Of course you are right, except that in this case it seems they just mean Ampere-hours, which is measure of the capacity for power output of a power source. Think of it... why would they convert to quantum units of all things?
I agree that gammas will always be there, but as long as you are inside a building during the blast, you are pretty much safe from them. High energy alphas have a range of a few centimeters in air and are stopped by the dead layers in your outer skin. Betas have a range of of several (~10) meters in air and are also stopped by clothes and skin. As I said if you happen to eat food that has byproduct isotopes in it, it's bad. For example milk has some Strontium-90 in it which came about during atmospheric testing of fission devices, fallout fell to the ground, cows ate the grass, Sr-90 got into the milk. It's still around because of its long half life. Also, the thing you were exposed to was not necessarily radioactive. It could have been some sort of other higly toxic substance, because a piece of radioactive material is unlikely to emit that strongly if it was just sitting there, because if it was it would take very little time for it to stop (because of decay).
alphas and betas are not rays. They are particles and your clothes are enough to stop them. The problem is when you inhale them, or something that emits them. You *can* make a device that does not result in a lot of alphas and betas.
Wrong. Dutch people made the dodo extinct. They ate all of them. I should know, since I've lived in Mauritius (where the dodo used to live 400 years ago). See, my user name means Marutius in French.
Nice try, but this has already been patented by Nicola Tesla in the early 1900s. He actually did the experiment and caused an earthquake in New Jersey I believe.
Depends what kinds of wavelengths you are talking about. There is no ionizing radiation coming out of the cell tower, but there is some coming from the Sun. That's the one that is dangerous (causes cancer). Anything UV or higher frequencies in general is bad.
No it won't, because of difraction. I checked my physics books and my formula was actually correct. It gives the theoretical limit of resolution by a circular aperture. For rectangular, the constant is 1 instead fo 1.22.
The resolving power of the eye is measured in degrees i.e. what is the smallest angle subtended by an object that can still be seen. This resolving power is related to wavelength, but is also related to the current open diameter of your pupils (changes with light conditions). When it is dark you can see much smaller objects (stars) because your pupils are dilated. If I remember correctly (could be wrong), for a circular aperture, like eye or optical telescope, the maximum resolving power is given by:
p = c*l/D
where D is diameter of aperture, l is wavelength of light and c is a constant (1.22 may be?). p is in radians.
Also, the densest material KNOWN to man would be neutronium (the zeroth element), i.e. the stuff neutron stars are made of. It is basically all neutrons, with density reaching up to megatons per cubic centimeter. Neutrons pack really well since they are, well neutral. They are also highly radioactive beta emitters with a half life of about 10 min, after which they decay into hydrogen.
IIRC for a long time now the dollar is no longer based on gold (i.e. the federal reseve does not hold equivalent amount of gold anymore). Ditto for other currencies.
Wrong. Iridium has 22.65 gr/cc. Osmium is 22.61 gr/cc. Platinum is 21.09. Rhenium is 21.02. So you see the math says iridium is the densest. Since these are all precious metals, the most common element used for ammunition after lead is uranium (19.05 gr/cc) that has been depleted (i.e. nuclear waste).
It would be interesting, however, to see if you can bump this electron down a wire or fiber to make a ultra high bandwidth network.
You can't for now, since the electron they used was part of a Cesium atom. The Cesium atom has one free valence electron which is probably the one they used. The electron has to be bound to an atom to store the information. Even if it didn't have to be, and you sent it across a wire, the drift velocity in the wire is more like 1mph than the speed of light, so it would take too long. And did I mention that electrons are indistinguishable from other electrons so you would lose it once you knock it off the Cs atom.
I think the key to the article is the last line where they say they have yet to see for how long they can store the information. An electron that is not in ground (or lowest energy) state will quickly decay to a lower state (in about 0.1 microseconds in Hydrogen atom). Since they use these states to represent the data, if the electron decides to make a random jump down, everything will be erased. Or in higher states, there is the possibility of the electron jumping off the atom, creating an ion.
The heavy launch vehicle was the N-1. There were 4 failed test launches after which the program was canceled since US went to the Moon. Many rockets explode during initial test launches, including the new Delta-3 from Boeing which had some big problems. Arianne also comes to mind (floating point overflow killed it). Also, the Russians have the most realiable rocket in the world, the Proton (yeah they had two explode recently because of new engines, but these count as a new model). I checked this on discovery.com.
The USA actually has a worse record in launching people in space -- Apollo 1, Challanger. The Russians IIRC have no (or may be just one) manned launch failures. So it is not fair to say the US has a "far safer" program.
IIRC The Russian space program has no failed launches of manned flights (maybe one during the 60s), compared to two for the US (Apollo, Challanger). On the other hand they do have reentry fatalities.
Isn't that Pythagoras' Theorem? I'd think Pythagoras proved it first. And yeah, you really don't need a coordinate system for geometry proofs (IIRC the proof for this involved drawing squares on each side and then comparing the areas).
h / (4*E) in order to get units of seconds -- Planck's is in Joule.sec and E is in Joules.
This is in fact Heisenberg's uncertainty principle applied to time-energy :
delta(t) * delta(E) >= h/4
I have some doubts about h/4, because it could be hbar/4 (which is equal to h/(16*PI)). But this makes almost no difference. delta(t) can be interpreted as the lifetime of the quantum state and delta(E) would be the uncertainty in the energy, which for ground state is close to the total energy and that is where this approximation comes from.
Earth's atmosphere cannot be ignited. A reaction to produce nitrogen oxides from air would require too much input energy. Besides, a nuke in vacuum is still a nuke. Just a big flash of energy and no hit wave, so it would do very very little physical damage.
Also the new jvm from Sun takes up about 40Mb for the compressed file
The runtime jvm takes far less than that. It's less than 10 megs. The developer kit is 40.
It is true that running java apps takes a lot of memory, but this is because the jvm itself has to be loaded and it takes about 20 megs. Also, I would personally be willing to sacrifice memory usage for speed and this is exactly what the jvm does - it uses more memory in order to keep natively compiled code so that it runs faster. RAM is not that expensive and 128 megs is about enough if you are running one virtual machine at a time. If you use Java3D intensively though, I would recommend more than that.
Also if you use C++ and OpenGL to display something versus Java3D it is not really fair, because Java3D has to create many objects in order to provide you with interactivity (mouse picking, etc), while OpenGL will just draw on the screen buffer.
But it's really sad that they seem to have sacrificed the lives of the crew to preserve the secret torpedo design, if that's why they kept the rescuers away from the damaged torpedo section.
If you try and think like a Russian you would see that people are a cheap expendable resource. A sub or even a torpedo is much more important and expensive than a handful of human lives. This is not a troll, I am just presenting the point of view of any high level military official.
Slashdot Mirror
Of course you are right, except that in this case it seems they just mean Ampere-hours, which is measure of the capacity for power output of a power source. Think of it... why would they convert to quantum units of all things?
Personal flight will never be widespread.
"Heavier than air flying machines will never be feasible"
--Lord Kelvin, late 1800s
Simple. 1/2 the diameter means 1/8 the volume. So there you go.
I agree that gammas will always be there, but as long as you are inside a building during the blast, you are pretty much safe from them. High energy alphas have a range of a few centimeters in air and are stopped by the dead layers in your outer skin. Betas have a range of of several (~10) meters in air and are also stopped by clothes and skin. As I said if you happen to eat food that has byproduct isotopes in it, it's bad. For example milk has some Strontium-90 in it which came about during atmospheric testing of fission devices, fallout fell to the ground, cows ate the grass, Sr-90 got into the milk. It's still around because of its long half life. Also, the thing you were exposed to was not necessarily radioactive. It could have been some sort of other higly toxic substance, because a piece of radioactive material is unlikely to emit that strongly if it was just sitting there, because if it was it would take very little time for it to stop (because of decay).
alphas and betas are not rays. They are particles and your clothes are enough to stop them. The problem is when you inhale them, or something that emits them. You *can* make a device that does not result in a lot of alphas and betas.
cats, dogs and pigs made the dodo extinct.
Wrong. Dutch people made the dodo extinct. They ate all of them. I should know, since I've lived in Mauritius (where the dodo used to live 400 years ago). See, my user name means Marutius in French.
Nice try, but this has already been patented by Nicola Tesla in the early 1900s. He actually did the experiment and caused an earthquake in New Jersey I believe.
Depends what kinds of wavelengths you are talking about. There is no ionizing radiation coming out of the cell tower, but there is some coming from the Sun. That's the one that is dangerous (causes cancer). Anything UV or higher frequencies in general is bad.
No it won't, because of difraction. I checked my physics books and my formula was actually correct. It gives the theoretical limit of resolution by a circular aperture. For rectangular, the constant is 1 instead fo 1.22.
The resolving power of the eye is measured in degrees i.e. what is the smallest angle subtended by an object that can still be seen. This resolving power is related to wavelength, but is also related to the current open diameter of your pupils (changes with light conditions). When it is dark you can see much smaller objects (stars) because your pupils are dilated. If I remember correctly (could be wrong), for a circular aperture, like eye or optical telescope, the maximum resolving power is given by:
p = c*l/D
where D is diameter of aperture, l is wavelength of light and c is a constant (1.22 may be?). p is in radians.
Also, the densest material KNOWN to man would be neutronium (the zeroth element), i.e. the stuff neutron stars are made of. It is basically all neutrons, with density reaching up to megatons per cubic centimeter. Neutrons pack really well since they are, well neutral. They are also highly radioactive beta emitters with a half life of about 10 min, after which they decay into hydrogen.
IIRC for a long time now the dollar is no longer based on gold (i.e. the federal reseve does not hold equivalent amount of gold anymore). Ditto for other currencies.
Wrong. Iridium has 22.65 gr/cc. Osmium is 22.61 gr/cc. Platinum is 21.09. Rhenium is 21.02.
So you see the math says iridium is the densest. Since these are all precious metals, the most common element used for ammunition after lead is uranium (19.05 gr/cc) that has been depleted (i.e. nuclear waste).
It would be interesting, however, to see if you can bump this electron down a wire or fiber to make a ultra high bandwidth network.
You can't for now, since the electron they used was part of a Cesium atom. The Cesium atom has one free valence electron which is probably the one they used. The electron has to be bound to an atom to store the information. Even if it didn't have to be, and you sent it across a wire, the drift velocity in the wire is more like 1mph than the speed of light, so it would take too long. And did I mention that electrons are indistinguishable from other electrons so you would lose it once you knock it off the Cs atom.
I think the key to the article is the last line where they say they have yet to see for how long they can store the information. An electron that is not in ground (or lowest energy) state will quickly decay to a lower state (in about 0.1 microseconds in Hydrogen atom). Since they use these states to represent the data, if the electron decides to make a random jump down, everything will be erased. Or in higher states, there is the possibility of the electron jumping off the atom, creating an ion.
The heavy launch vehicle was the N-1. There were 4 failed test launches after which the program was canceled since US went to the Moon. Many rockets explode during initial test launches, including the new Delta-3 from Boeing which had some big problems. Arianne also comes to mind (floating point overflow killed it). Also, the Russians have the most realiable rocket in the world, the Proton (yeah they had two explode recently because of new engines, but these count as a new model). I checked this on discovery.com.
The USA actually has a worse record in launching people in space -- Apollo 1, Challanger. The Russians IIRC have no (or may be just one) manned launch failures. So it is not fair to say the US has a "far safer" program.
IIRC The Russian space program has no failed launches of manned flights (maybe one during the 60s), compared to two for the US (Apollo, Challanger).
On the other hand they do have reentry fatalities.
That is c*c = a*a + b*b in your notation
Isn't that Pythagoras' Theorem? I'd think Pythagoras proved it first. And yeah, you really don't need a coordinate system for geometry proofs (IIRC the proof for this involved drawing squares on each side and then comparing the areas).
Man, that's right on. Except that they taught us Dylan (I hear they do Scheme now) at my university.
IIRC the only thing you can measure with arbitrary precision is time.
h / (4*E) in order to get units of seconds -- Planck's is in Joule.sec and E is in Joules.
This is in fact Heisenberg's uncertainty principle applied to time-energy :
delta(t) * delta(E) >= h/4
I have some doubts about h/4, because it could be hbar/4 (which is equal to h/(16*PI)). But this makes almost no difference. delta(t) can be interpreted as the lifetime of the quantum state and delta(E) would be the uncertainty in the energy, which for ground state is close to the total energy and that is where this approximation comes from.
Earth's atmosphere cannot be ignited. A reaction to produce nitrogen oxides from air would require too much input energy. Besides, a nuke in vacuum is still a nuke. Just a big flash of energy and no hit wave, so it would do very very little physical damage.
Also the new jvm from Sun takes up about 40Mb for the compressed file
The runtime jvm takes far less than that. It's less than 10 megs. The developer kit is 40.
It is true that running java apps takes a lot of memory, but this is because the jvm itself has to be loaded and it takes about 20 megs. Also, I would personally be willing to sacrifice memory usage for speed and this is exactly what the jvm does - it uses more memory in order to keep natively compiled code so that it runs faster. RAM is not that expensive and 128 megs is about enough if you are running one virtual machine at a time. If you use Java3D intensively though, I would recommend more than that.
Also if you use C++ and OpenGL to display something versus Java3D it is not really fair, because Java3D has to create many objects in order to provide you with interactivity (mouse picking, etc), while OpenGL will just draw on the screen buffer.
But it's really sad that they seem to have sacrificed the lives of the crew to preserve the secret torpedo design, if that's why they kept the rescuers away from the damaged torpedo section.
If you try and think like a Russian you would see that people are a cheap expendable resource. A sub or even a torpedo is much more important and expensive than a handful of human lives. This is not a troll, I am just presenting the point of view of any high level military official.