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Speed-of-light experiments yield baffling result at LHC

bbc.co.uk

41–50 of 255 posts

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

#42
post #32

Earlier quoted context omitted.

I'm not smart enough to explain it properly, but basically if information can be transmitted faster than the speed of light, it makes time travel possible. Read "Black Holes and Time Warps" By Kip S. Thorne for a 624 page explanation of why. More likely, it's experimental error. .0025% is meaningless compared to the scale of the earth, but over hundreds of light years it's huge.

http://en.wikipedia.org/wiki/Time_travel#Via_faster-than-lig... If we can send information even a little to the past, we can then send it a little more to the past, and by induction we can send information anywhere in time. So we have infinite power computers. Singularity starts here.

If you can send data a little into the past, compute something, then send the result back to the beginning, you can do an infinite amount of computation in a finite amount of time, just by reusing the same time over and over again. https://secure.wikimedia.org/wikipedia/en/wiki/Closed_timeli...

edit: OK, this blows my mind (from https://secure.wikimedia.org/wikipedia/en/wiki/Tachyon#Speed):

It has been argued that we can avoid the notion of tachyons traveling into the past using the Feinberg reinterpretation principle which states that a negative-energy tachyon sent back in time in an attempt to challenge forward temporal causality can always be reinterpreted as a positive-energy tachyon traveling forward in time. This is because observers cannot distinguish between the emission and absorption of tachyons. For a tachyon, there is no distinction between the processes of emission and absorption, because there always exists a sub-light speed reference frame shift that alters the temporal direction of the tachyon's world-line, which is not true for bradyons or luxons. The attempt to detect a tachyon from the future (and challenge forward causality) can actually create the same tachyon and sends it forward in time (which is itself a causal event).

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

#43

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.

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.

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

#45
post #2

It wouldn't break current theory, it would just mean that photons travel slower than "speed of light" and have non-zero rest mass. Constant c in relativity instead of speed of photons would just mean fastest speed possible.

Not really. The reason the idea of fixing c as the speed limit is that the number arises naturally as the speed of EM waves from Maxwell's equations. Briefly put, these these equations are valid in all frames, the Galilean speed addition rule has to be wrong and c should be standard in all inertial frames.

So you can't just use c for "the highest speed any particle can have in vacuum".

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

#46

Earlier quoted context omitted.

>>The speed of light is not constant I think this is wrong. Regardless of the medium the speed of light is always constant. It seems to slow down because the photons are getting absorbed and re-transmited by atoms. But the speed of light is always the same regardless.

That's splitting hairs in a way that makes you deviate from standard usage of the term. Physicists say things like "the speed of light in water is lower than the speed of light in a vacuum".

But to a lay person that statement does not mean the same thing as for a physicists. To a lay person it sounds as if literally the photons slow down. And I bet that a lot of people repeat this statement thinking that light actually slows down.

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

#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 per hour in relation to the sun, could this be explained by frame dragging / Gravomagnetism? This is pure speculation only because the numbers are with in the same order of magnitude.

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

#48

If I calculated correctly, that's only about .0025% faster than c. Practical implications?

> Practical implications? Print out 90% of physics articles from the century. Get big trash can. Put printout in trash can. Of course i'm exaggerating, but if the story is true, this is going to be big. Speed of light is the main block for things like time travel and a hard limit on communication speed. It doesn't matter that it is only 0.0025%, what matters is that it can be done(if it is confirmed). As a(very poor)…

This is it in a nut shell. While the ramifications are hard to predict at this moment, they are huge. E=mc^2 prob won't effect practical physics that we deal with on a daily basis. but as far theoretical physics the impact is enormous. time space fabric warping, wormholes (existence, creation and artificial stabilization), how fast the universe is speeding apart, our calculations for where things are in our solar system and beyond and a whole host of other things physics relies on the formula to calculate.

what i am most excited for is the possibility to travel faster than the speed of light. conventional theory dictated that the more mass you have the more fuel you would need to break the lightspeed barrier, however the closer you approach the speed of light the more fuel you would need therefore increasing your mass infinitely putting you in a perpetual null loop. but if that equation changes and we know that there are particles that travel faster than light speed limit we may have to re-examine this theorem. Especially with new power sources being discovered on the atomic and quantum levels. The splitting of those bonds if harnessed yield promising potential. Not to mention the existence of antimatter which releases catastrophic amounts of energy when in contact with matter. We can't seem to find any right now so were limited with how much we can make which is a miniscule amount. Limits the production seem to be on a physics level as opposed to a technological one. But who knows if the speed of light is up for discussion almost anything can be in a table.

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

#49

Earlier quoted context omitted.

Don't forget... c is the speed of light 'in a vacuum'. Light travels slower through gas, water or glass. Light has even been slowed down to walking speed in a laboratory. The speed of light is not constant. The speed of light in a vacuum is. We assume.

>>The speed of light is not constant I think this is wrong. Regardless of the medium the speed of light is always constant. It seems to slow down because the photons are getting absorbed and re-transmited by atoms. But the speed of light is always the same regardless.

No, it's correct. The light actually gets slowed down in material (anything else than a vacuum.) That has nothing to do with observation, it's an actual physical effect. The speed of light in a vacuum is constant and so is the speed of light in any particular pure material (like a pure gas.) It's just that those constant speeds are different.

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

#50
If this result is valid then it would mean that neutrinos are capable of traveling .0025% faster than light. There was a supernova that we observed in 1987 (SN 1987) that occurred 168,000 light years away from us. A neutrino burst was observed in 3 different labs about 3 hours before the light was observed. If neutrinos are capable of traveling .0025% faster than the speed of light then why would we observe these neutrinos at a time that is consistent with them traveling at almost exactly the speed of light (slightly less due to their finite mass)? A difference of .0025% would correspond to the neutrinos arriving 4 years earlier! This is the first experimental contradiction to this result that pops into my head but there are probably many more.

Plain and simple, this is most likely due to a systematic error in their experiment that isn't being properly taken into account. The result would tear apart well established theories that have been tested time and time again in thousands of different ways. Of course that doesn't mean that they're absolutely right but it does mean that any contradictory result has to be initially taken with a grain of salt (kudos to the article writer for doing this). It's easy to mess up a calibration in such a complicated system and 60 nanosecond errors could potentially pop up. It will be interesting to see the results from other labs but I would advise against getting your hopes up for any new physics.

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