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Faster-than-light neutrino experiment to be run again - Comments

PatW's Avatar Comment 1 by PatW

When I first read the article reported by the mainstream media, I found it interesting. At the same time, it raised this question for me. Could artificial acceleration have presented false results? We already know that the speed of light in a vacuum isn't the same speed when there is no vacuum. In order for the speed of light to remain a constant, it has to be measured in a vacuum.

Sun, 30 Oct 2011 15:50:28 UTC | #885427

canadian_right's Avatar Comment 2 by canadian_right

Light isn't accelerated. Due to its very nature, it always travel at "the speed of light" in whatever medium it happens to be in. The speed of light is highest in a vacuum, and all current theory says that nothing material (has mass) can reach this speed, and energy AND information cannot exceed this speed.

As we currently have strong evidence that neutrinos have a very, very, very small mass they should travel at less than the speed of light. There should be no way of accelerating them above the speed of light, not that we actually have any method of accelerating something that interacts so little with anything as neutrinos do. The speed of these neutrinos is very difficult to measure as they are very difficult to detect, and the previous experiment was creating them in a constant stream. This is very simplified, but they measured the speed by starting a stopwatch when the neutrino left the facility creating them, and stopped it when it reached the distant detector. If you know the elapsed time and distance you can calculate the speed. The issues are: do they know the distance, do they know when the neutrinos actually left, and do they know when they arrived, and how do you tell it is the same neutrinos you measured leaving? Lots of room for systematic errors.

Other labs are going to repeat the experiment, and the original lab is going to create short bursts of neutrinos in an effort to more closely define the start and stop times.

Sun, 30 Oct 2011 16:03:43 UTC | #885432

Zeuglodon's Avatar Comment 3 by Zeuglodon

Comment 2 by canadian_right

Other labs are going to repeat the experiment, and the original lab is going to create short bursts of neutrinos in an effort to more closely define the start and stop times.

Good - that's how the science should go. I guess it will turn out to be a false alarm once the experiments are complete, but let's see.

Sun, 30 Oct 2011 16:37:47 UTC | #885437

caseybvdc74's Avatar Comment 4 by caseybvdc74

I've heard that anything traveling about the speed of light can travel backwards in time. Is this true?

Sun, 30 Oct 2011 16:49:35 UTC | #885440

jbkaffe's Avatar Comment 5 by jbkaffe

Maybe we've started banging in the door of the speed of light?

A way of looking at it for a layman like me, could be compared to the speed of sound and the sonic boom. http://en.wikipedia.org/wiki/Sonic_boom

However when you break the speed of light barrier, it is a (for now at least) one way street, where the acceleration is infinite, because the loss of matter turns into negative mass(not in the gravity altering way) when breaking this barrier?

Now if only we could figure out how to reverse the process, and turn negative mass into "positive" matter. That would be a neat party trick. :-)

Sun, 30 Oct 2011 17:01:03 UTC | #885443

Red Dog's Avatar Comment 6 by Red Dog

Comment 4 by caseybvdc74 :

I've heard that anything traveling about the speed of light can travel backwards in time. Is this true?

When you travel at a significant percentage of the speed of light you essentially travel forward in time (relative to the place you started from). Its called the Twin Paradox. If a space ship leaves earth and does a round trip at close to the speed of light one year will pass on the space ship where as 100 years pass on earth (the exact numbers depend on how fast you travel and for how long of course).

In fact according to Einstein whenever you increase your velocity at all you travel forward in time. So when you fly in a plane or drive in a car time is slowing down an imperceptible amount for you compared to people standing still on the earth. Anything on earth travels at such a small percentage of the speed of light that the difference is imperceptible with normal clocks. However, satellites travel fast enough that the effect has to be taken into account to keep their clocks in synch with clocks on earth.

I think what you are referring to though is what happens if you travel faster than the speed of light. I have seen an enormous amount of nonsense from the woo community on this topic since the CERN results were announced. Here is an example from the Huffington Post. Claims that the CERN results show time travel is possible, that the laws of cause and effect don't hold, etc.

I'm a bit out of my depth here but I think there is a possibility that these particles could in effect be going back in time if they really are travelling faster than light. But it all depends on exactly how they are going faster than light. So far all the real scientists I've read say that its most likely some kind of experimental error but if its not its really too soon to say how this might effect our understanding of space/time since if the neutrinos did travel faster than light speed no one knows yet how they did it.

Sun, 30 Oct 2011 17:11:00 UTC | #885445

Alex, adv. diab.'s Avatar Comment 7 by Alex, adv. diab.

There should be no way of accelerating them above the speed of light, not that we actually have any method of accelerating something that interacts so little with anything as neutrinos do

There are ways, many have been published in the past weeks, they are just all pretty awkward, and mostly ruled out by other observations

I've heard that anything traveling about the speed of light can travel backwards in time. Is this true?

If you take special relativity and an object that can exceed the speed of light, this can indeed happen. An example for this would be for example a tachyon which is always FTL. But if the effect that produces this superluminal speed is not the same in all frames of reference, the time travel paradox can be avoided (for example if it's only FTL wrt to some observers.)

Sun, 30 Oct 2011 17:11:07 UTC | #885446

Stafford Gordon's Avatar Comment 8 by Stafford Gordon

Aparantly the sub-atomic particle doesn't slow as it passes through glass or water but refraction slows light fractionally, so in those conditions light is a tiny bit slower. And of course neutrenos also pass through solids and light doesn't. All very wierd!

Sun, 30 Oct 2011 17:12:14 UTC | #885448

Red Dog's Avatar Comment 9 by Red Dog

Comment 5 by jbkaffe :

Maybe we've started banging in the door of the speed of light?

A way of looking at it for a layman like me, could be compared to the speed of sound and the sonic boom. http://en.wikipedia.org/wiki/Sonic_boom

This is really nothing like the sound barrier. The speed of sound was an engineering problem. We knew that it was theoretically possible for things to travel faster than the speed of sound. The crack of a whip is caused by part of the whip traveling faster than the speed of sound for a brief moment. In fact rockets such as the V2 traveled faster than the speed of sound. The "sound barrier" was an engineering problem to design a plane that could withstand the stress created when it flew faster than the speed of sound.

The speed of light barrier is (or was -- probably still is) a fundamental theoretical limit. Its not a case of designing a better rocket or starship its that even in our thought experiments we can't imagine how any theoretical vehicle can travel faster than light.

Sun, 30 Oct 2011 17:17:47 UTC | #885449

jbkaffe's Avatar Comment 10 by jbkaffe

Well I wasn't really thinking about constructing vehicles, but Iooking at it as a way of wrapping my head around it. You scientists with your fundamental theoretical limits. ;-)

Strictly speaking, I think "time" is a pseudo-term not applicable in this context....but that's just me spitballing random ramblings...Sorry. :-)

Sun, 30 Oct 2011 17:30:35 UTC | #885454

Zeuglodon's Avatar Comment 11 by Zeuglodon

Comment 10 by jbkaffe

Well I wasn't really thinking about constructing vehicles, but Iooking at it as a way of wrapping my head around it. You scientists with your fundamental theoretical limits. ;-)

Brian Cox and Jeff Forshaw put forward a term in their book which I think is more appropriate: the Cosmic Speed Limit, where the amount of energy needed to reach that speed is practically infinite and your accelerating speed is always approaching an untouchable asymptote. That's probably why the scenarios of warping space-time itself or of using wormholes to travel FTL would be more credible than simply "going faster" - because in the first one technically the ship isn't moving, and in the second one it exploits the weird space-time inversions and causal breakdowns of black hole physics.

Strictly speaking, I think "time" is a pseudo-term not applicable in this context....but that's just me spitballing random ramblings...Sorry. :-)

Careful! Step away from the philosopher's pit, now. ;)

Sun, 30 Oct 2011 18:01:21 UTC | #885460

PatW's Avatar Comment 12 by PatW

When I read the following excerpt, it appears to raise more questions than it answers pertaining to the word neutrino:

http://hitoshi.berkeley.edu/neutrino/neutrino.html

"New experimental data, which show that neutrinos have mass, are forcing theorists to revise the Standard Model of particle physics Neutrino Physics

IF WE look deep into the universe, we see stars and galaxies of all shapes and sizes. What we do not see, however, is that the universe is filled with particles called neutrinos. These particles — have no charge and have little or no mass — created less than one second after the Big Bang, and large numbers of these primordial low-energy neutrinos remain in the universe today because they interact very weakly with matter. Indeed, every cubic centimetre of space contains about 300 of these uncharged relics."

If we are incapable of using any of 5 physical senses to prove neutrinos have physical mass, how do we know for certain they do? Unless we can physically detect neutrinos passing through physical mass, how do we know for certain that they physically exist and pass through mass?

Those questions are a part of the reason I have serious doubts that those called neutrinos were even capable of traveling faster than what we've physically proved is the constant number proved using a vacuum. Outside a vacuum, the speed of light isn't a constant.

Yes, I’m well aware that the word neutrino and what it does is hypothetical at this point. Theory has to have physical proof that neutrinos can actually physically exist. Hypothesis doesn’t.

Sun, 30 Oct 2011 18:11:23 UTC | #885461

jbkaffe's Avatar Comment 13 by jbkaffe

@ zeuglodon

LOL. Thanks mate, I owe you one, you just pulled me out of orbit. I saw the pit and figured; Why the hell not? :-D

Sun, 30 Oct 2011 18:18:22 UTC | #885464

RomeStu's Avatar Comment 14 by RomeStu

Comment 4 by caseybvdc74 :

I've heard that anything traveling about the speed of light can travel backwards in time. Is this true?

At the risk of lowering the tone of this august forum, I thought this idea came from the first Superman movie in the late 70s. At the end of the film Superman flies FTL around and around the world to go back in time and save Lois Lane ......

All good 1970s hard science I'm sure.

Sun, 30 Oct 2011 18:36:14 UTC | #885471

DaveUK9xx's Avatar Comment 15 by DaveUK9xx

As I predicted in the previous thread on this the potential error in the original experiment was sending the neutrinos in a relatively long burst (microseconds) and trying to use statistical analysis to calculate the departure and arrival time to the nanosecond level when there is no real way of knowing at what time each neutrino really departed and arrived.

I'm not sure why this obvious problem should have stumped such clever people for so long.

Sun, 30 Oct 2011 18:56:49 UTC | #885477

Stafford Gordon's Avatar Comment 16 by Stafford Gordon

Incidentally, the term neutrino was coined in the thirties, and derives from the Italian neutro, which means neutral, because it has a mass close to zero, where as light, of course, has no mass at all, hence it travels faster than anything else in the universe; and although not a gambler, I'd put money on the experiment having been faulty.

Sun, 30 Oct 2011 21:38:23 UTC | #885515

Stafford Gordon's Avatar Comment 17 by Stafford Gordon

Incidentally, the term neutrino was coined in the thirties, and derives from the Italian neutro, which means neutral, because it has a mass close to zero, where as light, of course, has no mass at all, hence it travels faster than anything else in the universe; and although not a gambler, I'd put money on the experiment having been faulty.

Sun, 30 Oct 2011 21:41:08 UTC | #885516

Agrajag's Avatar Comment 18 by Agrajag

Comment 14 by RomeStu

At the risk of lowering the tone of this august forum, I thought this idea came from the first Superman movie in the late 70s. At the end of the film Superman flies FTL around and around the world to go back in time and save Lois Lane ......

IIRC, the Man of Steel flew fast enough to reverse the rotation of the Earth, thereby going back in time to achieve his noble purpose. That certainly trumps G_d making the sun hold still for a day so some killings could be done in broad daylight.

@Comment 11 by Zeuglodon...
I'll toss this into the "pit":
"Time flies like an arrow;
fruit flies like a banana"
;-)
As for the neutrino FTL thing, it won't surprise me if the findings turn out to be wrong, but I admire the team for being cautious about them.

My understanding of time travel is that if you could travel faster than light, you would overtake the light representing the images of the past. You could then see those events by looking back. Given the inverse-square nature of light intensity, you'd need a really high-power telescope to see much. Interaction with the past would be impossible. And travel to the future wouldn't be possible either. That's the report from the "dim" zone. ;-)
Steve

Sun, 30 Oct 2011 23:31:06 UTC | #885544

some asshole's Avatar Comment 19 by some asshole

As I understand it (not that I really do), the Theory of Relativity does not state that nothing can exceed the speed of light; but rather that no matter can begin at a lower speed and then accelerate beyond the speed of light. It does not state that matter can always exist at speeds exceeding that of light. If neutrinos are born at speeds exceeding that of light, there's no Relativistic issue.

Mon, 31 Oct 2011 00:18:47 UTC | #885564

Red Dog's Avatar Comment 20 by Red Dog

Comment 18 by Agrajag :

My understanding of time travel is that if you could travel faster than light, you would overtake the light representing the images of the past. You could then see those events by looking back. Given the inverse-square nature of light intensity, you'd need a really high-power telescope to see much. Interaction with the past would be impossible. And travel to the future wouldn't be possible either. That's the report from the "dim" zone. ;-) Steve

I'm pretty sure that's wrong. The idea is that time slows down (and mass increases) as you go faster. Mass approaches infinity as you get closer to the speed of light which is why if you have mass you can't ever reach it. Similarly time passage approaches zero as you approach the speed of light and if you could go faster time would go negative theoretically. So if you could travel faster than the speed of light you could be traveling backward in time.

Mon, 31 Oct 2011 00:20:10 UTC | #885565

some asshole's Avatar Comment 21 by some asshole

Stupid typo in my comment above. I meant "It does not state that matter cannot always exist at speeds exceeding that of light."

Mon, 31 Oct 2011 00:36:25 UTC | #885574

mmurray's Avatar Comment 22 by mmurray

Comment 12 by PatW :

Yes, I’m well aware that the word neutrino and what it does is hypothetical at this point. Theory has to have physical proof that neutrinos can actually physically exist. Hypothesis doesn’t.

Neutrinos do exist. We can detect them it is just very hard. The supposed FTL neutrino experiment detects neutrinos when they arrive.

The neutrino[nb 1] was first postulated in 1930 by Wolfgang Pauli to preserve the conservation of energy, conservation of momentum, and conservation of angular momentum (spin) in beta decay.

In 1942 Kan-Chang Wang first proposed the use of beta-capture to experimentally detect neutrinos.[7] In the July 20, 1956 issue of Science, Clyde Cowan, Frederick Reines, F. B. Harrison, H. W. Kruse, and A. D. McGuire published confirmation that they had detected the neutrino,[8][9] a result that was rewarded almost forty years later with the 1995 Nobel Prize.[10]

From the wikipedia neutrino article.

Michael

Mon, 31 Oct 2011 05:19:50 UTC | #885621

rjohn19's Avatar Comment 23 by rjohn19

I'm keeping an open mind on this one. As I'm sure everyone on this board knows, Einstein has been wrong before. I'd prefer to say, "Nothing we know a great deal about can travel faster than light."

Assuming they are real because "the math works"- how do we know at what speeds the waves or particles of dark energy or dark matter travels? There are apparently particles in the quontum world that can be in more than one place at once. Who's to say this might not be a function of vastly faster than light speed, just leaving the impression of being in more than one place at once?

I am skeptical of all scientific absolutisms because the pile of "we really know" is exponentially dwarfed by the pile of "we used to think, but now we know." Science, as fast as it is progressing, is still in its infancy or, at best, its early teens.

I'm not even buying the "twins paradox." I'm not saying it is wrong that one twin would age more in the the same span of absolute time (I'll get an argument on that usage, I'm sure), I'm just saying that until we are able to accelerate an organism for a statistically significant time to quantify the difference in aging, I'll remain a skeptic.

That it works on a chalk board does not blow me away. See the cosmological constant.

Mon, 31 Oct 2011 05:34:53 UTC | #885624

mmurray's Avatar Comment 24 by mmurray

Comment 23 by rjohn19 :

I'm keeping an open mind on this one. As I'm sure everyone on this board knows, Einstein has been wrong before. I'd prefer to say, "Nothing we know a great deal about can travel faster than light."

Assuming they are real because "the math works"- how do we know at what speeds the waves or particles of dark energy or dark matter travels? There are apparently particles in the quontum world that can be in more than one place at once. Who's to say this might not be a function of vastly faster than light speed, just leaving the impression of being in more than one place at once?

Particles aren't really in two places at once. What is more correct is that quantum stuff is not particles. Neither is it waves.

I'm not even buying the "twins paradox." I'm not saying it is wrong that one twin would age more in the the same span of absolute time (I'll get an argument on that usage, I'm sure), I'm just saying that until we are able to accelerate an organism for a statistically significant time to quantify the difference in aging, I'll remain a skeptic.

That it works on a chalk board does not blow me away. See the cosmological constant.

What about a white board ?

Seriously this has been tested with atomic clocks on aeroplanes.

Michael

Mon, 31 Oct 2011 06:58:25 UTC | #885633

PatW's Avatar Comment 25 by PatW

Comment 22 by mmurray :

Comment 12 by PatW :

Yes, I’m well aware that the word neutrino and what it does is hypothetical at this point. Theory has to have physical proof that neutrinos can actually physically exist. Hypothesis doesn’t.

Neutrinos do exist. We can detect them it is just very hard. The supposed FTL neutrino experiment detects neutrinos when they arrive.

The neutrino[nb 1] was first postulated in 1930 by Wolfgang Pauli to preserve the conservation of energy, conservation of momentum, and conservation of angular momentum (spin) in beta decay.

In 1942 Kan-Chang Wang first proposed the use of beta-capture to experimentally detect neutrinos.[7] In the July 20, 1956 issue of Science, Clyde Cowan, Frederick Reines, F. B. Harrison, H. W. Kruse, and A. D. McGuire published confirmation that they had detected the neutrino,[8][9] a result that was rewarded almost forty years later with the 1995 Nobel Prize.[10]

From the wikipedia neutrino article. Michael

With all due respect, since I place the same criteria for physical proof on science as I do on such unproved claims as "God really exists.", I need to see, hear, taste, touch or feel physical proof.

Postulated means proposed not physical existence proved. I have no idea how what can't be detected can be physically proved except is actually physically detected. Not even an electrical charge exists according to physics and quantum researchers. Physical mass just passing through physical mass without being detected by that physical mass? Especially a physical mass with a language and vocal chords to express the physical sensation of detection of some physical mass passing right through his or her physical mass from the outside inward.

Mon, 31 Oct 2011 07:25:28 UTC | #885636

mmurray's Avatar Comment 26 by mmurray

Comment 25 by PatW :

Comment 22 by mmurray :

Comment 12 by PatW :

Yes, I’m well aware that the word neutrino and what it does is hypothetical at this point. Theory has to have physical proof that neutrinos can actually physically exist. Hypothesis doesn’t.

Neutrinos do exist. We can detect them it is just very hard. The supposed FTL neutrino experiment detects neutrinos when they arrive.

The neutrino[nb 1] was first postulated in 1930 by Wolfgang Pauli to preserve the conservation of energy, conservation of momentum, and conservation of angular momentum (spin) in beta decay.

In 1942 Kan-Chang Wang first proposed the use of beta-capture to experimentally detect neutrinos.[7] In the July 20, 1956 issue of Science, Clyde Cowan, Frederick Reines, F. B. Harrison, H. W. Kruse, and A. D. McGuire published confirmation that they had detected the neutrino,[8][9] a result that was rewarded almost forty years later with the 1995 Nobel Prize.[10]

From the wikipedia neutrino article. Michael

With all due respect, since I place the same criteria for physical proof on science as I do on such unproved claims as "God really exists.", I need to see, hear, taste, touch or feel physical proof.

For subatomic particles ? That is not going to happen.

Postulated means proposed not physical existence proved. I have no idea how what can't be detected can be physically proved except is actually physically detected. Not even an electrical charge exists according to physics and quantum researchers. Physical mass just passing through physical mass without being detected by that physical mass? Especially a physical mass with a language and vocal chords to express the physical sensation of detection of some physical mass passing right through his or her physical mass from the outside inward.

The neutrino was postulated by Pauli in 1930 and then detected in experiment in 1956. That is what those two quotes were about. They are not saying it is currently postulated. How do you think these guys are measuring the speed of a neutrino if they can't detect them ? They can detect them.

Michael

Mon, 31 Oct 2011 07:35:08 UTC | #885638

JoxerTheMighty's Avatar Comment 27 by JoxerTheMighty

I think it's probably some quirk with the experiment...otherwise the Standard Model would need major revision, since they basically send information faster than the speed of light(neutrino detected vs neutrino not detected is basic boolean information I assume).

I'm pretty sure that's wrong. The idea is that time slows down (and mass increases) as you go faster. Mass approaches infinity as you get closer to the speed of light which is why if you have mass you can't ever reach it. Similarly time passage approaches zero as you approach the speed of light and if you could go faster time would go negative theoretically. So if you could travel faster than the speed of light you could be traveling backward in time.

I'm not exactly sure about the time travel thing, however in the Lortentzian transformations equations of SR,which give the factors by which time is dilated(or length contracted, or mass increased), when you put velocity>c, you get a square root of a negative number, not a negative number itself. That is, a complex or imaginary number, not a negative one. However, tachyons, hypothetical particles that can carry information and travel faster than light, can supposedly communicate information from the future to the present. Again, I could be wrong.

Mon, 31 Oct 2011 08:08:47 UTC | #885646

hfaber's Avatar Comment 28 by hfaber

The dutch physicist Ronald van Elburg has proposed that the sattelite which has been used for the gps location has a speed which affects, by the laws of special relativity, the time measurement of the OPERA experiment. His calculations exactly compensate for the observed difference between neutrino- and lightspeed. I think it looks promising (and ironic since the problem would be solved by special relativity which seemed under attack by the OPERA experiment).

Mon, 31 Oct 2011 08:24:53 UTC | #885652

DavidMcC's Avatar Comment 29 by DavidMcC

Comment 28 by hfaber :

The dutch physicist Ronald van Elburg has proposed that the sattelite which has been used for the gps location has a speed which affects, by the laws of special relativity, the time measurement of the OPERA experiment. His calculations exactly compensate for the observed difference between neutrino- and lightspeed. I think it looks promising (and ironic since the problem would be solved by special relativity which seemed under attack by the OPERA experiment).

Surely, it was a GR effect, not SR, as the orbiting gps clocks concerned were at a different gravitational potential from ground clocks.

Mon, 31 Oct 2011 08:59:46 UTC | #885659

Alex, adv. diab.'s Avatar Comment 30 by Alex, adv. diab.

Comment 25 by PatW :

PatW, what are you on about? Of course they can be detected, we know what different kinds there are because of the reactions they make in the medium, we know how fast they change into each other, we know how to make them, we can observe them indirectly via kinematics of decays, and directly in experiments such as KAMIOKANDE, SNO and dozens more. We have counted their number by looking at the Z resonance, the width of which gives you the number of different particles in which the Z boson can decay. The only problem is that they only interact rarely, which is why one gets relatively low statistics in detection experiments. This weak strength of their interaction is exactly as predicted by the Standard Model, and originate because the W and Z bosons are so heavy. Your assertion that we do not know for sure whether neutrinos exist is beyond ridiculous.

@rjohn19

I'm just saying that until we are able to accelerate an organism for a statistically significant time to quantify the difference in aging, I'll remain a skeptic.

Well the large time dilation (proper time much larger than earth time) obviously works for elementary particles and all observed processes involving particles and particle interactions, which is why we on the ground get hit by atmospheric muons at all. I am not skeptical at all that this can therefore be extended to objects consisting of more particles, there is no reason to suspect that. Furthermore, the twin paradox has been tested for small time differences in airplanes. You would have to argue that it works for small amounts of matter at high speeds and for large amounts of matter at low speeds, but not for large amounts of matter at large speeds. There is no indication why one should think that.

@JoxerTheMighty

Yes what you say is correct, going to that frame of reference that goes FTL is problematic because the dilation factor is imaginary. If you simply assume that you have a tachyon at your disposal that you can divert, that gives you the possibility to send information backwards in time.

However, not every particle that is FTL has to be a tachyon, if there is a violation of Lorentz symmetries in nature. The source of this could be something fundamental in the laws of nature, or merely due to the presence of the earth as a medium. Both has been postulated in connection to the OPERA result.

Mon, 31 Oct 2011 09:23:39 UTC | #885664