Well, fine, if you want to think of it that way, go ahead, Pretty much every single physicist would say you're wrong, but what do they know, with their "degrees"...
PS: the speed of light is the fastest thing we know. Although it might be possible to go faster than that (why not? There is no solid justification for this being the absolute limit, other than our restricted perception and some old "I tell you so"s)
The "solid justification" is that anything faster than the speed of light would, in some reference frame, be equivalent to travelling backwards in time, which would break causality - a property our universe seems to hold with without exception.
Furthermore, the speed of light constant. To all observers. You can never reach the speed of light because light always moves away from you... at the speed of light. If you fly away from Earth at half the speed of light, any light you see will still travel at the speed of light (and both you and Earth would agree on this, even though one of you is travelling faster than the other)
It very much is the limit. It isn't just "very fast." We can't even get close. Literally. No matter how fast you go, you're always travelling at 299 792 458 m / s below the speed of light. It's a fundamental property of our spacetime.
The impracticality of what the other guy suggested is neither here nor there; I posted my reply in protest, really, at your overly critical pedantry.
If you could do what he suggested, then the consequences would indeed be as he suggested. It's a thought experiment. It's meant to be an example, to help you understand the reality, not to prove something.
They key can't be constructed until the participants have communicated over a classical (even public) channel to compare how they made their measurements. Until then, they sort of haven't opened the box with the cat in it.
I may have mixed my metaphors somewhere along the way...
It seems to me that they could very well use it for ftl communications. If you can change the state of one particle to a state that represents either a 1 or 0...
That's just it; you can't do that.
You can only make measurements; you can't influence the result.
"To improve system performance, Lenovo is leading an industry trend of adopting Raid [redundant array of independent disks] on the SSDs [solid state drives] in certain product configurations," it said.
"Lenovo does not intentionally block customers using other operating systems on its devices and is fully committed to providing Linux certifications and installation guidance on a wide range of products."
It added that once Linux-based operating system developers had updated the necessary code, their products should work on its machines.
Once you are in the possession of them, I modify the state of my own particles, which will modify the state of the ones you have as well. You will detect those modifications instantly, when I make them. Or "faster-than-light".
Nope. You can't "modify" anything - you can only make a measurement. And I can't "detect" anything either - I can't tell whether or not you've made a measurement at a certain time (not least because "at a certain time" takes on an indeterminate meaning over distance).
All either of us can do is make a measurement. When I do, which could be before, after, or at a time with an indeterminate relation to yours (thanks to special relativity and relativity of simultaneity) I will find - upon comparing it to a classical transmission from you, telling me what result you got - that I got the same (or a complimentary) result to you.
But what that result is is effectively random. And even then, it isn't a transmission of information. Without the classical confirmation, all I can do is infer that you got a correlated result - you might have messed up, broken the entanglement, and jiggled the photon to a random, uncorrelated state. Or you might have not bothered to make measurement at all, having been eaten by a velociraptor that escaped from the paleoclonology department.
At this point people start wondering why we can't just assume that the photon had this "state" already encoded in it before (as a "hidden variable"). Well... we just can't. Experiments have proved this. It's just weird.
Not really, but if you want a completely descriptive analogy for quantum entanglement... well, there isn't one.
Alice and Bob have two different ways of measuring particles, and each way can give two different results. They might do a "brightness" measurement (analogy) which returns either black or white. Or they might do a "colour" measurement, which returns either red or blue.
The trick is that, although you might think the results are predetermind, and therefore fixed, they're not. If Alice does a brightness measurement and Bob does a colour measurement, there is now no way for Alice to get a colour measurement that will definitely match Bob's. The information is gone. It might match by chance, but it equally might not.
So Alice and Bob measure at random - sometimes brightness, sometimes colour. Later they compare notes on which tests they made on which photons (they can do this in public), and discard any results where they didn't use the same test. The remaining results are what they use to make up their key - a 0 for black-or-red, a 1 for white-or-blue.
If they do a test encrypt, and find that it doesn't work, that indicates someone else was intercepting their photons and screwing up the entanglement (because that person would have no way of knowing whether to test for brightness or colour).
At least, that's my understanding. I could be wrong, and probably am.
How about "not trying"? Uber and their drivers aren't under any greater moral imperative than anyone else to go into a potentially unsafe area to get people home.
Slashdot Mirror
Well, fine, if you want to think of it that way, go ahead, Pretty much every single physicist would say you're wrong, but what do they know, with their "degrees"...
The video-sharing site is looking for "heroes." YouTube is looking for a few good users who want to be "Heroes."
Why not say it a third time, just to really hammer home the point that the editors are totally half-arsing the job they're paid to do?
PS: the speed of light is the fastest thing we know. Although it might be possible to go faster than that (why not? There is no solid justification for this being the absolute limit, other than our restricted perception and some old "I tell you so"s)
The "solid justification" is that anything faster than the speed of light would, in some reference frame, be equivalent to travelling backwards in time, which would break causality - a property our universe seems to hold with without exception.
Furthermore, the speed of light constant. To all observers. You can never reach the speed of light because light always moves away from you... at the speed of light. If you fly away from Earth at half the speed of light, any light you see will still travel at the speed of light (and both you and Earth would agree on this, even though one of you is travelling faster than the other)
It very much is the limit. It isn't just "very fast." We can't even get close. Literally. No matter how fast you go, you're always travelling at 299 792 458 m / s below the speed of light. It's a fundamental property of our spacetime.
The impracticality of what the other guy suggested is neither here nor there; I posted my reply in protest, really, at your overly critical pedantry.
If you could do what he suggested, then the consequences would indeed be as he suggested. It's a thought experiment. It's meant to be an example, to help you understand the reality, not to prove something.
One could easily sweep the spot of a laser across the surface of the moon faster than a light-speed signal would do so.
you could scan the particles and send signals through them
Nope. Doesn't work like that.
Bell's theorem rules out local hidden variables. There might still be non-local hidden variables, but that's just as weird, if not weirder.
Oh shit. I thought you were feeding the cat.
They key can't be constructed until the participants have communicated over a classical (even public) channel to compare how they made their measurements. Until then, they sort of haven't opened the box with the cat in it.
I may have mixed my metaphors somewhere along the way...
It seems to me that they could very well use it for ftl communications. If you can change the state of one particle to a state that represents either a 1 or 0...
That's just it; you can't do that.
You can only make measurements; you can't influence the result.
Based on news like this we've heard in the past, though, transporting to Mars is just 10 years away.
And will continue to be for at least another 50 years.
http://www.bbc.co.uk/news/tech...
"To improve system performance, Lenovo is leading an industry trend of adopting Raid [redundant array of independent disks] on the SSDs [solid state drives] in certain product configurations," it said.
"Lenovo does not intentionally block customers using other operating systems on its devices and is fully committed to providing Linux certifications and installation guidance on a wide range of products."
It added that once Linux-based operating system developers had updated the necessary code, their products should work on its machines.
Once you are in the possession of them, I modify the state of my own particles, which will modify the state of the ones you have as well. You will detect those modifications instantly, when I make them. Or "faster-than-light".
Nope. You can't "modify" anything - you can only make a measurement. And I can't "detect" anything either - I can't tell whether or not you've made a measurement at a certain time (not least because "at a certain time" takes on an indeterminate meaning over distance).
All either of us can do is make a measurement. When I do, which could be before, after, or at a time with an indeterminate relation to yours (thanks to special relativity and relativity of simultaneity) I will find - upon comparing it to a classical transmission from you, telling me what result you got - that I got the same (or a complimentary) result to you.
But what that result is is effectively random. And even then, it isn't a transmission of information. Without the classical confirmation, all I can do is infer that you got a correlated result - you might have messed up, broken the entanglement, and jiggled the photon to a random, uncorrelated state. Or you might have not bothered to make measurement at all, having been eaten by a velociraptor that escaped from the paleoclonology department.
At this point people start wondering why we can't just assume that the photon had this "state" already encoded in it before (as a "hidden variable"). Well... we just can't. Experiments have proved this. It's just weird.
No, you can't, and adding an expletive does not make you correct.
You cannot send random, or any other kind, of information faster than light. That's just not what entanglement/collapse does.
What about Rita, Sue and Bob too?
Not really, but if you want a completely descriptive analogy for quantum entanglement... well, there isn't one.
Alice and Bob have two different ways of measuring particles, and each way can give two different results. They might do a "brightness" measurement (analogy) which returns either black or white. Or they might do a "colour" measurement, which returns either red or blue.
The trick is that, although you might think the results are predetermind, and therefore fixed, they're not. If Alice does a brightness measurement and Bob does a colour measurement, there is now no way for Alice to get a colour measurement that will definitely match Bob's. The information is gone. It might match by chance, but it equally might not.
So Alice and Bob measure at random - sometimes brightness, sometimes colour. Later they compare notes on which tests they made on which photons (they can do this in public), and discard any results where they didn't use the same test. The remaining results are what they use to make up their key - a 0 for black-or-red, a 1 for white-or-blue.
If they do a test encrypt, and find that it doesn't work, that indicates someone else was intercepting their photons and screwing up the entanglement (because that person would have no way of knowing whether to test for brightness or colour).
At least, that's my understanding. I could be wrong, and probably am.
Yeah. You can send random information faster than the speed of light.
No. You can't.
Ah, Hognoxious! You'll have had your tea...
Or just right-click the empty space next to the tabs and select Menu bar. Now you don't have to press Alt at all!
Or, y'know, press Alt...
China Confirms Its Space Station Is Falling Back to Earth
Given that they just launched Tiangong-2 a few days ago, it might have been nice to clarify that it's Tiangong-1 which is falling to Earth.
Fix it fix it fix it fix it!
How about "not trying"? Uber and their drivers aren't under any greater moral imperative than anyone else to go into a potentially unsafe area to get people home.
Ask Slashdot: Why Aren't Techies Improving The World?
Slashdot reader marmot7 isn't impressed by "the latest app that solves some made up problem. I'm impressed by apps that solve real problems..."
Jesus Christ. If the first thing you think of when talking about solving the world's most problems is apps, I don't want you on the funding committee.
The atomic called, dubbed CACS or Cold Atomic Clock in Space, will slow down by only one second in a billion years.
If they know it's going to slow down, and by one second, why don't they just add a billionth of a second a year?
I assume what was meant was "drift by at most one second."