Can Relativity Explain Faster Than Light Particles? 315
gbrumfiel writes "Two weeks ago, researchers claimed particles called neutrinos were travelling faster-than-light and violating the laws of special relativity. But now it looks as though general relativity might be behind the experiment's unusual result. An independent analysis claims that the original experiment, known as OPERA, failed to take into account differences in earth's gravitational field between the neutrino source and the OPERA detector. As Nature News reports, gravity can distort time according to Einstein's theory, and the effect could explain why neutrinos appear to arrive 60 nanoseconds ahead of schedule. The OPERA team is now reviewing the new analysis."
Exactly what I was thinking (Score:2)
Except with all the math half-way worked out.
I'm impressed (Score:2)
Re:I'm impressed (Score:4, Funny)
I worked it out half way.
Then I worked out half of the remaining math.
Then I...
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I worked it out half way.
Then I worked out half of the remaining math.
Then I...
...died.
Re:I'm impressed (Score:4, Insightful)
Steve ?
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I'm lazy, and...
Dear CERN, (Score:3, Funny)
Nice try.
Sincerely,
Einstein
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Re:Dear CERN, (Score:4, Insightful)
Einstein was neither anonymous nor a coward.
How can you prove that Einstein was never anonymous?
The OPERA team is NOT reviewing the new analysis. (Score:5, Informative)
They are reviewing their own paper to make their methods clear. FTFA:
"Dario Autiero of the Institute of Nuclear Physics in Lyons (IPNL), France, and physics coordinator for OPERA, counters that Contaldi's challenge is a result of a misunderstanding of how the clocks were synchronized. He says the group will be revising its paper to try to make its method clearer."
Meaning: Contaldi didn't understand how OPERA did it, and thought they had commited a somewhat stupid mistake. OPERA says they didn't make that error, and that they'll rewrite that part of the paper to make this clear. In other words, this is not news at all.
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Mod parent up +5 informative - and thread over.
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Even if it is just a matter of clarifying the paper, it's still peer review in action. When OPERA responds, Contaldi will have the opportunity to review their clarifications. Maybe he'll respond again and point out that OPERA is still in the wrong. Or maybe he'll be satisfied and move on. This is how science is done. How is that not news?
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It's not news for one of two reasons, because one of two things is true:
Contaldi has poor reading skills. 'Peer review' is of low value from people who can't understand straightforward explanations that were understood by others.
or:
Science is proceeding as normal, and the outcome is still unknown .
Wake me when science reaches a conclusion, every minor typography fix on this paper is not newsworthy.
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I think you're being too harsh. Clarity is important. Misunderstandings get people on the wrong way. I think it's much better to add a clarification than to complain about people misreading the work.
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Oh, it's news all right. Just not end-of-the-world-as-we-know-it news. As pointed out in TFA, it's awfully hard to critique the experiment unless you're there seeing exactly what has been done. While I don't find it surprising that a few printed (or electronic) pages cannot describe hundreds of tons of equipment and countless hours of work it does speak to the complexity of modern science.
You wonder how much that is published isn't repeatable or understandable. Dropping rocks off off buildings and count
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"Dario Autiero of the Institute of Nuclear Physics in Lyons (IPNL), France, and physics coordinator for OPERA, counters that Contaldi's challenge is a result of a misunderstanding of how the clocks were synchronized. He says the group will be revising its paper to try to make its method clearer."
The heck with that! What I want to know is: How can a company that gives away a free browser possessing only a minuscule market share afford to employ a physics coordinator?
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I was about to mod you funny but then I tought it better: while he's not on peasant wages, the fact remains that even "just" senior engineers from Opera will probably earn more than that guy.
How the hell am I going to mod something funny when it makes me feel so depressed?
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Meaning: Contaldi didn't understand how OPERA did it, and thought they had commited a somewhat stupid mistake. OPERA says they didn't make that error.
OPERA says that they didn't make that error. But, they also learned about the mistake only through Contaldi's challenge.
Causality has been a bit off recently.
Seriously? (Score:3)
Re:Seriously? (Score:4, Funny)
Re:Seriously? (Score:5, Informative)
I hate to say this, because I know it's probably painfully obvious to most people, but I have no idea what you're talking about.
He's talking about GPS. In order for the triangulation to work correctly, relativity must be taken into account [ohio-state.edu].
That said, another poster pointed out [slashdot.org] that the researchers apparently did account for the effects of gravity when synchronizing their clocks. The paper just wasn't sufficiently clear on that point, and they're rewriting that section.
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Here's my thought, probably not worth the time I took to write it.
IF General Relativity is wrong, then all measurements depending upon it are also wrong. To Verify the results, we would need another form of measurement that doesn't depend on GR for accuracy at the distances and speeds we're using.
We are so dependent upon our view that if the glass we're viewing through is distorted, everything that follows would also be distorted. GR may be much like Newtonian theory of gravity, where it works fine in many
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Global Positioning System (GPS)
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I think he's trying to get at the fact that time distortion of gravity is well known and that GPS (the 18 year old system) wouldn't work or would not work well if this wasn't taken into effect.
I am not sure that his rant is correct though, it's a small (nanosecond according TFA) difference. GPS has known uncertainties and this may very well be much smaller than known / common causes of error. It's not like the US military planned on having physicists using the GPS system for off the wall research. They w
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I hate to say this, because I know it's probably painfully obvious to most people, but I have no idea what you're talking about.
Don't let that get in the way of giving your opinion! ;)
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"What is GPS?"
I suppose the comma could have been in the first line as well... curse you Slashdot!
Re:Seriously? (Score:5, Insightful)
They did consider it, the critic had a brain fail and misunderstood their paper. The researchers are doing him a kindness and 'clarifying' it for him, even though everyone else got that they had, in fact, accounted for this.
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Disappointing, but expected. (Score:2)
WRONG! (Score:5, Informative)
THIS IS CORRECT SCIENTIFIC PROCEDURE!
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THIS IS CORRECT SCIENTIFIC PROCEDURE!
Aside from the part where it gets plastered all over the media rather than a quiet discussion with their peers.
Re:WRONG! (Score:5, Interesting)
That's what you get with open access science. The alternatives are simple: make the public smarter or treat them like dumb animals and don't tell them anything. I prefer the former, even if it is more difficult.
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I think you're reading the surface words rather than the universally-understood subtext.
It's like when a scientific paper says "We were unable to replicate the results of Jones et al".
This doesn't mean "we were unable to replicate the results of Jones et al". Instead it means "Jones et al were either a bunch of nincompoops who didn't understand what they were doing, or they actively falsified their work".
Or when you call someone a poopie-head. It doesn't mean you think their head is made of poop; it means y
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I think maybe you overreacted a bit there? I'm sure the false cold fusion fiasco left a bitter taste in the mouth, but the announcement of this was nothing like that, and was much more careful. Yes the news topic here changed the meaning slightly, but you honestly think as a result that people might harpoon CERN and say "You promised these particles were faster that light, and you were wrong - shock! horror! etc.".
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At least (Score:2)
challenges to research are actively encouraged in some aspects of science whereas they are unfortunately denounced in others. I am glad to see this team inviting others to find the faults if any, now to see this applied to more politically sensitive subjects would be nice
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challenges to research are actively encouraged in some aspects of science whereas they are unfortunately denounced in others. I am glad to see this team inviting others to find the faults if any, now to see this applied to more politically sensitive subjects would be nice
You are not the first person to drop this in to this discussion so I'll answer that. There are two fields that people typically mean by "others" evolution and climate change; the main other ones I can think of are RF radiation risks and cigarette safety. In both of these, I, a layman from each field, have been able to quickly identify fundamentally missing literature from each challenge I have seen. I don't mean "they were wrong"; I don't mean "they misunderstood". I mean, they either failed to find th
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Media: "Scientists say: FUCK YOU EINSTEIN!!! YEAH THAT'S RIGHT MOTHERFUCKE
"Speed" (Score:4, Interesting)
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All of relativity is premised on the (very consistently verified) notion that speed isn't just distance/time as Newtonian mechanics would understand it, and that you must also take in to account the effects of gravity on spacetime.
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The article states that because they moved the atomic clock used for measuring time, their time synchronization would be different for the clock while it was in italy, then when the clock was in switzerland. The difference in time synchronization is what they measured, not the speed of light.
Of course, they knew about this effect, & tried to off-set it by using GPS signals from the same satellite to correct. TFA says that GPS signal has error in time sync about 100ns, which is in scale with their
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Are they using some other measurement of "speed" that isn't distance / time? It seems that slowing time down and going the same "speed" has the same net effect as going faster than the speed of light.
To your first question, ... yes, kind of. But to point, the article apparently suggests that they made an error in measuring the amount of time that the particles traveled the distance. This isn't much different than my acknowledgement that a 60 ns error could be accounted for by an ~60 foot discrepancy in the distance measurement. (Note: when I say "measurement" here, I'm really meaning more "calculation"... at these exacting standards measurement alone is insufficient, you need to make multiple measuremen
Should already be considered (Score:2)
If it turns out that time dilation due to gravity is the reason, then the error must be in the ETRF2000 or it was applied incorrectly in this case (Neutrinos moving from A to B). Considering that hundreds of people work on this project it seems unlikely t
I believe GR & SR (Score:2)
I personally chalk it up to the measurement between the emitter and the detector.
Yes I know they say they are very confident within a margin of error and that amount they are observing is within that margin of error so it must be right??
Personally I aint gonna start changing C based upon their confidence that their variation is within the margin of error that they say is within the margin of error of the distance between the gun and the target since everything else in GR & SR has been demonstrated corre
Time dilation of the earth? (Score:2)
failed to take into account differences in earth's gravitational field
Even if they didn't account for it, so what?
The Schwarzschild solution for Time dilation has a C squared in the divisor.
Unless I'm doing the math wrong, It wouldn't even amount to 1 nanosecond, much less 60.
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The article claims they had to move a device between the two locations to synchronize the clocks, and that not all GRT effects have been taken into account while this device was moving.
On use of duct tape to fix cracked pots (Score:2)
"let us assume that the TTD was stationary at the LNGS site for 4 days while the appara-tus for clock comparison was set up. Using the value of V/c2 quoted above this would result in a total shift of t 30 ns."
Let us assume a scenario which fits our desired outcome has actually occured without any supporting evidence since our own figures fall far short of a cogent explanation for the discrepancy.
Let us further overlook the fact PTB was mearly used to independantly *VERIFY* the nanosecond level clock synchr
Nitpicking the title of the post... (Score:2)
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Actually, the theory of special relativity has no problem with particles going faster than light.
Yes it does [wikipedia.org], since SR assumes a causal universe. The sending of any kind of information* faster than light results in a violation of causality according to some frame of reference. And SR also assumes the relativity principle that the laws of physics hold for all frames. But once given FTL travel/communication, you can create a scenario where causality is violated according to all reference frames and create a paradox.
* And thus particle, or anything else that could affect the outcome of some experiment
One possible test (Score:3)
Would it be possible to have neutrino generators and detectors at both sites and test the speed in both directions? That would probably mean testing the speed between CERN and Fermilab. That way, if there was an error in clock synchronisation, it would show up because the neutrinos would take longer in one direction than the other.
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Sure. Build another LHC to bookend the problem.
Actually, if the result continues to hold up, that may be a justifiable use of $100e9...
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They didn't use the LHC to generate the neutrinos, and Fermilab won't be using their decommissioned Tevatron to generate theirs when they try to replicate the experiment.
Supernova observation discounts FTL neutrinos. (Score:4, Informative)
After I saw this quote I figured they'd have to find some error in their observations. (Emphasis added.)
"...If the observation is confirmed, it may be the most important discovery in science in the last 100 years.
"However, a big fly in the ointment is the supernova in the Large Magellanic Cloud, which sits just outside our galaxy 168,000 light-years from Earth. It was first seen by the naked eye on February 24, 1987. Three hours before the visible light reached Earth, a handful of neutrinos were detected in three independent underground detectors. If the CERN result is correct, they should have arrived in 1982. So, if I were a wagering man, I would bet the effect will go away because of some systematic error no one has yet been able to think of."
(Quote stolen from Quark Soup [blogspot.com])
a bunch of papers (Score:5, Informative)
The arxiv blog recently had a roundup of papers discussing this: http://www.technologyreview.com/blog/arxiv/27212/ [technologyreview.com] They fall into three groups: (1) Suggestions of how the experiment might have given a wrong result. (2) Theoretical arguments that constrain the interpretation and make the result seem implausible if taken at face value. (3) Theoretical papers saying what it could mean if it really was new physics. The Nature article seems to show that the Contaldi paper was based on a misunderstanding of how the experiment was done. However, the Nature article points to a new paper by Henri that wasn't included in the arxiv roundup: http://arxiv.org/abs/1110.0239 [arxiv.org]
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Re:Now we know why (Score:5, Funny)
c++
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Re:Now we know why (Score:5, Funny)
They didn't have to raise the speed of light; they just raised it a semitone.
That's right. The universal constant for the speed of light is c#.
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If C# is now the speed of light- does that mean that Java exceeds the speed of light?
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Maybe, but the promise of "emit once, observe everywhere" never panned out....
Re:Now we know why (Score:5, Funny)
If C# is now the speed of light- does that mean that Java exceeds the speed of light?
No, Java is still slow.
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huh??
The speed of light is constant across all frames of reference. Frames of reference that are moving relative to each other will perceive light generated by the other frame of reference as having a different "clock" (i.e., frequency), but the speed of the red/blue shifted light will be the same in both frames of reference. The speed of light itself does vary across mediums (say, water vs glass vs air vs vacuum), but that doesn't come into play here. Also, they weren't measuring, directly, the speed
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" In other words, c isn't a constant in all cases depending on the frame of reference. At least for now that's my opinion, and there has been an oversight."
Except that it is. Unless, of course, you can offer us an experiment where two different observers do in fact get a different value of c (that is, speed of light in vacuum). You can think loud all you want, but show me the experiment.
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But then when in stronger gravity you'll have to slow it down again. It's not just the clocks speeding up and slowing down. The gravity from stars and other massive astronomical objects wouldn't bend light if gravity didn't affect its speed too. The same principle that makes a refracting medium bend light can be used to explain how light bends in a vacuum in the presence of strong gravity.
In other words, c isn't a constant in all cases depending on the frame of reference. At least for now that's my opinion, and there has been an oversight.
Seems to me c is a constant across all reference frames, and that's exactly the property that caused this observation.
They measured neutrinos.
Checked the speed and saw it was > c.
Said "OH SHIT!".
Observers see a particle traveling at c.
They check with their buddies who sent it.
To the people measuring the shit, that incoming particle (which they observed at speed c) had to have been sent 60 nanoseconds (or whatever it was) before their buddies claimed to have sent it.
But according to the timestamps, the sp
Re:Now we know why (Score:4, Informative)
The bending of light by the deformation of space-time is completely unlike or related to the refraction of light. The first is light following the curvature of space, and all frequencies of light would follow the same path (remember Galileo's experiment from the tower of Pisa? Two different particles are accelerated by gravity in precisely the same way.) The second is a wave function across the boundary of two different optical media. Waves with longer period (lower frequency) are bent more than waves of shorter period (higher frequency.) You can do this experiment with water in a wave tank and see the phenomenon clearly. Unrelated phenomena.
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"Beware, you who seek first and final principles, for you are trampling the garden of an angry God and he awaits you just beyond the last theorem."
-Sister Miriam Godwinson
Sorry, everything reminds me of a SMAX quote after i've been playing. :)
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Bummed SMAC/X no longer runs on my Mac after Lion update. Am dusting off an old Mac Mini to set up as game machine now. Wish someone would write a new SMAC/X style game. Other than time killers on phone, don't do any computer gaming anymore.
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Faster than light is still possible, but now it's due to gravitational effects instead of innate property of neutrinos. It makes finding the Higgs boson more important than ever.
Don't jumble words and think you know what's going on.
Let me guess - you're in management?
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*golf clap*
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Perhaps what they're saying is that the computed distance isn't taking the warp into effect, basically treating space-time as flat in the presence of the Earth. This would cause the distance to be underestimated, making the velocity of the neutrinos appear higher?
I thought they said they took gravitational factors into account, though.
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Don't neutrinos have mass? Can particles with mass be accelerated to light speed? Without reading the article or the paper and not having taken even a college physics class, I would have expected that a neutrino should have been traveling at near light speed rather than "exactly the speed of light".
We have very strong evidence that at least two of the three neutrinos must have mass due to neutrino oscillation (used to be at least one of three, until we saw the other type of oscillation iirc), and from this we hypothesize that all the neutrinos have mass.
That mass, though, is extremely small (don't recall the experimental upper bound, but it's orders of magnitude smaller than electrons), so they would be traveling very close to c.
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But rather massive more Neutrinos.
What?
Regardless Relativity does not allow for particles to be accelerated to the speed of light because of the amount of energy needed.
However, and this is important, particles already traveling at the speed of light are allowed.
No, that's not true if you mean a mass-full particle. A particle with rest mass traveling at the speed of light is forbidden for the same reason accelerating it to the speed of light is forbidden -- that particle would have infinite energy. It takes infinite energy to accelerate a particle to the speed of light because at the speed of light it has infinite energy. If you somehow suppose it is already at the speed of light, then it would already have infinite energy.
Particles without mass, on the oth
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But if a particle lacks mass - is it still limited by the speed of light?
Re:I called it (Score:4, Informative)
If a particle has mass, its velocity will be less than C. If a particle has no mass, its velocity will equal C.
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If a particle has mass, its velocity will be less than C. If a particle has no mass, its velocity will equal C.
REST mass... </pedantic>
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REST mass... </pedantic>
I did my physics degree about 10 years ago, and the concept of rest mass was already deprecated then. A particle has only one mass, the one formerly called rest mass.
The notion of mass increasing with velocity makes sense as a kind of Newtonian analogy. You could use Newtonian mechanics in limited ways to explain the mechanics of a particle, if you replaced the mass with a relativistically varying mass. One problem is that the conversion factor varies according to the direction, and you get confusing ter
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Well, I will grant you that the notion of "rest mass" is as odd a notion as distinguishing between spacial and temporal dimensions. But the distinction is there (even if only by archaic categorization).
From what I was reading there is a distinction made between rest mass and relativistic mass. Rest mass being a hypothetical value that represents the minimum mass that a particle could possibly have, while everything else in reality deals with the relativistic mass.
But I take all your criticism to heart, you'
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Santa Claus has mass and can go faster than C. I think it is explained by string theory or something.
Re:I called it (Score:4, Funny)
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Santa Claus is completely imaginary, and therefore also has a completely imaginary mass. It is well known that objects with imaginary mass are tachyonic. Being tachyonic, Santa Claus can even be at two places at the same time!
Re:I called it (Score:5, Insightful)
E = mc^2 refers to rest energy, it is the amount of energy you get if you convert an unmoving mass directly into energy. Photons, having no mass, have no rest energy by definition. 0 * c * c = 0. E / 0 is undefined, not infinite. Literally the only line of your reply without a significant error is the first one. E=mc^2 has nothing to do with the assertion that massless particles must travel at c, that comes from other parts of special relativity.
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Photons, having no mass, have no rest energy by definition.
Photons are at rest in their frame of reference. They still have energy.
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"Basically, a theory that has never been proved says it to be so"
Only if you forget the minor detail that it *has* been proved... by predicting everything that Newton's did and then something where Newton was wrong (i.e. Mercury's orbit). Now it's your turn.
"So, let's just say some faster than light strings perturbed the sensors"
Let' say so, why not... Oh, wait! We already stated that it was your turn! It is YOU the one that has to tell us how these "some" particles look like and how an experiment should h
Re:I called it (Score:5, Informative)
no experiment has yet to show that photons have no mass.
That's because it's a very hard thing to show. What they have shown experimentally is that the mass has to be smaller than 10^-18 eV/c, which is 1.782662 x 10^-54 kg, which is 1 / 10^-24th the mass of an electron which is by far the lightest particle predicted.
And I'd be interested to hear how E=mc^2, a central component of special relativity, causes it to conflict with general relativity. Do tell!
Basically the sun revolves around the earth - what ever we think now is correct no matter what anyone else says.
We used to think the earth was flat, and we were wrong. Then we thought the earth was a sphere and we were wrong (it's actually an oblate spheroid). But if you think believing the earth is a sphere is just as wrong as thinking the earth is flat, then you're wronger than the both of them. (paraphrased from Asimov). We know Newtonian physics is wrong, relativity significantly improves on the accuracy of Newtons predictions. That doesn't mean I drop an apple and expect it not to fall because Newton was wrong. Similarly, we know that relativity is wrong (the predictions break down in several extreme situations), but that doesn't mean that I expect E=mc^2 to be wrong tomorrow or time dilation to be proven wrong or any of the other well known relativistic effects. They have been shown empirically to be correct to fractions of fractions of a percentage point, that evidence doesn't just go 'poof' when a more refined theory comes along.
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Use the full equation:
E = (mc) + (pc).
If p=0 (p is the momentum; so if you're at rest, p=0), E=mc.
If m=0 (the case for photons, for example), E=pc.
If neither p nor m are zero, E = sqrt(E0^2 + (pc)^2), where E0=mc^2 is the rest energy.
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(Well, no evidence until OPERA.)
Dude has a clown in his basement (Score:2)
Conversely, there is nothing preventing a clown from being in your basement, so you should engage in scientific testing of that idea and go check for one.
I am fascinated by your 'clown in the basement' metaphor. I think I need to work on integrating this into everyday conversation.
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That's not the problem with this, though. The problem here is the supernova explosion in Andromeda, where neutrinos and photons arrived here at about the same time. (I forget the exact difference.) If their speeds were any different, then over that distance they shouldn't have arrived at anywhere near the same time. This makes almost all explanations of the time difference detected that don't involve experimental error to be very dubious.
I mean, if neutrinos can cycle into a fourth variety (the "sterile
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What if they oscillate into some form that is slightly faster than light? They'd be traveling slightly slower than light part of
Yes it does in all cases involving information. (Score:3)
SR is based upon three assumptions or principles:
1. Causality (cause before effect)
2. Relativity (the laws of physics are the same for all reference frames, i.e. there is no 'privileged' reference)
3. Constancy of the speed of light (as was implied by Maxwell's equations)
Maintaining all three principles at once is how we end up at the rules of time dilation. Because of time dilation, if one could communicate between two inertial reference frames faster than light, then some observer would say that the messa
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Perhaps they have a mass that varies based on electrical charge! We could call it 'the mass effect'.
Perhaps all this is just a ARG for Mass Effect 3.
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this site is not a joke (well, not intentionally) and it has more than 0 contributors:
http://conservapedia.com/Counterexamples_to_Relativity [conservapedia.com]
#s 13 and 25 are my personal favorites.
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Magnetic field has nothing to do with this. The speed of light is constant, no matter what "absolute origin" you are measuring from. That's the whole "relative" part about relativity. Where exactly is this "absolute origin" you speak of?
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Neutrinos do have mass, this is why they oscillate between 3 states. However the mass is very slight.
Also the neutrinos arrived ahead of the photons in SN1997 by a small amount (days, IIRC. it should be years at the speed discrepancy quoted by CERN). This different is explained by the fact that neutrinos hardly interact with matter and so could escape the core of the supernova before the photons could.