I've been running IPCop on a crappy old 486, with 3-6 computers downstream of it, running various linux (RH6.0 -> Ubuntu 7.1) and Windows (95->XP), and while I can't say I've never had a problem, I've never been able to find a problem, nor have any of the AV programs running on the windows machines.
It's been running great for 4 years, and it's been incredibly easy to install and update. That's one solid piece of work they've done.
You can buy or build a cantenna. They're illegal. But with a bit of work and patience, they function well. I dunno if a simple can-based setup can handle half a kilometer (and if it can, it's going to need a good solid connection to the house to keep it aligned) but I do know that a cantenna operated at the focal point of a used satellite dish will work fine up into the several kilometer range. They're really cheap to build. You generally need to find reverse-polarity RF connectors to hook to the card in the computer. Digikey.com, newark.com, and mouser.com all sell reverse-polarity rf connectors. Traditionally people put n-type rf connectors on the antenna but that's a pain: I built mine using a bnc bulkhead connector on the can, and a rp-sma-to-bnc converter connector on my wireless adapter card, and just ran bnc cable from one to the other.
Mine only runs 40 meters through a couple of walls. Hopefully other people will correct this if it's the wrong solution for 500 meters.
>I'd like to see the interface get to a point where you can actually jump in and do something with it.
Like MS Paint? which can't do anything *but* jump in and work with it a little?
If you want to get across the street you walk. If you want to get across the ocean in under two hours you fly a jet plane -- which takes a whole lot more skill to pilot than just walking across the street.
It would be very nice if an incredibly powerful program could have an intuitively obvious interface, but I don't think that's the interface designers' problem: I think that's a problem that humans aren't mentally capable of this. You set a person who hasn't ever seen a computer down in front of *any* program and you'll get a whole lot of nothing. Every program takes learning, and programs that are conceptually challenging take a lot more learning. It's an intrinsic part of how people learn.
Yep. 50 years of engineering on diesel/electric locomotives. The other big plus is that a diesel engine can burn just about anything, even hydrogen, and a fuel cell could be integrated in beside the diesel so you could run on one or both if you had specific needs.
>If we had a "clean coal" steamer service, we'd be way ahead of the curve...
A hydrogen-powered locomotive would have a number of advantages over hydrogen-powered cars: it's pulling tens of thousands of tons already and won't mind the weight of thick-wall stainless steel tubing that doesn't leak or embrittle badly, and one big fuel depot can handle the cryogenic storage requirements, with a small number of people who have had training in doing cryo fuel transfers, rather than having to build thousands of hydrogen storage tanks at gas stations and make something that's sufficiently idiot-proof that the morons who think it's a good idea to drive down the highway while talking on the phone and trimming their nose hairs don't explode themselves.
(that isn't the longest sentence I've ever written, but it's probably the longest I've written on slashdot...)
BTW, I'm not saying that a hydrogen economy is a good idea. I am saying that if we were to try it, locomotives would be a better beneficiary than automobiles.
I'm in a similar situation to the poster: I have an old Latitude LM with 24MB of memory. I've looked at puppylinux a bit, but what I want is a system that doesn't have any graphical interface -- just a console/shell. I could hack inittab to have it come up in runlevel 3, but what I'd rather do is find a distro that will let me install what I want, meaning no windows managers or support stuff to save space. (I'm going to use it and several other old laptops for remote data acquisition.) Which is a long way of asking: does your experience with puppylinux indicate that it'd be easy to get a console-only install on a machine that can only boot from floppy or hard drive? (I can make a boot floppy that installs CDROM drivers, install that, and then swap in the CDROM and get the rest of the stuff from it, and I suppose I'll have to do that, but I really don't know the ins and outs of that, either.)
Statements that include stuff like "it's absolutely, positively, completely, irrevocably, unarguably impossible" push my buttons, I admit, and then I go looking for technicalities.
However, and I don't know that this is the case for China and, say, online sexual predator registries/databases -- in many heavily controlled contries there is official denial that many antisocial or embarrassing movements happen. Iran's President is famous for having claimed that there are no homosexuals in Iran, and throughout the '80's the USSR claimed that no Soviet citizens had AIDS. It's quite possible that there aren't any online sexual predator databases in China -- or if there are, private citizens can't access them, because it would cast the country in a poor light. It's fairly easy to set up a crime report mashup using Google to show where high-crime neighborhoods exist in the US: does anything even vaguely like that happen in China? That's censorship of information, and you could argue that that's harming individuals. You could also argue that the mere existence of sexual predator databases harms individuals, of course, especially people who find themselves on the list by mistake or because of eg being caught peeing in public. Censorship can have unexpected results. (and in this specific example, if the regime decides that sex crimes don't exist, there won't be any way for me to make your life miserable by falsely ratting you out to your neighbors, so censorship WOULD help you -- although that wouldn't stop me telling the police. We just hope they won't take some malicious yahoo's word for it, where neighbors almost certainly would.)
So... if I use my computer to hack your savings account and take all your money, and upload a bunch of illegal files to your computer, and then use VoIP to call the police on you, and for good measure get you listed on a bunch of sexual offender databases that your neighbors can see, your rights haven't been infringed upon?
>There is no majority large enough that stripping even one person of their rights against their will is justified.
I agree with the intent of your statement. But as the old sayings goes: your rights stop where my nose begins. You have a right to eat meat, even though I'm a vegetarian. You don't have the right to eat my kids. The point being: we have rights and one of those rights is to not have other people imposing what they want when it harms us.
As such, some human rights are necessarily infringed. In fact, I think that's 90% of the point of what government should be doing: it referees the conflicts that arise when individuals have disagreements about what their rights let them do. So, if a government is responsive to the people it represents (which, of course, they rarely are) then it is *required* to strip some people of their rights if that's what its people require. A well-formed government will be constrained in how and when it can do that, so the tyranny of the majority is blunted, but even so, that's still what governments do.
In the US, the whole point of the Constitution is telling the government exactly what rights of the people it is allowed to infringe upon, and why. It was designed specifically to allow us as much freedom as possible while still maintaining a civilized set of rules for interaction. But *some* limits on individual rights are always necessary because people are selfish.
Watson is overcredited, in part because of sexism and in part because he and Crick made very sure they were credited while others (Franklin, Wilkins) were painted as just assistants. However, Watson and Crick did figure out some vital stuff. Before they came along, DNA was considered some strange stuff that only had four constituents, so it was considered highly unlikely that it did anything useful. Rosalind Franklin showed that it had a helical structure, and Watson and Crick synthesized that knowledge, along with Pauling's incorrect suggestions that information was encoded in helical structures of collagen. Crick came to the fundamentally important conclusion that the x-ray crystallography indicated an antiparallel double helix, and everything else depended on that realization. (Many good summaries exist. this one is pretty good. But Watson did have a central influence on the discovery of what DNA did, as did, to a lesser extent, Franklin, Wilkins, Gosling, and Pauling, any of whom could've figured it out if they'd gotten to work with each other, as Crick and Watson did.
I've always been curious about this. If you must have a compressor, why not have a big, divergent duct, that slows the air down to subsonic speeds before it hits the compressor? Does the shockwave in the intake make the airflow too turbulent for the compressor blades to handle? Is there a huge drag? But if you can go that fast, why bother with a compressor, aside from using it to accelerate for takeoff? Just use a ramjet, no moving parts, who cares how fast it goes (as long as you can still get the fuel mixed into the air before it's out the back.)
I agree with your claim that there's lots and lots of room left in the US. Part of the reason for that is: those places mostly suck. I've lived in Wyoming, and New Mexico. There are parts of Wyoming -- large areas, as it happens -- where they get roughly 20 cm of precipitation a year, all of it snow. They get actual rainstorms with actual measurable accumulation, during the part of the year when crops can grow, maybe once every two or three years. Their aquifers have maybe 40 years' worth of water if you drill and start pumping them for irrigation. When you get done with that, you're back to dryland farming, and you can't get Kansas crop yield on wheat that never gets rain.
Likewise New Mexico is great if you want to grow squash and pumpkins and other things that can handle blisteringly hot temperatures, as long as you have lots of water to feed them. Not so hot when all your water rights have been stolen by Southern California to fill their swimming pools.
There are enormous areas of unused land -- Nevada is 70% Federal land, that's uninhabited, but that's because it's desert and nothing grows there. The Colorado and the Rio Grande have had 100% of their flow purchased and allocated since the 1930's, and it's not like we're adding new water to them. Kansas, Wyoming, and Oklahoma are already sucking huge holes in their aquifers and seeing actual ground subsidence because the empty aquifers are crushing under the overburden. Unless you're planning a Cadillac Desert scenario where you reroute the Columbia down to water California so the mountain rivers can water Wyoming and New Mexico you're not going to get much out of them. As far as I can tell, that's generally the case everywhere: people live where it's reasonable to live, and the places people aren't living aren't going to sustain that many people unless you're proposing moving San Francisco to Nevada. Now that might work: reclaim the good, fertile lands for farming and have people live in the hellholes. I think there are other problems to contend with before you can do that.
A lot of people don't understand the second law of thermodynamics. (It's nice that some people do...) I think that if we could find some way of representing it graphically, that's what we should be sending out on interstellar probes, because I think that's one of the unambiguous things that any race capable of any sort of reason would understand as a sign there are other reasoning species out there.
So I shouldn't argue with you since we're on the same page -- and there's a whole side-issue here that people over on the evolution/creation debate boards are discussing: should scientists have open debates about details, and strive to present everything as openly as possible or should they present a united front of "this is the Truth"? because people who don't really understand the second law of thermodynamics aren't going to get what I'm on about, they're just going to see that I appear to be arguing that it's viable to try electrolysis and then burn the H2 and O2 formed and get power. Sigh. But anyway: I was thinking about iron. We know lots of asteroids are iron-core -- and, more to the point, apparently mostly metallic iron. Iron's more electronegative than hydrogen. So, *if* you got yourself an asteroid that has a big ol' metallic iron core and a lot of frozen water on the surface, you could potentially build yourself something like one of those handwarmers that relies on oxidation of iron -- H2O + Fe0 going to Fe2O3 + H2 -- and hey, you've actually got an energy source. I've never read anything about this, and now I'm curious if that's ever been suggested. It's not much power, and it's likely that solar cells would be much more productive -- but it'd last indefinitely, given the size of the asteroid they're talking about.
You're generally right, and I'm being pedantic, I admit. But -- and I'm positing something wildly unlikely, I admit again -- what if it turns out the asteroid's half elemental sodium? You mix sodium and water, you're gonna get lots and lots of energy out (as well as molecular hydrogen.) Very unlikely to happen, but hey, it's outer space. We don't know what asteroids are made of. We *know* that on earth water is a final reaction product of hydrogen, as sand is of silicon and rust or laterite is of iron. But in an oxygen-poor environment, if such a thing exists, maybe there will be reactive species that are more electronegative than hydrogen. Actually, now that I think of it, on an asteroid, with insufficient gravity to retain gaseous oxygen, there's a driving force towards reduction, that opposes the thermodynamic stability of oxides. If you have a reaction A+B = C+D, and your C+D is incredibly stable (like water) but you have something removing A (in this case oxygen) you'll drive the reaction to the left, to large amounts of B, even if it otherwise would be driven thermodynamically strongly to the right. So I guess it's *possible* that you might find an asteroid chock-full of highly reactive, unoxidized species. And, now that I think of it, we've found lots of iron and nickel-rich meteorites, where the iron isn't particularly rusted, particularly when it's cut apart and the insides, which weren't eaten by the Earth's atmosphere on reentry, are exposed.
Again: I admit I'm being pedantic, and there are lots of goofballs who just don't understand that you can't crack water for free and use the result to power some whizbang machinery, and that's what you're talking about. But there *are* circumstances where water might be useful as fuel, and it's (very very) remotely possible that we might find such a circumstance on an asteroid.
Well, to be fair, you can't *ever* create energy, right? All you can do is use naturally occurring resources to extract some energy by converting some resource to a lower-energy state by increasing entropy. Which is to say: if you could find a reaction that resulted in products more thermodynamically stable than water, and you had a large excess of the starting materials, you could extract energy from water. It's just that after 15 billion years, a lot of that has already happened and that's why we have a lot of water. But it's not impossible. There are plenty of things that'll burn water and release energy that you can then extract.
There exist some anticollision devices for light powered aircraft that are similar -- well, essentially, so's aircraft-carried radar, right? but these are sensitive radio receivers that tell you when someone's transmitting on aviation bands within a short distance (making some assumptions about transmitter power) and set off an alarm with a direction to help you with see-and-avoid. I think it's a great idea. The only rational way, in MY opinion, of doing anticollision handling is to do it much like the Internet: give everyone up there an identification number and a transponder and set up a network so that they're all talking to each other. Trickier in your situation, where you're essentially ground-hugging a short ways up on thermals, because radio reception can be very inconsistent, but it'd beat what we have now. More to the point, it could very effectively augment what we have now and the ADSB system as well. It'd suck to start requiring sophisticated electronics on every plane (especially for the homebuilt/no electrical system crowd) but we're already halfway there.
You're right: it IS because the flying population is low. One part of that, though, is that you can fly just about anywhere: higher, lower, off to one side or the other. There aren't highways, so the traffic density is inherently vanishingly low: lots, and lots, and lots of space in the sky. But at the same time, when you look at where the traffic density is high, at airports, that's where the majority of accidents happen, and if there were more people flying, that number would rise disproportionately, like pilots^1.3 or something.
The thing I often think about when driving on a big fast multilane highway is that it's like flying in *very* close formation with idiots playing with their radios and cellphones, while a bunch of other idiots are flying in very close formation practically head-on at me. That's really scary.
As Bruce Schneier often says: we underestimate the dangers of things we know well, and overestimate the dangers of things we don't know. Since I know flying, I'm probably underestimating the danger of airplanes, but *everyone* underestimates the danger of driving.
>The skills needed to fly are a lot higher than those to drive.
As a regular driver and a semi-regular pilot, I'm not sure I agree with that. Driving takes continuous alertness and work because you're surrounded by dangerous stuff, much of it being driven in the opposite direction only a meter or so away by crazy idiots talking on cellphones. In a plane, somewhere between 70 and 95% of the time, you have nothing more than air molecules in all directions for better than 2 km. I know pilots who have set alarm clocks, gotten the plane in stable flight with their 3 axis autopilot, and then gone to sleep for an hour while the plane tooled through the sky: a damned bad idea, but perfectly viable in a plane. Aircraft demand some skill in handling the plane in takeoff, and rather a lot in landing, and *enormous* amounts when there's an emergency and you have to do a bunch of intelligent things in the right order to survive. But overall, as regards routine flying, I don't think they require anywhere near as much consistent skill as driving.
>>I'm going to get bashed by Apple fanatics, but if people were buying based on features, they wouldn't be buying iPods. The iPod is nice, but feature-wise there are better players.
>Such as?
I agree with what you're saying but I feel impelled to respond. My company gave me a 5G video ipod and I gave it to my girlfriend because I have my own mp3 player (homebuilt, enormous, ugly, primitive) that does what I want. She spent about a year trying to get her videos on it, rather than stuff she bought off itunes, complaining that it didn't have a radio tuner, fighting with itunes to get her music off her CD's onto the player, fighting with it sometimes locking up, and went and bought a Creative Zen M, which interfaces beautifully with our linux systems, easily accepts video stuff she's found, has a tuner, blah blah. And all our friends, who have ipods, say "I'm looking to get a new mp3 player" and she says "look at my Zen! it has ALL THESE GREAT FEATURES!" and they look and say "hey, that's really cool!" and then they go buy another ipod.
One of the features of the ipod that isn't listed on the box, along with the form factor and user interface, is that it's what everyone else buys. I'm reminded of Neal Stephenson's vision of the operating system stores in "in the beginning was the command line" where the linux people are standing along the street with megaphones advertising free tanks and the people are flocking to buy the Windows sometimes-exploding buggies because that's where everyone else shops.
Value is perception, and the ipod has enormous value.
Are you sure about that? I'm not. CO2 + H2O -> H2CO3, aka carbonic acid. It's not particularly toxic -- we drink tons of it in carbonated drinks -- but it's not neutral, it does eat rock (*particularly* the rock that makes up most caves, because that's how the caves were formed in the first place) and pumping thousand or millions of tons of it into groundwater might have some effects we haven't thought about. There's a carbonated spring near where I grew up: the water comes out of carbonate-rich rocks and is bubbling and fizzing. Not much grows in or around the water in that spring, for quite a ways downstream. Maybe there's arsenic in there and that's what's killing everything: I don't know. My point is that CO2 can have some chemical activity and I don't know what research has been done on the effects of putting a hundred thousand tons of CO2 into groundwater and leaving it indefinitely.
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I've been running IPCop on a crappy old 486, with 3-6 computers downstream of it, running various linux (RH6.0 -> Ubuntu 7.1) and Windows (95->XP), and while I can't say I've never had a problem, I've never been able to find a problem, nor have any of the AV programs running on the windows machines.
It's been running great for 4 years, and it's been incredibly easy to install and update. That's one solid piece of work they've done.
1. I build flamethrowers for fun: I see your toothbrush and raise you 2000 degrees.
2. It was my understanding that modifying the antenna on an FCC-licensed device was illegal. I may be wrong.
You can buy or build a cantenna. They're illegal. But with a bit of work and patience, they function well. I dunno if a simple can-based setup can handle half a kilometer (and if it can, it's going to need a good solid connection to the house to keep it aligned) but I do know that a cantenna operated at the focal point of a used satellite dish will work fine up into the several kilometer range.
They're really cheap to build. You generally need to find reverse-polarity RF connectors to hook to the card in the computer. Digikey.com, newark.com, and mouser.com all sell reverse-polarity rf connectors. Traditionally people put n-type rf connectors on the antenna but that's a pain: I built mine using a bnc bulkhead connector on the can, and a rp-sma-to-bnc converter connector on my wireless adapter card, and just ran bnc cable from one to the other.
Mine only runs 40 meters through a couple of walls. Hopefully other people will correct this if it's the wrong solution for 500 meters.
You could call it Rot180 and get your own patent, and they'd be legally prevented from decrypting it to see if it infringed upon their patent.
>I'd like to see the interface get to a point where you can actually jump in and do something with it.
Like MS Paint? which can't do anything *but* jump in and work with it a little?
If you want to get across the street you walk. If you want to get across the ocean in under two hours you fly a jet plane -- which takes a whole lot more skill to pilot than just walking across the street.
It would be very nice if an incredibly powerful program could have an intuitively obvious interface, but I don't think that's the interface designers' problem: I think that's a problem that humans aren't mentally capable of this. You set a person who hasn't ever seen a computer down in front of *any* program and you'll get a whole lot of nothing. Every program takes learning, and programs that are conceptually challenging take a lot more learning. It's an intrinsic part of how people learn.
That looks really good. Thank you.
Yep. 50 years of engineering on diesel/electric locomotives. The other big plus is that a diesel engine can burn just about anything, even hydrogen, and a fuel cell could be integrated in beside the diesel so you could run on one or both if you had specific needs.
I would *love* a service like that.
>If we had a "clean coal" steamer service, we'd be way ahead of the curve...
A hydrogen-powered locomotive would have a number of advantages over hydrogen-powered cars: it's pulling tens of thousands of tons already and won't mind the weight of thick-wall stainless steel tubing that doesn't leak or embrittle badly, and one big fuel depot can handle the cryogenic storage requirements, with a small number of people who have had training in doing cryo fuel transfers, rather than having to build thousands of hydrogen storage tanks at gas stations and make something that's sufficiently idiot-proof that the morons who think it's a good idea to drive down the highway while talking on the phone and trimming their nose hairs don't explode themselves.
(that isn't the longest sentence I've ever written, but it's probably the longest I've written on slashdot...)
BTW, I'm not saying that a hydrogen economy is a good idea. I am saying that if we were to try it, locomotives would be a better beneficiary than automobiles.
I'm in a similar situation to the poster: I have an old Latitude LM with 24MB of memory. I've looked at puppylinux a bit, but what I want is a system that doesn't have any graphical interface -- just a console/shell. I could hack inittab to have it come up in runlevel 3, but what I'd rather do is find a distro that will let me install what I want, meaning no windows managers or support stuff to save space. (I'm going to use it and several other old laptops for remote data acquisition.) Which is a long way of asking: does your experience with puppylinux indicate that it'd be easy to get a console-only install on a machine that can only boot from floppy or hard drive? (I can make a boot floppy that installs CDROM drivers, install that, and then swap in the CDROM and get the rest of the stuff from it, and I suppose I'll have to do that, but I really don't know the ins and outs of that, either.)
Statements that include stuff like "it's absolutely, positively, completely, irrevocably, unarguably impossible" push my buttons, I admit, and then I go looking for technicalities.
However, and I don't know that this is the case for China and, say, online sexual predator registries/databases -- in many heavily controlled contries there is official denial that many antisocial or embarrassing movements happen. Iran's President is famous for having claimed that there are no homosexuals in Iran, and throughout the '80's the USSR claimed that no Soviet citizens had AIDS. It's quite possible that there aren't any online sexual predator databases in China -- or if there are, private citizens can't access them, because it would cast the country in a poor light. It's fairly easy to set up a crime report mashup using Google to show where high-crime neighborhoods exist in the US: does anything even vaguely like that happen in China? That's censorship of information, and you could argue that that's harming individuals. You could also argue that the mere existence of sexual predator databases harms individuals, of course, especially people who find themselves on the list by mistake or because of eg being caught peeing in public. Censorship can have unexpected results. (and in this specific example, if the regime decides that sex crimes don't exist, there won't be any way for me to make your life miserable by falsely ratting you out to your neighbors, so censorship WOULD help you -- although that wouldn't stop me telling the police. We just hope they won't take some malicious yahoo's word for it, where neighbors almost certainly would.)
So... if I use my computer to hack your savings account and take all your money, and upload a bunch of illegal files to your computer, and then use VoIP to call the police on you, and for good measure get you listed on a bunch of sexual offender databases that your neighbors can see, your rights haven't been infringed upon?
>There is no majority large enough that stripping even one person of their rights against their will is justified.
I agree with the intent of your statement.
But as the old sayings goes: your rights stop where my nose begins.
You have a right to eat meat, even though I'm a vegetarian. You don't have the right to eat my kids. The point being: we have rights and one of those rights is to not have other people imposing what they want when it harms us.
As such, some human rights are necessarily infringed. In fact, I think that's 90% of the point of what government should be doing: it referees the conflicts that arise when individuals have disagreements about what their rights let them do. So, if a government is responsive to the people it represents (which, of course, they rarely are) then it is *required* to strip some people of their rights if that's what its people require. A well-formed government will be constrained in how and when it can do that, so the tyranny of the majority is blunted, but even so, that's still what governments do.
In the US, the whole point of the Constitution is telling the government exactly what rights of the people it is allowed to infringe upon, and why. It was designed specifically to allow us as much freedom as possible while still maintaining a civilized set of rules for interaction. But *some* limits on individual rights are always necessary because people are selfish.
Watson is overcredited, in part because of sexism and in part because he and Crick made very sure they were credited while others (Franklin, Wilkins) were painted as just assistants.
However, Watson and Crick did figure out some vital stuff. Before they came along, DNA was considered some strange stuff that only had four constituents, so it was considered highly unlikely that it did anything useful. Rosalind Franklin showed that it had a helical structure, and Watson and Crick synthesized that knowledge, along with Pauling's incorrect suggestions that information was encoded in helical structures of collagen.
Crick came to the fundamentally important conclusion that the x-ray crystallography indicated an antiparallel double helix, and everything else depended on that realization.
(Many good summaries exist. this one is pretty good.
But Watson did have a central influence on the discovery of what DNA did, as did, to a lesser extent, Franklin, Wilkins, Gosling, and Pauling, any of whom could've figured it out if they'd gotten to work with each other, as Crick and Watson did.
That answered a *lot* of my questions, actually. Thanks.
I've always been curious about this.
If you must have a compressor, why not have a big, divergent duct, that slows the air down to subsonic speeds before it hits the compressor? Does the shockwave in the intake make the airflow too turbulent for the compressor blades to handle? Is there a huge drag?
But if you can go that fast, why bother with a compressor, aside from using it to accelerate for takeoff? Just use a ramjet, no moving parts, who cares how fast it goes (as long as you can still get the fuel mixed into the air before it's out the back.)
I agree with your claim that there's lots and lots of room left in the US. Part of the reason for that is: those places mostly suck. I've lived in Wyoming, and New Mexico.
There are parts of Wyoming -- large areas, as it happens -- where they get roughly 20 cm of precipitation a year, all of it snow. They get actual rainstorms with actual measurable accumulation, during the part of the year when crops can grow, maybe once every two or three years. Their aquifers have maybe 40 years' worth of water if you drill and start pumping them for irrigation. When you get done with that, you're back to dryland farming, and you can't get Kansas crop yield on wheat that never gets rain.
Likewise New Mexico is great if you want to grow squash and pumpkins and other things that can handle blisteringly hot temperatures, as long as you have lots of water to feed them. Not so hot when all your water rights have been stolen by Southern California to fill their swimming pools.
There are enormous areas of unused land -- Nevada is 70% Federal land, that's uninhabited, but that's because it's desert and nothing grows there. The Colorado and the Rio Grande have had 100% of their flow purchased and allocated since the 1930's, and it's not like we're adding new water to them. Kansas, Wyoming, and Oklahoma are already sucking huge holes in their aquifers and seeing actual ground subsidence because the empty aquifers are crushing under the overburden. Unless you're planning a Cadillac Desert scenario where you reroute the Columbia down to water California so the mountain rivers can water Wyoming and New Mexico you're not going to get much out of them.
As far as I can tell, that's generally the case everywhere: people live where it's reasonable to live, and the places people aren't living aren't going to sustain that many people unless you're proposing moving San Francisco to Nevada. Now that might work: reclaim the good, fertile lands for farming and have people live in the hellholes. I think there are other problems to contend with before you can do that.
A lot of people don't understand the second law of thermodynamics. (It's nice that some people do...) I think that if we could find some way of representing it graphically, that's what we should be sending out on interstellar probes, because I think that's one of the unambiguous things that any race capable of any sort of reason would understand as a sign there are other reasoning species out there.
So I shouldn't argue with you since we're on the same page -- and there's a whole side-issue here that people over on the evolution/creation debate boards are discussing: should scientists have open debates about details, and strive to present everything as openly as possible or should they present a united front of "this is the Truth"? because people who don't really understand the second law of thermodynamics aren't going to get what I'm on about, they're just going to see that I appear to be arguing that it's viable to try electrolysis and then burn the H2 and O2 formed and get power.
Sigh.
But anyway: I was thinking about iron. We know lots of asteroids are iron-core -- and, more to the point, apparently mostly metallic iron. Iron's more electronegative than hydrogen. So, *if* you got yourself an asteroid that has a big ol' metallic iron core and a lot of frozen water on the surface, you could potentially build yourself something like one of those handwarmers that relies on oxidation of iron -- H2O + Fe0 going to Fe2O3 + H2 -- and hey, you've actually got an energy source. I've never read anything about this, and now I'm curious if that's ever been suggested. It's not much power, and it's likely that solar cells would be much more productive -- but it'd last indefinitely, given the size of the asteroid they're talking about.
You're generally right, and I'm being pedantic, I admit. But -- and I'm positing something wildly unlikely, I admit again -- what if it turns out the asteroid's half elemental sodium? You mix sodium and water, you're gonna get lots and lots of energy out (as well as molecular hydrogen.) Very unlikely to happen, but hey, it's outer space. We don't know what asteroids are made of. We *know* that on earth water is a final reaction product of hydrogen, as sand is of silicon and rust or laterite is of iron. But in an oxygen-poor environment, if such a thing exists, maybe there will be reactive species that are more electronegative than hydrogen. Actually, now that I think of it, on an asteroid, with insufficient gravity to retain gaseous oxygen, there's a driving force towards reduction, that opposes the thermodynamic stability of oxides. If you have a reaction A+B = C+D, and your C+D is incredibly stable (like water) but you have something removing A (in this case oxygen) you'll drive the reaction to the left, to large amounts of B, even if it otherwise would be driven thermodynamically strongly to the right. So I guess it's *possible* that you might find an asteroid chock-full of highly reactive, unoxidized species. And, now that I think of it, we've found lots of iron and nickel-rich meteorites, where the iron isn't particularly rusted, particularly when it's cut apart and the insides, which weren't eaten by the Earth's atmosphere on reentry, are exposed.
Again: I admit I'm being pedantic, and there are lots of goofballs who just don't understand that you can't crack water for free and use the result to power some whizbang machinery, and that's what you're talking about. But there *are* circumstances where water might be useful as fuel, and it's (very very) remotely possible that we might find such a circumstance on an asteroid.
Well, to be fair, you can't *ever* create energy, right? All you can do is use naturally occurring resources to extract some energy by converting some resource to a lower-energy state by increasing entropy. Which is to say: if you could find a reaction that resulted in products more thermodynamically stable than water, and you had a large excess of the starting materials, you could extract energy from water.
It's just that after 15 billion years, a lot of that has already happened and that's why we have a lot of water. But it's not impossible. There are plenty of things that'll burn water and release energy that you can then extract.
There exist some anticollision devices for light powered aircraft that are similar -- well, essentially, so's aircraft-carried radar, right? but these are sensitive radio receivers that tell you when someone's transmitting on aviation bands within a short distance (making some assumptions about transmitter power) and set off an alarm with a direction to help you with see-and-avoid. I think it's a great idea. The only rational way, in MY opinion, of doing anticollision handling is to do it much like the Internet: give everyone up there an identification number and a transponder and set up a network so that they're all talking to each other. Trickier in your situation, where you're essentially ground-hugging a short ways up on thermals, because radio reception can be very inconsistent, but it'd beat what we have now. More to the point, it could very effectively augment what we have now and the ADSB system as well. It'd suck to start requiring sophisticated electronics on every plane (especially for the homebuilt/no electrical system crowd) but we're already halfway there.
You're right: it IS because the flying population is low. One part of that, though, is that you can fly just about anywhere: higher, lower, off to one side or the other. There aren't highways, so the traffic density is inherently vanishingly low: lots, and lots, and lots of space in the sky.
But at the same time, when you look at where the traffic density is high, at airports, that's where the majority of accidents happen, and if there were more people flying, that number would rise disproportionately, like pilots^1.3 or something.
The thing I often think about when driving on a big fast multilane highway is that it's like flying in *very* close formation with idiots playing with their radios and cellphones, while a bunch of other idiots are flying in very close formation practically head-on at me. That's really scary.
As Bruce Schneier often says: we underestimate the dangers of things we know well, and overestimate the dangers of things we don't know. Since I know flying, I'm probably underestimating the danger of airplanes, but *everyone* underestimates the danger of driving.
>The skills needed to fly are a lot higher than those to drive.
As a regular driver and a semi-regular pilot, I'm not sure I agree with that. Driving takes continuous alertness and work because you're surrounded by dangerous stuff, much of it being driven in the opposite direction only a meter or so away by crazy idiots talking on cellphones. In a plane, somewhere between 70 and 95% of the time, you have nothing more than air molecules in all directions for better than 2 km. I know pilots who have set alarm clocks, gotten the plane in stable flight with their 3 axis autopilot, and then gone to sleep for an hour while the plane tooled through the sky: a damned bad idea, but perfectly viable in a plane.
Aircraft demand some skill in handling the plane in takeoff, and rather a lot in landing, and *enormous* amounts when there's an emergency and you have to do a bunch of intelligent things in the right order to survive. But overall, as regards routine flying, I don't think they require anywhere near as much consistent skill as driving.
>>I'm going to get bashed by Apple fanatics, but if people were buying based on features, they wouldn't be buying iPods. The iPod is nice, but feature-wise there are better players.
>Such as?
I agree with what you're saying but I feel impelled to respond. My company gave me a 5G video ipod and I gave it to my girlfriend because I have my own mp3 player (homebuilt, enormous, ugly, primitive) that does what I want. She spent about a year trying to get her videos on it, rather than stuff she bought off itunes, complaining that it didn't have a radio tuner, fighting with itunes to get her music off her CD's onto the player, fighting with it sometimes locking up, and went and bought a Creative Zen M, which interfaces beautifully with our linux systems, easily accepts video stuff she's found, has a tuner, blah blah. And all our friends, who have ipods, say "I'm looking to get a new mp3 player" and she says "look at my Zen! it has ALL THESE GREAT FEATURES!" and they look and say "hey, that's really cool!" and then they go buy another ipod.
One of the features of the ipod that isn't listed on the box, along with the form factor and user interface, is that it's what everyone else buys. I'm reminded of Neal Stephenson's vision of the operating system stores in "in the beginning was the command line" where the linux people are standing along the street with megaphones advertising free tanks and the people are flocking to buy the Windows sometimes-exploding buggies because that's where everyone else shops.
Value is perception, and the ipod has enormous value.
>CO2 doesn't contaminate groundwater.
Are you sure about that?
I'm not. CO2 + H2O -> H2CO3, aka carbonic acid. It's not particularly toxic -- we drink tons of it in carbonated drinks -- but it's not neutral, it does eat rock (*particularly* the rock that makes up most caves, because that's how the caves were formed in the first place) and pumping thousand or millions of tons of it into groundwater might have some effects we haven't thought about.
There's a carbonated spring near where I grew up: the water comes out of carbonate-rich rocks and is bubbling and fizzing. Not much grows in or around the water in that spring, for quite a ways downstream. Maybe there's arsenic in there and that's what's killing everything: I don't know. My point is that CO2 can have some chemical activity and I don't know what research has been done on the effects of putting a hundred thousand tons of CO2 into groundwater and leaving it indefinitely.