9 ms·

CERN Confirms Neutrinos Not Faster Than Light

37 points by sparknlaunch 14y ago

acex 14y ago
were likely goes both ways.
simcop2387 14y ago
While it's awesome that the experiment has been corrected and is now working properly, it is a little disappointing to me that the answer isn't so strange. I would have loved it if it turned out to be something real just because it would have made some form of communication between planets without a delay possible.
- patdennis 14y ago
  Eh, this was never about instantaneous travel, this was about a slight increase in speed. Instantaneous communication causes some serious problems with time/causality anyway. That said, there's always Tachyons. [0] and I think the information transfer that happens during quantum teleportation is faster than light [1] [0]http://en.wikipedia.org/wiki/Tachyon http://en.wikipedia.org/wiki/Tachyon [1]http://en.wikipedia.org/wiki/Quantum_teleportation http://en.wikipedia.org/wiki/Quantum_teleportation
  - mattheww 14y ago
    FYI, quantum teleportation does not transmit information faster than light. You'll notice from the explanation in your link that some information still needs to be transmitted through a classical channel (ie at light speed).
    - patdennis 14y ago
      I am aware... I just thought it was something the commenter would find interesting. Edit: to be clear... I know that quantum transportation doesn't allow for FTL communication... but the fact that the change is not subject to a speed of light delay is what's interesting.
  - planetguy 14y ago
    Eh, this was never about instantaneous travel, this was about a slight increase in speed. The thing you need to understand about relativity is that travelling even slightly faster than the speed of light in any frame of reference is instantaneous communication, in some other frame of reference. If I send a signal from point A and it arrives at point B just infinitesimally faster than the speed of light, then according to an observer in some other reference frame the transmission from A and arrival at B happened simultaneously, and according to some other observer the arrival actually happened before the transmission. It's also important to note that once you have any FTL travel you automatically have time travel (or at least, backwards-in-time communication). But I'd have to draw a diagram to explain why.
    - patdennis 14y ago
      I think you misunderstand >travelling even slightly faster than the speed of light in any frame of reference is instantaneous communication, in some other frame of reference. Even traveling at the speed of light is instantaneous communication... from the photon's frame of reference. If neutrinos were traveling at 3.7 miles per second faster than light it would indicate that we simply don't understand how the universe works. Let me put it this way: Given our current understanding of the universe going faster than the speed of light should violate causality. It should be impossible to travel 3.7 miles per second faster than light without arriving before you left. But that doesn't mean that if these neutrinos were traveling 3.7 miles per second faster than light that it would enable instantaneous communication. C + 3.7 miles per second would still take a long time to travel interstellar distances.
      - planetguy 14y ago
        >Even traveling at the speed of light is instantaneous communication... from the photon's frame of reference. Photons don't have a frame of reference. It makes no sense, in relativity, to talk about a frame in which a photon is at rest, and trying to talk about them only leads to nonsense. I say this not to nitpick, but because the fact that you're trying to use the concept suggests to me that your grasp on relativity might not be that strong. >But that doesn't mean that if these neutrinos were traveling 3.7 miles per second faster than light that it would enable instantaneous communication. C + 3.7 miles per second would still take a long time to travel interstellar distances. An object travelling at c+3.7mps in your reference frame is travelling at infinity miles per second in some other (sensible, subluminal) reference frame, that's the point. This is all undergrad-level stuff.
- zerostar07 14y ago
  But It would also violate causality And render the reply button below irrelevant:
  - excuse-me 14y ago
    Not necessarily, if you pick your reference frame, v>c doesn't necessary violate causality http://www.science20.com/alpha_meme/faster_light_neutrinos_do_not_time_travel_spoil_your_date-83029 http://www.science20.com/alpha_meme/faster_light_neutrinos_d...
    - deleted 14y ago
      [deleted]
    - zerostar07 14y ago
      That requires that the source and detector move relative to each other which is not the case here.
- fusiongyro 14y ago
  It never made sense to me why they publicized the result, since it looked so clearly like some kind of experimental screw up. All it could do is make them look like amateurs when it inevitably came out that they bungled something.
  - okamiueru 14y ago
    I think they were aware of how it looked, as well as the most likely explanation. However, if you have results you cannot explain, you show it to your peers so they can find the error, or confirm the discovery. They never went public and said "we made a discovery". They went public and said "this is what we did, this is what we got".
    - fusiongyro 14y ago
      I question their ability to perform science if they have to rely on their peers to find problems in their own equipment. When my car breaks down, I go to a mechanic to have it fixed, but when my software fails, I don't publish it and ask the community to figure out why it doesn't work.
      - ThePherocity 14y ago
        I question your understanding of how science works. Actually, I question your ability to program also. I often go out to the community to find out if there are other issues, or maybe something simple that I forgot. Using your peers for help is not a weakness, it's a strength.
        fusiongyro 14y ago
        Science is about performing experiments and replicating them, not about debugging hardware. A friend of mine famously complained that his computer was broken because his C programs weren't compiling. He had misspelled "include." The "community" didn't need to step up and help him. He needed to learn how to use his tools.
keypusher 14y ago
In other news: sky is blue, grass is green.
acex 14y ago
end of the article "After months of investigation, physicists have ruled that the speedy neutrinos observed were likely due to a faulty connection in an optical fiber of the Master Clock." i really do wonder why negative attitude to my "were likely goes both ways" - they have ruled (not proved) that something is likely. please. either the article is stupid or those who have ruled.
weichi 14y ago
A very good post on this by Matt Strassler from earlier this year: http://profmattstrassler.com/articles-and-posts/particle-physics-basics/neutrinos/neutrinos-faster-than-light/opera-what-went-wrong/ http://profmattstrassler.com/articles-and-posts/particle-phy... There were apparently two problems: 1. An improperly calibrated clock 2. A fiber optic cable was not fully plugged in. This led to a little bit of light leaking out from the cable, which lead to a (very small) delay in recognition of the arrival of a pulse on the fiber. Yes, modern physics experiments are pretty complicated and lots of things can go wrong!

37 points by sparknlaunch 14y ago

acex 14y ago

were likely goes both ways.

While it's awesome that the experiment has been corrected and is now working properly, it is a little disappointing to me that the answer isn't so strange. I would have loved it if it turned out to be something real just because it would have made some form of communication between planets without a delay possible.

patdennis 14y ago
Eh, this was never about instantaneous travel, this was about a slight increase in speed. Instantaneous communication causes some serious problems with time/causality anyway. That said, there's always Tachyons. [0] and I think the information transfer that happens during quantum teleportation is faster than light [1] [0]http://en.wikipedia.org/wiki/Tachyon http://en.wikipedia.org/wiki/Tachyon [1]http://en.wikipedia.org/wiki/Quantum_teleportation http://en.wikipedia.org/wiki/Quantum_teleportation
- mattheww 14y ago
  FYI, quantum teleportation does not transmit information faster than light. You'll notice from the explanation in your link that some information still needs to be transmitted through a classical channel (ie at light speed).
  - patdennis 14y ago
    I am aware... I just thought it was something the commenter would find interesting. Edit: to be clear... I know that quantum transportation doesn't allow for FTL communication... but the fact that the change is not subject to a speed of light delay is what's interesting.
- planetguy 14y ago
  Eh, this was never about instantaneous travel, this was about a slight increase in speed. The thing you need to understand about relativity is that travelling even slightly faster than the speed of light in any frame of reference is instantaneous communication, in some other frame of reference. If I send a signal from point A and it arrives at point B just infinitesimally faster than the speed of light, then according to an observer in some other reference frame the transmission from A and arrival at B happened simultaneously, and according to some other observer the arrival actually happened before the transmission. It's also important to note that once you have any FTL travel you automatically have time travel (or at least, backwards-in-time communication). But I'd have to draw a diagram to explain why.
  - patdennis 14y ago
    I think you misunderstand >travelling even slightly faster than the speed of light in any frame of reference is instantaneous communication, in some other frame of reference. Even traveling at the speed of light is instantaneous communication... from the photon's frame of reference. If neutrinos were traveling at 3.7 miles per second faster than light it would indicate that we simply don't understand how the universe works. Let me put it this way: Given our current understanding of the universe going faster than the speed of light should violate causality. It should be impossible to travel 3.7 miles per second faster than light without arriving before you left. But that doesn't mean that if these neutrinos were traveling 3.7 miles per second faster than light that it would enable instantaneous communication. C + 3.7 miles per second would still take a long time to travel interstellar distances.
    - planetguy 14y ago
      >Even traveling at the speed of light is instantaneous communication... from the photon's frame of reference. Photons don't have a frame of reference. It makes no sense, in relativity, to talk about a frame in which a photon is at rest, and trying to talk about them only leads to nonsense. I say this not to nitpick, but because the fact that you're trying to use the concept suggests to me that your grasp on relativity might not be that strong. >But that doesn't mean that if these neutrinos were traveling 3.7 miles per second faster than light that it would enable instantaneous communication. C + 3.7 miles per second would still take a long time to travel interstellar distances. An object travelling at c+3.7mps in your reference frame is travelling at infinity miles per second in some other (sensible, subluminal) reference frame, that's the point. This is all undergrad-level stuff.
zerostar07 14y ago
But It would also violate causality And render the reply button below irrelevant:
- excuse-me 14y ago
  Not necessarily, if you pick your reference frame, v>c doesn't necessary violate causality http://www.science20.com/alpha_meme/faster_light_neutrinos_do_not_time_travel_spoil_your_date-83029 http://www.science20.com/alpha_meme/faster_light_neutrinos_d...
  - deleted 14y ago
    [deleted]
  - zerostar07 14y ago
    That requires that the source and detector move relative to each other which is not the case here.
fusiongyro 14y ago
It never made sense to me why they publicized the result, since it looked so clearly like some kind of experimental screw up. All it could do is make them look like amateurs when it inevitably came out that they bungled something.
- okamiueru 14y ago
  I think they were aware of how it looked, as well as the most likely explanation. However, if you have results you cannot explain, you show it to your peers so they can find the error, or confirm the discovery. They never went public and said "we made a discovery". They went public and said "this is what we did, this is what we got".
  - fusiongyro 14y ago
    I question their ability to perform science if they have to rely on their peers to find problems in their own equipment. When my car breaks down, I go to a mechanic to have it fixed, but when my software fails, I don't publish it and ask the community to figure out why it doesn't work.
    - ThePherocity 14y ago
      I question your understanding of how science works. Actually, I question your ability to program also. I often go out to the community to find out if there are other issues, or maybe something simple that I forgot. Using your peers for help is not a weakness, it's a strength.
      - fusiongyro 14y ago
        Science is about performing experiments and replicating them, not about debugging hardware. A friend of mine famously complained that his computer was broken because his C programs weren't compiling. He had misspelled "include." The "community" didn't need to step up and help him. He needed to learn how to use his tools.

keypusher 14y ago

In other news: sky is blue, grass is green.

acex 14y ago

end of the article "After months of investigation, physicists have ruled that the speedy neutrinos observed were likely due to a faulty connection in an optical fiber of the Master Clock." i really do wonder why negative attitude to my "were likely goes both ways" - they have ruled (not proved) that something is likely. please. either the article is stupid or those who have ruled.

weichi 14y ago

A very good post on this by Matt Strassler from earlier this year: http://profmattstrassler.com/articles-and-posts/particle-physics-basics/neutrinos/neutrinos-faster-than-light/opera-what-went-wrong/ http://profmattstrassler.com/articles-and-posts/particle-phy... There were apparently two problems: 1. An improperly calibrated clock 2. A fiber optic cable was not fully plugged in. This led to a little bit of light leaking out from the cable, which lead to a (very small) delay in recognition of the arrival of a pulse on the fiber. Yes, modern physics experiments are pretty complicated and lots of things can go wrong!