How does Hawaii compare to Wyoming, which has virtually no gun laws at all? I am guessing that you are quite wrong about more gun control resulting in fewer murders.
It's not a dumb thing to say. Criminals who are not also cops are far less likely to injure or kill you than are cops. Most cops are also criminals. They just aren't prosecuted as such and can get away with killing you without even getting fired.
Personally, my thought is that we should return to the overall taxes & spending setup that helped spur the creation of the Internet and the space program,
What are you talking about? Are you under the impression that what we have now is not tax and spend?
Would that 10x better thruster you mention be the DS4G (dual stage four grid) ESA (European Space Agency) ion thruster? That is the most advanced ion thruster I have found that is actually under development. The theoretical numbers for that are 250 kW of power to produce 2.5 Newtons of thrust, a 4000 km/sec exhaust speed,and a specific impulse of 19,300 seconds, using a 30kV (the maximum) beam voltage.
F=mA; Let the mass of the spacecraft be 1000 kg (about the weight of a light car). A = F/m = 0.0025 m/s^2. Only slightly less than your example. For a distance I'll use your Proxima Centauri example of 4E16 meters. Of that 2E16 meters is acceleration. The midpoint velocity can be found by V = sqrt(2a*dx) = sqrt(0.005*2E16) = 10 million m/s or 0.03c. Now for time. t = dx / Vav = 2E16m / 5 million m/s = 126 years and 9 months to the midpoint. So 253 1/2 years to get to Proxima Centauri with the DS4G thruster. That is a long time considering that it manages to reach 0.03c.
I think this illustrates the problem with such low thrust. Yes, eventually you can go very fast, but the time it takes to get to that speed is so long that the greater engine efficiency loses out to higher thrust. For a 1000 ly trip the fact that it takes 127 years to reach 0.03c isn't such an issue, but for a 4 ly trip it is. Orion can reach 0.03c in a week instead of 127 years. I wonder if a trip to Gliese 581 would have been a better comparison.
But what if you placed 100 DS4Gs in parallel with a 25 MW power supply? Would it give you 250 newtons of thrust, resulting in 0.25 m/sec^2 acceleration, a midpoint velocity of 0.33c (this can't be right), and around 12 1/2 years to the midpoint or 25 years to Proxima Centauri? Of course a 25 MW PSU would be more massive than a 250 kW PSU and you would need 100 times more Xenon, but I doubt that is the only problem with this.
You are of course correct that if someone could figure out how to accelerate the propellant to 0.1c you would have one hell of an interstellar drive. For grid based thrusters I guess breakdown voltages can be a limiting problem. Also ion thrusters are not without wear issues. The grids can corrode over time (sputtering) from what I've read.
VASIMR gets around the sputtering erosion problem by using a magnetic field to accelerate the ions. Ad Astra claims their VX-200 engine can generate 5.7 newtons of thrust from 200 kW of power using argon as a propellant and an exhaust velocity of 50 km/s. VASIMR calcs: m = 1000 kg; F = 5.7 N; a = 0.0057 m/s; Vmid = 0.05c; t = dx / Vav = 2E16/(Vmid/2) = 2E16/7549834 = 84 years to midpoint or 168 years to Proxima Centauri.
Incidentally the 0.08c - 0.1c megaton fusion bomb Orion numbers are for flyby missions. For realistic missions which stop at the destination those numbers would need to be halved to 0.04c - 0.05c. While those numbers are similar to the VASIMR it takes 84 years to reach that speed instead of a week or two. Of course if you could use 10 of those VX-200 thrusters in parallel fed by a 2 MW reactor and the amount of argon wasn't impractical it could be a very interesting system. 8.4 years is still a lot longer than a week, but it's short enough for most interstellar purposes and 0.05c is fast enough to make interstellar travel worthwhile. So what I'm really curious about is why you can't just stack these ion thrusters in parallel?
I was assuming that an Orion ship would have to be built either on a Lagrange point space station and launched from there.
As for ion drives, what I'm reading doesn't inspire confidence:. That article claims an ion drive based on current tech would take around 81000 years to get to alpha centuari, whereas Orion would only take 85 years. Not a subtle difference there. I also read something that claims ion drives have a theoretical top speed of 200,000 mph which of course is much too slow. Compare 200,000 mph to the theoretical limit of a 'practical' Orion powered ship: around 54 million mph.
It sounds to me like ion drives are waiting for a fundamental breakthrough to be useful for practical sized ships and long journeys. An Orion powered ship doesn't require any fundamental breakthroughs. They probably could have built one in the 60s. We could at least test a scaled down version launched from the moon to refine the pusher plate system. There is a lot of engineering work that would need to be done, but that is very different from waiting for a fundamental breakthrough.
Hmm. As far as ion drives I was kind of hoping for something like a feasibility study for use in interstellar travel. Consider, say, a small ship, or if easier, a large ship, whatever is optimal and see how long it would take to accelerate it to as high a speed as you can. I've heard of ion drives, I just haven't seen anyone claim they are practical for interstellar travel. It sounds to me like the best case scenario might be a small unmanned probe, but I'd like to see some numbers.
Why do you say that top speed is meaningless for space travel? It seems like it is the main issue with space travel. The problem with interstellar travel is that you have to reach a meaningful percentage of c. Supposedly a sufficiently large Orion ship could reach something like 0.08c, which isn't that bad. In order to do an apples to apples comparison with ion drives you'd want to know what percentage of c you can reach with a practical ship that can be built with current tech.
I forgot about fusion power. We'll have that in just a couple of decades, right? I haven't seen any estimates of using ion drives for interstellar travel. What is the practical top speed supposed to be? It sounds a bit too good to be true.
As far as the warheads themselves, at this point we simply don't know whether they would be useful in their current state or not. It would probably be premature to dismantle them, but even if we did the plutonium and conventional explosives could presumably be modified to reduce yield and make them useful again.
Also, can you feed plutonium into a nuclear reactor? I thought they mostly ran on U238.
Building the ship alone might take several centuries, but we have to start sometime. We could put these warheads aside to be earmarked for our first interstellar ship. Russia could also set theirs aside for the same purpose. An interstellar trip would ideally by a global effort of multiple generations.
Crude, innacurate, short range nukes are not the reason NK hasn't been attacked. This is all just talk: the barking of a dog that doesn't bite. The rest of the world is aware of this. There is no reason for anyone to attack them. Aside from that there is the problem that any war with NK is likely to result in, at the very least, a Seoul that consists mostly of rubble and, again, that isn't in anyone's best interest.
And if China cuts off North Korea, its a pretty safe bet than North Korea would invade South Korea before they collapse.
I don't agree. North Korea would certainly suffer even more if China cut them off, but, based on what happened when the Soviet Union cut off aid to Cuba, I think North Korea would be able to feed their people after a relatively brief 'special period' where people were nearly starving. This image of North Koreans being insane and doing insane things is itself a kind of propaganda.
North Koreans citizens aren't robots and their leaders aren't suicidal or crazy. Communism doesn't work as well as Capitalism at producing goods, but it has proven itself to work well enough to feed its populace at least enough to avoid mass starvation.
So patriotism is what you are referring to as fanaticism? If so then the US also has a fanatic populace. Was anyone suggesting that North Koreans wouldn't fight a foreign invader? Obviously the whole country isn't just going to surrender without a fight.
I'm not sure I understand what you are saying. Just that citizens of a corrupt communist regime believe everything their government tells them? Let me assure you that that is not the case.
Needs to be quick? The only way to insure a quick conflict is to walk away after whatever your time limit is. Based on the previous Korean War I don't think 'quick' would be in the cards.
I've never heard that, but I have heard that people who drive trucks: pickups, SUVs etc are compensating for the size of their equipment. People with small cars don't seem to compensating for anything.
Well what happened to me was that I was facing up to several years in jail and a very expensive court case that I really couldn't afford. I mean in the sense that I would have actually had to borrow half a year's income in order to go to trial. There were no human witnesses. It was my word against one or more cops. Juries tend to believe cops over suspects and don't like to believe that cops are running around beating people up and then filing false charges against the victim. That doesn't make people feel very safe or good about their country. When people really don't want to believe something very often they don't.
So I figured that I had no more than a 50% chance of winning a jury trial (and a 0% chance of winning a bench trial because judges always side with cops) and if convicted I was facing enough time in jail that, for me, suicide would be far preferable. And in fact I was planning to kill myself in jail if convicted. So when the prosecutor offered me a deal without even a day of jail time and only 3 months probation I took it even though I had to lie to the judge and admit to doing what I did not do. Because I was forced to agree to the prosecution's bullshit story I was not able to file any lawsuits afterward. The whole point of the cover charges was to get that result. On the one hand you have the potential for a lawsuit and some justice if you win. On the other you have a 50% chance of death or something even worse than death. What is the rational choice? I still feel guilty about committing perjury and lying directly to that judge about what happened, but I'm neither in prison nor dead.
Then i realized exactly that without ads 3/4 of the internet would not exist.
The way I see it is that with ads the internet does not exist. On the very, very rare occasion that I try to browse without noscript + adblock it is unbearable. I'd rather not use the internet at all if it is ever reduced to that. I genuinely feel sorry for the stupid, technically ignorant 50% who don't know about noscript and adblockers. I don't think adblockers are really hurting advertisers at all because people smart enough to use them are also smart enough not to click on banner ads for any reason. The people who click on them are the same ones who respond to email spam. In that sense the internet is being funded by 100% pure stupidity.
I also am less likely to purchase a brand that is advertising on the internet with some kind of banner ad. I agree that it can make them seem cheap. The only time it doesn't bother me is when a company is sponsoring some kind of specialist forum, but I still don't want to see a banner ad for them. Just a text link to their website is more than enough. I also only click on sponsor links, not on regular ads. That would be encouraging spam and is wrong.
I agree with you. That single line of text is sufficiently unobtrusive that I don't care about blocking it. Assuming I even could. Obviously 99.99999999999999% of ads are nothing like that. Rather than whine about it the site in this article could just switch to ads that the combination of adblock plus lite and noscript (probably the most common setup) doesn't stop.
Only until ad blockers figure a way around the ad blocker detector. I've seen sites that ask me to disable my ad blocker before entering. Unless it is life or death information that only they have I will simply go elsewhere.
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Obviously they don't. Which is why it should be illegal for cops to carry them.
How does Hawaii compare to Wyoming, which has virtually no gun laws at all? I am guessing that you are quite wrong about more gun control resulting in fewer murders.
It's not a dumb thing to say. Criminals who are not also cops are far less likely to injure or kill you than are cops. Most cops are also criminals. They just aren't prosecuted as such and can get away with killing you without even getting fired.
Believe it or not, police try to make an effort to ascertain the veracity of their intel before making a move like you've imagined.
I don't believe it. Not for a second. They have itchy trigger fingers and are looking for targets.
What are you basing that guess on?
Personally, my thought is that we should return to the overall taxes & spending setup that helped spur the creation of the Internet and the space program,
What are you talking about? Are you under the impression that what we have now is not tax and spend?
Would that 10x better thruster you mention be the DS4G (dual stage four grid) ESA (European Space Agency) ion thruster? That is the most advanced ion thruster I have found that is actually under development. The theoretical numbers for that are 250 kW of power to produce 2.5 Newtons of thrust, a 4000 km/sec exhaust speed,and a specific impulse of 19,300 seconds, using a 30kV (the maximum) beam voltage.
F=mA; Let the mass of the spacecraft be 1000 kg (about the weight of a light car). A = F/m = 0.0025 m/s^2. Only slightly less than your example. For a distance I'll use your Proxima Centauri example of 4E16 meters. Of that 2E16 meters is acceleration. The midpoint velocity can be found by V = sqrt(2a*dx) = sqrt(0.005*2E16) = 10 million m/s or 0.03c. Now for time. t = dx / Vav = 2E16m / 5 million m/s = 126 years and 9 months to the midpoint. So 253 1/2 years to get to Proxima Centauri with the DS4G thruster. That is a long time considering that it manages to reach 0.03c.
I think this illustrates the problem with such low thrust. Yes, eventually you can go very fast, but the time it takes to get to that speed is so long that the greater engine efficiency loses out to higher thrust. For a 1000 ly trip the fact that it takes 127 years to reach 0.03c isn't such an issue, but for a 4 ly trip it is. Orion can reach 0.03c in a week instead of 127 years. I wonder if a trip to Gliese 581 would have been a better comparison.
But what if you placed 100 DS4Gs in parallel with a 25 MW power supply? Would it give you 250 newtons of thrust, resulting in 0.25 m/sec^2 acceleration, a midpoint velocity of 0.33c (this can't be right), and around 12 1/2 years to the midpoint or 25 years to Proxima Centauri? Of course a 25 MW PSU would be more massive than a 250 kW PSU and you would need 100 times more Xenon, but I doubt that is the only problem with this.
You are of course correct that if someone could figure out how to accelerate the propellant to 0.1c you would have one hell of an interstellar drive. For grid based thrusters I guess breakdown voltages can be a limiting problem. Also ion thrusters are not without wear issues. The grids can corrode over time (sputtering) from what I've read.
VASIMR gets around the sputtering erosion problem by using a magnetic field to accelerate the ions. Ad Astra claims their VX-200 engine can generate 5.7 newtons of thrust from 200 kW of power using argon as a propellant and an exhaust velocity of 50 km/s. VASIMR calcs: m = 1000 kg; F = 5.7 N; a = 0.0057 m/s; Vmid = 0.05c; t = dx / Vav = 2E16/(Vmid/2) = 2E16/7549834 = 84 years to midpoint or 168 years to Proxima Centauri.
Incidentally the 0.08c - 0.1c megaton fusion bomb Orion numbers are for flyby missions. For realistic missions which stop at the destination those numbers would need to be halved to 0.04c - 0.05c. While those numbers are similar to the VASIMR it takes 84 years to reach that speed instead of a week or two. Of course if you could use 10 of those VX-200 thrusters in parallel fed by a 2 MW reactor and the amount of argon wasn't impractical it could be a very interesting system. 8.4 years is still a lot longer than a week, but it's short enough for most interstellar purposes and 0.05c is fast enough to make interstellar travel worthwhile. So what I'm really curious about is why you can't just stack these ion thrusters in parallel?
I was assuming that an Orion ship would have to be built either on a Lagrange point space station and launched from there.
As for ion drives, what I'm reading doesn't inspire confidence:. That article claims an ion drive based on current tech would take around 81000 years to get to alpha centuari, whereas Orion would only take 85 years. Not a subtle difference there. I also read something that claims ion drives have a theoretical top speed of 200,000 mph which of course is much too slow. Compare 200,000 mph to the theoretical limit of a 'practical' Orion powered ship: around 54 million mph.
It sounds to me like ion drives are waiting for a fundamental breakthrough to be useful for practical sized ships and long journeys. An Orion powered ship doesn't require any fundamental breakthroughs. They probably could have built one in the 60s. We could at least test a scaled down version launched from the moon to refine the pusher plate system. There is a lot of engineering work that would need to be done, but that is very different from waiting for a fundamental breakthrough.
Hmm. As far as ion drives I was kind of hoping for something like a feasibility study for use in interstellar travel. Consider, say, a small ship, or if easier, a large ship, whatever is optimal and see how long it would take to accelerate it to as high a speed as you can. I've heard of ion drives, I just haven't seen anyone claim they are practical for interstellar travel. It sounds to me like the best case scenario might be a small unmanned probe, but I'd like to see some numbers.
Why do you say that top speed is meaningless for space travel? It seems like it is the main issue with space travel. The problem with interstellar travel is that you have to reach a meaningful percentage of c. Supposedly a sufficiently large Orion ship could reach something like 0.08c, which isn't that bad. In order to do an apples to apples comparison with ion drives you'd want to know what percentage of c you can reach with a practical ship that can be built with current tech.
I forgot about fusion power. We'll have that in just a couple of decades, right? I haven't seen any estimates of using ion drives for interstellar travel. What is the practical top speed supposed to be? It sounds a bit too good to be true.
As far as the warheads themselves, at this point we simply don't know whether they would be useful in their current state or not. It would probably be premature to dismantle them, but even if we did the plutonium and conventional explosives could presumably be modified to reduce yield and make them useful again.
Also, can you feed plutonium into a nuclear reactor? I thought they mostly ran on U238.
Building the ship alone might take several centuries, but we have to start sometime. We could put these warheads aside to be earmarked for our first interstellar ship. Russia could also set theirs aside for the same purpose. An interstellar trip would ideally by a global effort of multiple generations.
Do we even need a thousand nuclear warheads?
If we ever want to travel to Alpha Centauri we do. How about putting those nukes toward the construction of an interstellar pulsed nuclear space drive?
Crude, innacurate, short range nukes are not the reason NK hasn't been attacked. This is all just talk: the barking of a dog that doesn't bite. The rest of the world is aware of this. There is no reason for anyone to attack them. Aside from that there is the problem that any war with NK is likely to result in, at the very least, a Seoul that consists mostly of rubble and, again, that isn't in anyone's best interest.
And if China cuts off North Korea, its a pretty safe bet than North Korea would invade South Korea before they collapse.
I don't agree. North Korea would certainly suffer even more if China cut them off, but, based on what happened when the Soviet Union cut off aid to Cuba, I think North Korea would be able to feed their people after a relatively brief 'special period' where people were nearly starving. This image of North Koreans being insane and doing insane things is itself a kind of propaganda.
North Koreans citizens aren't robots and their leaders aren't suicidal or crazy. Communism doesn't work as well as Capitalism at producing goods, but it has proven itself to work well enough to feed its populace at least enough to avoid mass starvation.
So patriotism is what you are referring to as fanaticism? If so then the US also has a fanatic populace. Was anyone suggesting that North Koreans wouldn't fight a foreign invader? Obviously the whole country isn't just going to surrender without a fight.
I'm not sure I understand what you are saying. Just that citizens of a corrupt communist regime believe everything their government tells them? Let me assure you that that is not the case.
Needs to be quick? The only way to insure a quick conflict is to walk away after whatever your time limit is. Based on the previous Korean War I don't think 'quick' would be in the cards.
How do you know they have a fanatic populace? Have you been there? How do you know most people believe everything their government tells them?
I've never heard that, but I have heard that people who drive trucks: pickups, SUVs etc are compensating for the size of their equipment. People with small cars don't seem to compensating for anything.
Can't wait until I pull onto a freeway with one of these, driven by an idiot
So you claim to be an idiot then?
Well what happened to me was that I was facing up to several years in jail and a very expensive court case that I really couldn't afford. I mean in the sense that I would have actually had to borrow half a year's income in order to go to trial. There were no human witnesses. It was my word against one or more cops. Juries tend to believe cops over suspects and don't like to believe that cops are running around beating people up and then filing false charges against the victim. That doesn't make people feel very safe or good about their country. When people really don't want to believe something very often they don't.
So I figured that I had no more than a 50% chance of winning a jury trial (and a 0% chance of winning a bench trial because judges always side with cops) and if convicted I was facing enough time in jail that, for me, suicide would be far preferable. And in fact I was planning to kill myself in jail if convicted. So when the prosecutor offered me a deal without even a day of jail time and only 3 months probation I took it even though I had to lie to the judge and admit to doing what I did not do. Because I was forced to agree to the prosecution's bullshit story I was not able to file any lawsuits afterward. The whole point of the cover charges was to get that result. On the one hand you have the potential for a lawsuit and some justice if you win. On the other you have a 50% chance of death or something even worse than death. What is the rational choice? I still feel guilty about committing perjury and lying directly to that judge about what happened, but I'm neither in prison nor dead.
Then i realized exactly that without ads 3/4 of the internet would not exist.
The way I see it is that with ads the internet does not exist. On the very, very rare occasion that I try to browse without noscript + adblock it is unbearable. I'd rather not use the internet at all if it is ever reduced to that. I genuinely feel sorry for the stupid, technically ignorant 50% who don't know about noscript and adblockers. I don't think adblockers are really hurting advertisers at all because people smart enough to use them are also smart enough not to click on banner ads for any reason. The people who click on them are the same ones who respond to email spam. In that sense the internet is being funded by 100% pure stupidity.
I also am less likely to purchase a brand that is advertising on the internet with some kind of banner ad. I agree that it can make them seem cheap. The only time it doesn't bother me is when a company is sponsoring some kind of specialist forum, but I still don't want to see a banner ad for them. Just a text link to their website is more than enough. I also only click on sponsor links, not on regular ads. That would be encouraging spam and is wrong.
I agree with you. That single line of text is sufficiently unobtrusive that I don't care about blocking it. Assuming I even could. Obviously 99.99999999999999% of ads are nothing like that. Rather than whine about it the site in this article could just switch to ads that the combination of adblock plus lite and noscript (probably the most common setup) doesn't stop.
Only until ad blockers figure a way around the ad blocker detector. I've seen sites that ask me to disable my ad blocker before entering. Unless it is life or death information that only they have I will simply go elsewhere.