Look up relativity of simultaneity. I'm not talking about perceived simultaneity (observation) but actual simultaneity corrected for propagation delay. If two events are simultaneous for one observer (after correcting for propagation delay), a different observer with a different speed will disagree. There is no objective way of defining simultaneity. This can be exploited by sending a message back and forth using different frames of reference to really send it back in time.
Relativity says that simultaneity is subjective. One observer will say that lightning strikes two ends of a train at the same time, while another observer will say that the front was struck first, and yet another will say that the back was struck first. I'm not just saying that they see the strikes at different times. They will come to this conclusion based on the time they saw the strikes, the distance to the strikes, and the speed of light in their reference frame (which is always c relative to themselves).
What's more, all of them are correct. There is no prefered reference frame. As long as nothing can travel faster than light, this never leads to any real contradictions. Who cares which lightning strike hit first, if the different strikes were far enough apart so that neither could have possibly influenced the other. Causality is still preserved, simultaneity at different locations is just a matter of labeling.
Things get more complicated, however, if you could send information faster than light. Let's say Alice could send a signal to Bob "instantaneously", meaning Bob's reception is simultaneous with Alice's transmission. A different observer, traveling at a significant speed, will correctly say that Bob received the signal before Alice sent it. This might not immediately cause problems because Alice and Bob are far apart, however things get more complicated when you start sending messages back and forth using different reference frames.
Example: Alice and Bob are 10 light minutes apart from each other, but not moving relative to each other. They synchronize their clocks: Alice sets her clock to 11:30 when she sees 11:20 on Bob's clock, taking the 10 minute time delay into account. At 11:40, Bob sees 11:30 on Alice's clock. They both agree that this means their clocks are synchronized, since it takes 10 minutes for light to travel from one to the other. Now, at 12:00, Alice "instantaneously" sends a message to Bob who receives it at 12:00. Looking at Alice through his binoculars, Bob can still see her clock indicating 11:50 and it will take another 10 minutes before he can see her type the message, but his magical entanglement transmitter has already received it. Imagine at the same time, at 12:00 on Bob's clock, Carol happens to be passing by Bob at high speed, moving away from Alice at a speed of 60% of the speed of light. Of course, in Carol's frame of reference, she is standing still while Alice and Bob are moving with 60% c relative to her. The distance between Alice and Bob, in Carol's reference frame, is only 8 light minutes due to Lorentz contraction. Carol can see exactly the same image from Alice's clock ("11:50"), but since Alice is moving away from Carol at 60% c, this means the clock image must have left Alice exactly 5 minutes ago. At that time, Alice was 5 light minutes away and she has traveled a further 3 light minutes away in the 5 minutes after that. In Carol's reference frame, light travels at a speed of c relative to Carol. So Alice's clock was indicating "11:50" 5 minutes ago. Due to time dilation, her clock is ticking more slowly (80%) so in those 5 minutes it will have advanced to 11:54. So that's what Alice's clock is indicating "now", and Carol is entirely correct when she says that, in fact, the two clocks are not synchronized at all. There is no objective reason to say who is right, different observers can agree to disagree on whether or not two clocks are synchronized. Alice and Bob say the clocks are synchonized, while Carol says that Alice's clock is 6 minutes behind Bob's, and that's OK. This does mean, though, that from Carol's point of view, Alice has not even sent the message yet. Her clock is only indicating 11:54 while she will only send it when her clock shows 12:00. Bob received the message before Alice sent it! But it gets weirder: let's say Bob gives the message to Carol as she is passing by, and she "instantaneously" sends the message back to Alice. Bingo, Alice receives the message at 11:54 (which is "now" according to Carol) befor
That's not how entanglement works. In your example, with entangled photons being sent from halfway between A and B, all A and B can do is measure their particles and then, afterwards, find out that their measurements matched. Neither A nor B can choose which information to send.
It can be proven that both particles really were in a superposition of states until they were measured, and they did not contain any hidden variables that would determine the outcome, so the "information" of what state the particles ended up in had to travel faster than light from one to the other, but A and B have no control whatsoever over this information. All they can do is compare their measurements and find that they somehow ended up matching.
If someone ever did find out how to transmit actual, usable information faster than light in any way, that would automatically mean that it would also be possible to send information back in time. Things that are simultaneous for some observer are actually not simultaneous at all for a different observer who has a different speed (as has been proven with GPS satellites). So something that travels "instantaneously" for one observer, is actually traveling back in time from another point of view. Repeat this back and forth to send information back in time to the same location, allowing you to get tomorrow's stock quotes, or possibly hiring a hit man to kill you before you could send the message you hired him with.
Now, with parallel universes this could still work without contradictions (you might get a message from one universe but end up living in another universe where things are completely different) but it certainly is not as problem free and straightforward as you make it seem.
Trust me, people are not just saying FTL is impossible because they are narrow minded. Scientists that are much smarter than you have thought about this a lot longer and harder than you. That does not mean that they cannot possibly be wrong, but you certainly ought to educate yourself on the subject before dismissing their hard work like that. It's not as simple as you think.
Actually, what they are doing is sending entangled pairs of photons (both of them) through a classical channel (at the speed of light) and using complicated mathematical quantum tricks to make it slightly more likely for the message to arrive without errors. Apparently, using entangled photons allows a more efficient transmission (less errors) than just using ordinary pairs of photons. But the message still travels at the speed of light.
The only faster than light effect that has ever been observed (and has in fact repeatedly been demonstrated), is the situation where a journalist sees the word "entanglement" and immediately starts typing "faster than light communication" without any time delay whatsoever.
In this case, the experiment is about sending entangled photons along a classical channel (interstellar space), using the entanglement to reduce noise a little bit. Those photons still travel at the speed of light, but using a particular quantum trick the error rate can be slightly lower than that achieved by sending non-entangled photons. It's not even a spectacular gain, but I guess every photon counts when you're sending information from a probe that's far away in space.
No faster than light communcation to see here, move along.
Nothing about faster than light communication (which is still impossible as far as we know, and highly unlikely to ever be discovered as it would allow sending messages back in time if our current understanding of relativity is correct).
What they are researching, is sending a larger amount of information over a long distance through space with the same number of photons, by using entanglement to reduce noise somewhat. The idea is quite complicated, google "quantum-enhanced classical communication" for more details, you can find a few related papers that are not behind pay walls (like here), but I couldn't find a decent explanation that doesn't involve pages full of math.
It's definitely not faster than light. Just a clever trick to make it a little (not even a lot) more likely for a message to arrive intact without errors.
Oh, thank god, I mean, it's not like you could use the cranes that move fuel in and out of the plant to cause any havok with radioactive material, right?
Not to mention they're the reason why so many old reactors are having their lives extended. We can't build new, safer ones because "nukes are dangerous".
I bet they are talking about the Airbus Navaero electronic flight bag (EFB) system. It's a standalone add-on system with a large touch screen used for electronic charts, manuals and performance calculations, separate from the actual airplane systems. It can receive certain information from the Flight Management System (airplane and flight ID, GPS position) but as far as I know cannot send anything back. At least I hope it can't. We certainly have to copy the performance data from the EFB into the FMS manually.
Guess what wonderful choice they made for the EFB operating system? Yep, why use common sense if you can use Windoze? It has two USB ports that are strictly for maintenance use (updates), and in my company they screwed a metal plate over those ports to keep us from charging our phones from them. I guess that was a wise precaution, although I doubt it would be enough to keep a determined hacker at bay.
Just wait until they start attacking US websites. It doesn't even have to be sophisticated, DDOS attacks can be quite a bother already. But I wouldn't rule out actual hacking, I mean, it's not like the US government and certainly US companies haven't been hacked before, is it? They have more than enough money to rent some botnets or buy hacking kits. And many of them actually have a university background.
I'm not sure it was a good idea to make so much publicity about these cyberattacks, it might have been a better idea to do them in silence.
Malaria used to be widespread in countries like the Netherlands, which is decidedly non-tropical. They managed to eradicate it by treating patients and killing mosquitos using DDT. The reason it's now a "tropical" disease is because tropical countries are poor.
What I don't get is how a human issues 500 commands in a minute? That's more than 8 per second? What kind of commands are we talking about here? It's been a while since I last played Starcraft, I remember most stuff was mouse based except for some shortcut keys, how do you move the mouse so fast? Any good videos to see these guys in action?
That still makes it unlikely for there to be an infinite series of simulations. In our own universe, for example, we only have a limited amount of time left before we run out of usable energy. OK, it's a lot of time, but still, at some point we'll reach heat death. If the universes below us keep getting slower and slower, there will be one that doesn't get to the point of running simulations before our own universe's computer gets terminated.
And it's a bit unlikely that there would be an infinite series of simulations enclosing us, but not enclosed by us.
Unless our universe is just an unimportant side branch, and the chain of really infinite universes carries on via some other branch.
Let's say our universe is #0, the universe running us is #1, and the universe running that one is #2, and so on.
Sure, #1 won't have to simulate our entire universe, just the "hot" parts we are looking at. But how much of universe #1 is being simulated on #2? Even if the computer in #2 is only evaluating the hot parts of #1, that will still include the entire computer simulating #0. The whole thing needs to be hot in order for it to be able to simulate our hot parts.
That means the computers do get "bigger" (more entropy) as you go up the chain, since each one must at least simulate the entire computer at the level below.
Must be some computer, though, if it can simulate our entire universe. You would think that each simulation must be a bit simpler than the previous one, as it has to "fit" inside. A computer containing all the data of a universe must be "larger" (have more entropy) than that simulated universe.
I know they'll be using compression and last minute calculation for 'observed' events only to keep data size down, but that would be true for the universes above as well. All the actively calculated parts of our universe must be part of the actively calculated parts of the enclosing one, hence the computers need to get bigger as you travel up the chain.
Then again, if universes are infiite anyway, maybe the higher levels are just constantly adding more computing power. I wonder how we are ever going to achieve that, in our expanding universe that has a limited amount of energy that we'll ever be able to access.
It's not a photographic art series. It's a piece of public deception to further Greenpeace's agenda. They try to silence critics by adding the disclaimer "it's just art, it doesn't mean anything" but meanwhile they have reinforced the image of "nuclear power is dangerous" in the minds of the majority of people who don't even bother to read what the lines mean and who don't know that it's perfectly normal for granite stone to emit higher radiation levels.
Typical of Greenpeace. Scare tactics with total disregard of the facts, and hiding behind some lame excuse like "it's just art, it doesn't mean anything".
Meanwhile you can expect news networks to pick this up and show the pictures while saying how all this radiation is threatening the health of those poor school children.
Slashdot Mirror
I, for one, welcome our new Frankenstein overlords.
At least it could if FTL transmission were possible.
Look up relativity of simultaneity. I'm not talking about perceived simultaneity (observation) but actual simultaneity corrected for propagation delay. If two events are simultaneous for one observer (after correcting for propagation delay), a different observer with a different speed will disagree. There is no objective way of defining simultaneity. This can be exploited by sending a message back and forth using different frames of reference to really send it back in time.
Relativity says that simultaneity is subjective. One observer will say that lightning strikes two ends of a train at the same time, while another observer will say that the front was struck first, and yet another will say that the back was struck first. I'm not just saying that they see the strikes at different times. They will come to this conclusion based on the time they saw the strikes, the distance to the strikes, and the speed of light in their reference frame (which is always c relative to themselves).
What's more, all of them are correct. There is no prefered reference frame. As long as nothing can travel faster than light, this never leads to any real contradictions. Who cares which lightning strike hit first, if the different strikes were far enough apart so that neither could have possibly influenced the other. Causality is still preserved, simultaneity at different locations is just a matter of labeling.
Things get more complicated, however, if you could send information faster than light. Let's say Alice could send a signal to Bob "instantaneously", meaning Bob's reception is simultaneous with Alice's transmission. A different observer, traveling at a significant speed, will correctly say that Bob received the signal before Alice sent it. This might not immediately cause problems because Alice and Bob are far apart, however things get more complicated when you start sending messages back and forth using different reference frames.
Example:
Alice and Bob are 10 light minutes apart from each other, but not moving relative to each other. They synchronize their clocks: Alice sets her clock to 11:30 when she sees 11:20 on Bob's clock, taking the 10 minute time delay into account. At 11:40, Bob sees 11:30 on Alice's clock. They both agree that this means their clocks are synchronized, since it takes 10 minutes for light to travel from one to the other.
Now, at 12:00, Alice "instantaneously" sends a message to Bob who receives it at 12:00. Looking at Alice through his binoculars, Bob can still see her clock indicating 11:50 and it will take another 10 minutes before he can see her type the message, but his magical entanglement transmitter has already received it.
Imagine at the same time, at 12:00 on Bob's clock, Carol happens to be passing by Bob at high speed, moving away from Alice at a speed of 60% of the speed of light. Of course, in Carol's frame of reference, she is standing still while Alice and Bob are moving with 60% c relative to her. The distance between Alice and Bob, in Carol's reference frame, is only 8 light minutes due to Lorentz contraction. Carol can see exactly the same image from Alice's clock ("11:50"), but since Alice is moving away from Carol at 60% c, this means the clock image must have left Alice exactly 5 minutes ago. At that time, Alice was 5 light minutes away and she has traveled a further 3 light minutes away in the 5 minutes after that. In Carol's reference frame, light travels at a speed of c relative to Carol. So Alice's clock was indicating "11:50" 5 minutes ago. Due to time dilation, her clock is ticking more slowly (80%) so in those 5 minutes it will have advanced to 11:54. So that's what Alice's clock is indicating "now", and Carol is entirely correct when she says that, in fact, the two clocks are not synchronized at all. There is no objective reason to say who is right, different observers can agree to disagree on whether or not two clocks are synchronized. Alice and Bob say the clocks are synchonized, while Carol says that Alice's clock is 6 minutes behind Bob's, and that's OK.
This does mean, though, that from Carol's point of view, Alice has not even sent the message yet. Her clock is only indicating 11:54 while she will only send it when her clock shows 12:00. Bob received the message before Alice sent it! But it gets weirder: let's say Bob gives the message to Carol as she is passing by, and she "instantaneously" sends the message back to Alice. Bingo, Alice receives the message at 11:54 (which is "now" according to Carol) befor
That's not how entanglement works. In your example, with entangled photons being sent from halfway between A and B, all A and B can do is measure their particles and then, afterwards, find out that their measurements matched. Neither A nor B can choose which information to send.
It can be proven that both particles really were in a superposition of states until they were measured, and they did not contain any hidden variables that would determine the outcome, so the "information" of what state the particles ended up in had to travel faster than light from one to the other, but A and B have no control whatsoever over this information. All they can do is compare their measurements and find that they somehow ended up matching.
If someone ever did find out how to transmit actual, usable information faster than light in any way, that would automatically mean that it would also be possible to send information back in time. Things that are simultaneous for some observer are actually not simultaneous at all for a different observer who has a different speed (as has been proven with GPS satellites). So something that travels "instantaneously" for one observer, is actually traveling back in time from another point of view. Repeat this back and forth to send information back in time to the same location, allowing you to get tomorrow's stock quotes, or possibly hiring a hit man to kill you before you could send the message you hired him with.
Now, with parallel universes this could still work without contradictions (you might get a message from one universe but end up living in another universe where things are completely different) but it certainly is not as problem free and straightforward as you make it seem.
Trust me, people are not just saying FTL is impossible because they are narrow minded. Scientists that are much smarter than you have thought about this a lot longer and harder than you. That does not mean that they cannot possibly be wrong, but you certainly ought to educate yourself on the subject before dismissing their hard work like that. It's not as simple as you think.
Yes, but where did that 'h' come from in his calculation? Dividing $ by W does not give you $/Wh.
If you want $/Wh, you need to divide by the number of hours the plant is expected to operate.
Not to mention superposition.
But if nobody saw them do it, she can be both pregnant and not pregnant at the same time.
Actually, what they are doing is sending entangled pairs of photons (both of them) through a classical channel (at the speed of light) and using complicated mathematical quantum tricks to make it slightly more likely for the message to arrive without errors. Apparently, using entangled photons allows a more efficient transmission (less errors) than just using ordinary pairs of photons. But the message still travels at the speed of light.
The only faster than light effect that has ever been observed (and has in fact repeatedly been demonstrated), is the situation where a journalist sees the word "entanglement" and immediately starts typing "faster than light communication" without any time delay whatsoever.
In this case, the experiment is about sending entangled photons along a classical channel (interstellar space), using the entanglement to reduce noise a little bit. Those photons still travel at the speed of light, but using a particular quantum trick the error rate can be slightly lower than that achieved by sending non-entangled photons. It's not even a spectacular gain, but I guess every photon counts when you're sending information from a probe that's far away in space.
No faster than light communcation to see here, move along.
Nothing about faster than light communication (which is still impossible as far as we know, and highly unlikely to ever be discovered as it would allow sending messages back in time if our current understanding of relativity is correct).
What they are researching, is sending a larger amount of information over a long distance through space with the same number of photons, by using entanglement to reduce noise somewhat. The idea is quite complicated, google "quantum-enhanced classical communication" for more details, you can find a few related papers that are not behind pay walls (like here), but I couldn't find a decent explanation that doesn't involve pages full of math.
It's definitely not faster than light. Just a clever trick to make it a little (not even a lot) more likely for a message to arrive intact without errors.
Excess heat causes the keyboard to expand and flex, breaking the internal wiring.
That's actually a feature.
That might work. Just send a mail to the invoice guys telling them to contact your financial manager at the nigerian address.
Oh, thank god, I mean, it's not like you could use the cranes that move fuel in and out of the plant to cause any havok with radioactive material, right?
In fact, eat a staggering pile of shit.
What kind of advice is that, do you know how much radiation a pile of shit emits?!
Not to mention they're the reason why so many old reactors are having their lives extended. We can't build new, safer ones because "nukes are dangerous".
I bet they are talking about the Airbus Navaero electronic flight bag (EFB) system. It's a standalone add-on system with a large touch screen used for electronic charts, manuals and performance calculations, separate from the actual airplane systems. It can receive certain information from the Flight Management System (airplane and flight ID, GPS position) but as far as I know cannot send anything back. At least I hope it can't. We certainly have to copy the performance data from the EFB into the FMS manually.
Guess what wonderful choice they made for the EFB operating system? Yep, why use common sense if you can use Windoze? It has two USB ports that are strictly for maintenance use (updates), and in my company they screwed a metal plate over those ports to keep us from charging our phones from them. I guess that was a wise precaution, although I doubt it would be enough to keep a determined hacker at bay.
Just wait until they start attacking US websites. It doesn't even have to be sophisticated, DDOS attacks can be quite a bother already. But I wouldn't rule out actual hacking, I mean, it's not like the US government and certainly US companies haven't been hacked before, is it? They have more than enough money to rent some botnets or buy hacking kits. And many of them actually have a university background.
I'm not sure it was a good idea to make so much publicity about these cyberattacks, it might have been a better idea to do them in silence.
That means there will be a hell of a lot of dimensions as you travel further up the chain. And there won't be many below us.
Malaria used to be widespread in countries like the Netherlands, which is decidedly non-tropical. They managed to eradicate it by treating patients and killing mosquitos using DDT. The reason it's now a "tropical" disease is because tropical countries are poor.
What I don't get is how a human issues 500 commands in a minute? That's more than 8 per second? What kind of commands are we talking about here? It's been a while since I last played Starcraft, I remember most stuff was mouse based except for some shortcut keys, how do you move the mouse so fast? Any good videos to see these guys in action?
That still makes it unlikely for there to be an infinite series of simulations. In our own universe, for example, we only have a limited amount of time left before we run out of usable energy. OK, it's a lot of time, but still, at some point we'll reach heat death. If the universes below us keep getting slower and slower, there will be one that doesn't get to the point of running simulations before our own universe's computer gets terminated.
And it's a bit unlikely that there would be an infinite series of simulations enclosing us, but not enclosed by us.
Unless our universe is just an unimportant side branch, and the chain of really infinite universes carries on via some other branch.
Let's say our universe is #0, the universe running us is #1, and the universe running that one is #2, and so on.
Sure, #1 won't have to simulate our entire universe, just the "hot" parts we are looking at. But how much of universe #1 is being simulated on #2? Even if the computer in #2 is only evaluating the hot parts of #1, that will still include the entire computer simulating #0. The whole thing needs to be hot in order for it to be able to simulate our hot parts.
That means the computers do get "bigger" (more entropy) as you go up the chain, since each one must at least simulate the entire computer at the level below.
Must be some computer, though, if it can simulate our entire universe. You would think that each simulation must be a bit simpler than the previous one, as it has to "fit" inside. A computer containing all the data of a universe must be "larger" (have more entropy) than that simulated universe.
I know they'll be using compression and last minute calculation for 'observed' events only to keep data size down, but that would be true for the universes above as well. All the actively calculated parts of our universe must be part of the actively calculated parts of the enclosing one, hence the computers need to get bigger as you travel up the chain.
Then again, if universes are infiite anyway, maybe the higher levels are just constantly adding more computing power. I wonder how we are ever going to achieve that, in our expanding universe that has a limited amount of energy that we'll ever be able to access.
It feels real because I am actually a player from the outer universe that is fully immersed in this simulation.
It's not a photographic art series. It's a piece of public deception to further Greenpeace's agenda. They try to silence critics by adding the disclaimer "it's just art, it doesn't mean anything" but meanwhile they have reinforced the image of "nuclear power is dangerous" in the minds of the majority of people who don't even bother to read what the lines mean and who don't know that it's perfectly normal for granite stone to emit higher radiation levels.
Typical of Greenpeace. Scare tactics with total disregard of the facts, and hiding behind some lame excuse like "it's just art, it doesn't mean anything".
Meanwhile you can expect news networks to pick this up and show the pictures while saying how all this radiation is threatening the health of those poor school children.