In other words they are designed around high thrust to weight ratios, and fairly high G forces.
There have been a few other concepts for rockets, including variable thrust and SCRAM jets, (for the in atmosphere portion at least) that do not have the same requirements for thrust to weight, and can be less costly to operate.
High thrust is a requirement. Your acceleration upward is only (thrust - 1 gravity), so having thrust low drops your efficiency considerably.
Scramjets are useful because they take their oxidizer from the atmosphere, dropping fuel weight by a huge amount (if you can do most of your boosting with them). This makes lower thrust tolerable (but not desired).
Now, here's my thinking. The Shuttle was a severe compromise of an originally good system (Flight launch Horizontal TakeOff and Landing) but ended up with the return vehicle pointlessly (and expensively) attached to an SRB+LOX rocket system.
Um, no SRB+LOX, no orbit. To get the delta-v you need a fuel:cargo ratio on the order of 30-50:1. People have been trying and failing to build a single-stage craft like that for quite some time. Materials aren't there yet, and certainly weren't there when the shuttle was designed.
You're going to have to attach the orbiter to _something_, because it's not getting into orbit on its own.
What NASA ought to be doing is saving the pennies by retiring the shuttle - not neccesarily immediately, but soon and putting out to tender a contract for a brand-new cost-effective launch system.
We have one - disposable rockets. Much easier - and cheaper - to build, and no hugely expensive maintenance cycle after launch.
Reusable rockets will only be cost-effective when materials improve to the point where they're relatively easy and cheap to build. The bar for this is higher the larger you want your payload to be, so heavy lifting may _still_ be done with disposable rockets even when a cost-effective light orbital transport is built.
Not really, it depends on your problem. If you're working on a large dataset, but in a streaming manner, then memory bandwidth is the bottleneck. It's really only if you're randomly accessing the entire dataset that latency becomes the bottleneck.
The majority of the CPU-bound problems that I know about are not streaming problems.
Re:Who writes these articles? Or am I iggernint?
on
Non-Spherical Stars
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· Score: 1
Plasma is a collection of charged particles that have some of the properties of a gas, but is different in that it's a good conductor of electricity and can be affected by magnetic fields. It won't try to fill the space it's in, and you can't pour it.
Actually, it will try to fill the space it's in, just like any other gas. It can be impeded from doing so by magnetic fields (including fields generated by its own motion), but this is not a permanent state of affairs.
It's about time that AMD got some recognition for their work, and, more specifically, their R&D. 3DNow! was miles ahead of MMX, and the Athlon was vastly superior to the P3. The AthlonXP in turn beats the P4, Mhz for Mhz. The widespread opinion is that AMD processors are the poor-man's Intel. "Good, but not as good". Hopefully the new Opertron (it will be amazing if the Itanium does nearly as well in the 64-bit marked) and announcements like this will help redress the balance.
While I like AMD chips too (and use them almost exclusively), I'm afraid that most of the arguments you raise don't hold water.
3Dnow was wonderful compared to MMX, but it was a different beast - SIMD floating-point, where MMX was SIMD integer. MMX was a mistake - it let you do in software what good 2D graphics cards did in hardware, while SIMD FP was useful. AMD gets credit for being the first, and for doing something useful without having to add extra registers, but SSE in the P3 was at least as good. No clear win here. (Athlon vs. P3 gave marginally better performance to the Athlon, but not overwhelmingly; Athlon won because it was "just as good and a lot cheaper").
The Athlon was vastly superior to the P_2_, not the P_3_. This was due to the P2's lack of SIMD floating-point. The Athlon was designed as a P2-killer. It won against the P3 by delivering roughly equal performance for a lower price.
The Athlon XP/MP beats the P4 MHz-per-MHz because the P4 is designed to run at a much higher clock rate. At any given time, a state-of-the-art P4 runs with about a 30-50% higher clock than the Athlon. A _valid_ comparison is to compare the state of the art offerings from both companies, as what the real question is is "if I build the best machine I can, will an Intel or AMD based machine be faster?". The answer isn't *quite* clear-cut, but in most of the benchmarks I've seen the P4 wins for at least two thirds of the test cases. Close, but a slight advantage to Intel. Again, AMD wins on price, but without the "just as good or slightly better" angle, they don't have a market advantage.
The Itanium I was called the "Itanic" for a reason. At best, it was a technology testbed for a number of radically different architecture features. A mechanical calculator run by a hamster wheel could outperform it. The Itanium 2, designed by HP, is what the Opteron has to face in the server market. Opteron is good, but we won't know which outperforms which for a few months yet (when the Opteron matures, and the I2 gets a new design revision). In the consumer market, the Opteron must face improved versions of the P4. In practice, the deciding factor will likely be HyperTransport vs. Intel's memory bus, as enough benchmarks are memory bound to make a big difference. Again, we'll only know for sure in a few months.
nowadays I think that the last component of a PC which needs speeding up is the CPU. Many other components act as a brake on the real-world efficiency of systems; one particularly close to my heart is the cache size. Most computational problems which I come across are too large to fit in less than 2 Mb; therefore, on processors which have a much lower clock speed than x86 offerings, but a much larger cache, I get much better results.
If you're doing any serious scientific computation, your data set will be _far_ larger than your cache size no matter what you're using. For many problems you can tweak access patterns to work on chunks small enough to fit in the cache. How well this works depends on your compiler, your libraries, and availability of things like pre-fetch instructions.
In cases where you can't sub-block the problem to fit in cache, you're out of luck no matter what you do - the limit will be the latency (and to a lesser extent, bandwidth) of your memory subsystem.
In summary, I'd be hesitant to blame poor performance of your x86 machines on cache (compiler and math libraries would be my first guess).
Actually, it's surprising how quickly memory banwidth has improved. The new Canterwoord P4's have an incredible 6.4GB/sec of memory bandwidth. I'd say that memory bandwidth is keeping pace quite well with CPU speeds these days.
Latency, not bandwidth, is what limits you if you're working on a computation problem that doesn't fit in cache. This has improved a bit, but not nearly as quickly as CPU speed has increased.
Previous events, hosted in peoples' houses, were one thing. You're now trying to host one in a space you have to pay for. You're going to have costs for the space, costs for auxiliary supplies, and lots of other costs that you won't see ahead of time.
Make sure your party will pay for itself. You can do this by a cover charge, or by getting crates of pop and munchies from costco and reselling them, or what-have-you, but make sure that money in is greater than money out.
Rules of thumb from similar events friends have organized are that voluntary donations (e.g. donation bowl) will fall far short of costs (maybe covering a quarter of it), and that hosting a first-time event will cost at least twice as much as you think it will.
You're also going to have to have somewhere for gamers to sleep. Having them all crash in the party room will probably not go down well with hotel management. Make sure you also clear any selling of food/whatever on-site with the hotel - they may have rules about this kind of thing.
It sounds like a cool event, and with luck, it'll be one, but make sure you aren't taken to the cleaners in the process.
Empirical evidence suggests that, if a safe way to release work-produced code exists at all, it's to get an ironclad release statement written in blood and signed by the CEO and the company's legal department.
In short, I wouldn't try it. Convince management to do it, and make sure there's a paper trail.
The challenge, for these type pf products is still price. I think, is that for only a few hundred more you get a full featured PC... consider that for $800, you can get a Nforce2 board, Athlon XP 17-2000 processor, HD, 15" Monitor, and CDRW for only a *little* more... [...] Now if you could get a machine that would surf the net, read email, and play DVDs and MP3s, for $150 then you have a winner.
The problem, AFAICT, is the accessories. At bare minimum, you'd need a CD burner (in lieu of disk drive) and a monitor on the thing. Unless your target market has HDTV in their homes and CD writers have dropped more than I think they have, this isn't happening anywhere close to cheaply.
You could build an integrated system-on-chip die with an x86 core and peripheral controllers easily - in fact, you can buy these already. The problem is that while people will accept a lousy machine for $150, at $400 it seems to be more of a sticking point.
We'll eventually get there. Cheap display technology is the main sticking point, IMO.
No, I'm in favour of Orbital industry (it makes no sense to put industry at the bottom of a gravity well, when most of where the results of that industry will be needed is in space anyway.
Production of bulk items in space is only economically viable _if_ they are to be used mostly in space. In practice, they'll be used wherever most of the population is. For the forseeable future, this is on earth.
Further, most pollution is from three areas - chemical processing (be it smelting, the plastics industry, or what-have-you), growing crops (fertilizer runoff), and supporting population and industry power consumption (generating electricity, running cars).
If you're planning to move either of the first two into space, you'll have to make them closed-loop processes due to shortage of materials (hydrogen, carbon, and nitrogen are hard to come by in the inner solar system; the belt is far enough away to present *serious* transport problems). If you're making these processes closed-loop, you might as well build the same factories on earth, as they will no longer pollute.
The last is tied in considerable part to where your population is (as it's what uses power). That's mostly on earth, due to the difficulty moving the earth's population off-planet.
In summary, unless the population is primarily based in space, I don't believe it would be beneficial to move industry there. Focus on making industry less polluting down here (and on closing the other end of the loop by using landfills as chemical feedstock for manufacturing).
What about stuff such as UWB? Wouldn't the massive SS aspect, which helps with making it very jamm-resistant, help make it EMP resistant?
These are different effects. Jamming works by swamping the airwaves with noise; UWB is resistant to some forms of jamming because it's less sensitive to the types of noise used to jam normal signals. EMP, however, works by sending strong enough RF to the receiver to induce currents large enough to destroy the device. This is independent of the type of data processing used.
I don't have a real firm grasp of EMP stuff. I can understand that a huge EM wave could screw with electronics, but that is easy to defend against.
It turns out to be a mixed bag. Shunting works (as described in my previous message) if the antenna is the main source of coupling, but passive shunts sometimes aren't fast enough to prevent damage, and active shunts can be tricky to build. You can also get damage to the antenna, the housing, and so forth if you're close enough or using a big enough antenna to get arcing (which you normall aren't).
It's a real bitch when you have MOSFET's on your receiver front-end looking for micro-volt signals, and they suddenly get spark-gap voltages. I'm sure that there's a real art to building hardened electronics.
This is typically handled by putting some kind of shunt across the signal lines that activates when voltage or current exceeds a threshold. This can be active (a sensor and shunt transistors) or passive (a Zener diode pair). I'm afraid it isn't my area of expertise, so I can't give more detail.
The signal is swamped, of course, but at least your radio survives.
Don't you think religion might have something to do with religious wars?
You miss the point.
Your religion or lack thereof is irrelevant to the person trying to kill you because their god told them to.
Your philosophy and outlook are similarly irrelevant to the person who wants something you posess (be it on an individual level or a national level) and decides to take it by force.
The upshot of this is that you can't make *all* people "not aggressive towards you".
Your non-lethal kung fu doesn't help if they're smart and armed. Or if they decide to come back with friends and baseball bats.
I do not advocate a philosophy of proactive violence. However, I do not feel that a philosophy of absolute non-violence (or minimum-at-all-costs violence) is practical either, for reasons outlined above.
Nowadays EMP protection is not a big problem in military environment - the "faraday's cage" is simple and effective enough.
A faraday cage around a radio is pretty pointless, as it prevents your radio from transmitting or receiving.
Any break in the shield allows leaks. Any antenna penetrating the shield acts as a waveguide - you might as well not have the shield in the first place if you do this.
EMP hardening for transceivers is done by making them able to tolerate large induced currents in the antennas. There will always be a point at which this ceases to work well (you try to make it past the point where it's no longer worth lobbing EMP bombs around).
As I sure you are aware EMP enters into every conversation when dealing with electronics in the battle field. I think main objective to get the bandwidth first them adapt some form of emp sheilding around it.
Shielding against EMP prevents the device from working (it's an EM transceiver, remember). What they'd actually do is harden the receiver so that it can survive EMP-induced currents, and make contingency plans for the situations where it is destroyed.
Re:Contamination is not a problem - it's desirable
on
Might Mars Contain Life?
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· Score: 2, Insightful
What for to keep th planet in its strile status? Contamenate it! Make a garden there!By the end of this centure, when Earth will be deadly overcrowded, you will deeply regret if you don't contamenate Mars now and thus don't prepare it for future colonists. You save either few billions of people from dying on earth or few billions of "native martian" bacteria from killing by contamentating terrastrian life forms.
Two problems with your argument.
First, evacuation to Mars is not practical, period. Figure out how much ten billion people weigh. Now figure out the amortized travel cost per kilogram for an earth/mars transport, bearing in mind that infrastructure is not free. Put these two numbers together, and you see why evacuation scenarios are laughed at.
Second, if the population of the earth keeps growing (as you seem to be assuming), colonizing Mars won't help. The doubling time is under a century, so you'll face exactly the same problem very soon.
The only stable scenario is one in which the population no longer grows. This seems to be happening on its own in the first world.
If we can find life somewhere else out there it's going to be fascinating.
For example, is the life DNA based? All life on earth is DNA based, and if the life elsewhere isn't then we are going to learn a lot by studying it - it will be an using an entirely different mechanism to do essentially the same thing as DNA. How does it work? How did it evolve?
There is evidence for at least _some_ cross-contamination between Earth and Mars occurring. If we find DNA or RNA based organisms there it may just be that they were seeded from here (or vice versa, back when Mars had water and a thicker atmosphere).
The place to look for *really* interesting things is environments that are isolated from ours, or that have conditions different enough that a different basic chemistry would be required.
Thermal vents on Io would be one option - there's lots of interesting sulphur-based chemistry upon which complex organisms could be based.
The oceans of Europa would also be an interesting spot - it's far from earth, and the potentially (earth-like-) life-bearing areas are beneath a thick crust of ice, so cross-contamination is less likely.
Cold worlds like tidally-heated moons of the outer gas giants would also be an interesting place to look. At those temperatures, life would a) run much more slowly and b) have to be based on lower-energy processes and substances with weaker binding forces for the available energy to be used to break down and rebuild biochemicals.
When we finally have probes capable of doing really detailed chemical and biological surveys of the outer solar system, we're going to find some very interesting things. Our own world shows us that microbes, at least, will show up wherever there's the energy and chemistry to support them.
There seem to be two major misconceptions in this thread. First, it takes way way more mass than the Earth has (several orders of magnitude), possibly more matter than the entire solar system has, to make a stable black hole.
It turns out that the required mass is much lower - asteroidal or less. Anything produced in an accelerator, however, would certainly decay quickly (depending on your definiton of "stable", threshold mass for stability is 1e5-1e8 tonnes; maximum possible mass from an accelerator collision is about 1.7e-24 kg/TeV).
How many of the effects that will limit the possibility of the black hole gaining mass have been verified?
Interaction cross-section for neutral particles, and the fact that matter acts as if it's mostly empty space, have been verified by just about every particle accelerator or radioactivity-based experiment ever performed.
The fact that a black hole with mass this low would be extremely tiny is a consequence of the equations that tell us black holes are possible at all.
The fact that black holes, if they exist, would evaporate is shown independently by multiple approaches, some hinging on theoretical constructs (it shows up when you model black holes with string theory), some hinging on physical laws (it's required for black holes to be consistent with thermodynamics), and some hinging on observed processes (we know virtual particles exist and know how they act, and near an event horizon, you get evaporation as a direct consequence of their existance).
What if hawking was wrong, and hawking radiation doesn't kill them off? Then how are we going to stop them from eating us all?
A black hole small enough to evaporate that quickly would be almost unfathomably tiny. Its interaction cross-section with normal matter would thus be extremely low - they'd behave like very heavy particles that don't interact with anything (think "giant neutrino" only less reactive).
There is very strong theoretical evidence for Hawking evaporation occurring, however. Among other things, it's what makes black holes mesh with thermodynamics. It's also a direct consequence of virtual particles, which are indirectly observed through things like the Casimir effect. If it *didn't* occur, something very fundamental would be wrong.
I don't see how the LHC would be able to make micro-black-holes, though. I'd thought you'd need a Planck-energy accelerator for that, which is just a wee bit larger.
Galium Arsenide is the material of the future, and always will be.
What about SiGe? Almost as good, much easier to fabricate, and much easier to use in mixed processes (i.e. a silicon wafer with a small region of SiGe process material for the high-speed analog stuff).
Re:forging sender address
on
I, Spammer
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· Score: 1
How do you equate a desire to not have your personal life broadcast to the world with a desire to get bombarded with unwanted, bandwidth stealing, trash?
Because with true anonymity, there is no accountability. With no accountability, spammers and so forth can do whatever they please, without fear of prosecution.
If they can be tracked down, you can be tracked down. End of anonymity.
Whether anonymity is worth the resulting abuse is a question that people have varying opinions on.
Oh really? You should tell that to the thousands of computer scientists in this little field we call "formal methods"
This was addressed in my previous message - formal methods are next to impossible to apply to programs of significant complexity, because the correct-behavior specification is as complex as the code itself (what is code, but a specification of what the program should do?).
Prove that Quake works.
Prove that $browser_of_choice works.
If you can construct a specification of correct behavior for these that's less than a thousand pages long and isn't just a restatement of the code, I'll buy your team dinner.
Slashdot Mirror
In other words they are designed around high thrust to weight ratios, and fairly high G forces.
There have been a few other concepts for rockets, including variable thrust and SCRAM jets, (for the in atmosphere portion at least) that do not have the same requirements for thrust to weight, and can be less costly to operate.
High thrust is a requirement. Your acceleration upward is only (thrust - 1 gravity), so having thrust low drops your efficiency considerably.
Scramjets are useful because they take their oxidizer from the atmosphere, dropping fuel weight by a huge amount (if you can do most of your boosting with them). This makes lower thrust tolerable (but not desired).
Now, here's my thinking. The Shuttle was a severe compromise of an originally good system (Flight launch Horizontal TakeOff and Landing) but ended up with the return vehicle pointlessly (and expensively) attached to an SRB+LOX rocket system.
Um, no SRB+LOX, no orbit. To get the delta-v you need a fuel:cargo ratio on the order of 30-50:1. People have been trying and failing to build a single-stage craft like that for quite some time. Materials aren't there yet, and certainly weren't there when the shuttle was designed.
You're going to have to attach the orbiter to _something_, because it's not getting into orbit on its own.
What NASA ought to be doing is saving the pennies by retiring the shuttle - not neccesarily immediately, but soon and putting out to tender a contract for a brand-new cost-effective launch system.
We have one - disposable rockets. Much easier - and cheaper - to build, and no hugely expensive maintenance cycle after launch.
Reusable rockets will only be cost-effective when materials improve to the point where they're relatively easy and cheap to build. The bar for this is higher the larger you want your payload to be, so heavy lifting may _still_ be done with disposable rockets even when a cost-effective light orbital transport is built.
Why do we need a reusable vehicle?
Not really, it depends on your problem. If you're working on a large dataset, but in a streaming manner, then memory bandwidth is the bottleneck. It's really only if you're randomly accessing the entire dataset that latency becomes the bottleneck.
The majority of the CPU-bound problems that I know about are not streaming problems.
Plasma is a collection of charged particles that have some of the properties of a gas, but is different in that it's a good conductor of electricity and can be affected by magnetic fields. It won't try to fill the space it's in, and you can't pour it.
Actually, it will try to fill the space it's in, just like any other gas. It can be impeded from doing so by magnetic fields (including fields generated by its own motion), but this is not a permanent state of affairs.
While I like AMD chips too (and use them almost exclusively), I'm afraid that most of the arguments you raise don't hold water.
In summary, I question your sources of data.
nowadays I think that the last component of a PC which needs speeding up is the CPU. Many other components act as a brake on the real-world efficiency of systems; one particularly close to my heart is the cache size. Most computational problems which I come across are too large to fit in less than 2 Mb; therefore, on processors which have a much lower clock speed than x86 offerings, but a much larger cache, I get much better results.
If you're doing any serious scientific computation, your data set will be _far_ larger than your cache size no matter what you're using. For many problems you can tweak access patterns to work on chunks small enough to fit in the cache. How well this works depends on your compiler, your libraries, and availability of things like pre-fetch instructions.
In cases where you can't sub-block the problem to fit in cache, you're out of luck no matter what you do - the limit will be the latency (and to a lesser extent, bandwidth) of your memory subsystem.
In summary, I'd be hesitant to blame poor performance of your x86 machines on cache (compiler and math libraries would be my first guess).
Actually, it's surprising how quickly memory banwidth has improved. The new Canterwoord P4's have an incredible 6.4GB/sec of memory bandwidth. I'd say that memory bandwidth is keeping pace quite well with CPU speeds these days.
Latency, not bandwidth, is what limits you if you're working on a computation problem that doesn't fit in cache. This has improved a bit, but not nearly as quickly as CPU speed has increased.
Does anyone know if this is press-release hype or a real breakthrough?
Neither - it's incremental improvement. That's how most progress is made.
Previous events, hosted in peoples' houses, were one thing. You're now trying to host one in a space you have to pay for. You're going to have costs for the space, costs for auxiliary supplies, and lots of other costs that you won't see ahead of time.
Make sure your party will pay for itself. You can do this by a cover charge, or by getting crates of pop and munchies from costco and reselling them, or what-have-you, but make sure that money in is greater than money out.
Rules of thumb from similar events friends have organized are that voluntary donations (e.g. donation bowl) will fall far short of costs (maybe covering a quarter of it), and that hosting a first-time event will cost at least twice as much as you think it will.
You're also going to have to have somewhere for gamers to sleep. Having them all crash in the party room will probably not go down well with hotel management. Make sure you also clear any selling of food/whatever on-site with the hotel - they may have rules about this kind of thing.
It sounds like a cool event, and with luck, it'll be one, but make sure you aren't taken to the cleaners in the process.
Empirical evidence suggests that, if a safe way to release work-produced code exists at all, it's to get an ironclad release statement written in blood and signed by the CEO and the company's legal department.
In short, I wouldn't try it. Convince management to do it, and make sure there's a paper trail.
The challenge, for these type pf products is still price. I think, is that for only a few hundred more you get a full featured PC... consider that for $800, you can get a Nforce2 board, Athlon XP 17-2000 processor, HD, 15" Monitor, and CDRW for only a *little* more...
[...]
Now if you could get a machine that would surf the net, read email, and play DVDs and MP3s, for $150 then you have a winner.
The problem, AFAICT, is the accessories. At bare minimum, you'd need a CD burner (in lieu of disk drive) and a monitor on the thing. Unless your target market has HDTV in their homes and CD writers have dropped more than I think they have, this isn't happening anywhere close to cheaply.
You could build an integrated system-on-chip die with an x86 core and peripheral controllers easily - in fact, you can buy these already. The problem is that while people will accept a lousy machine for $150, at $400 it seems to be more of a sticking point.
We'll eventually get there. Cheap display technology is the main sticking point, IMO.
No, I'm in favour of Orbital industry (it makes no sense to put industry at the bottom of a gravity well, when most of where the results of that industry will be needed is in space anyway.
Production of bulk items in space is only economically viable _if_ they are to be used mostly in space. In practice, they'll be used wherever most of the population is. For the forseeable future, this is on earth.
Further, most pollution is from three areas - chemical processing (be it smelting, the plastics industry, or what-have-you), growing crops (fertilizer runoff), and supporting population and industry power consumption (generating electricity, running cars).
If you're planning to move either of the first two into space, you'll have to make them closed-loop processes due to shortage of materials (hydrogen, carbon, and nitrogen are hard to come by in the inner solar system; the belt is far enough away to present *serious* transport problems). If you're making these processes closed-loop, you might as well build the same factories on earth, as they will no longer pollute.
The last is tied in considerable part to where your population is (as it's what uses power). That's mostly on earth, due to the difficulty moving the earth's population off-planet.
In summary, unless the population is primarily based in space, I don't believe it would be beneficial to move industry there. Focus on making industry less polluting down here (and on closing the other end of the loop by using landfills as chemical feedstock for manufacturing).
What about stuff such as UWB? Wouldn't the massive SS aspect, which helps with making it very jamm-resistant, help make it EMP resistant?
These are different effects. Jamming works by swamping the airwaves with noise; UWB is resistant to some forms of jamming because it's less sensitive to the types of noise used to jam normal signals. EMP, however, works by sending strong enough RF to the receiver to induce currents large enough to destroy the device. This is independent of the type of data processing used.
I don't have a real firm grasp of EMP stuff. I can understand that a huge EM wave could screw with electronics, but that is easy to defend against.
It turns out to be a mixed bag. Shunting works (as described in my previous message) if the antenna is the main source of coupling, but passive shunts sometimes aren't fast enough to prevent damage, and active shunts can be tricky to build. You can also get damage to the antenna, the housing, and so forth if you're close enough or using a big enough antenna to get arcing (which you normall aren't).
It's a real bitch when you have MOSFET's on your receiver front-end looking for micro-volt signals, and they suddenly get spark-gap voltages. I'm sure that there's a real art to building hardened electronics.
This is typically handled by putting some kind of shunt across the signal lines that activates when voltage or current exceeds a threshold. This can be active (a sensor and shunt transistors) or passive (a Zener diode pair). I'm afraid it isn't my area of expertise, so I can't give more detail.
The signal is swamped, of course, but at least your radio survives.
Don't you think religion might have something to do with religious wars?
You miss the point.
Your religion or lack thereof is irrelevant to the person trying to kill you because their god told them to.
Your philosophy and outlook are similarly irrelevant to the person who wants something you posess (be it on an individual level or a national level) and decides to take it by force.
The upshot of this is that you can't make *all* people "not aggressive towards you".
Your non-lethal kung fu doesn't help if they're smart and armed. Or if they decide to come back with friends and baseball bats.
I do not advocate a philosophy of proactive violence. However, I do not feel that a philosophy of absolute non-violence (or minimum-at-all-costs violence) is practical either, for reasons outlined above.
Nowadays EMP protection is not a big problem in military environment - the "faraday's cage" is simple and effective enough.
A faraday cage around a radio is pretty pointless, as it prevents your radio from transmitting or receiving.
Any break in the shield allows leaks. Any antenna penetrating the shield acts as a waveguide - you might as well not have the shield in the first place if you do this.
EMP hardening for transceivers is done by making them able to tolerate large induced currents in the antennas. There will always be a point at which this ceases to work well (you try to make it past the point where it's no longer worth lobbing EMP bombs around).
As I sure you are aware EMP enters into every conversation when dealing with electronics in the battle field. I think main objective to get the bandwidth first them adapt some form of emp sheilding around it.
Shielding against EMP prevents the device from working (it's an EM transceiver, remember). What they'd actually do is harden the receiver so that it can survive EMP-induced currents, and make contingency plans for the situations where it is destroyed.
What for to keep th planet in its strile status? Contamenate it! Make a garden there!By the end of this centure, when Earth will be deadly overcrowded, you will deeply regret if you don't contamenate Mars now and thus don't prepare it for future colonists. You save either few billions of people from dying on earth or few billions of "native martian" bacteria from killing by contamentating terrastrian life forms.
Two problems with your argument.
First, evacuation to Mars is not practical, period. Figure out how much ten billion people weigh. Now figure out the amortized travel cost per kilogram for an earth/mars transport, bearing in mind that infrastructure is not free. Put these two numbers together, and you see why evacuation scenarios are laughed at.
Second, if the population of the earth keeps growing (as you seem to be assuming), colonizing Mars won't help. The doubling time is under a century, so you'll face exactly the same problem very soon.
The only stable scenario is one in which the population no longer grows. This seems to be happening on its own in the first world.
If we can find life somewhere else out there it's going to be fascinating.
For example, is the life DNA based? All life on earth is DNA based, and if the life elsewhere isn't then we are going to learn a lot by studying it - it will be an using an entirely different mechanism to do essentially the same thing as DNA. How does it work? How did it evolve?
There is evidence for at least _some_ cross-contamination between Earth and Mars occurring. If we find DNA or RNA based organisms there it may just be that they were seeded from here (or vice versa, back when Mars had water and a thicker atmosphere).
The place to look for *really* interesting things is environments that are isolated from ours, or that have conditions different enough that a different basic chemistry would be required.
Thermal vents on Io would be one option - there's lots of interesting sulphur-based chemistry upon which complex organisms could be based.
The oceans of Europa would also be an interesting spot - it's far from earth, and the potentially (earth-like-) life-bearing areas are beneath a thick crust of ice, so cross-contamination is less likely.
Cold worlds like tidally-heated moons of the outer gas giants would also be an interesting place to look. At those temperatures, life would a) run much more slowly and b) have to be based on lower-energy processes and substances with weaker binding forces for the available energy to be used to break down and rebuild biochemicals.
When we finally have probes capable of doing really detailed chemical and biological surveys of the outer solar system, we're going to find some very interesting things. Our own world shows us that microbes, at least, will show up wherever there's the energy and chemistry to support them.
There seem to be two major misconceptions in this thread. First, it takes way way more mass than the Earth has (several orders of magnitude), possibly more matter than the entire solar system has, to make a stable black hole.
It turns out that the required mass is much lower - asteroidal or less. Anything produced in an accelerator, however, would certainly decay quickly (depending on your definiton of "stable", threshold mass for stability is 1e5-1e8 tonnes; maximum possible mass from an accelerator collision is about 1.7e-24 kg/TeV).
How many of the effects that will limit the possibility of the black hole gaining mass have been verified?
Interaction cross-section for neutral particles, and the fact that matter acts as if it's mostly empty space, have been verified by just about every particle accelerator or radioactivity-based experiment ever performed.
The fact that a black hole with mass this low would be extremely tiny is a consequence of the equations that tell us black holes are possible at all.
The fact that black holes, if they exist, would evaporate is shown independently by multiple approaches, some hinging on theoretical constructs (it shows up when you model black holes with string theory), some hinging on physical laws (it's required for black holes to be consistent with thermodynamics), and some hinging on observed processes (we know virtual particles exist and know how they act, and near an event horizon, you get evaporation as a direct consequence of their existance).
So to answer your question, "all of them".
What if hawking was wrong, and hawking radiation doesn't kill them off? Then how are we going to stop them from eating us all?
A black hole small enough to evaporate that quickly would be almost unfathomably tiny. Its interaction cross-section with normal matter would thus be extremely low - they'd behave like very heavy particles that don't interact with anything (think "giant neutrino" only less reactive).
There is very strong theoretical evidence for Hawking evaporation occurring, however. Among other things, it's what makes black holes mesh with thermodynamics. It's also a direct consequence of virtual particles, which are indirectly observed through things like the Casimir effect. If it *didn't* occur, something very fundamental would be wrong.
I don't see how the LHC would be able to make micro-black-holes, though. I'd thought you'd need a Planck-energy accelerator for that, which is just a wee bit larger.
Galium Arsenide is the material of the future, and always will be.
What about SiGe? Almost as good, much easier to fabricate, and much easier to use in mixed processes (i.e. a silicon wafer with a small region of SiGe process material for the high-speed analog stuff).
How do you equate a desire to not have your personal life broadcast to the world with a desire to get bombarded with unwanted, bandwidth stealing, trash?
Because with true anonymity, there is no accountability. With no accountability, spammers and so forth can do whatever they please, without fear of prosecution.
If they can be tracked down, you can be tracked down. End of anonymity.
Whether anonymity is worth the resulting abuse is a question that people have varying opinions on.
You can't prove that most software works.
Oh really? You should tell that to the thousands of computer scientists in this little field we call "formal methods"
This was addressed in my previous message - formal methods are next to impossible to apply to programs of significant complexity, because the correct-behavior specification is as complex as the code itself (what is code, but a specification of what the program should do?).
Prove that Quake works.
Prove that $browser_of_choice works.
If you can construct a specification of correct behavior for these that's less than a thousand pages long and isn't just a restatement of the code, I'll buy your team dinner.