and the electric fields associated with the radio waves would amount to millions of volts per meter
If you could by some means focus all this RF power on a volume of air the size of one wavelenght, and the voltages work up to the many-mV/m range, you'd be mostly ionizing air.
I guess this would result in a very spectacular lightshow, and a missile could be severely damaged by both EM radiating from the discharge in mid air and the heat it delivers to that air.
However, I don't think that there is any feasible way to concentrate RF energy to a space the size of a wavelenght at any serious distance (i.e. over 100s of waveleghts away).
Strictly speaking, a LP does not occupy any space at all, that's why its called a 'point' in the first place.
If you are slightly off in any direction, you'd 'fall' further in that direction, it is more like the top of a mountain than like the bottom of a valley.
In practice, any craft or station placed on such a point would need thrusters to stay in place, unpowered it would drift (due to solar wind, particle impact, air leaks and what not) and start 'falling'.
I guess the region where you can reasonably compensate against falling would be quite large, depening on thruster output, weight and fuel reserves. Even if it were a sphere with a radius of 10 km, this would be a huge volume of space, and could hold many ISS-sized stations and or comsats.
I must say it is a remarkable piece of work, creating two different documents that make sense after rendering. In case of these documents, some evidence of tampering might be easy to find upon closer examination of the files, but its still a very important thing.
This also makes me wonder on how widespread the consequences may be. Using MD5 and similar digests is common practice, and was until recently considered quite safe.
As the bittorrent protocol uses extensive hash checking, could this new discovery mean that MPAA and the likes will be able to insert corrupt data to torrent networks? I can imagine this would be a very real 'application' of this research, if it allows one to create blocks of data with hashes and sizes as desired.
Even worse, in torrent networks, these poisoned blocks will probably be re-distributed by all peers - or am I missing something?
Even if the algorithms would be independent, what would the benefit be over running higher-bit version of either algorithm?
The only benefit I can think of is that if one of the methods proves to be fundamentally flawed, whereas the other would be fundamentally sound. This would be odd, since most strong hashing algorithmes rely on similar principles... however, only time will tell.
12V might sound nice for some low power equipment, but its not really suitable for most household appliances.
Imagine something like a vacuum cleaner; these things are rated 1000 to 2000 watts these days. A 1200 watt model would need a whopping 100 amps. Plugs for this sort of current tend to be huge.
A standard european socket provides 230 volts at 16 amps, well over 3.5 kW. To give the same power output at 12 volts, it would need to supply over 300 amps... cables suitable for that voltage are a few CM in diameter.
Actually, this only holds true in some instances - mainly where landlines are in place already.
It's quite possible to interconnect cellphone masts to a certain degree using point-to-poing RF links. This is not uncommon, especially if the cell sites are far from existing lines, such as alongside highways or even out in the country.
If you take a close look at a cell tower, you sometimes notice and object that resembles a drum on its side - this is a highly directional antenna, and quite likely an point-to-point beam that carries the calls to the next mast (which may relay it even further).
Actually, I wonder which technology uses more energy if you account for the infrastructure too.
Digging and closing holes to fit many many miles of telephone wire will lead to a fair amount of fuel being used. Also, the copper wires have to be produced which is quite energy intensive too.
I have no idea on the total energy and monetery requirement to operate a mobile vs a land-based service, but I do have a gut feeling that the mobile service will be cheaper to construct in both aspects.
Of course, there is quite a lot of pre-existing landline infrastructure, but that will have to be replaced some day, and new infrastructure is also required when new areas are built up. If you'd have to start from scratch, the mobile solution seems cheaper and faster to construct... many emerging nations even skip most of the landline phase.
It seems somewhat counter-intuitive, but the energy density of high explosives such as TNT is much lower that that of, say, a mixture of gasoline or hydrogen and the oxygen required to combust it. TNT is used as an explosive not because of its high energy density, but because of its ability to release this energy very rapidly.
TNT has an energy density of around 4.6 MJ/kg, a 1:8 H2/O2 mixture achieves 13 MJ/kg. Hydrogen has little density however (even the liquid), so volume is a major problem there.
Much higher energy densities require more exotic techniques, with Uranium (235) fission at 90 TJ/kg. This is 6 magnitues beyond regular fuels.
Antimatter/matter annihilation is the most energy dense fuel possible so far, and would be 1000 times denser in energy compared to U235.
Ofcourse, if a big metal sphere would strike the earth, most of its mass would end up impacting the planet. With an object this size, that would be 'end-of-all-life' kind of bad.
These calculations were made assuming the object could/would be fragmented before hitting the athmosphere, with fragments so small they would burn up before striking the ground.
All in all, breaking up a huge object before it strikes seems to lead to a 'better' outcome of the whole ordeal.
I didn't check the calculations, but I see a few problems with the assumptions:
We'll assume the atmosphere is of uniform density, distribution, and composition, and about 120km high (not a terrible approximation, but not a good one either).
The atmosphere is not that thick really. There is atmosphere up to this height, but its density is minuscule at an altitude of say 100 km. If you would assume constant density, it would be safe to assume a thickness twice the altitude where pressure is half that at sea level. This equates to around 2*5km, since at 5km pressure is 0.5 atm, and 50% of the air mass is contained below this level.
This would increase the temperature rise 60-fold, an increase of 15K... which would probably not kill us all, but would have great impact on life.
On the positive side, much of the energy generated will be radiated into space (over half of all radiation produced is directed away from earth). As the whole process probably occurs at high temperature, much of the energy will be radiant.
Finally, the other half of the radiant energy will strike the ground, heating up soil and water, increasing the total amount of mass that absorbes the energy.
Pretty complex stuff;)
Re:Cost and price aren't that closely related
on
Hacking Vodka
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· Score: 1
If any taste from the biological source matter is desireable, fermentation sounds like a good idea. This would be valid for some liquors such as scotch, brandy and possibly tequila.
However, liquors that should have no taste other than alcohol itself such as vodka, and liqours where all taste is added after destillation (gin, fruity liquors, etc.) would be more efficiently produced from synthetic alcohol.
As for the price argument: $1 for a litre of 96% ethanol, that could be diluted to well over 2 litres of normal-strength liquor. Also, the biological sources for producing that tequila could probably have been used for more efficient applications - such as food;)
Vodka shouldn't be produced as it is
on
Hacking Vodka
·
· Score: 1
If you are looking for the pure taste of ethanol and water, and nothing else, vodka shouldn't be made from biological materials.
In fact, you can create a very drinkable beverage from cheap laboratory alcohol (96%, the rest being water) and purified water. This mixture is quite odor- and tasteless, apart from the typical ethanol taste and odor.
Oddly, in most countries law requires that liqour is produced from alcohol obtained trough fermentation and distillation after that.
Industrially, ethanol is produced from the addition of water to ethene - a much more efficient, cheap and clean process. I believe we should adopt this route for liquour too. Ethanol sythesized from the ethene/water process costs less than $1 per litre - not counting taxes. After some basic purification, the end product is free from all toxic compounds found in liquour - including nasties such as methanol, propanol or formaldehyde.
In magnetic recording devices, the data density limited by either the size of the head or the size of magnetic domains in the platter material. As I understand it, at this time the platter is the limiting factor. The density on a modern HD platter exceeds that of a CD or DVD disc.
With optical storage, the data density is limited by the wavelength of the photons interacting with the medium, as well as the detail of the medium itself. A DVD can store more data than a CD because of the smaller wavelength of its red laser. The blue laser in blu-ray discs as an even smaller wavelength, and yields even more data per disc. Obviously, the media need to be altered to accept the higher data density - and photon energy for recordable discs.
The size of the laser unit itself is not really relevant, as its output is focussed into a tiny point on the recording layer.
The US is no longer considered the ideal place for many types of businesses, and anti-american sentiments are definitely growing in europe and asia.
With more and more privacy-invading legislation being installed, the US will rapidly become unusable to any business that has trade secrets to protect, or deals with private customer data.
Canada has put in a nice document with recommendations what most of the world already knows and acts on.
I think most (decent) web designers check their work for some compatibility with browsers like mozilla/firefox.
IE is still the browser used by the vast majority of visitors (like it or not), so that is and should be the main target for any professional web designer. Even if you don't like IE yourself, you work for a client and should respect their wishes.
However, the market share of other browsers is growing, and we should all realise that that relatively small percentage of visitors should be able to visit the website as well.
Honesty, I don't go out of my way to get pages identical to the pixel in all browsers, but I ensure that firefox-users have a pretty good user experience too. Getting it pixel-perfect usually is qutie some work (IE's quirks are mostly at fault there), but giving all visitors an acceptable user experience is really not that hard!
If you really look at it, it is not very different from what most IT people are used to in freelance negotiations.
If a company needs an amount of manpower, they usually collect some offers from various freelancers, and then pick the ones with the best prices (or quality/price ratio).
In this case, it would be even more efficient, since the education of licensed nurses must be quite similar.
To me, it sounds like free market taken to a new level!
Quite a lot of them, specially considering there are few really massive ones. No such objects with a mass greater than 1% of earth have been discovered.
But even if such an object would exist, it would not affect two probes in different locations in a similar way. Even if there were many massive undiscoverd objects out there, chances to these effects are very slim.
The Pioneer probes are currently also way beyond the Kuiper belt, so the influence of a pluto-like object would be very very small.
Your idea is basically correct. Any object that has mass excerts a gravitational force on any other object that has mass. As far as we know, this force is not quantized, so there is no lower limit to how small it can become.
That said, you would have to consider 'how much force?'. The force depends on the masses of both objects involved, and on their distance squared. The acceleration one object experiences is independant of its mass, since this mass cancels out when combining the formulas for gravity and acceleration. You could calculate that the gravitational force of the sun overwhelms that of any planet unless very close to the planet.
To get any feel of the relative masses: 99.9% of the solar systems mass is in the sun alone. Compared to the earth, the sun is over 330.000 times more massive. Compared to jupiter, the sun is roughly 1000 times more massive.
However, a more important argument is that we -know- the masses and positions of all major bodies in the solar system, and any deviation due to those is -not- unexpected or unexplained.
There is some debate, the scientific consensus at the moment is that (ordinary) glass is NOT a liquid. Wikipedia has some
interesting background info on this discussion.
In general, the composition of glass makes a huge different in properties such as hardness, inertness, transparancy and color. In ordinary glass, CaO is added to lower solubility in water and various other solvents.
Really, it would not be that hard to temporarely disable the RFID function. I can imagine how this RFID feature would be usefull when 'reading' the passport at, for example, an airport.
However, the RFID feature has no use when you just walk around with the passport in your wallet. In fact, this could be a privacy concern, since you could be 'tracked' without your consent. If you worry about this, loose the tinfoil hat and buy the tinfoil wallet.
Or you could carry your passport and other RFID-enabled documents and cards in a fancy metal case such as the ones used for cigarettes - unreadable as long as you do not open the case!
These birds falling from the sky are a true observation in very-high-power RF systems. I have heard of this fenomenon occurring around (military/naval) high-power radar installations as well.
However, the cause of this effect is not at all related to the suspected relation between RF and cancer.
Things that drop dead nearly instantly close to transmitters (beit birds or careless engineers) generally suffer from thermal exposure - i.e. their (brain) tissue heats up to dangerous levels - very similar to putting a bird in a microwave oven and turning it on.
Your traffic tips and hints seem mostly correct, bad driving is something that definitively causes many problems such as traffic jams. However, bad driving can be modelled to a certain extent so it does not make all models useless per se.
About the left/right lane and Europe: ALL european countries on the mainland drive on the right (as opposed to left) side of the road, just as Americans do. The left lane is therefore the fast lane in Europe as well. On highways, nearly all off-ramps are on the right side.
There is 1 country in Europe that drives on the left site: the UK. All other countries that I've visited that drive on the left side are in Asia.
Its all about being realistic about how 'toxic' a substance actually is. 10% by volume is a huge concentration to breathe for any gas, except oxygen and nitrogen.
My point was, and still is, that breating this substance is not more dangerous than breathing a common and wellknown gas like CO2. Both can kill you, given high enough concentration and exposure time, but neither should be considered hazardous substances.
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If you could by some means focus all this RF power on a volume of air the size of one wavelenght, and the voltages work up to the many-mV/m range, you'd be mostly ionizing air.
I guess this would result in a very spectacular lightshow, and a missile could be severely damaged by both EM radiating from the discharge in mid air and the heat it delivers to that air.
However, I don't think that there is any feasible way to concentrate RF energy to a space the size of a wavelenght at any serious distance (i.e. over 100s of waveleghts away).
Strictly speaking, a LP does not occupy any space at all, that's why its called a 'point' in the first place.
If you are slightly off in any direction, you'd 'fall' further in that direction, it is more like the top of a mountain than like the bottom of a valley.
In practice, any craft or station placed on such a point would need thrusters to stay in place, unpowered it would drift (due to solar wind, particle impact, air leaks and what not) and start 'falling'.
I guess the region where you can reasonably compensate against falling would be quite large, depening on thruster output, weight and fuel reserves. Even if it were a sphere with a radius of 10 km, this would be a huge volume of space, and could hold many ISS-sized stations and or comsats.
I must say it is a remarkable piece of work, creating two different documents that make sense after rendering. In case of these documents, some evidence of tampering might be easy to find upon closer examination of the files, but its still a very important thing.
This also makes me wonder on how widespread the consequences may be. Using MD5 and similar digests is common practice, and was until recently considered quite safe.
As the bittorrent protocol uses extensive hash checking, could this new discovery mean that MPAA and the likes will be able to insert corrupt data to torrent networks? I can imagine this would be a very real 'application' of this research, if it allows one to create blocks of data with hashes and sizes as desired.
Even worse, in torrent networks, these poisoned blocks will probably be re-distributed by all peers - or am I missing something?
Diamonds will not turn into graphite under normal conditions, they're pretty stable as long as you don't heat them.
;)
However, diamonds will turn into graphite and, if oxygen is present, burn at elevated temperatures.
Therefore, all diamonds on earth will be destroyed once the sun goes nova and gobbles up the planet
Even if the algorithms would be independent, what would the benefit be over running higher-bit version of either algorithm?
The only benefit I can think of is that if one of the methods proves to be fundamentally flawed, whereas the other would be fundamentally sound. This would be odd, since most strong hashing algorithmes rely on similar principles... however, only time will tell.
12V might sound nice for some low power equipment, but its not really suitable for most household appliances.
Imagine something like a vacuum cleaner; these things are rated 1000 to 2000 watts these days. A 1200 watt model would need a whopping 100 amps. Plugs for this sort of current tend to be huge.
A standard european socket provides 230 volts at 16 amps, well over 3.5 kW. To give the same power output at 12 volts, it would need to supply over 300 amps... cables suitable for that voltage are a few CM in diameter.
Those warez of mass destruction have got to be somewhere!
Actually, this only holds true in some instances - mainly where landlines are in place already.
It's quite possible to interconnect cellphone masts to a certain degree using point-to-poing RF links. This is not uncommon, especially if the cell sites are far from existing lines, such as alongside highways or even out in the country.
If you take a close look at a cell tower, you sometimes notice and object that resembles a drum on its side - this is a highly directional antenna, and quite likely an point-to-point beam that carries the calls to the next mast (which may relay it even further).
Actually, I wonder which technology uses more energy if you account for the infrastructure too.
Digging and closing holes to fit many many miles of telephone wire will lead to a fair amount of fuel being used. Also, the copper wires have to be produced which is quite energy intensive too.
I have no idea on the total energy and monetery requirement to operate a mobile vs a land-based service, but I do have a gut feeling that the mobile service will be cheaper to construct in both aspects.
Of course, there is quite a lot of pre-existing landline infrastructure, but that will have to be replaced some day, and new infrastructure is also required when new areas are built up. If you'd have to start from scratch, the mobile solution seems cheaper and faster to construct... many emerging nations even skip most of the landline phase.
TNT has an energy density of around 4.6 MJ/kg, a 1:8 H2/O2 mixture achieves 13 MJ/kg. Hydrogen has little density however (even the liquid), so volume is a major problem there.
Much higher energy densities require more exotic techniques, with Uranium (235) fission at 90 TJ/kg. This is 6 magnitues beyond regular fuels.
Antimatter/matter annihilation is the most energy dense fuel possible so far, and would be 1000 times denser in energy compared to U235.
These calculations were made assuming the object could/would be fragmented before hitting the athmosphere, with fragments so small they would burn up before striking the ground.
All in all, breaking up a huge object before it strikes seems to lead to a 'better' outcome of the whole ordeal.
We'll assume the atmosphere is of uniform density, distribution, and composition, and about 120km high (not a terrible approximation, but not a good one either).
The atmosphere is not that thick really. There is atmosphere up to this height, but its density is minuscule at an altitude of say 100 km. If you would assume constant density, it would be safe to assume a thickness twice the altitude where pressure is half that at sea level. This equates to around 2*5km, since at 5km pressure is 0.5 atm, and 50% of the air mass is contained below this level.
This would increase the temperature rise 60-fold, an increase of 15K... which would probably not kill us all, but would have great impact on life.
On the positive side, much of the energy generated will be radiated into space (over half of all radiation produced is directed away from earth). As the whole process probably occurs at high temperature, much of the energy will be radiant.
Finally, the other half of the radiant energy will strike the ground, heating up soil and water, increasing the total amount of mass that absorbes the energy.
Pretty complex stuff ;)
If any taste from the biological source matter is desireable, fermentation sounds like a good idea. This would be valid for some liquors such as scotch, brandy and possibly tequila.
;)
However, liquors that should have no taste other than alcohol itself such as vodka, and liqours where all taste is added after destillation (gin, fruity liquors, etc.) would be more efficiently produced from synthetic alcohol.
As for the price argument: $1 for a litre of 96% ethanol, that could be diluted to well over 2 litres of normal-strength liquor. Also, the biological sources for producing that tequila could probably have been used for more efficient applications - such as food
If you are looking for the pure taste of ethanol and water, and nothing else, vodka shouldn't be made from biological materials.
In fact, you can create a very drinkable beverage from cheap laboratory alcohol (96%, the rest being water) and purified water. This mixture is quite odor- and tasteless, apart from the typical ethanol taste and odor.
Oddly, in most countries law requires that liqour is produced from alcohol obtained trough fermentation and distillation after that.
Industrially, ethanol is produced from the addition of water to ethene - a much more efficient, cheap and clean process. I believe we should adopt this route for liquour too. Ethanol sythesized from the ethene/water process costs less than $1 per litre - not counting taxes. After some basic purification, the end product is free from all toxic compounds found in liquour - including nasties such as methanol, propanol or formaldehyde.
In magnetic recording devices, the data density limited by either the size of the head or the size of magnetic domains in the platter material. As I understand it, at this time the platter is the limiting factor. The density on a modern HD platter exceeds that of a CD or DVD disc.
With optical storage, the data density is limited by the wavelength of the photons interacting with the medium, as well as the detail of the medium itself. A DVD can store more data than a CD because of the smaller wavelength of its red laser. The blue laser in blu-ray discs as an even smaller wavelength, and yields even more data per disc. Obviously, the media need to be altered to accept the higher data density - and photon energy for recordable discs.
The size of the laser unit itself is not really relevant, as its output is focussed into a tiny point on the recording layer.
The US is no longer considered the ideal place for many types of businesses, and anti-american sentiments are definitely growing in europe and asia.
With more and more privacy-invading legislation being installed, the US will rapidly become unusable to any business that has trade secrets to protect, or deals with private customer data.
Canada has put in a nice document with recommendations what most of the world already knows and acts on.
I think most (decent) web designers check their work for some compatibility with browsers like mozilla/firefox.
IE is still the browser used by the vast majority of visitors (like it or not), so that is and should be the main target for any professional web designer. Even if you don't like IE yourself, you work for a client and should respect their wishes.
However, the market share of other browsers is growing, and we should all realise that that relatively small percentage of visitors should be able to visit the website as well.
Honesty, I don't go out of my way to get pages identical to the pixel in all browsers, but I ensure that firefox-users have a pretty good user experience too. Getting it pixel-perfect usually is qutie some work (IE's quirks are mostly at fault there), but giving all visitors an acceptable user experience is really not that hard!
If you really look at it, it is not very different from what most IT people are used to in freelance negotiations.
If a company needs an amount of manpower, they usually collect some offers from various freelancers, and then pick the ones with the best prices (or quality/price ratio).
In this case, it would be even more efficient, since the education of licensed nurses must be quite similar.
To me, it sounds like free market taken to a new level!
Quite a lot of them, specially considering there are few really massive ones. No such objects with a mass greater than 1% of earth have been discovered.
But even if such an object would exist, it would not affect two probes in different locations in a similar way. Even if there were many massive undiscoverd objects out there, chances to these effects are very slim.
The Pioneer probes are currently also way beyond the Kuiper belt, so the influence of a pluto-like object would be very very small.
Your idea is basically correct. Any object that has mass excerts a gravitational force on any other object that has mass. As far as we know, this force is not quantized, so there is no lower limit to how small it can become.
That said, you would have to consider 'how much force?'. The force depends on the masses of both objects involved, and on their distance squared. The acceleration one object experiences is independant of its mass, since this mass cancels out when combining the formulas for gravity and acceleration. You could calculate that the gravitational force of the sun overwhelms that of any planet unless very close to the planet.
To get any feel of the relative masses: 99.9% of the solar systems mass is in the sun alone. Compared to the earth, the sun is over 330.000 times more massive. Compared to jupiter, the sun is roughly 1000 times more massive.
However, a more important argument is that we -know- the masses and positions of all major bodies in the solar system, and any deviation due to those is -not- unexpected or unexplained.
There is some debate, the scientific consensus at the moment is that (ordinary) glass is NOT a liquid. Wikipedia has some interesting background info on this discussion.
In general, the composition of glass makes a huge different in properties such as hardness, inertness, transparancy and color. In ordinary glass, CaO is added to lower solubility in water and various other solvents.
Really, it would not be that hard to temporarely disable the RFID function. I can imagine how this RFID feature would be usefull when 'reading' the passport at, for example, an airport.
However, the RFID feature has no use when you just walk around with the passport in your wallet. In fact, this could be a privacy concern, since you could be 'tracked' without your consent. If you worry about this, loose the tinfoil hat and buy the tinfoil wallet.
Or you could carry your passport and other RFID-enabled documents and cards in a fancy metal case such as the ones used for cigarettes - unreadable as long as you do not open the case!
These birds falling from the sky are a true observation in very-high-power RF systems. I have heard of this fenomenon occurring around (military/naval) high-power radar installations as well.
However, the cause of this effect is not at all related to the suspected relation between RF and cancer.
Things that drop dead nearly instantly close to transmitters (beit birds or careless engineers) generally suffer from thermal exposure - i.e. their (brain) tissue heats up to dangerous levels - very similar to putting a bird in a microwave oven and turning it on.
Your traffic tips and hints seem mostly correct, bad driving is something that definitively causes many problems such as traffic jams. However, bad driving can be modelled to a certain extent so it does not make all models useless per se. About the left/right lane and Europe: ALL european countries on the mainland drive on the right (as opposed to left) side of the road, just as Americans do. The left lane is therefore the fast lane in Europe as well. On highways, nearly all off-ramps are on the right side. There is 1 country in Europe that drives on the left site: the UK. All other countries that I've visited that drive on the left side are in Asia.
My point was, and still is, that breating this substance is not more dangerous than breathing a common and wellknown gas like CO2. Both can kill you, given high enough concentration and exposure time, but neither should be considered hazardous substances.