# The speed of light may have been broken.

Discussion in 'Physics & Math' started by Pincho Paxton, Sep 22, 2011.

1. ### TachBannedBanned

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Nope, you are wrong on TWO accounts:

1. (already pointed out) $m^2<0 =>m=iz$ and not $m<0$
2. experiment shows that the more energetic neutrinos are faster. Theory of tachyons shows that $\frac{v^2}{c^2}=1+(\frac{zc^2}{E})^2$, so higher energy tachyons are predicted to be slower than lower energy tachyons, so neutrinos cannot be tachyons.

On the positive side, you posted an interesting website , though.

3. ### originIn a democracy you deserve the leaders you elect.Valued Senior Member

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This is a pretty fascinating story. The is already work being done to try and replicat the experiement. At the meeting where the findings were presented there were a lot of tough questions asked but there were no glaring problems with the experimental protocol.

If it turns out that the speed of light was not exceeded there are going to be some red faces. If it turns out the speed of light was exceeded there should be some pretty cool research over the next decades.

5. ### James RJust this guy, you know?Staff Member

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Conclusion of the paper:

Would anybody like to bet that sometime in the next year a systematic error will be discovered?

7. ### OnlyMeValued Senior Member

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Probably will turn out that way.

But would it not be more interesting to be there as things change, should it turn out repeatable?

8. ### areasysRegistered Senior Member

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So if it turns out that these neutrinos actually DID go faster than the speed of light, what does that mean? Does that open the door to things like warp drives, FTL travel, FTL communication, or teleportation?

9. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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Yes, I do understand what you are saying.
The speed of light is a constant, and distance is defined by it.
So if a neutrino travels more than 299,792,458 metres in a second, the same as light in a vacuum, then it will be travelling faster than the speed of light.

But what I am saying is that the speed of light in a vacuum can only be estimated, not measured, so couldn't that estimation be wrong by a tiny amount.

That would in turn make the definition of distance wrong.
The definition is dependent upon the estimated speed, c, not the other way round.

@someone else.
Am I talking nonsense?

10. ### originIn a democracy you deserve the leaders you elect.Valued Senior Member

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The articles talks about a beam of neutrinos. How could you make a neutrino beam?

11. ### OnlyMeValued Senior Member

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The paper itself mentions the process and shows diagram. Making the beam is actually far easier than detecting a small part of it after it has been made.

12. ### OnlyMeValued Senior Member

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It would be unlikely, though it really would depend at least in part on how it is that we come to understand it.

Neutrinos are, to the best of my knowledge, the smallest particles with mass that can be considered independently stable. Even working from the scales of protons, neutrons and electrons the speed of light limit seems to hold up well.

A neutrino has a mass some 100,000 times less than an electron and seems to originate with a velocity near c, or in the current context just greater then c. They don't need to be accelerated to that velocity, or that acceleration is instantaneous.

It would be very difficult to project the conditions equivalent to those a neutrino is subject, to ordinary material objects. In this case where ordinary material refers to atomic structures or atoms and molecules. Neutrinos do not interact electromagnetically within the limits of our ability to observe them. They interact with other matter only when they actually hit an atom's nucleus. Even then perhaps only some small part of the time.

It is far more likely that if this were reproduced and confirmed it might lead to some greater understanding of the fine structure of the universe. And as I mentioned earlier perhaps in some part inertia itself.

13. ### rpennerFully WiredRegistered Senior Member

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So, you can't sensibly talk about FTL travel until you have confirmation of a framework which allows neutrinos to be localizable and faster-than-light and hold the rest of physics. If we only had confirmation that neutrinos are localizable and faster-than-light we still wouldn't have them unified in physical theory and they would stand outside physics, like magic, until we did understand them in a unified physical theory. But right now, we have a very complicated claim that a certain distance and a certain time interval was measured with certain associated precisions that lead one to conclude the claim is neutrinos travelled marginally faster than light. Not all parts of the claim are on the Internet -- many details are in one person's doctoral dissertation and it only takes one sign error or double-counting to render the claim invalid.

14. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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You missed the point again.

Light travels at a constant speed in a vacuum. By definition, the meter is the distance light travels in a vacuum in 1/299,792,458 of a second. Since the meter is defined by light travel time, the speed of light is 299,792,458 m/s, by definition.

It can not be different than 299,792,458 m/s because the very definition of a meter is the distance light travels in 1/299,792,458 of a second.

You do not measure the speed of light by measuring the elapsed time it takes light in a vacuum to travel a meter. How would you know what a meter is unless you know the speed of light, as the meter is DEFINED by the distance light travels in 1/299,792,458 of a second.

It is impossible for the speed of light to be different, because the speed of light is defined, not measured.

15. ### OnlyMeValued Senior Member

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This while to some extent true is really circular reasoning...

A meter is defined as the distance that light travels in 1/299,792,458 of a second and the speed of light is 299,792,458 meters per second.

That's circular the meter is defined by the speed of light and the speed of light is defined by the meter.

And we did not even get into a definition of a second, which could be the time it takes light to travel 299,792,458 meters, in a vacuum.

The speed of light has been measured, and defined by that measurement. Standardizing the meter to the speed of light came later and was intended to add constancy to the length of a meter. The previous standard had come to be known to be flawed and inconsistent over time.

16. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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It is not circular.

The constancy of light travel in a vacuum is used as a standard to define the meter. The speed of light is the result of defining the meter by light travel time.

17. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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With the current definition of a meter as it stands being defined by light travel time means your statement above is circular.

In order to know a meter one must measure light travel time.

However, if you had a different definition of a meter which didn't involve light travel time, then you could define the second by the time it takes light to travel 299,792,458 meters.

18. ### OnlyMeValued Senior Member

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What part of the above is not circular reasoning?

It has only been defined relative to the distance light travels in a vacuum since the early 1980s and the speed of light in vacuum predates that by just under 100 years.

The meter began as a fraction of the distance between the equator and the poles. You can obviously see how with our current knowledge that could be a problem.

The number involved, 299,792,458 should be a dead give away that the length of a meter predated its association with the distance light travels in 1/299,792,458 of a second. Who in their right mind would have chosen such number had they not already had some reference for the length of a meter?

Still, the point was that defining a meter based on the speed of light and the speed of light on a meter, is circular reasoning.

19. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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You fail to understand what is being said.

I want to create a new unit of measure of distance called the "dltios"
I define the dltios as the distance light travels in a vacuum in 1 second.
The speed of light is therefore 1 dltios/second.

That is not circular, nor does it require measurement to know the speed of light using the unit of measure of distance the "dltios."

20. ### CptBorkRobbing the Shalebridge CradleValued Senior Member

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Units of time can be unambiguously defined by looking at atomic decays where known frequencies of light are emitted, and measuring the time elapsed after this light of known frequency has completed a given number of cycles. Then you can define distance in terms of how far a beam of light travels in this time or the wavelength associated with each cycle (which will always give you the same result).

The speed of light in vacuum is a constant of nature because that's what every measurement to date has shown, and that's the result which would be consistent with our knowledge of electromagnetism. Unfortunately for Motor Daddy, it's not some arbitrary definition scientists came up with just to be pricks and make sure physics wouldn't agree with his everyday ordinary intuition.

21. ### Motor Daddy☼☼☼☼☼☼☼☼☼☼☼Valued Senior Member

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The speed of light is actually 1 dltios/second. Put that in your pipe and smoke it!

22. ### OnlyMeValued Senior Member

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I had no idea you were talking about dild.., dltios. Now everything make perfect sense!

23. ### OnlyMeValued Senior Member

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So they are also flammable? Do they cause cancer?

This has gotten way off subject and I really like the original subject.