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Speed-of-light experiments yield baffling result at LHC

bbc.co.uk

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Re: Speed-of-light experiments yield baffling result at LHC

#121

Post by zeratul »

DanielBMarkham wrote: post #3

A news article where both the scientists and the reporter understate the claims, publish the data, and ask other teams to please prove them wrong. I like this. Most of the time the reporters overstate the research, the scientists keep the data secret, and the general public is left scratching their heads.

This seems to be solid work. First, the group proved that the neutrino speed can be accurately measured in OPERA:

http://arxiv.org/abs/1106.2822 http://iopscience.iop.org/1367-2630/13/5/053051

Second, they compared the neutrino results with light results. Third, they ask to replicate the results in some other environment. This is a normal scientific procedure.

Please also note the number and variety of authors on this work. They will make sure that there is no overstate, understate, secrets, or head scratching.

Re: Speed-of-light experiments yield baffling result at LHC

#122

Post by arcdrag »

bestes wrote: post #62
lutorm wrote: post #43

Earlier quoted context omitted.

Most of the time ... the scientists keep the data secret Um, no. There are plenty of data being released, and in even more cases the scientists are happy to give you the data if you ask. It's very dependent on discipline, though. In astronomy, pretty much all data obtained with publicly funded facilities (e.g. including all large space instruments) are accessible by anyone after a proprietary period of 1 year.

Maybe not secret then, but to be released at a later date. Or released in one of those journals that most of cannot access.

There's often cases of the data literally being measured in tera or peta bytes. Releasing the raw data isn't always feasible.

Re: Speed-of-light experiments yield baffling result at LHC

#123

Post by nikcub »

fleitz wrote: post #47

Keep in mind that given that they said a few billionths of a second that the adjustment to c would be on the order of: (5 nanoseconds) / ((732 km) / c) = 0.000204776269 percent update: AP says it's 60 nanoseconds so (60 nanoseconds) / ((732 km) / c) = 0.00245731523 percent Also in different units: ((60 nanoseconds) / ((732 km) / c)) * c = 16 479.1646 miles per hour Interestingly, the earth moves about 60,000 miles pe…

this isn't about adjusting c, c will always be c

the speed of light in a vacuum is a known quantity, it isn't changing. this is about relativity being void

Re: Speed-of-light experiments yield baffling result at LHC

#124

Post by gue5t »

cpeterso wrote: post #109
nickolai wrote: post #70

Similar results seem to have already been obtained in the past http://en.wikipedia.org/wiki/Neutrino#Speed QUOTE In the early 1980s, first measurements of neutrino speed were done using pulsed pion beams (produced by pulsed proton beams hitting a target). The pions decayed producing neutrinos, and the neutrino interactions observed within a time window in a detector at a distance were consistent with the speed of lig…

> ... found the speed of 3 GeV neutrinos to be 1.000051(29) c. What does the "(29)" in "1.000051(29) c" mean?

http://www.numericana.com/answer/rounding.htm#significant

Re: Speed-of-light experiments yield baffling result at LHC

#125

Post by kpanghmc »

lutorm wrote: post #85
nickolai wrote: post #63

Earlier quoted context omitted.

Um... is there any trace of neutrino bursts before that? Im not sure anyone bothered checking, since such a correlation would have been very hard to justify. A neutrino burst 4 years before a supernova... so what? Could a physicist clarify whether neutrinos could travel at different speeds in vacuum like any 'normal' particle, or are 'fixed speed' like photons. We could well have had several waves with the bulk arriv…

Well, the point is that there was a neutrino burst coincident with SN87a. So if there was one 4yr earlier, too, then you'd have to explain how the same event produced two bursts of neutrinos with different speeds, while within the burst they apparently had exactly the same speed. If neutrinos have mass, they can travel at any speed (Edit: In fact, the arrival interval of those neutrinos puts an upper limit on the neu…

Maybe the neutrinos that appeared 3 hours before the event are from another event altogether (one that occurred even further away, whose light particles haven't even reached us yet)?

Re: Speed-of-light experiments yield baffling result at LHC

#126

Post by artursapek »

nikcub wrote: post #123
fleitz wrote: post #47

Keep in mind that given that they said a few billionths of a second that the adjustment to c would be on the order of: (5 nanoseconds) / ((732 km) / c) = 0.000204776269 percent update: AP says it's 60 nanoseconds so (60 nanoseconds) / ((732 km) / c) = 0.00245731523 percent Also in different units: ((60 nanoseconds) / ((732 km) / c)) * c = 16 479.1646 miles per hour Interestingly, the earth moves about 60,000 miles pe…

this isn't about adjusting c, c will always be c the speed of light in a vacuum is a known quantity, it isn't changing. this is about relativity being void

I think the suggestion is we've mis-measured c, and it should be redefined as the speed these Neutrinos are reaching (if it's a constant maximum)

Re: Speed-of-light experiments yield baffling result at LHC

#127

Post by realou »

buckwild wrote: post #104

I wonder how accurate their time measurements are. If nothing can exceed the speed of light, what makes them think they can rig together hardware that will accurately measure speed at that magnitude?

Light is not that fast. In the time it takes for a photon to travel between your computer screen and your eyes, modern CPUs will be able to execute many instructions.

Re: Speed-of-light experiments yield baffling result at LHC

#128

Post by eavc »

RickHull wrote: post #74
felipemnoa wrote: post #52

Earlier quoted context omitted.

I say you are incorrect. Read this: http://physlink.com/Education/AskExperts/ae509.cfm Here is a relevant piece: When light enters a material, photons are absorbed by the atoms in that material, increasing the energy of the atom. The atom will then lose energy after some tiny fraction of time, emitting a photon in the process. This photon, which is identical to the first, travels at the speed of light until it is abs…

> The delay between the time that the atom absorbs the photon and the excited atom releases as photon causes it to appear that light is slowing down. If the photon is traveling less D over the same amount of T, I am ok with saying the velocity is lower, and it has slowed down.

But equating decrease in velocity with "slowing down" would be confusing for most laypeople, at least.

Nobody would say that they slowed down if they increased their speed as they went through a turn.

Re: Speed-of-light experiments yield baffling result at LHC

#129

Post by VladRussian »

steverb wrote: post #4

I desperately want to believe that this will somehow enable us to live in a Star-Trek future, even though I'm sure it won't. Would someone with some knowledge of physics care to break down the ramifications of this (if it's not some sort of measurement error)? Please?

The Star Trek future, ie. travel with speed faster than light, will most likely happen through "warp drive", ie. using the space expansion(contraction) - this is how the natural faster than light movement does happen in the current Universe, and it doesn't violate Special Relativity.

Special Relativity holds only for space with static and continuous metric (to preview the complexity of the theory otherwise, try to play with Maxwell equations where integration would happen over non-static volumes/surfaces :) . The space expansion doesn't fit the premises of Special Relativity and thus there is no contradiction. Special Relativity is pretty artificial theory which applies to the true world of our expanding (ie. non static metric) Universe only by approximation - this approximation works only as much as the speed of expansion is slow and either time period under consideration is small or distances are small (but not very small as the space continuity premise of SR seems to get broken as we get to Planck distances)

In this particular case of neutrinos, i think, if they integrate Earth gravity time dilation variations along the neutrinos path, it would be correction on the scale around this billionth of second.

Re: Speed-of-light experiments yield baffling result at LHC

#130

Post by [deleted] »

tjic wrote: post #89
olihb wrote: post #53

Earlier quoted context omitted.

Scientist rarely keep the data secret. It's the basis of peer review. There's a reason why open access journals (PLoS One) are getting so popular, scientists want to be known and publish. In my experience, ego is a currency much more valuable than money in academic circles.

> Scientist rarely keep the data secret. It's the basis of peer review. In a better world, that would be true. In this world, it's not. Most of the climate science data that Phil Jones and others have worked with, and most of their models are secret. It is THIS that makes me keep at least one ear open for the "anti-" side in the climate debate. Real science SHOULD be conducted out in the open.

[deleted]
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