12
   

The speed of light? Can it be broken?

 
 
Reply Thu 22 Sep, 2011 07:32 pm
Quote:
The AP is reporting results from a group of Italian researchers using equipment from the European Organization for Nuclear Research (CERN) that claims they've measured particles traveling at a speed greater than the speed of light.


For the rest of the story:
http://m.npr.org/story/140713791?url=/blogs/thetwo-way/2011/09/22/140713791/scientists-report-breaking-the-speed-of-light-but-can-it-be-true

So amateur scientists of a2k, are these guys' claims credible? Or are we looking at another cold fusion fiasco?
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Type: Discussion • Score: 12 • Views: 8,409 • Replies: 38
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parados
 
  1  
Reply Thu 22 Sep, 2011 07:48 pm
@tsarstepan,
The full story reports they are reluctant to publish until it has been confirmed.

If true and if others can duplicate it, it will be huge. The title says how big it will be.

Einstein's Theory of Relativity at Risk?
0 Replies
 
oralloy
 
  1  
Reply Fri 23 Sep, 2011 03:25 am
@tsarstepan,
tsarstepan wrote:
Quote:
The AP is reporting results from a group of Italian researchers using equipment from the European Organization for Nuclear Research (CERN) that claims they've measured particles traveling at a speed greater than the speed of light.


For the rest of the story:
http://m.npr.org/story/140713791?url=/blogs/thetwo-way/2011/09/22/140713791/scientists-report-breaking-the-speed-of-light-but-can-it-be-true

So amateur scientists of a2k, are these guys' claims credible? Or are we looking at another cold fusion fiasco?


The particles are neutrinos. I wouldn't expect that this is something that would lead to faster-than-light travel of normal matter.

Anyway, the speed of light rule really only limits the travel of information; it doesn't have to prohibit traveling faster than the speed of light so long as no information is carried. There are other ways the speed of light can be exceeded without carrying information (quantum entanglement for example).

Now, if those neutrinos could be made to carry information faster than the speed of light, that would be something.

As to whether it is true, who knows.

But I suspect that if it is true, it will turn out that there is no way to make a faster-than-light neutrino carry information.
rosborne979
 
  1  
Reply Fri 23 Sep, 2011 04:55 am
@oralloy,
I have forgotten, are neutrinos massless?

These people definitely need to confirm before they publish. I suspect the conditions are not exactly what they assume they are.
rosborne979
 
  1  
Reply Fri 23 Sep, 2011 07:13 am
@oralloy,
oralloy wrote:
Anyway, the speed of light rule really only limits the travel of information; it doesn't have to prohibit traveling faster than the speed of light so long as no information is carried. There are other ways the speed of light can be exceeded without carrying information (quantum entanglement for example).

It's not just information that Special Relativity addresses. It specifically defines the fact that an object with mass (even a particle) cannot be pushed to (or beyond) the speed of light. This has to do with energy constraints which part of the fabric of our reality, so they are not an arbitrary limit to velocity.

During quantum entanglement no mass is being moved across any distance, so it does not conflict with special relativity. However, I have never quite understood why they claim that no information is being transferred (by entanglement) faster than light, since corresponding locations of quanta seem to align instantly in two different locations. Theoretically, this could be construed as information transfer since the location of a single quanta could be used as a "bit" (on or off) in a digital system.

I know they "say" no information is being transferred faster than light, but I've never quite understood their argument for this given the seemingly obvious way to glean information from corresponding entangled structures.

Do you understand the details of this phenomena? I would like to understand it better.
oralloy
 
  1  
Reply Fri 23 Sep, 2011 07:35 pm
@rosborne979,
rosborne979 wrote:
I have forgotten, are neutrinos massless?

These people definitely need to confirm before they publish. I suspect the conditions are not exactly what they assume they are.


I'd forgotten too, but it looks like they have small mass:

http://en.wikipedia.org/wiki/Neutrino

I think they were/are one of the WIMP particles proposed as the source of dark matter.

---

I think I heard in passing tonight that the claimed speed was only slightly faster than the speed of light.

Since "the speed of light in a given medium" is slower than "the speed of light in a vacuum" due to the interaction of light with the medium it is passing through, and since neutrinos don't interact with matter, could it be that they are just traveling a more-pure vacuum (from the neutrinos' perspective) than the light that they are supposedly outrunning?
oralloy
 
  1  
Reply Fri 23 Sep, 2011 08:22 pm
@rosborne979,
rosborne979 wrote:
During quantum entanglement no mass is being moved across any distance, so it does not conflict with special relativity. However, I have never quite understood why they claim that no information is being transferred (by entanglement) faster than light, since corresponding locations of quanta seem to align instantly in two different locations. Theoretically, this could be construed as information transfer since the location of a single quanta could be used as a "bit" (on or off) in a digital system.

I know they "say" no information is being transferred faster than light, but I've never quite understood their argument for this given the seemingly obvious way to glean information from corresponding entangled structures.

Do you understand the details of this phenomena? I would like to understand it better.




Not sure I understand it well enough to be explaining it, but here is a cut-n-paste from Wikipedia:

Quote:
More generally, it is normally impossible for information or energy to travel faster than c. One argument for this follows from the counter-intuitive implication of special relativity known as the relativity of simultaneity. If the spatial distance between two events A and B is greater than the time interval between them multiplied by c then there are frames of reference in which A precedes B, others in which B precedes A, and others in which they are simultaneous. As a result, if something were travelling faster than c relative to an inertial frame of reference, it would be travelling backwards in time relative to another frame, and causality would be violated.[Note 6][33] In such a frame of reference, an "effect" could be observed before its "cause". Such a violation of causality has never been recorded,[15] and would lead to paradoxes such as the tachyonic antitelephone.[34]


From this page: http://en.wikipedia.org/wiki/Speed_of_light

The text I quoted refers to this page as well: http://en.wikipedia.org/wiki/Relativity_of_simultaneity



As for quantum entanglement specifically, here is another quote from Wikipedia's speed of light page:

Quote:
An example involves the quantum states of two particles that can be entangled. Until either of the particles is observed, they exist in a superposition of two quantum states. If the particles are separated and one particle's quantum state is observed, the other particle's quantum state is determined instantaneously (i.e., faster than light could travel from one particle to the other). However, it is impossible to control which quantum state the first particle will take on when it is observed, so information cannot be transmitted in this manner.[38][39]


I suspect that for every possible way of traveling faster than light, there will always be some sort of corresponding reason that information transfer is impossible. But that's just my own personal suspicion.
0 Replies
 
Thomas
 
  2  
Reply Fri 23 Sep, 2011 08:38 pm
@tsarstepan,
tsarstepan wrote:
So amateur scientists of a2k, are these guys' claims credible? Or are we looking at another cold fusion fiasco?

During my 10-year career in physics, at least three papers have been published in which the authors claimed that something had travelled faster than light. (The advisor of my diploma (= masters) and doctor thesis told me that similar claims have been made several times a decade before I started studying physics.) Every time, stricter scrutiny revealed that there had been some kind of subtle measurement error---and sometimes they weren't even subtle.

As scrutiny on this particular finding increases, I expect yet another similar outcome.
Chinspinner
 
  1  
Reply Fri 23 Sep, 2011 08:57 pm
@Thomas,
Thank you, it is a mistake, it will be dismissed in a week, why did they even raise it? Publicity? Shame..
rosborne979
 
  1  
Reply Sat 24 Sep, 2011 05:01 am
@oralloy,
oralloy wrote:
Since "the speed of light in a given medium" is slower than "the speed of light in a vacuum" due to the interaction of light with the medium it is passing through, and since neutrinos don't interact with matter, could it be that they are just traveling a more-pure vacuum (from the neutrinos' perspective) than the light that they are supposedly outrunning?

That's an interesting way of looking at it. And I guess it's possible. But I think they will find some type of measurement error before they find anything really interesting. Just have to wait and see I guess.
0 Replies
 
Thomas
 
  2  
Reply Sat 24 Sep, 2011 05:08 am
@Chinspinner,
I didn't say it definitely is a mistake, and I don't think CERN would raise such an issue for publicity's sake. They seem to be very guarded in their statement. It's the journalists who make such a fuzz about it.
0 Replies
 
Brandon9000
 
  1  
Reply Sat 24 Sep, 2011 08:13 am
@oralloy,
oralloy wrote:

tsarstepan wrote:
Quote:
The AP is reporting results from a group of Italian researchers using equipment from the European Organization for Nuclear Research (CERN) that claims they've measured particles traveling at a speed greater than the speed of light.


For the rest of the story:
http://m.npr.org/story/140713791?url=/blogs/thetwo-way/2011/09/22/140713791/scientists-report-breaking-the-speed-of-light-but-can-it-be-true

So amateur scientists of a2k, are these guys' claims credible? Or are we looking at another cold fusion fiasco?


The particles are neutrinos. I wouldn't expect that this is something that would lead to faster-than-light travel of normal matter.

Anyway, the speed of light rule really only limits the travel of information...

False. The Theory of Relativity indicates that no matter which is travelling below the speed of light can accelerate up to it. To do so would require an infinite amount of energy. Whether neutrinos are matter, though, is not clear. When I was going through school, they were thought to be massless and to travel at exactly the speed of light.
BumbleBeeBoogie
 
  2  
Reply Fri 18 Nov, 2011 11:21 am
@tsarstepan,
Second experiment confirms faster-than-light particles
By Brian Vastag - Washington Post
November 17, 2011

A second experiment at the European facility that reported subatomic particles zooming faster than the speed of light — stunning the world of physics — has reached the same result, scientists said late Thursday.

The “positive outcome of the [second] test makes us more confident in the result,” said Fernando Ferroni, president of the Italian Institute for Nuclear Physics, in a statement released late Thursday. Ferroni is one of 160 physicists involved in the international collaboration known as OPERA (Oscillation Project with Emulsion Tracking Apparatus) that performed the experiment.

While the second experiment “has made an important test of consistency of its result,” Ferroni added, “a final word can only be said by analogous measurements performed elsewhere in the world.”

That is, more tests are needed, and on other experimental setups. There is still a large crowd of skeptical physicists who suspect that the original measurement done in September was an error.

Should the results stand, they would upend more than a century of modern physics.

In the first round of experiments, a massive detector buried in a mountain in Gran Sasso, Italy, recorded neutrinos generated at the CERN particle accelerator on the French-Swiss border arriving 60 nanoseconds sooner than expected. CERN is the French acronym for European Council for Nuclear Research.

A chorus of critiques from physicists soon followed. Among other possible errors, some suggested that the neutrinos generated at CERN were smeared into bunches too wide to measure precisely.

So in recent weeks, the OPERA team tightened the packets of neutrinos that CERN sent sailing toward Italy. Such tightening removed some uncertainty in the neutrinos’ speed.

The detector still saw neutrinos moving faster than light.

“One of the eventual systematic errors is now out of the way,” said Jacques Martino, director of the National Institute of Nuclear and Particle Physics in France, in a statement.

But the faster-than-light drama is far from over, Martino added. The OPERA team is discussing more cross-checks, he added, including possibly running a fiber the 454 miles between the sites.

For more than a century, the speed of light has been locked in as the universe’s ultimate speed limit. No experiment had seen anything moving faster than light, which zips along at 186,000 miles per second.

Much of modern physics — including Albert Einstein’s famous theory of relativity — is built on that ultimate speed limit.

The scientific world stopped and gaped in September when the OPERA team announced it had seen neutrinos moving just a hint faster than light.

“If it’s correct, it’s phenomenal,” said Rob Plunkett, a scientist at Fermilab, the Department of Energy physics laboratory in Illinois, in September. “We’d be looking at a whole new set of rules” for how the universe works.
sozobe
 
  2  
Reply Fri 18 Nov, 2011 11:51 am
@BumbleBeeBoogie,
BumbleBeeBoogie wrote:
“a final word can only be said by analogous measurements performed elsewhere in the world.”


Yes.

If the original experiment had fundamental flaws, getting the same result when repeating it doesn't prove anything.
0 Replies
 
Thomas
 
  1  
Reply Fri 18 Nov, 2011 02:49 pm
@Brandon9000,
Brandon9000 wrote:
oralloy wrote:
Anyway, the speed of light rule really only limits the travel of information...

False. The Theory of Relativity indicates that no matter which is travelling below the speed of light can accelerate up to it. To do so would require an infinite amount of energy.

Not so false if you account for quantum mechanics: Every particle can be represented by a wave packet. The particle's traveling velocity then corresponds to the wave packet's group velocity. This group velocity is where travel-of-information arguments can attach if one wishes to make them. To be sure, it's okay if one doesn't wish to, but it's not false in itself if one does.

EDIT: On the third hand, the particle itself is the information if one interprets the particle as an amplitude-modulated wave. So oralloy's conclusion about possible neutrino speeds is invalid, whether the neutrino has a mass or not.
0 Replies
 
rosborne979
 
  1  
Reply Fri 18 Nov, 2011 07:59 pm
I thought this mystery was solved by an error in the satellite timing alignment. Was that not correct? Why are they still testing this? Or is the media just lagging a bit behind.
0 Replies
 
montesway
 
  1  
Reply Fri 18 Nov, 2011 10:38 pm
Well, I heard that right after the Big Bang some of the energy was traveling faster than the speed of light.
rosborne979
 
  1  
Reply Sat 19 Nov, 2011 04:19 am
@montesway,
montesway wrote:

Well, I heard that right after the Big Bang some of the energy was traveling faster than the speed of light.
That would be incorrect. Do you remember where you heard that?
0 Replies
 
Thomas
 
  1  
Reply Sat 17 Mar, 2012 06:30 am
@Thomas,
Thomas wrote:
During my 10-year career in physics, at least three papers have been published in which the authors claimed that something had travelled faster than light.[. . .]Every time, stricter scrutiny revealed that there had been some kind of subtle measurement error---and sometimes they weren't even subtle.

As scrutiny on this particular finding increases, I expect yet another similar outcome.


Today, the New York Times wrote:
Einstein Proved Right in Retest of Neutrinos’ Speed

European researchers said Friday they had measured again the speed of a subatomic particle that a September experiment suggested traveled faster than the speed of light, violating Einstein’s special theory of relativity, which underlies much of modern physics.

The research team, led by the Nobel Prize-winning physicist Carlo Rubbia, found that the particles, neutrinos, do not travel faster than light. [. . .]

Doubts about the Opera results were heightened last month when researchers said they had found a flaw in the technical setup that could have distorted the experiment’s figures.

Antonio Ereditato, a member of the Opera team and the head of the Albert Einstein Center for Fundamental Physics, said he welcomed the latest results.

“These results are in line with our recent findings about the possible misfunctioning of some of the components of our experimental setup,” he said.
Brandon9000
 
  1  
Reply Sun 1 Apr, 2012 08:21 am
@montesway,
montesway wrote:

Well, I heard that right after the Big Bang some of the energy was traveling faster than the speed of light.

That doesn't count because the speed is partly due to space itself expanding, rather than just motion through space.
0 Replies
 
 

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