# Can neutrinos travel Faster Than Light **URL:** \ **Category:** Factual Questions\ **Created:** [September 22, 2011, 10:59pm UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266 "2011-09-22T22:59:06Z")\ **Posts on this page:** 20\ **Page:** 21
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [November 20, 2011, 10:13am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/401 "2011-11-20T10:13:32Z")
nm ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 20, 2011, 1:10pm UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/402 "2011-11-20T13:10:46Z")
> [@Half\_Man\_Half\_Wit](#): > > … As for the whole mass and higher dimensions thing… Thank you for walking me through that and I think I even follow it … mostly. Well, okay, somewhat. 🙂 ---
**Author:** ![nivlac](https://avatars.discourse-cdn.com/v4/letter/n/3bc359/32.png) [@nivlac](https://boards.straightdope.com/u/nivlac)\ **Post date:** [November 20, 2011, 8:33pm UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/403 "2011-11-20T20:33:54Z")
I’ve read this entire thread with great interest, as well as the original OPERA paper. I don’t pretend to understand all (or for that matter, much) of it. However, seeing the scientific process work itself out is awesome to me. The OPERA scientists did as diligent a job as they could and put forth their findings for all to review and criticize. Other scientists have offered counter explanations for the OPERA results. The OPERA scientists reran their experiment in a modified form to remove another source of systematic uncertainty. And the work to replicate their results go on. Ain’t this grand? Wouldn’t it be equally grand if the OPERA results are indeed confirmed? That would force refinements to existing theory, and who knows, that could lead to breakthroughs in answering the big open questions in physics. Exciting times for sure! ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [November 20, 2011, 10:41pm UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/404 "2011-11-20T22:41:24Z")
Now if they could only set up an apparatus where if neutrinos from the future are detected, the accellerator won’t make them… 😃 ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [November 21, 2011, 2:17am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/405 "2011-11-21T02:17:58Z")
Two contradictory updates… [New test finds neutrinos still faster than light](http://www.reuters.com/article/2011/11/18/us-science-neutrinos-light-idUSTRE7AH0T720111118) [Study Rejects Faster Than Light Finding.](http://www.reuters.com/article/2011/11/20/us-science-neutrinos-idUSTRE7AJ0ZX20111120) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 21, 2011, 5:48am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/406 "2011-11-21T05:48:18Z")
That “rejection” link is something that folks have been talking about since immediately after the experiment. Basically, all it is is saying that they can’t be superluminal, because the laws of physics say that superluminal particles would lose all of their energy. Personally, I think it’s a rather silly argument, since so far as we can tell, the laws of physics also say that superluminal particles can’t exist in the first place. Either way, if the experimental results hold up under extensive further tests, what it means is that our current understanding of the laws of physics are flawed. And if the laws saying that superluminal particles can’t exist at all are flawed, who’s to say that the laws saying that those nonexistent particles would lose all their energy might not also be flawed? ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [November 21, 2011, 6:14am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/407 "2011-11-21T06:14:06Z")
I noticed earlier on in this thread the speculation that the “speed of light” is maybe just a bit higher than we thought it was, eg its the speed of neutrinos and the speed of photons in a vacuum is slightly lower for some reason. (Vacuum polarization?) Is there another mathematical way of determining the speed of light from first principles or has it only ever been measured experimentally? Or another way to put it, would the finding that our measurement of c (from photons) was a little lower than the absolute speed limit overthrow lots of other areas of physics? ---
**Author:** ![Koxinga](https://avatars.discourse-cdn.com/v4/letter/k/4af34b/32.png) [@Koxinga](https://boards.straightdope.com/u/Koxinga)\ **Post date:** [November 21, 2011, 7:42am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/408 "2011-11-21T07:42:26Z")
> [@coremelt](#): > > Is there another mathematical way of determining the speed of light from first principles or has it only ever been measured experimentally? Given that Einstein’s theories were published over 100 years ago, I’m guessing it had to be mathematics first and experimentation later. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [November 21, 2011, 9:26am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/409 "2011-11-21T09:26:16Z")
> [@Koxinga](#): > > Given that Einstein’s theories were published over 100 years ago, I’m guessing it had to be mathematics first and experimentation later. I am not a physicist, but I was under the impression that special relativity and general relativity establish relationships between energy, mass and the speed of light, but do they actually define numerically a value for the speed of light? AFAIK, that’s always been measured experimentally and then plugged into Einstein’s equations. The speed of light was first measured quite a while before Einstein. “After Maxwell published his theory of electromagnetism it became possible to calculate the speed of light indirectly from the magnetic permeability and electric permitivity of free space. This was first done by Weber and Kohlrausch in 1857. In 1907 Rosa and Dorsey obtained 299,788 km/s in this way. It was the most accurate value at that time.” > **[How is the speed of light measured?](https://www.desy.de/user/projects/Physics/Relativity/SpeedOfLight/measure_c.html)** ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [February 21, 2012, 12:38am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/410 "2012-02-21T00:38:15Z")
A [blog post](http://www.science20.com/hammock_physicist/great_neutrino_tsunami-87080), a few days ahead of the 25th anniversary\* of Supernova 1987a, has a link to a [del]brand new[/del] 14 year old [paper (PDF)](http://www.ltscotland.org.uk/Images/OnVelocities_tcm4-649521.pdf), analyzing some neutrino detections almost five hours earlier than the ones typically associated with the Supernova, and showing that they are consistent with superluminal neutrinos for at least one of the mass eigenstates. - Feb. 23. Only two shopping days left! The relevant part about the earlier detections: > [@](#): > > Indeed, it has been possible to reconstruct that the first photografic obser- > vation of SN1987A was recorded between 09h:36min and 10h:38min GMT, > while the neutrino burst was observed at 07h:36min GMT [20], [23], [27]. > Hence the delay was within 2 and 3 hours. > > The picture seems consistent, however there is an experimental observation > which is currently un-explained: the LSD experiment at Mont Blanc observed > 5 events within 7 sec, with energy between 5.8 and 7.8 MeV [21], [28] (errors > of about 1-2 MeV according to [28], energy resolution of about 15% or 25% > according to [30]), earlier than K2 and IMB by 4h:43min:4.58sec [21], [28]. The > events were consistent with electron neutrinos events [21], [29]. Obviously the speed won’t match the OPERA speed, but it’s intriguing, and I thought others would want to read it. ETA: I’d be interested in whether developments since the paper was written, e.g. better knowledge of neutrino mass differences, affect the results. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [February 21, 2012, 1:09am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/411 "2012-02-21T01:09:56Z")
Also, what’s the current status of the faster-than-light neutrino results from last year? My most recent result from a google search is over a month old. It lists some reasons to be skeptical, but maintains an inconclusive note: [http://arstechnica.com/science/news/2012/01/if-them-neutrinos-are-faster-than-light-physicists-have-a-lot-of-work-to-do.ars](http://arstechnica.com/science/news/2012/01/if-them-neutrinos-are-faster-than-light-physicists-have-a-lot-of-work-to-do.ars) ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [February 21, 2012, 1:12am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/412 "2012-02-21T01:12:15Z")
Here’s something more recent, from just today: [http://www.foxnews.com/scitech/2012/02/20/answer-to-shocking-faster-than-light-particles-expected-soon/](http://www.foxnews.com/scitech/2012/02/20/answer-to-shocking-faster-than-light-particles-expected-soon/) It just says that some experiments designed to confirm or disconfirm the results will come out this Spring. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 21, 2012, 1:42am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/413 "2012-02-21T01:42:47Z")
Huh, I hadn’t realized that the MINOS experiment was proceeding so quickly. That’s great. ---
**Author:** ![Fiendish\_Astronaut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fiendish_astronaut/32/3295_2.png) [@Fiendish\_Astronaut](https://boards.straightdope.com/u/Fiendish_Astronaut)\ **Post date:** [February 21, 2012, 3:19am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/414 "2012-02-21T03:19:25Z")
What annoys me about this whole thing is that the GPS technology used to measure the distances involved is based on Einsteins relativity work. So isn’t it the case that any experiment that might test relativity but also uses GPS must necessarily be flawed? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 21, 2012, 3:24am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/415 "2012-02-21T03:24:36Z")
> [@](#): > > What annoys me about this whole thing is that the GPS technology used to measure the distances involved is based on Einsteins relativity work. So isn’t it the case that any experiment that might test relativity but also uses GPS must necessarily be flawed? The GPS system is extremely well tested, via means which don’t as directly depend on relativity (in fact, GPS is the best experiment we have, for some aspects of the theory). And ultimately, any experiment to test some theory _must_ involve predictions of that theory: At worst, if you invalidate the theory, you just can’t tell which aspect of it you’re invalidating. Then there’s the problem that everything is all interconnected: Question _too_ far, and you end up just wondering whether you might be a brain in a jar. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [February 21, 2012, 3:40am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/416 "2012-02-21T03:40:34Z")
> [@Fiendish\_Astronaut](#): > > What annoys me about this whole thing is that the GPS technology used to measure the distances involved is based on Einsteins relativity work. So isn’t it the case that any experiment that might test relativity but also uses GPS must necessarily be flawed? In **Frylock** ’s link in Post 412, in the section **Other sources of error** a little over halfway down: > [@](#): > > For example, some worried that the use of GPS satellites to time the departure of the neutrinos from CERN in the original experiment was introducing flaws. In response, the OPERA physicists conducted the experiment again, using only atomic clocks to measure timing, and still came up with the same result. ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [February 21, 2012, 5:19am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/417 "2012-02-21T05:19:04Z")
> [@Chronos](#): > > Huh, I hadn’t realized that the MINOS experiment was proceeding so quickly. That’s great. The key is that the lab recently decided to delay the upcoming year-long accelerator shutdown, which allows MINOS to collect a small amount of data with new timing equipment, which in turn lets one better calibrate older data. (The shutdown was actually delayed for unrelated reasons; the benefit to the MINOS time-of-flight measurement is a side bonus.) This year’s result won’t have the ultimate MINOS sensitivity, but it will be a significant improvement over the earlier MINOS result and will hopefully have enough precision to say something strong about the OPERA claim. The full MINOS precision will still come after the accelerator complex starts back up next year and MINOS takes additional data. ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [February 22, 2012, 9:51pm UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/418 "2012-02-22T21:51:18Z")
And just in time for another [hypothesis](http://arstechnica.com/science/news/2012/02/faster-than-light-neutrino-result-apparently-a-mistake-due-to-loose-cable.ars)to explain the FTL result: ---
**Author:** ![Koxinga](https://avatars.discourse-cdn.com/v4/letter/k/4af34b/32.png) [@Koxinga](https://boards.straightdope.com/u/Koxinga)\ **Post date:** [February 22, 2012, 11:56pm UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/419 "2012-02-22T23:56:17Z")
> [@leahcim](#): > > And just in time for another [hypothesis](http://arstechnica.com/science/news/2012/02/faster-than-light-neutrino-result-apparently-a-mistake-due-to-loose-cable.ars)to explain the FTL result: From what I gather from the above discussion, the atomic clocks in question were only used on a second experiment undertaken to confirm the first experiment hadn’t been distorted by the use of GPS satellites? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 23, 2012, 12:53am UTC](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266/420 "2012-02-23T00:53:17Z")
Atomic clocks were used in all of the experiments. The difference between the two experiments was just in how the clocks at the different locations were synchronized with each other. [Previous page](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266.md?page=20) [Next page](https://boards.straightdope.com/t/can-neutrinos-travel-faster-than-light/597266.md?page=22)