Faster than the speed of light?

Brogan

🦶 Leg end
Staff member
Puzzling results from Cern, home of the LHC, have confounded physicists - because it appears subatomic particles have exceeded the speed of light.

Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away seemed to show up a tiny fraction of a second early.

The result - which threatens to upend a century of physics - will be put online for scrutiny by other scientists.

In the meantime, the group says it is being very cautious about its claims.
I'm not sure what to make of this really.
It throws everything up in the air, as far as physics is concerned.

http://www.bbc.co.uk/news/science-environment-15017484
 

mjo

Procrastinating
Contributor
I suppose it just shows how fast physics has come when they can measure in billionths of a second. But as you say, a century of physics research could be thrown up into the air. I think that it would have to be tested numerous times though before any real conclusions can be drawn. But still, this is quite remarkable.
 

Brogan

🦶 Leg end
Staff member
They've been testing for 3 years apparently, so they must be fairly confident to put it out for peer review.
 

jez101

Bookies drive nice cars because of people like me
Contributor
I have no basis for wondering this, but it always seemed a bit easy saying nothing coould travel faster than light, when we have always used light to investigate... If something is faster than light, you can't see it using light?
 
The fact that the discrepancy in the rule is measured in billionths points to un discovered flaws in the measuring system or some other process

If the relativity law was incorrect with regards to sub atomic particles why wouldn't they be twice or ten times faster than light?

I think that's the reason there is no attempt to claim a big discovery, instead inviting others to find the error

If the particles were clocked at twice the speed of light I am sure there would be a massive claim of a breakthrough
 

ExtremeNinja

Karting amateur
Contributor
This is where the "Ph" comes from in "PhD". The "Ph" stands for "Philosophy" which is a much humbler title than the "one truth" claimed by many religions.
 

Road of Bones

MTC Mole
Premium Contributor
Interesting, but the fact that it's such a small discrepancy makes me concur with CFS - it's probably a measurement error. Having said that, if they've logged over 15,000 events in 3 years, you'd have thought they'd have checked their instruments. Do they say if it's a consistent difference?

I don't think we'll be able to construct a warp drive yet, sadly...
 

Road of Bones

MTC Mole
Premium Contributor
I enjoyed the bit about the "magnetic horns", and the part about the kicker signal being used as an arbitrary time measurement baseline made me ROFL. Those crazy Swiss, eh? Too much (navel) Lindt, if you ask me...

I take it all back - I expect a warp drive within 0.7933 x 10(-4) of a century, at the very earliest (+ 2/3 of a man-week, give or take a neutrino or two...).

:twisted:
 

Bill Boddy

Professional layabout
Premium Contributor
I suppose it just shows how fast physics has come when they can measure in billionths of a second. ....
In the early seventies we were measuring events in the tens of picoseconds. The R&D people were working on fantosecond devices. I was surprised when they said nanoseconds, at light speeds that is an age.
 

sushifiesta

Champion Elect
Contributor
Ok well I'll come out the closet - I'm spending the last year of my Physics Masters degree at CERN and I've been in Switzerland for two weeks now. This caught my attention so I actually went to the seminar on it yesterday afternoon. The room was packed full, lots of people with cameras (mainly scientists) and lots of loud applause and questions at the end.

Before I attempt any sort of answers to any comments be warned that although I'm at CERN don't take me as some expert. I'm spending the last year of my undergraduate degree here, which basically makes me the least qualified person here (the only qualifications I've completed officially so far are A Levels :D). Also, I'm writing this at 3am so bear with me!

I think that it would have to be tested numerous times though before any real conclusions can be drawn.
This is the key really. You won't find many people rewriting the laws of Physics before at least one/two independent experiments get the same result. There has been a couple of previous experiments (in particular one by MINOS and one based on neutrinos from a Supernova) that did not find neutrinos travelling faster than light, or at least couldn't claim that when the error in their experiments is taken into account (I think MINOS found a neutrino speed above the speed of light but the error in their result meant it still could be less).

They've been testing for 3 years apparently, so they must be fairly confident to put it out for peer review.
Yep, they've made it public because it's got to the point where they've gone through and checked everything multiple times so they're looking for suggestions from the scientific community to see whether someone can find a flaw/error in their method/results.

I have no basis for wondering this, but it always seemed a bit easy saying nothing coould travel faster than light, when we have always used light to investigate... If something is faster than light, you can't see it using light?
Not quite, that's a bit like saying you couldn't measure the speed of a car because you can't run as fast as it. The experiment is just measuring the time taken for the neutrinos to travel a large distance, nothing needs to be moving faster than the speed of light. It's basically just the equivalent of you tellling a friend a mile away to sound a foghorn at 12pm and then you measuring the time you heard it. I'm not sure this will satisfy you so feel free to probe me more...

The fact that the discrepancy in the rule is measured in billionths points to un discovered flaws in the measuring system or some other process

If the relativity law was incorrect with regards to sub atomic particles why wouldn't they be twice or ten times faster than light?
The difference is small like you say, but the error in their measurements is smaller. From memory I think the neutrinos arrive 6 billionths of a second earlier than expected, with an error of +/- 1 billionth of a second, so at worst within this measurement the neutrinos are 4 billionths of a second 'faster' than expected. It's also measured to the six sigma level, which (from memory again...) means there is only around a 1 in 500 million chance that this effect is just down to chance (just a fluke). These may not be the correct numbers exactly, but the reasoning is the same - a small difference but a difference nevertheless.

Your second question is something that physicists will probably be spending the next few decades figuring out if this measurements proves to be correct. I suspect the explanation would come from a complicated new treatment of neutrinos or extra dimensions or something, rather than a reformation of the whole of Physics that would result from removing the 'natural speed limit' that is the speed of light.

Has anyone attempted reading the report ? :dizzy::coffee:
I haven't tried myself, I might do if I get some free time, but I didn't really understand any of the talk yesterday either :thinking:, so don't feel too bad!!

I'll leave it at that for now - I am happy to try my bit at answering any more questions etc. though (once I've had sleep). Basically the impression I got from the talk was that they've been very thorough in their work so I definitely don't think it's just a load of hype. Having said that the general consensus seems to be that they've made an innocent mistake or haven't taken into account some effect that would account for the discrepancy, and it's just a matter of time before someone finds it.

If the Higgs Boson isn't found within a year or so that will also create a lot of head scratching.

EDIT: Actually, just a quick point. CERN (the neutrino source) seems to be getting a lot of credit for this, but I'm pretty the bulk of the analysis was done by physicists at Gran Sasso laboratory (the neutrino arrival point). Even more worrying is that I've seen articles that link it to the LHC when in fact the LHC has basically nothing to do with it at all. The neutrinos are accelerated by a differenct particle accelerator at CERN - the SPS (Super Proton Synchrotron). This is also used to inject protons into the LHC but that's where the LHC link ends.
 
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