Aerogel is very light, but it's still about three times as heavy as air. Regardless of what gas you use to fill in the spaces, it won't float. In fact, even if you "filled" it with a vacuum, it still wouldn't float.
1. Xenon is pretty heavy per atom. Because of how the ideal gas law works, that means a given mass of Xenon takes less volume than lighter gases at equal pressure / temp.
2. As a noble gas, Xenon is mostly inert -- important for a long mission where you don't want, for example, vaporized mercury corroding parts in your ion drive.
3. The cost of Xenon is non-existant compared to overall mission cost ($500 million or more? No idea, but moon shots ain't cheap).
You'd think if you told most people that they could have a desktop that didn't crash every 5 minutes and set them up with 5 desktop icons of the stuff they use the most they'd be more than happy to use it. Nope!
The whole "crash every 5 minutes" thing is so pre-XP. In 2004, this is basically a straw man argument. Like it or not, Windows has left its reliability problems behind for desktop users.
My Linux fileserver / NAT box has never crashed. My cat turned off the power once, and I've shut it down to move apartments, but never a crash, per se. So what? When you're talking about desktop / home machines, that sort of reliability is not a value-add. Most home users shut their computer down every night.. I leave my XP box running for weeks at a time, but never get problems.
The problem is people are so stubborn. I think if you did the same for someone on Mac OSX very few would switch even though the GUI is far superior to Windows.
OS X's GUI is fine, but no better than Windows. Most people would say it's prettier than XP, but so what? People aren't going to buy new computers, and pay big bucks to re-buy their OS and applications, for a slightly prettier face.
Welcome to the world of the "good enough". People running home computers and office desktops don't need six-nine uptime, heck they don't even need individual user accounts. They're not "stubborn" for wanting to use the OS they've already learned. They're rational. They aren't going to burn 500 hours learning a new operating system, unless there's a compelling reward for doing so.
I mean look at all the things Windows doesn't have. It doesn't even come with a ram disk driver!! And the one MS lets you download it utter crap.
I think I speak for 99% of computer users when I say, "WTF is a RAM disk driver? GUI-less operation..? Scripting..? WTF is 'weak SSL support', some sort of training bra???"
The common conceit amongst slashdotters is that if people took the time to learn what these things were, suddenly they would want them. I doubt it. Most people want their computers for some pretty simple tasks like web, email, running a spreadsheet at work, etc. Windows does these tasks admirably.
ever try to get to a major airport by mass transit?
Yeah actually; I take the MBTA right to Boston Logan.
You're missing the whole point. Maglevs are dumb and wasteful, because regular express trains are good enough for medium-haul routes, and airplanes are better for long-haul. What's maglev's "value add", for costing three to five times as much? Turns a 50 minute trip into a 35 minute trip, if you live near a station? Big deal.
your comment about 80kmh vs 400kmh is so stupid and juvenile it's not even worth discussing.
Stupid and juvenile? Uh, nice arguments.. I guess the discussion's over. You're an ATP / CFI? That's nice, I'm a pilot too. I'm also an engineer, and if you don't think it's easier to destroy a train which has 25 times the kinetic energy to work with, well, "it is".
Look, it's not a question of how often the train leaves. If you happen to live right across the street from the central train station, then yes, it would certainly be convenient. But in fact, most people will have to commute to the train station, just like they commuted to the airport. And often, that commute will be the biggest obstacle to getting on the super-train or airplane.
Maglev, however, presents larger obstacles. Trains with wheels are at least able to share tracks with "normal" trains for a few miles, to get outside of the downtown area. Obviously with maglev, that's impossible. So maglev stations would serve very large metropolitan areas, and would probably have to be located some distance from the city center. Expect a sizable commute by subway or car just to get to your maglev train. It might be a bit faster to get on a train, but then again, planes go a lot faster once they get going. I don't see any plans for a plane that goes Mach 0.9.
As far as searching everyone for bombs, etc: Don't be obtuse. Blowing up a bomb on a train going 80 km/h will kill whoever's near the bomb, and maybe some more people. Do the same on a train moving 400 km/h, and you'll certainly kill everyone behind the bomb (which will assumedly be placed up front).
In fact, enroute security favors airplanes. An airplane at 33,000 feet is essentially immune from interference, even by shoulder-fired missiles. A maglev train going 400 km/h is extremely vulnerable to track sabotage. How do you plan to protect the thousands of miles of track in the middle of nowhere?
Why would train stations "suck" any less than airports, anyway?
We're not talking about the subway station on the corner. Maglevs would only be used for very long-haul routes, meaning you would be going to a central train station serving an entire metropolitan area. There would be a lot of people and luggage there, trying to get processed. And given the extreme speed, you would have to search everyone for bombs, weapons, etc. Sound familiar?
This called for a 40-million-ton spacecraft to be powered by the sequential release of ten million bombs.
Orion, they argued, was simple, capacious, and above all affordable.
I would love to see the more expensive option. Even paying "only" $1 million per nuclear bomb, that works out to $10,000,000,000,000.00 (ten trillion). 40-million-ton spacecraft not included, some assembly required.
Nope, I drive a Honda Civic. Despite all these kneejerk "American cars suck" responses, cars today are more reliable than cars of 20 years ago, regardless of where they're made.
Change your oil every 10000 miles? PLeeeeease don't sell a car to me.
Most drivers throw out ten or twenty quarts of perfectly good motor oil every year. The myth that changing your oil every 3,000 miles will make your car run longer is just that, a myth. Almost all modern cars have a 7,500 mile service schedule; the highest quality engines (e.g., my Honda) will go 10,000 miles.
Who talked you into the idea of replacing perfectly good motor oil after 3,000 miles? Oil change shops, service departments, and manufacturers of motor oil. Not exactly neutral third parties. Maybe you believed Phillip Morris when they said smoking was healthy?
As for me, I'll trust the automotive engineers who actually built the engine, and wrote the maintenance schedule.
maybe they want a vehicle.. that doesn't have all the electronics and sensors that 'just runs', and costs less to maintain and own in general.
This is bull. Cars to day are paragons of reliability compared to the stone-age contraptions from 20 years ago.
When was the last time you saw someone desperately tweaking their carbuerator to get their car started? Or pumping the gas, flooding the engine, and turning it over for an eternity trying to clear it? You turn the key and it goes.
Don't even get me started on old, mechanically controlled automatic transmissions. These collections of flywheels, springs, valves, gaskets, and hydraulic clutches are practically works of art.. The result? A lousy transmission which breaks all the time. My friend and I drove an '85 K-5 Blazer (4x4) to Mexico and went thru two automatic transmissions in one trip, I shit you not. The first replacement didn't work, and ended up partially shredding itself. To its credit, AAMCO replaced it free of charge.
Of course, electronic ignition and computerized fuel injection allow spark plugs to go 100,000 miles or more. Did I mention that modern emission standards would be impossible without them? My current car only needs its oil changed every 10,000 miles, for goodness sake.
Indeed. Casinos regard high rollers as one step removed from Mohammed. These are people who stop by a few times a year and drop off $250,000. You think the casino's going to piss them off? There are a dozen tier-one casinos on the LV strip alone.
That's fine, though. Sneak and peek searches are a lot of work; they'll only go to that much trouble for John Gotti and the like. If they really want to listen to someone, and can get a judge to sign off on it, well, have at it.
Widespread cryptography keeps law enforcement types in line, by making widespread eavesdropping impractical. If they really get a bug up their ass about a particular person, they will tap his house, or simply bribe the other party to let them listen in.
By moving to a hash like MD5, you can use a much larger "salt". This makes pre-encrypted dictionaries infeasible. Current crypt()-based scemes use a mere 12 bits of salt. A more advanced hash lets you use any length salt you'd like (though anything longer than the hash size is worthless).
Quick primer for those wondering what "salt" is. UNIX stores not only your encryped password, but also a 12-bit salt. The salt is essentially part of your password, which the OS stores in plaintext. Its sole function is to make pre-encrypted password databases difficult. The crypt function is not a true "hash", so UNIX cheats by permuting the encryption boxes using the salt. The effect is the same as adding the salt to a password before hashing it with MD5.
The scheme was developed for the express purpose of defeating attacks like this one. However, 12 bits ain't what it used to be. With only 4096 salts available, pre-encrypted dictionaries are now becoming feasible.
The Solution (TM) is to use a modern hash like MD5, and store a salt which is as long as the hash itself. In essence, this renders encrypted dictionaries worthless -- it's just as easy to brute-force a password from scratch.
When did Open Source simply become a way to avoid paying for Windows?
It didn't. But a lot of people want to use Linux to do productive work. Work which has nothing to do with kernel development, or writing your own drivers, or GNOME programming. You might consider that kind of stuff a "complete waste of time," but it's how your parents pay your college tuition.
A lot of hardware will never have drivers for anything other than Windows. Is it a "waste of time" to let people use this hardware on their Linux machines?
All excellent points, but I still think an air-shot would do more damage.
1. Advantages of submerged detonation are outweighed by the obvious requirement to detonate below sea level. Air shots are designed to maximize the size of the horizon, as seen from the point of detonation. Keep in mind that the firestorm is caused by heat which travels in a stright line.
2. Sure, the Baker test destoryed more ships. But ships are on water.. If a terrorist had one nuke, he'd want to take out a city, not ships.
3. The tsunami might not even be that high. Remember, much of the water will flash to steam.
1. Submarines managed to get stealthier than the oceans they were plying. That's pretty darn stealthy. Still, point taken, these things will be inherently stealthy, which is a lot cheaper.
2. I doubt a non-nuclear payload would do enough damage to be worth the trouble. You might sink one ship, if you could keep up with it (these gliders make less than 5 knots). Seems like a lot of work for something you could accomplish with a rubber raft and someone willing to die (see Yemen/USS Cole).
3. If you did have a nuke, I think I'd prefer it be set off underwater. Bad news for longshoremen, but taking it to the observation deck of the Sears Tower would be a lot worse.
4. One thing it might be handy for is getting a nuke into the US. Still, I think the most likely delivery method is FedEx and lots of gamma shielding. Gliding submarines? Seems needlessly complex.
5. But I bet drug-runners would like one of these.
Thanks, but it was a rhetorical question. "WTF is chaff" is the response of the entire U.S. electorate, upon hearing that some geek somewhere thinks a voting machine might be flawed. "Does chaff have something to do with hanging chads??"
Back to my original point: voting machines are a non-solution to a problem that never existed. The post I responded to seemed to think that requiring poll watchers to show up with networked notebook computers running god-knows-what software, would solve all these problems.
See Rivest's paper on chaffing and winnowing
How about an alternative: use a vote-counting system which doesn't actually require a PhD to understand. My cleaning lady doesn't understand information theory or steganography, but she would still like some assurance that her vote is being counted. A locked box with paper ballots works better, and no one needs it explained to them.
The point isn't that people will get the receipt and double-check it.
Actually, that is the point. If no one looked at what was on the paper ballots, they would be no more reliable than the electronic ballots. The basic problem with electronically recording votes is that people can't SEE their vote be recorded.
Being printed on paper and stored in a locked box is worthless if people never look at the paper and see what's printed there.
Refresh my memory: what was wrong with just giving people a piece of pasteboard, a sharpie pen, and some privacy? That's how I voted when I lived in California, and it seemed to work well enough. Feed the ballots through a vote-validator, and you will even eliminate spoiled ballots.
You want poll watchers to show up with laptops and sort "chaff" off a 100baseT network? WTF is chaff? What if someone's cheating? 99% of the electorate won't even understand how you know they're cheating.
A box which is shown to be empty when polling starts, into which ballots are placed -- that's easy to understand and almost impossible to tinker with.
These quantum-encrypted, fusion-powered voting machines are accomplishing what, exactly?
Slashdot Mirror
Aerogel is very light, but it's still about three times as heavy as air. Regardless of what gas you use to fill in the spaces, it won't float. In fact, even if you "filled" it with a vacuum, it still wouldn't float.
Plenty of people hate their job, but most of them keep doing it.
2. As a noble gas, Xenon is mostly inert -- important for a long mission where you don't want, for example, vaporized mercury corroding parts in your ion drive.
3. The cost of Xenon is non-existant compared to overall mission cost ($500 million or more? No idea, but moon shots ain't cheap).
Food
Water
Getting there
Getting back
Getting funded
etc...
Basically, the usual suspects.
My Linux fileserver / NAT box has never crashed. My cat turned off the power once, and I've shut it down to move apartments, but never a crash, per se. So what? When you're talking about desktop / home machines, that sort of reliability is not a value-add. Most home users shut their computer down every night.. I leave my XP box running for weeks at a time, but never get problems.
OS X's GUI is fine, but no better than Windows. Most people would say it's prettier than XP, but so what? People aren't going to buy new computers, and pay big bucks to re-buy their OS and applications, for a slightly prettier face.Welcome to the world of the "good enough". People running home computers and office desktops don't need six-nine uptime, heck they don't even need individual user accounts. They're not "stubborn" for wanting to use the OS they've already learned. They're rational. They aren't going to burn 500 hours learning a new operating system, unless there's a compelling reward for doing so.
I think I speak for 99% of computer users when I say, "WTF is a RAM disk driver? GUI-less operation..? Scripting..? WTF is 'weak SSL support', some sort of training bra???"The common conceit amongst slashdotters is that if people took the time to learn what these things were, suddenly they would want them. I doubt it. Most people want their computers for some pretty simple tasks like web, email, running a spreadsheet at work, etc. Windows does these tasks admirably.
You're missing the whole point. Maglevs are dumb and wasteful, because regular express trains are good enough for medium-haul routes, and airplanes are better for long-haul. What's maglev's "value add", for costing three to five times as much? Turns a 50 minute trip into a 35 minute trip, if you live near a station? Big deal.
Stupid and juvenile? Uh, nice arguments.. I guess the discussion's over. You're an ATP / CFI? That's nice, I'm a pilot too. I'm also an engineer, and if you don't think it's easier to destroy a train which has 25 times the kinetic energy to work with, well, "it is".Maglev, however, presents larger obstacles. Trains with wheels are at least able to share tracks with "normal" trains for a few miles, to get outside of the downtown area. Obviously with maglev, that's impossible. So maglev stations would serve very large metropolitan areas, and would probably have to be located some distance from the city center. Expect a sizable commute by subway or car just to get to your maglev train. It might be a bit faster to get on a train, but then again, planes go a lot faster once they get going. I don't see any plans for a plane that goes Mach 0.9.
As far as searching everyone for bombs, etc: Don't be obtuse. Blowing up a bomb on a train going 80 km/h will kill whoever's near the bomb, and maybe some more people. Do the same on a train moving 400 km/h, and you'll certainly kill everyone behind the bomb (which will assumedly be placed up front).
In fact, enroute security favors airplanes. An airplane at 33,000 feet is essentially immune from interference, even by shoulder-fired missiles. A maglev train going 400 km/h is extremely vulnerable to track sabotage. How do you plan to protect the thousands of miles of track in the middle of nowhere?
We're not talking about the subway station on the corner. Maglevs would only be used for very long-haul routes, meaning you would be going to a central train station serving an entire metropolitan area. There would be a lot of people and luggage there, trying to get processed. And given the extreme speed, you would have to search everyone for bombs, weapons, etc. Sound familiar?
Who talked you into the idea of replacing perfectly good motor oil after 3,000 miles? Oil change shops, service departments, and manufacturers of motor oil. Not exactly neutral third parties. Maybe you believed Phillip Morris when they said smoking was healthy?
As for me, I'll trust the automotive engineers who actually built the engine, and wrote the maintenance schedule.
When was the last time you saw someone desperately tweaking their carbuerator to get their car started? Or pumping the gas, flooding the engine, and turning it over for an eternity trying to clear it? You turn the key and it goes.
Don't even get me started on old, mechanically controlled automatic transmissions. These collections of flywheels, springs, valves, gaskets, and hydraulic clutches are practically works of art.. The result? A lousy transmission which breaks all the time. My friend and I drove an '85 K-5 Blazer (4x4) to Mexico and went thru two automatic transmissions in one trip, I shit you not. The first replacement didn't work, and ended up partially shredding itself. To its credit, AAMCO replaced it free of charge.
Of course, electronic ignition and computerized fuel injection allow spark plugs to go 100,000 miles or more. Did I mention that modern emission standards would be impossible without them? My current car only needs its oil changed every 10,000 miles, for goodness sake.
Indeed. Casinos regard high rollers as one step removed from Mohammed. These are people who stop by a few times a year and drop off $250,000. You think the casino's going to piss them off? There are a dozen tier-one casinos on the LV strip alone.
Widespread cryptography keeps law enforcement types in line, by making widespread eavesdropping impractical. If they really get a bug up their ass about a particular person, they will tap his house, or simply bribe the other party to let them listen in.
Where do I buy a DVD player that lets me skip the FBI warning and trailers? I would like to just play the movie I already paid for.
By moving to a hash like MD5, you can use a much larger "salt". This makes pre-encrypted dictionaries infeasible. Current crypt()-based scemes use a mere 12 bits of salt. A more advanced hash lets you use any length salt you'd like (though anything longer than the hash size is worthless).
Quick primer for those wondering what "salt" is. UNIX stores not only your encryped password, but also a 12-bit salt. The salt is essentially part of your password, which the OS stores in plaintext. Its sole function is to make pre-encrypted password databases difficult. The crypt function is not a true "hash", so UNIX cheats by permuting the encryption boxes using the salt. The effect is the same as adding the salt to a password before hashing it with MD5.
The scheme was developed for the express purpose of defeating attacks like this one. However, 12 bits ain't what it used to be. With only 4096 salts available, pre-encrypted dictionaries are now becoming feasible.
The Solution (TM) is to use a modern hash like MD5, and store a salt which is as long as the hash itself. In essence, this renders encrypted dictionaries worthless -- it's just as easy to brute-force a password from scratch.
A lot of hardware will never have drivers for anything other than Windows. Is it a "waste of time" to let people use this hardware on their Linux machines?
All excellent points, but I still think an air-shot would do more damage.
1. Advantages of submerged detonation are outweighed by the obvious requirement to detonate below sea level. Air shots are designed to maximize the size of the horizon, as seen from the point of detonation. Keep in mind that the firestorm is caused by heat which travels in a stright line.
2. Sure, the Baker test destoryed more ships. But ships are on water.. If a terrorist had one nuke, he'd want to take out a city, not ships.
3. The tsunami might not even be that high. Remember, much of the water will flash to steam.
1. Submarines managed to get stealthier than the oceans they were plying. That's pretty darn stealthy. Still, point taken, these things will be inherently stealthy, which is a lot cheaper.
2. I doubt a non-nuclear payload would do enough damage to be worth the trouble. You might sink one ship, if you could keep up with it (these gliders make less than 5 knots). Seems like a lot of work for something you could accomplish with a rubber raft and someone willing to die (see Yemen/USS Cole).
3. If you did have a nuke, I think I'd prefer it be set off underwater. Bad news for longshoremen, but taking it to the observation deck of the Sears Tower would be a lot worse.
4. One thing it might be handy for is getting a nuke into the US. Still, I think the most likely delivery method is FedEx and lots of gamma shielding. Gliding submarines? Seems needlessly complex.
5. But I bet drug-runners would like one of these.
Back to my original point: voting machines are a non-solution to a problem that never existed. The post I responded to seemed to think that requiring poll watchers to show up with networked notebook computers running god-knows-what software, would solve all these problems.
How about an alternative: use a vote-counting system which doesn't actually require a PhD to understand. My cleaning lady doesn't understand information theory or steganography, but she would still like some assurance that her vote is being counted. A locked box with paper ballots works better, and no one needs it explained to them.Being printed on paper and stored in a locked box is worthless if people never look at the paper and see what's printed there.
You want poll watchers to show up with laptops and sort "chaff" off a 100baseT network? WTF is chaff? What if someone's cheating? 99% of the electorate won't even understand how you know they're cheating.
A box which is shown to be empty when polling starts, into which ballots are placed -- that's easy to understand and almost impossible to tinker with.
These quantum-encrypted, fusion-powered voting machines are accomplishing what, exactly?
Woohoo! Score one for the good guys.
What's 2005, in AMD years?