You're probably right on the extra color; as I think on it that sounds more familiar than my dimly remembered 'violet' receptor.
There are still some people that see indigo as a more distinct color than the shade of blue that I (and many) people see it as, that may be yet another variation on the cone genes (or not).
Birds have a 4-color system, the last I heard; mammals lost theirs when they became nocturnal, and we have not fully recovered ours because, basically, primate evolution has not had long enough for it to reappear- perhaps the selection pressure is not that great.)
Actually some humans (and presumably, other primates) do have a 4-color system. It tends to occur more frequently (but still rarely overall) in females than males, perhaps for the same reasons that color-blindness tends to be more frequent in males. If I recall correctly the extra receptor is toward the violet end, and to these people indigo is actually a different color rather than just a shade of blue.
(Compare with mantis shrimp that have 12 color channels, extending into the ultra-violet and infra-red, plus receptors to distinguish circularly polarized light.)
Question: I have a picture of the LAST man on the moon in my screensaver - can you name him without looking it up?
Depends, do you mean the last (most recent) person to step on to the Lunar surface, or the last (most recent) person actually standing on the surface? The former was Harrison Schmitt, the only geologist to walk on the Moon, the latter was Gene Cernan, the commander of the Apollo 17 mission (thus the first one out and last one back into the LM).
they would simply shrug and say something like "what's the point, we've been to the moon already"
I recall a meeting of some space advocates debating Moon vs Mars for the next major mission, one of the Apollo astronauts (Buzz Aldrin, I think) was present and said almost those exact words. Several other people immediately chimed in with "no, you've been to the moon, we haven't."
Anyone who thinks the gold standard is the answer needs to review their history, in particular what happened to Spain after the conquest of the Aztecs and Incas. The sudden influx of huge amounts of gold led to runaway inflation just as much as printing too much paper money does.
Gold (aside from some industrial uses for which it is well suited) has no more intrinsic value than paper money or bits in a computer memory.
Personally I like the idea of radioactive money, which encourages rapid circulation and discourages hoarding.
cell phone cables need to be able to support digital data, power and analog multi-channel audio input(microphones) and output (speakers). Some also need to support RGB or S-video out
USB can do the first two. I may be mistaken but I don't think that USB can support those analog channels.
Actually my iPAQ uses a USB headset, supporting both audio in and out (via analog/digital conversion in the headset). Personally I wish it also had a regular analog port.
If you're proposing what I think you are, that won't work out very well. You see, when you heat the surface of an asteroid (or comet) to the point where out-gassing occurs, it will act as a propellant pushing itself in the opposite direction.
Consider the differences between a nickel-iron meteoroid/asteroid and a comet.
Consider that with reflectors you can simultaneously heat several sides of a body.
Consider that you can take advantage of asymmetry to make a body go in a preferred direction.
Consider that some people have spent a fair bit of time thinking these issues through.
One small nickel-iron type asteroid will also yield plenty of platinum, iridium and similar metals. Heck, there's still some disagreement over what they're mining in Sudbury, Ontario, is there because of magma upwelling after the original impact (circa 2bya) or remnants of the original impactor.
Separating them out can be done in space with a number of processes using large reflectors and solar heating. (Zone refining, fractional distillation, carbonyl extraction, etc..)
If we'd had the guts to start moving towards that when some people first started suggesting it seriously, we'd be there or nearly so by now.
We don't have self-replicators yet, but you can just about see them from here.
Of course, we may run into unexpected problems between here and there. There's also the issue not addressed (but an earlier poster hints at): if the replication mechanism is anything less than perfect, these replicators are going to evolve.
Currently fuels like Lithium or Xenon are preferred, though I don't know precisely why.
Because they're easier to ionize, for one. (Hadn't heard of lithium being used. Cesium, yes.)
I'm not sure if the atomic mass is a factor, like it is in chemical rockets. Lighter exhaust means the heat of the reaction makes it go faster, increasing specific impulse; with electrical acceleration of the exhaust different criteria apply.
Think about the transit time, think about the number that would be lost. You can't really assume a straight geometric progression for something so incredibly fraught.
Well, almost, at least for the purposes of ballpark calculations.
Now, we have to make a couple of assumptions -- such as that they have the technology to send out self-replicators that will last long enough to get to the next star, which is a function of speed and durability. For the sake of argument, let's assume that the Voyager spacecraft (which just left the Solar System) are capable of self-replication, have a very long-lived power supply (long half-life radioisotope, for example) and their electronics will survive long exposure to galactic cosmic rays. (All big assumptions, but imaginably within range of our technology.)
Also assume an average spacing of about five light years apart for stars.
At the current speed (about 16 km/sec), it would take a Voyager about 90,000 years to reach the next start. Allow 10,000 years for the laborious process of self-replicating from raw materials and launching another of itself on its way, for a total of 100,000 years per generation. Assume each vehicle replicates itself only twice, and stays put (perhaps assembling large black monoliths on the local planets for the mystification of any eventual inhabitants). So we have a doubling rate of once per 0.1 million years.
Assume about 100 billion stars in our galaxy (this is the number I found most frequently mentioned), it would take between 36 and 37 doublings to send a probe to every star in the galaxy (less because stars are closer nearer the core). Call it 40 to allow for probe loss.
So in a mere four million years, self-replicating probes travelling no faster than Voyager could visit every star in the galaxy -- except for the speed problem. That growth rate can be maintained initially, but like any spreading colony (such as bacteria in a petri dish) the edge of the colony can only advance at a certain speed, and the doubling rate has to fall off (it's ludicrous to think that the number of visited stars could go from half the galaxy to the whole galaxy in a mere 100,000 years, the probes would have to be approaching lightspeed for that).
Take the galaxy diameter as 100,000 light years, it'd take nearly 2 billion years for a Voyager-speed probe to cross it, or near 3 billion to go around half the circumference (to avoid the black hole at the core). The galaxy is old enough that there probably sun-like stars (our Sun being a second-generation star, necessary if you want enough heavy elements for terrestrial planet formation) a couple of billion years older than ours. (And if we assume faster travel speed, say 0.01 c instead of 0.000055 c, the numbers get a lot better.)
So Fermi's question was simply "where are they?". If they're really not around (vs simply ignoring us or being undetectable to us), then the above assumptions are too optimistic.
I don't know of any place on the Internet where an author can get paid for a science fiction story.
At pro rates (ie, SFWA qualifying), there's Jim Baen's Universe and Orson Scott Card's Intergalactic Medicine Show. There are a few others around (eg, Raygun Revival) that pay quite a bit less than pro rates. (And even pro fiction rates are far, far below typical non-fiction rates. Back when, Byte magazine paid me for an article the better part of an advance on a first novel, and that's not too atypical.)
But the exposure on the internet fiction sites is far below what the magazines, even in these days of declining circulation, can give. And you can pick up a magazine years later and 'discover' an author you hadn't read before, but internet stories are (often) evanescent.
Certainly, so long as "held accountable" doesn't automatically mean "punished". They should account for their refusal to obey the order; if the reason was valid (the order was unlawful), then enough said. (If anything, the soldier should be commended in such case - but it has to be investigated to determine if that is the case.)
You skipped two paragraphs with that "..." in your quote.
The court martial was referring to someone who carries out a summary execution, not necessarily someone who issues an illegal order.
While I agree that someone who gives an illegal order should face investigation and consequences, it's a lot easier to sweep under the rug if the order is verbal and obeyed without question.
The Constitution isn't that long, a couple of pages, and the language isn't even that complicated. If you're swearing an oath to support and defend something, don't you think it'd be your duty to read it once in a while?
Given that Area 51 is in Nevada (nowhere near Roswell), that the place is on a dry lake bed (nice and flat), and that its official designation is the Air Force Flight Test Center, your #2 is obviously correct.
Besides, those really in the know are aware that all the secret UFO technology is actually at the Wright-Patterson Air Force Base in Dayton, Ohio. (Seriously, look where Project Blue Book and its predecessors were HQ'd.) A couple of nondescript hangars in the middle of a busy Air Force base, who'd notice?
and no protection from charges of insubordination if they do refuse an unlawful order
No protection from charges, perhaps, but certainly protection from conviction. Sometimes life hands you a shitty situation; honour is about making the right choices in such situations, not about the choices you make where it's easy.
Studies have shown that people follow orders from authority figures remarkably well.
Sure, and they follow them better if they think they won't be held responsible for their own actions.
Holding them accountable by disallowing the "I was just following orders" defense might actually discourage some people from following said orders. All Milgram showed was that, if you give people the opportunity to act on their baser feelings without repercussion, many of them will.
Civilization is about holding ourselves to higher standards than that.
Everyone is responsible for their own actions. "He told me to" doesn't cut it as an excuse with kids any more than "I was just following orders" cut it at the Nuremberg trials.
While admittedly problematic in a combat situation, a soldier has the right to request orders in writing, and to take it up the chain of command if he believes the orders to be illegal. If the orders are technically legal but immoral, then it's up to the soldier's conscience as to whether to follow them or to respectfully refuse to.
Note that US soldiers (marines, etc) swear an oath first to support and defend the Constitution - the ideals embodied in it - before swearing to obey orders. If a given order is believed to be unconstitutional, the soldier has a duty to disobey it.
(And to the Marine above who mentioned that in wartime refusal to obey orders could result in summary execution: that's right, but you knew the job was dangerous when you took it. If it's any consolation, the officer or NCO will probably face court martial.)
Guarantee me a big enough market* and I can deliver that for only $2 a liter. Well, maybe a bit more allowing for inflation from the last time I worked it out.
May take a few years for the first delivery, but that's just to get the pipeline started; once the tap is turned on it's a steady delivery rate. Startup costs might be a bit steep, but only a fraction of the current bailout.
(google "Aresian well". There used to be a wikipedia page but it was deleted during the Great Purge.) --- *About six billion litres a year, less than 4% of current world sales of bottled water. Bottling charges extra.
If he has an Analog TV, then he is entitled to a coupon.... actually this statement is not true.
Actually it is true, if said TV is not connected to cable or satellite (ie, is only receiving OTA signals).
It doesn't matter if you happen to own a digital TV or not, if you own an analog receiver and don't have cable or satellite, you qualify (and that latter restriction only kicked in for part of the coupon distribution). Obviously you don't need a converter for any digital receivers you own.
This isn't welfare, it's reimbursing analog set owners for what could otherwise be considered a 'taking' of their property by rendering the analog receivers useless (hence valueless).
This is, of course, bullshit, at least in my experience.
My HDTV picks up both analog and digital transmissions with the same set of cheap rabbit ears perched on top. The digital signals are far superior, some of the analog channels are unwatchable (unless you enjoy watching triple ghosts with heavy overlay of snow, and sound that sounds like frying bacon).
I picked up a couple of cheap converter boxes for the analog TV and VCRs. When I went to test them out, not wanting to mess with my existing antenna setup, I just attached a little 2" stub antenna with a coax fitting directly to the box. While it certainly didn't pick up as many channels as the rabbit ears, it picked up all the main network digital channels without a problem. (By way of comparison, the same antenna connected to the analog TV directly didn't pick up squat.)
Signal reach is highly dependent of course on transmitter strength, and in the middle of the city you should be (on average) closer to the transmitters than out in the middle of the boonies. Because a digital signal can reject the kind of echoing you're going to get with signal reflections off of buildings in a city, you're going to get a better picture with digital.
(And actually the digital signal doesn't "just break"; at the fringe you'll get periods of good stable image with the occasional blocking or mosaic if something temporarily interferes with the signal. Beyond that, yeah, it's just off -- but there's no "graceful" to the way an analog signal would have degraded by that point.)
Nope, shipping it back in time just means waiting around for hard disks to be developed to be able to read it. You need to ship it forward in time far enough that nobody will care about the data.
Mind, so many people have been doing this that Milliways (The Restaurant at the End of the Universe) is starting to complain about the disposal problem.
Slashdot Mirror
You're probably right on the extra color; as I think on it that sounds more familiar than my dimly remembered 'violet' receptor.
There are still some people that see indigo as a more distinct color than the shade of blue that I (and many) people see it as, that may be yet another variation on the cone genes (or not).
Birds have a 4-color system, the last I heard; mammals lost theirs when they became nocturnal, and we have not fully recovered ours because, basically, primate evolution has not had long enough for it to reappear- perhaps the selection pressure is not that great.)
Actually some humans (and presumably, other primates) do have a 4-color system. It tends to occur more frequently (but still rarely overall) in females than males, perhaps for the same reasons that color-blindness tends to be more frequent in males. If I recall correctly the extra receptor is toward the violet end, and to these people indigo is actually a different color rather than just a shade of blue.
(Compare with mantis shrimp that have 12 color channels, extending into the ultra-violet and infra-red, plus receptors to distinguish circularly polarized light.)
Question: I have a picture of the LAST man on the moon in my screensaver - can you name him without looking it up?
Depends, do you mean the last (most recent) person to step on to the Lunar surface, or the last (most recent) person actually standing on the surface? The former was Harrison Schmitt, the only geologist to walk on the Moon, the latter was Gene Cernan, the commander of the Apollo 17 mission (thus the first one out and last one back into the LM).
they would simply shrug and say something like "what's the point, we've been to the moon already"
I recall a meeting of some space advocates debating Moon vs Mars for the next major mission, one of the Apollo astronauts (Buzz Aldrin, I think) was present and said almost those exact words. Several other people immediately chimed in with "no, you've been to the moon, we haven't."
I also have a couple questions like, "IFR Capable?" Or is this just only a "VFR" kind of car?
While not strictly necessary for IFR, deicing gear for the wing is a bit problematic. I sure wouldn't want to fly it through any clouds.
Anyway, given the car's capabilities, it doesn't need to follow roads. ;-)
Anyone who thinks the gold standard is the answer needs to review their history, in particular what happened to Spain after the conquest of the Aztecs and Incas. The sudden influx of huge amounts of gold led to runaway inflation just as much as printing too much paper money does.
Gold (aside from some industrial uses for which it is well suited) has no more intrinsic value than paper money or bits in a computer memory.
Personally I like the idea of radioactive money, which encourages rapid circulation and discourages hoarding.
That's for hitting the water flat, as in a belly-flop.
With this thing you're hanging from it feet first, it'll be like jumping off a diving tower or cliff.
Yeah, you might break a leg if you land (splash) wrong, but that's true in plenty of other sports too.
cell phone cables need to be able to support digital data, power and analog multi-channel audio input(microphones) and output (speakers). Some also need to support RGB or S-video out
USB can do the first two. I may be mistaken but I don't think that USB can support those analog channels.
Actually my iPAQ uses a USB headset, supporting both audio in and out (via analog/digital conversion in the headset). Personally I wish it also had a regular analog port.
Or in other words, radar.
If you're proposing what I think you are, that won't work out very well. You see, when you heat the surface of an asteroid (or comet) to the point where out-gassing occurs, it will act as a propellant pushing itself in the opposite direction.
Consider the differences between a nickel-iron meteoroid/asteroid and a comet.
Consider that with reflectors you can simultaneously heat several sides of a body.
Consider that you can take advantage of asymmetry to make a body go in a preferred direction.
Consider that some people have spent a fair bit of time thinking these issues through.
One small nickel-iron type asteroid will also yield plenty of platinum, iridium and similar metals. Heck, there's still some disagreement over what they're mining in Sudbury, Ontario, is there because of magma upwelling after the original impact (circa 2bya) or remnants of the original impactor.
Separating them out can be done in space with a number of processes using large reflectors and solar heating. (Zone refining, fractional distillation, carbonyl extraction, etc..)
If we'd had the guts to start moving towards that when some people first started suggesting it seriously, we'd be there or nearly so by now.
We don't have self-replicators yet, but you can just about see them from here.
Of course, we may run into unexpected problems between here and there. There's also the issue not addressed (but an earlier poster hints at): if the replication mechanism is anything less than perfect, these replicators are going to evolve.
Valid points.
Currently fuels like Lithium or Xenon are preferred, though I don't know precisely why.
Because they're easier to ionize, for one. (Hadn't heard of lithium being used. Cesium, yes.)
I'm not sure if the atomic mass is a factor, like it is in chemical rockets. Lighter exhaust means the heat of the reaction makes it go faster, increasing specific impulse; with electrical acceleration of the exhaust different criteria apply.
Think about the transit time, think about the number that would be lost. You can't really assume a straight geometric progression for something so incredibly fraught.
Well, almost, at least for the purposes of ballpark calculations.
Now, we have to make a couple of assumptions -- such as that they have the technology to send out self-replicators that will last long enough to get to the next star, which is a function of speed and durability. For the sake of argument, let's assume that the Voyager spacecraft (which just left the Solar System) are capable of self-replication, have a very long-lived power supply (long half-life radioisotope, for example) and their electronics will survive long exposure to galactic cosmic rays. (All big assumptions, but imaginably within range of our technology.)
Also assume an average spacing of about five light years apart for stars.
At the current speed (about 16 km/sec), it would take a Voyager about 90,000 years to reach the next start. Allow 10,000 years for the laborious process of self-replicating from raw materials and launching another of itself on its way, for a total of 100,000 years per generation. Assume each vehicle replicates itself only twice, and stays put (perhaps assembling large black monoliths on the local planets for the mystification of any eventual inhabitants). So we have a doubling rate of once per 0.1 million years.
Assume about 100 billion stars in our galaxy (this is the number I found most frequently mentioned), it would take between 36 and 37 doublings to send a probe to every star in the galaxy (less because stars are closer nearer the core). Call it 40 to allow for probe loss.
So in a mere four million years, self-replicating probes travelling no faster than Voyager could visit every star in the galaxy -- except for the speed problem. That growth rate can be maintained initially, but like any spreading colony (such as bacteria in a petri dish) the edge of the colony can only advance at a certain speed, and the doubling rate has to fall off (it's ludicrous to think that the number of visited stars could go from half the galaxy to the whole galaxy in a mere 100,000 years, the probes would have to be approaching lightspeed for that).
Take the galaxy diameter as 100,000 light years, it'd take nearly 2 billion years for a Voyager-speed probe to cross it, or near 3 billion to go around half the circumference (to avoid the black hole at the core). The galaxy is old enough that there probably sun-like stars (our Sun being a second-generation star, necessary if you want enough heavy elements for terrestrial planet formation) a couple of billion years older than ours. (And if we assume faster travel speed, say 0.01 c instead of 0.000055 c, the numbers get a lot better.)
So Fermi's question was simply "where are they?". If they're really not around (vs simply ignoring us or being undetectable to us), then the above assumptions are too optimistic.
I don't know of any place on the Internet where an author can get paid for a science fiction story.
At pro rates (ie, SFWA qualifying), there's Jim Baen's Universe and Orson Scott Card's Intergalactic Medicine Show. There are a few others around (eg, Raygun Revival) that pay quite a bit less than pro rates. (And even pro fiction rates are far, far below typical non-fiction rates. Back when, Byte magazine paid me for an article the better part of an advance on a first novel, and that's not too atypical.)
But the exposure on the internet fiction sites is far below what the magazines, even in these days of declining circulation, can give. And you can pick up a magazine years later and 'discover' an author you hadn't read before, but internet stories are (often) evanescent.
Certainly, so long as "held accountable" doesn't automatically mean "punished". They should account for their refusal to obey the order; if the reason was valid (the order was unlawful), then enough said. (If anything, the soldier should be commended in such case - but it has to be investigated to determine if that is the case.)
You skipped two paragraphs with that "..." in your quote.
The court martial was referring to someone who carries out a summary execution, not necessarily someone who issues an illegal order.
While I agree that someone who gives an illegal order should face investigation and consequences, it's a lot easier to sweep under the rug if the order is verbal and obeyed without question.
The Constitution isn't that long, a couple of pages, and the language isn't even that complicated. If you're swearing an oath to support and defend something, don't you think it'd be your duty to read it once in a while?
Given that Area 51 is in Nevada (nowhere near Roswell), that the place is on a dry lake bed (nice and flat), and that its official designation is the Air Force Flight Test Center, your #2 is obviously correct.
Besides, those really in the know are aware that all the secret UFO technology is actually at the Wright-Patterson Air Force Base in Dayton, Ohio. (Seriously, look where Project Blue Book and its predecessors were HQ'd.) A couple of nondescript hangars in the middle of a busy Air Force base, who'd notice?
and no protection from charges of insubordination if they do refuse an unlawful order
No protection from charges, perhaps, but certainly protection from conviction. Sometimes life hands you a shitty situation; honour is about making the right choices in such situations, not about the choices you make where it's easy.
Studies have shown that people follow orders from authority figures remarkably well.
Sure, and they follow them better if they think they won't be held responsible for their own actions.
Holding them accountable by disallowing the "I was just following orders" defense might actually discourage some people from following said orders. All Milgram showed was that, if you give people the opportunity to act on their baser feelings without repercussion, many of them will.
Civilization is about holding ourselves to higher standards than that.
Everyone is responsible for their own actions. "He told me to" doesn't cut it as an excuse with kids any more than "I was just following orders" cut it at the Nuremberg trials.
While admittedly problematic in a combat situation, a soldier has the right to request orders in writing, and to take it up the chain of command if he believes the orders to be illegal. If the orders are technically legal but immoral, then it's up to the soldier's conscience as to whether to follow them or to respectfully refuse to.
Note that US soldiers (marines, etc) swear an oath first to support and defend the Constitution - the ideals embodied in it - before swearing to obey orders. If a given order is believed to be unconstitutional, the soldier has a duty to disobey it.
(And to the Marine above who mentioned that in wartime refusal to obey orders could result in summary execution: that's right, but you knew the job was dangerous when you took it. If it's any consolation, the officer or NCO will probably face court martial.)
Martian Water: Now only $1,000 a liter!
Guarantee me a big enough market* and I can deliver that for only $2 a liter. Well, maybe a bit more allowing for inflation from the last time I worked it out.
May take a few years for the first delivery, but that's just to get the pipeline started; once the tap is turned on it's a steady delivery rate. Startup costs might be a bit steep, but only a fraction of the current bailout.
(google "Aresian well". There used to be a wikipedia page but it was deleted during the Great Purge.)
---
*About six billion litres a year, less than 4% of current world sales of bottled water. Bottling charges extra.
If he has an Analog TV, then he is entitled to a coupon.... actually this statement is not true.
Actually it is true, if said TV is not connected to cable or satellite (ie, is only receiving OTA signals).
It doesn't matter if you happen to own a digital TV or not, if you own an analog receiver and don't have cable or satellite, you qualify (and that latter restriction only kicked in for part of the coupon distribution). Obviously you don't need a converter for any digital receivers you own.
This isn't welfare, it's reimbursing analog set owners for what could otherwise be considered a 'taking' of their property by rendering the analog receivers useless (hence valueless).
analog has a far wider reach,
This is, of course, bullshit, at least in my experience.
My HDTV picks up both analog and digital transmissions with the same set of cheap rabbit ears perched on top. The digital signals are far superior, some of the analog channels are unwatchable (unless you enjoy watching triple ghosts with heavy overlay of snow, and sound that sounds like frying bacon).
I picked up a couple of cheap converter boxes for the analog TV and VCRs. When I went to test them out, not wanting to mess with my existing antenna setup, I just attached a little 2" stub antenna with a coax fitting directly to the box. While it certainly didn't pick up as many channels as the rabbit ears, it picked up all the main network digital channels without a problem. (By way of comparison, the same antenna connected to the analog TV directly didn't pick up squat.)
Signal reach is highly dependent of course on transmitter strength, and in the middle of the city you should be (on average) closer to the transmitters than out in the middle of the boonies. Because a digital signal can reject the kind of echoing you're going to get with signal reflections off of buildings in a city, you're going to get a better picture with digital.
(And actually the digital signal doesn't "just break"; at the fringe you'll get periods of good stable image with the occasional blocking or mosaic if something temporarily interferes with the signal. Beyond that, yeah, it's just off -- but there's no "graceful" to the way an analog signal would have degraded by that point.)
Nope, shipping it back in time just means waiting around for hard disks to be developed to be able to read it. You need to ship it forward in time far enough that nobody will care about the data.
Mind, so many people have been doing this that Milliways (The Restaurant at the End of the Universe) is starting to complain about the disposal problem.