happen to agree with you, expect well both be up against the wall come the revolution - either for opposing the winners, or for not showing enough zeal in supporting them.
Rational environmentalism is tricky though: Imagine that rather pessimistic environmental scenarios are true, that there is climate change that causes widespread starvation. Over the next 200 years how many additional deaths will there be? (Hint - if you were to wipe out the entire human race tomorrow, integrated from today over the next 200 years there would be fewer deaths than there are now). Its rather difficult to come up with a metric for environmental costs.
The Germans built some of the trains. I think the Chinese are starting to build their own now. Certainly their trains are faster than anywere else in the world: 350Km/h for conventional and 430Km/h for the (somewhat silly) maglev.
You don't need take it the whole way. At 300Km/h average, a 1000km trip might be faster by rail than by air (city center to city center and counting airport delays).
I've ridden Chinese high speed rail - its a nice system, as good as the European or Japanese, and somewhat faster.
Slashdot Mirror
Scientists also care about where an equation is valid. G=8piT is great - describes gravity everywhere (in classical GR). Unfortunately it is so for insolvable and ferociously difficult to simulate in the general case. Scientists are happy to find simpler versions of equations that are valid under a limited set of conditions. To a significant extent, science is the art of approximation.
If the universe contained areas of matter and areas of antimatter, you would see annihilation radiation at the boundaries. I think (not completely sure) that would be detectable for a wide variety of different sized regions. As another poster points out, it would be difficult to explain such a separation without introducing new physics.
An airplane that can be driven would be great - if there were no other disadvantages. The problem is that aircraft are already such optimized designs that you take a big performance hit when you modify them for road use. You end up with something that is a mediocre airplane and a mediocre car. If you look at the specs, the "useful load" is 430 pounds. Useful load includes fuel (30 pounds an hour). This means you can barely carry 2 average sized adults. For such a low speed aircraft (100 Kts) it needs a lot of runway (1700' to 50' obstacle clearance). These are all worse performance numbers than an ancient Cessna 172.
Flying also isn't as simple as just driving onto the runway and taking off. Most pilots insist on doing a pre-flight inspection of the plane and some amount of flight planning. In principal you can get a sport pilot license in 20 hours, but in practice few pilots are comfortable doing cross country trips until they have > 100 hours.
Maintenance may also be an issue - do you need a certified mechanic to do anything to your car / plane? That would make its road use very expensive.
We give police guns, but don't allow them to randomly shoot people on the streets (it happens but is very rare). It is possible to control law enforcement - but I agree that it can be difficult.
I think there are a couple of reasons we haven't seen this yet (as far as I know). DNA evidence is most useful in violent crimes (doesn't help much with securities fraud). I expect violent crimes are in general perpetrated by less educated and less sophisticated criminals. (of course there are exceptions). Also, DNA evidence so far is mostly used as a back-up to other evidence. If it becomes more important I think we will see more faking / framing.
Same argument applies to cell phone tracking. As this is used more by law enforcement I expect we will see various hacks on cell phones to mis-report locations, or to appear as a different phone.
I don't think the important issue is whether the data is collected, but how it can be used. For example if law enforcement can try to match a sample from a crime scene against EVERY person in their database, you need a really low rate of false positives. Nationwide there are probably something like a million crimes committed each year (just guessing from the prison population). If you can match each against 300 million people in a database, that gives you 3x10^14 chances to make a mistake. We can't expect perfect justice, but even with a 1 in a 10 BILLION error rate, that is 30,000 false positives per year. Some of those will have enough other (weak) evidence to get convictions. Yet what jury wouldn't be convinced by a (true) claim that the chance of a false match is "only" one in 10 billion?
Also, once the data exists, is (should?) the government be required to check everyone in prison against DNA evidence if it exists? Personally I think this is very desirable, but it would be very expensive.
Also can the DNA evidence be used to predict tendencies to crime. This isn't practical yet, but we might in the future detect genetic markers that have correlation with types of criminal behaviour. Is it fair to say in court that the accused "has genetic markers that indicate a propensity to violence"?
The final problem is that once DNA evidence is very common use, as the poster above mentions criminals will start to plane evidence. Murder someone - plant a few hairs that you collected from someone else. Framing someone becomes much easier.
Juries need to understand that the existence of DNA evidence at a crime scene only shows that ....the person's DNA was at the crime scene - it doesn't say the person was there, or that they committed the crime.
Many of these arguments apply to various other high tech information gathering.
Though I might have put it more politely, I agree to some extent. How many deaths a year do we have from terrorism? Is that number really big enough to justify giving up some of our rights?
On the other hand, we already consider rights to be a trade off against security. Most people support allowing some forms of surveillance with a court order. Laws haven't kept up with improving technology, so there isn't really a black and white "this violates our rights and that does not".
I don't have serious objections to collecting information to stop terrorism. what I object to is using that information to stop other crimes. We already accept the idea that our military is given different tools than our police: We don't give the police attack helicopters, grenade launchers and nukes. By the same sort of argument, I don't mind the military having extensive surveillance technology to stop international terrorism, but I DO object to that technology or information obtained from it being used to stop other crimes like copyright violations.
Class IV is serious. Not only can a direct hit or specular reflection blind you, but you can get eye damage from a diffuse reflection. That means that if you point it at a sheet of paper and stare at the paper, the spot can do damage. This happens faster than you can blink.
I used to work with class IV lasers in my lab - required goggles, interlocks, and vast amounts of paper work. Set my shirt on fire once with a similarly powered laser.
I think its OK for these to be available to the public but they should require some form of licensing and training of the sort used for firearms. Because of its range and lack of traceability, I think this is every bit as dangerous as a gun.
I don't even want to suggest in an open forum the sort of things you could do with this to cause serious injury and death - but if you have some imagination you can figure out what I might be thinking of.
Tianamen Square was a difficult situation - handled disastrously badly. Thousands of protesters had occupied the center of the city - there were no coherent demands with extremists of various sorts pushing for conflicting agendas. Sending in the army was the WRONG thing to do - but its not clear what is the right thing. Thailand recently found itself in a similar situation and didn't do a whole lot better at solving it.
I've been to China recently and it doesn't "feel" oppressive - people there are willing to discuss and criticize the government. I believe that North Korea is a whole different level of oppressive.
Not saying China is good, but they aren't that bad.
Its actually not easy to put a price tag on ITER. I was just at a conference in Kyoto where I heard a talk from one of the project directors on this. The various national contributions to the project are "in kind". This means that each country agrees to supply some part of the ITER - say a magnet coil. Then the cost of producing the coil within that country is at the whim of internal politics, and international exchange rate fluctuations. Some countries may decide to spend additional money to increase their ability to produce similar products (superconducting magnets for example) - then do you count that extra expense or not?
In any event ITER is something on the order of $10B. Whether that is a lot or not depends on your perspective. Its not very big compared to health-care costs, or projected global warming costs. Its probably similar to what the gulf oil spill will cost BP.
Will it give us usable fusion energy? I think its a long shot - but maybe a gamble that is worth taking. We don't have a lot of attractive options for long term future energy production.
This can extend to the way people behave. People with fuel efficient cars tend to drive in a more fuel efficient fashion, trying to get 50mpg rather than just 45 because 50 sounds impressive. People with inefficient cars don't really worry if they are getting 12 or 16, doesn't seem like much of a difference - but of course it is.
It seems unfortunate that to have secure code you need to use a pre-release version. There is a need for a secure, but not feature-rich document format - I don't need dancing bears.
Only reading documents from "trusted" sources doesn't work - those sources may have been compromised.
Its not so clear that this has much military application. Its unlikely to be stealthy at that speed - aerodynamic heating will make it very obvious in IR. I suspect the efficiency isn't very good, and it needs a rocket for initial launch. I'm sure there are some cases where it would be preferable to a spy satellite, but I think the us has stopped using SR-71s because those cases are pretty rare.
I'd love to have scramjet technology for launch vehicles, but so far they seem to be single Mach number designs, so the don't work for that either.
My feeling is that there is a sort of technological no-mans-land between ~Mach 3 and sub-orbital trajectories.
I'm happy to see the research continue (I also love fast planes), but it really isn't clear how it would be used.
I think there are 2 independent issues: Lack of competition and usage dependent pricing.
Lack of competition will continue to produce problems, but is somewhat difficult to solve.
Usage dependent pricing actually seems like a good idea: it removes the incentive for companies to block bit-torrent and the like. If the pricing system is fair, then the low volume users will not need to pay to support the high volume users or vice-versa. I understand the argument about adds, but I think most volume probably comes from large scale downloading, not web-browsing.
Hopefully they will just threaten you until you provide passwords.
Its clear that only criminals would use an operating system other than windows.
For a lot of applications, speed isn't the limit, development time is. I use Matlab a lot (I'm an accelerator physicist), and most of the time the programs run almost instantly on a modern computer. I'm mostly interested in a language that lets me develop quickly. I almost never use integers so the lack of 64 bit integer arithmetic isn't a problem - didn't even know about the lack until seeing this.
I've tried Scilab, Octave and Python for this sort of use, but I've found Matlab best meets my requirements - but of course depending on the the application, different languages will be superior.
They may not want simple physical resources, but rather the technological resources of a planetary civilization. They may not be impressed with our overall level of technology, but there may still be some things we know how to do well. For example maybe we are unusually good at making silicon chips. That could be a minor niche market for an alien civilization, but still worth sending a cargo ship every few hundred years.
A really advanced civilization might even subtly manipulate our civilization until a significant fraction of all our engineering and production capacity went into making this niche product.
They could enforce it by requiring ISPs to check that the computer has a working copy of the spyware. There would the usual hacking war against this, but with regular updates to the spyware it would be too much effort for the majority of users to fight. Add criminal penalties if you are found to have a computer without the spyware and the the MPAA wins.
Companies could get exemptions. (You can pay a $100K "licensing" fee for your organization to not need the scanning software.
I'm worried that this could be sold on some sort of "protect the children" / "stop child porn" / "prevent terrorism" argument.
Would they dare? I've seen a lot of things recently that are beyond the limit of what I thought people would dare.
Anyone know at what density the ash is a hazard? This is the first large scale grounding of commercial aircraft due to a volcanic eruption that I can remember. Wikipedia lists an all engine out on a 747 in 1982 but maybe there are more cases.
Volcanic ash above some concentration is certainly a hazard, but this seems like a lot of airspace for a modest eruption.
The moon missions were a long time ago - but its not clear that we have progressed much with technology needed for aerospace. The basic technology hasn't changed, launch costs aren't that different. It was hard then, and its still hard now. Mars is a lot harder. We could do it if we wanted to, but we aren't willing to put in the require effort, or take the required risks. Its not that I think Obama's plan is fundamentally flawed, but when he talks about a mars mission in the 2030s, it sounds like another of the every 10 years "lets go to mars" talk, never followed by any action. I think I will likely live to see the day when no living man has been beyond 1000 miles from earth.
Maybe China will do it - they have the will and are willing to take the risks. Not the flag I'd most like to see flying over a mars base though. Not what I imagined when I watched the first moon landing 2 generations ago.
Exploring and colonizing space doesn't have a point - it IS the point.
There are 2 different issues here. One is whether the government's definition of child porn makes sense. Personally I think that including drawings makes it unreasonable. The second is whether the wikipedia images meet the government's definition - I think they probably do.
The way to change the first problem is through political action / voting. If you think it is unreasonable to send someone to prison for looking at a DRAWING of a naked child, write your congress person.
The second is a different issue. On line as well as off line organizations should follow the law - or engage in specific legal challenges.
The demonic version might sell: "Look at this website - you know you want to...."
Like most people with well thought out reasonable opinions, you don't do well in revolutions. I happen to agree with you, expect well both be up against the wall come the revolution - either for opposing the winners, or for not showing enough zeal in supporting them.
Rational environmentalism is tricky though: Imagine that rather pessimistic environmental scenarios are true, that there is climate change that causes widespread starvation. Over the next 200 years how many additional deaths will there be? (Hint - if you were to wipe out the entire human race tomorrow, integrated from today over the next 200 years there would be fewer deaths than there are now). Its rather difficult to come up with a metric for environmental costs.
The Germans built some of the trains. I think the Chinese are starting to build their own now. Certainly their trains are faster than anywere else in the world: 350Km/h for conventional and 430Km/h for the (somewhat silly) maglev.
You don't need take it the whole way. At 300Km/h average, a 1000km trip might be faster by rail than by air (city center to city center and counting airport delays).
I've ridden Chinese high speed rail - its a nice system, as good as the European or Japanese, and somewhat faster.