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Evidence of a Correction To the Speed of Light

Soulskill posted about 4 months ago | from the fault-is-not-in-our-stars-but-in-ourselves dept.

Space 347

KentuckyFC writes: In the early hours of the morning on 24 February 1987, a neutrino detector deep beneath Mont Blanc in northern Italy picked up a sudden burst of neutrinos. Three hours later, neutrino detectors at two other locations picked up a second burst. These turned out to have been produced by the collapse of the core of a star in the Large Magellanic Cloud that orbits our galaxy. And sure enough, some 4.7 hours after this, astronomers noticed the tell-tale brightening of a blue supergiant in that region, as it became a supernova, now known as SN1987a. But why the delay of 7.7 hours from the first burst of neutrinos to the arrival of the photons? Astrophysicists soon realized that since neutrinos rarely interact with ordinary matter, they can escape from the star's core immediately. By contrast, photons have to diffuse through the star, a process that would have delayed them by about 3 hours. That accounts for some of the delay but what of the rest? Now one physicist has the answer: the speed of light through space requires a correction.As a photon travels through space, there is a finite chance that it will form an electron-positron pair. This pair exists for only a brief period of time and then goes on to recombine creating another photon which continues along the same path. This is a well-known process called vacuum polarization. The new idea is that the gravitational potential of the Milky Way must influence the electron-positron pair because they have mass. This changes the energy of the virtual electron-positron pair, which in turn produces a small change in the energy and speed of the photon. And since the analogous effect on neutrinos is negligible, light will travel more slowly than them through a gravitational potential. According to the new calculations which combine quantum electrodynamics with general relativity, the change in speed accounts more or less exactly for the mysterious time difference.

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Which means (-1)

Anonymous Coward | about 4 months ago | (#47309881)

Einstein was WRONG!

E = mc^3 !!

Which by the way, still works!

Re:Which means (4, Interesting)

VernonNemitz (581327) | about 4 months ago | (#47310151)

There seems to me to be a slight error in the original article. Neutrinos have been determined to possess mass. It is only a slight amount of mass, but it precludes them from being able to travel at exactly the speed of light. How close to light-speed do they normally travel? I can't say. But it is reasonable to think that the distance from Supernova 1987A to Earth should have led to a slightly later arrival time, for neutrinos, than if they had actually traveled at light-speed.

The preceding relates to another thing, the quantum-mechanical mechanism for interfering with the actual speed of light. Those pairs of virtual particles that form also have mass. That means, while they temporarily exist, they also cannot be traveling at exactly light-speed; they have to be traveling slightly slower.

Re:Which means (-1)

Anonymous Coward | about 4 months ago | (#47310847)

There seems to me to be a slight error in the original article. Neutrinos have been determined to possess mass. It is only a slight amount of mass, but it precludes them from being able to travel at exactly the speed of light.

This line of thought has always bugged me.

Neutrinos assumed to have rest mass because it is assumed time must pass for flavour oscillation to occur... yet it must be very very very small or else we would be wrong... and oh by the way photons can momentarily turn into other shit on their journeys yet somehow neutrinos can't. Assumptions piled atop assumptions.

I realize all of science is based on combinations of measurement and theory but the cherry picking of properties and lack of observational evidence showing neutrinos propagate any faster or slower than light is disheartening.

Re:Which means (0)

Anonymous Coward | about 4 months ago | (#47311029)

and oh by the way photons can momentarily turn into other shit on their journeys yet somehow neutrinos can't

Yet that ability to turn into other things is already factored into the speed of light, just as it is factored into other measurements. Quantum field theory that discusses such processes is quite aware of the idea we only measure the final result and not the individual pieces... then goes on to make predictions to 15 digits of precision. And neutrinos can turn into other stuff, as can another other particle, but it is more limited by not being a charged particle and not interacting with electromagnetism directly.

Re:Which means (0)

Anonymous Coward | about 4 months ago | (#47311047)

There seems to me to be a slight error in the original article. Neutrinos have been determined to possess mass. It is only a slight amount of mass, but it precludes them from being able to travel at exactly the speed of light. How close to light-speed do they normally travel? I can't say. But it is reasonable to think that the distance from Supernova 1987A to Earth should have led to a slightly later arrival time, for neutrinos, than if they had actually traveled at light-speed.

The preceding relates to another thing, the quantum-mechanical mechanism for interfering with the actual speed of light. Those pairs of virtual particles that form also have mass. That means, while they temporarily exist, they also cannot be traveling at exactly light-speed; they have to be traveling slightly slower.

False. Neutrinos can go faster than the speed of light. It's a common mistake by laymen that relativity says that nothing can travel at or above the speed of light. In fact, relativity only says that it is impossible to accelerate to or above the speed of light. It says nothing about particles that already travel at or faster than light speed.

Re:Which means (0)

i_ate_god (899684) | about 4 months ago | (#47310343)

well no

E = m(c*1.2481005830886023468204621)^2

Re:Which means (0)

Anonymous Coward | about 4 months ago | (#47310651)

If it really was a ~24% difference then pretty much every physicist should be called incompetent.

Re:Which means (0)

Anonymous Coward | about 4 months ago | (#47310737)

energy = matter is the gist of it. the speed of light was thrown in, and squared, only for effect. as in, the enery in matter is HUGE! every school boy - outside america - knows this.

So, what's the correction? (1)

TWX (665546) | about 4 months ago | (#47309889)

Since they've established the difference between the theoretically-idealized neutrino and the observed photon, do they correct the idealized, or do they correct the observed?

Re:So, what's the correction? (5, Funny)

ShanghaiBill (739463) | about 4 months ago | (#47309953)

do they correct the idealized, or do they correct the observed?

Neither. You cannot correct the speed of light, because it isn't measured, it is DEFINED as EXACTLY 299,792,458 meters per second. So it is not the speed of light that needs to be updated, but the length of the meter.

Re:So, what's the correction? (5, Insightful)

Anonymous Coward | about 4 months ago | (#47310213)

You have this the wrong way around. The speed of light is not defined, it is a universal constant. It is the length of the meter that is defined based on a combination of this constant, and the international standard of time. So you are correct that if light turned out to travel slower, the length of the meter would be slightly shorter, and the speed of light would still be exactly 299792458 meter per second. This would be according to the new length of the meter though, when expressed in the old length (which is what the poster is implicitly asking for), it would most certainly be less, and could be given as such.

Of course the truth is that the speed of light is perfectly fine as it is. It's just that light isn't always exactly 'light' when it travels through space.

Re:So, what's the correction? (1)

hsthompson69 (1674722) | about 4 months ago | (#47310783)

It's just that light isn't always exactly 'light' when it travels through space.

*This*.

It would've been better if they had focused on the transformation of light over time as it travels through space - that shit is interesting as all hell.

Re:So, what's the correction? (1)

lazy genes (741633) | about 4 months ago | (#47310861)

I would never trust a photon for more than 1 million light years.

Re:So, what's the correction? (0, Interesting)

Anonymous Coward | about 4 months ago | (#47310239)

"c" is defined as 299,792,458 meters per second, which is the idealized speed of light. The practical speed of light can be slower, like when propagating through glass. If this new data is correct, then neutrinos move faster than photons through a gravitational potential.

Re:So, what's the correction? (5, Informative)

Em Adespoton (792954) | about 4 months ago | (#47310399)

None of this is the issue; speed of light stays constant, as does distance measurements. What changes is the understanding of the stability of a photon of light in a vacuum and the effect of this instability on travel time while passing near a gravitational well.

So while it's a photon of light, it travels light speed. When the energy converts to kinetic energy for a breather, it is affected by the gravitational pull, in a manner significantly stronger than a neutrino is affected. When it then flops back to being a photon, it is once again traveling at the speed of light.

What intrigues me about this is that this will also have implications regarding relativity, as every time the light flips state, it is essentially anchoring itself to a location in space from which the next photon flop can take its bearing. My mind can't quite grasp the further implications of this right now, but it could really mess with observation of light from a moving point (which all points are).

The recalibration is mostly on how we project distances based on light measurements; it's now become significantly trickier, as we need to account for gravity at specific moments.

Re:So, what's the correction? (0)

Anonymous Coward | about 4 months ago | (#47310695)

Depends on the base really..... In base "speed-of-light" the speed of light is actually just "1.0".
As a percentage it's 100% and most things in the universe are at less than 1%.

Hell I could even change the base notation *before* meters.... Meters are now in Hex... you have 0xFF meters.
Or since speed references time, I could argue that time itself is simply warping around an object due to it's excessive speed making it "seem" to be faster.

How do we know time isn't the variable that changes here.... the objects were *always* moving at the speed of light, but time was experienced differently because the two objects (us and the particles) were moving at drastically different speeds over enough distance that the time-difference is measurable.

I'd say this proves time warps more than any proof over changing speed of light. When time changes how do you measure speed?

Re:So, what's the correction? (4, Informative)

jae471 (1102461) | about 4 months ago | (#47309997)

Neither. Because neither is wrong. And the article is trying to sensationalize a claim the scientists didn't make.

It is the average speed of the light over very large distances that needs a correction, to account for the portions of travel where the light, well, is not light. The photons still move at 2.99x10^8m/s. It's the electrons and positrons that move slower.

Re:So, what's the correction? (-1, Offtopic)

Anonymous Coward | about 4 months ago | (#47310105)

Every time I fuck my wife, she says I'm "correcting the speed of light".

Even that Sounds Wrong (2)

Roger W Moore (538166) | about 4 months ago | (#47310195)

The photons still move at 2.99x10^8m/s. It's the electrons and positrons that move slower.

This whole premise sounds wrong and needs data to confirm it. The problem is that the article is wrong to claim that neutrinos move at the speed of light - they have a non-zero mass and so must move slower than this. However their mass is incredibly small (probably ~100,000 times less than an electron - so small that we have not actually measured it yet!) so they move very close to the speed of light. What sounds dodgy is that they are claiming that the primary effect of the non-zero neutrino mass is negligible while the secondary effect of the zero-mass photon coupling to virtual electron-positron pairs is more significant. A quick back of the envelope calculation suggests that the neutrino mass could cause a ~30 minute delay in the neutrino arrival over such a distance.

In addition they are basing this on being able to accurately calculate the scattering delay time of photons in a super nova. Less than a decade ago super nova models could not even get the star to explode (the explosion was not powerful enough and was overcome by gravity) so I have a hard time believing that they have perfected things to the extent where can really give a reliable number for the scattering delay time.

As usual extraordinary claims require extraordinary evidence and so far there is much of the former and none of the latter. Although it is also possible that the article is completely misrepresenting the claims but if so it is doing an even worse job of it that you suggest!

Re:Even that Sounds Wrong (1)

jae471 (1102461) | about 4 months ago | (#47310323)

I am not a particle physicist, so I cannot comment as to how many vacuum polarisation events a single photon would undergo during the 168000-year trip, nor how much this would actually affect the average transit time. And I agree that this claim seems off -- especially since a photon takes ~4000 years, give or take an order of magnitude, to leave the center of our sun, which has a lower density than what is present in a core-collapse supernova.

OTOH, this is an interesting idea, and it may have greater implications in cosmology.

Re:Even that Sounds Wrong (1)

pla (258480) | about 4 months ago | (#47310985)

The problem is that the article is wrong to claim that neutrinos move at the speed of light - they have a non-zero mass and so must move slower than this.

I suspect the actual study, if not TFA, took that into consideration.

I actually find it more odd that the effects of mass on the neutrinos slowed them less than the effects of quantum gravity on the photons - The photons still lagged the neutrinos, rather than making up for a mere three hours' lag on a journey of 168,000 light-years? Truly mind-boggling! Kinda like driving from NYC to LA and still beating a flight that transfers at every airport on the way.

Re:So, what's the correction? (1)

msauve (701917) | about 4 months ago | (#47310487)

That's my understanding, too. They're simply trying to describe the index of refraction for deep space.

Or Change the Theory (0)

Anna Merikin (529843) | about 4 months ago | (#47310085)

This could lead to the acceptance of alternative cosmologies that have been bubbling up for years. Try these links:

http://www.dailygalaxy.com/my_... [dailygalaxy.com]
http://vixra.org/pdf/1404.0123... [vixra.org]
http://www.researchgate.net/pu... [researchgate.net]

Re:Or Change the Theory (2)

MightyMartian (840721) | about 4 months ago | (#47310109)

Or it could be a badly written summary and article that completely misrepresent what is being stated.

If every science journalist on the planet were to spontaneously combust, not only would it introduce a whole new physical phenomenon, it would cause the average IQ of the planet to jump by at least 5 points.

Re:Or Change the Theory (0)

hsthompson69 (1674722) | about 4 months ago | (#47310793)

I'm shocked. We completely agree on this one. :)

Re:Or Change the Theory (1)

fibonacci8 (260615) | about 4 months ago | (#47310805)

Or the average IQ would remain 100, since it's a fixed number.

Re:Or Change the Theory (1)

meglon (1001833) | about 4 months ago | (#47310355)

What could lead to the acceptance of an alternate cosmology is when one of them is more refined than Relativity. So far there's a lot of BS out there, but nothing coming close to Relativity.

I'll at least give you points for not putting up a link to that Plasma Cosmology bullshit.

one part in 200,000,000 (1)

peter303 (12292) | about 4 months ago | (#47310107)

Distance to Magellanic Cloud (158K LY) divided by 7.7 hours. Light travels 300,000,000 meters a second. So that would be a delta of a couple feet per second. I'd think we'd see something large in our solar system.

Don't mess with "c" (4, Interesting)

NReitzel (77941) | about 4 months ago | (#47309903)

There's an alternative explanation. Space-Time could have non-zero viscosity, and slow down photons.

There are a lot of reasons to consider that space might have a viscosity. For one thing, it would neatly explain the expansion of the universe, without the necessity of invoking dark matter and dark energy.

We live in interesting times!

-- Norm Reitzel

Re:Don't mess with "c" (1)

Anonymous Coward | about 4 months ago | (#47309965)

Isn't this essentially what the article is saying -- that photons are slowed down by a "viscosity" that is relative to the mass of the galaxy? Since neutrinos don't interact with that mass, they are not slowed down by it.

They are definitely not saying that the physical constant is wrong, just that light doesn't always travel at that speed, even when in a vacuum.

dom

Re:Don't mess with "c" (1)

meglon (1001833) | about 4 months ago | (#47310321)

No, it's saying that the photons travel at the speed of light, but are not always photons..... and when they're not photons, they travel slower than the speed of light.

Re:Don't mess with "c" (1)

Em Adespoton (792954) | about 4 months ago | (#47310441)

Based on this, I'd like to know what the distance spread is on the lifetime of a photon, and what affects this lifetime. Because we're obviously seeing state change as part of the energy transfer.

Re:Don't mess with "c" (1)

muridae (966931) | about 4 months ago | (#47310733)

It isn't a fixed length of time or distance (same thing at the speed of light in a vacuum, excepting spacial expansion). It's a statistical chance; each high energy photon has a chance at each and every point in time to split into an electron-positron pair (annihilation of the pair create gamma and higher photons, so it should only be those photons that split) and then those will travel for some time, being effected by gravity and all the other forces, before re-combining into a photon.

That's my complex way of saying "eh, I dunno, I got far enough in physics but that's above my head to figure out." If you want to understand the Schrodinger equation, or can find a Feynman diagram that lists the chance over time, good luck. I tried googleing phrases I thought would get me an abstract or brief but came up empty.

Re:Don't mess with "c" (1)

Em Adespoton (792954) | about 4 months ago | (#47310883)

Yeah; that's about how far I got... but "statistical chance" is just a handwavy method of saying "we don't know the full mechanism, but we can predict the frequency of the results."

If it's purely a case of, for example, the Higgs field state at that moment, then it would follow that SOME photons would travel the entire distance, and we should be able to measure that. In fact, there should be a fairly even distribution that should be measurable, representing the specific probability curve. However, if it's flat, that implies a definite lack of chance and some other unknown factor influencing the time/energy/location relationship of a photon.

These are areas that will likely be explored ad-nausea now that the underlying observation has been made. I'm interested in the results without having to be the one to do the work :D

Re:Don't mess with "c" (2)

jovius (974690) | about 4 months ago | (#47310197)

Space has a sort of viscosity if it would mean gravity and expansion, but that doesn't have an effect on the speed but the frequency of a photon. So it's more like a spectral filter.

In nearly 15 years, I've never done this... (5, Funny)

bmajik (96670) | about 4 months ago | (#47309945)

FIRST POST

(however, the apparent local time when you see this post may differ based on the apparently non-constant nature of c )

Re:In nearly 15 years, I've never done this... (2, Insightful)

Dins (2538550) | about 4 months ago | (#47310019)

Maybe you should have stuck with not doing it. Just sayin' ;)

Re:In nearly 15 years, I've never done this... (1)

Ceriel Nosforit (682174) | about 4 months ago | (#47310417)

J.D. Franson's research appears to be Nobel prize worthy for its implications, and how much it could simplify our understanding of the universe. Wanting a first post on this is understandable.

Anyway, nothing 'virtual' at all about virtual particles. - Who would thought?

Re:In nearly 15 years, I've never done this... (1)

sammyo (166904) | about 4 months ago | (#47310037)

Perhaps you forgot to take into consideration the speed of light through fiber is less than c?

Re:In nearly 15 years, I've never done this... (5, Funny)

rsborg (111459) | about 4 months ago | (#47310077)

Perhaps you forgot to take into consideration the speed of light through fiber is less than c?

And the speed of light over Verizon fiber will vary based on whether it's sending Netflix photons or not.

In nearly 15 years, I've never done this... (0)

Anonymous Coward | about 4 months ago | (#47310057)

I read some of the article*, it didn't sound like 'c' was changing. You just shouldn't try to make your first post over large distances of space.

* Disclaimer: I am not a physicist.

Re:In nearly 15 years, I've never done this... (1)

Dancindan84 (1056246) | about 4 months ago | (#47310393)

If this joke goes over someone's head who's sufficiently dense, does that affect it's arrival time?

Ummm (1)

NoNonAlphaCharsHere (2201864) | about 4 months ago | (#47309967)

The electron-positron pair CAN'T travel at c, so there must be a deceleration when the pair is formed. Sure, when they recombine to become a photon again, they must (by definition) be traveling at c once more. So, by my thinking, either c varies with distance, or there's something wrong with this model. Could one of you astrophysics guys speak to this?

Re:Ummm (1)

mrsquid0 (1335303) | about 4 months ago | (#47310049)

Photons need to have gamma-ray energies before they can create virtual electro-positron pairs. Visible light simply does not have enough energy to do this.

Re:Ummm (1)

NoNonAlphaCharsHere (2201864) | about 4 months ago | (#47310115)

1) Irrespective of frequency, my question stands. Electrons/positrons CAN'T travel at c, photons MUST. So EM radiation (happy now?) must travel like a dotted line.
2) We're talking about visible photons in this case, anyways.

Re:Ummm (1)

muridae (966931) | about 4 months ago | (#47310841)

No, we aren't talking about visible photons. The emissions from the supernova were neutrinos and a gamma ray burst, the visible light travels still separately because of the other things in space that it interacts with that are transparent to gamma energy and above. But, yes, over the very large distances between us and the supernova it was not just a few photons that traveled at less than c for some time, but the chance rose high enough that it was nearly all of the photons.

All EM radiation travels at the speed of light. High energy photons can, briefly, become virtual particle pairs that do not travel at the speed of light. The article author noted that the chance, over the time and distance between us and this specific supernova, was high enough that it would account for all of the gamma ray and higher energy photons traveling as particle pairs for some part of their trip and that time would account for the known time delay. This only applies to gamma rays above (i think) 511 keV (one of the gamma rays emitted in an electron-positron annihilation. might need to be 1022keV for a single ray to form both particles from a single photon; ask a particle physicist, not a programmer like me). According to Alpha [wolframalpha.com] , a 500nm green photon has only around 2eV. Violet light gets up to 3 eV and a little higher; still not enough to create any particle. E=mc^2, so you need a good deal of energy just to create a very tiny electron.

Re:Ummm (2)

shoor (33382) | about 4 months ago | (#47310503)

Ah, this is getting off topic, but your comment raised a question in my mind. Suppose the light is blue shifted for an observer approaching it so that it does have the energy to form an electron-positron pair, but for another observer not approaching it as fast, it doesn't have the energy. Might one observer see the pair formation while the other did not?

Re:Ummm (1)

TapeCutter (624760) | about 4 months ago | (#47310719)

It gets even stranger from the POV of the photon/neutrino. Anything travelling at the speed of light does not experience time or distance. As far as these particles are concerned they hit the telescope at the same time they leave supernova.

Re:Ummm (1)

Culture20 (968837) | about 4 months ago | (#47310731)

I never saw light without not seeing the positron/electron pair formation. Ask Mr. Cat.

Re:Ummm (1)

muridae (966931) | about 4 months ago | (#47310953)

Bloody good question. They are called virtual particles, though. If forced to answer, I would suspect that the energy added by the observer traveling fast enough to blue shift the light that far, 50,000 times the wavelength (talking about a 500nm green down to 10picometer gamma) and 50,000x to 100,000x energy in keV, would require a good portion of c and would reduce the apparent distance covered to a lower amount that does not offer a high enough chance of a virtual particle interaction.

But that's just me making stuff up and pulling a WAG.

Re:Ummm (1)

Ungrounded Lightning (62228) | about 4 months ago | (#47310987)

Photons need to have gamma-ray energies before they can create virtual electro-positron pairs. Visible light simply does not have enough energy to do this.

No, they don't

They need those energies to create REAL, PERSISTENT electron-positron pairs, which fly away and last until they interact with something else - maybe centuries or eons later - that changes them to some other particle.

Virtual particle pairs, as long as their lifetime is less than a time that puts the product of the "error' in energy with the lifetime of the error under the uncertainty principle limit, can be created by photons that are far too small to create free particles. In fact, if the lifetime of the virtual particle pair is short enough, you don't even need the photon.

Re:Ummm (2)

tpjunkie (911544) | about 4 months ago | (#47310099)

The time period over which pair production-annhilation occurs might be a small part of the correction here, but from my quick reading of TFA, I think the key phrase is "This results in a small correction to the angular frequency of a photon and thus its velocity," where velocity is the key word. Velocity of course is a vector quantity, consisting of both a speed (c) and a direction. The key aspect here is the direction; when the pair recombines, the total energy of the system is slightly different as the positron-electron pair is affected by gravity and thus may pick up a small positive or negative acceleration from the gravitational potential they are traveling through. When they recombine this will be reflected in the new velocity (c d) of the resultant photon, which is not exactly the same as the photon prior to pair production. At least thats what I got, but I'm the wrong kind of doctor to be an expert in this. Any PhD's wanna weigh in and correct me, please do!

Re:Ummm (1)

NoNonAlphaCharsHere (2201864) | about 4 months ago | (#47310155)

Ahh. So you're saying it follows a zig-zag path. Now THAT makes more sense. So the TOTAL travel speed isn't c, just each individual leg of the journey is.

Re:Ummm (1)

muridae (966931) | about 4 months ago | (#47311013)

That's what the article seems to suggest, yes. And that the virtual particle pair, if they exist for real time, would move at less than c for their short life-span. But the major change from Earth's perspective is that the gamma rays we saw did not travel in the straight line that the neutrinos did.

That might also explain the second neutrino burst (maybe, wild guess from a programmer). If some of the neutrinos went through a virtual particle state (Z boson, I think?) then they would also arrive at a different time. That would account for neutrinos that made the trip with no virtual particles, those that slowed down due to the mass of Z boson interactions, and, according to the research summarized in the article, all the gamma rays that went through a virtual particle phase and dealt with gravity. If it all works that way, it would be beautiful science explaining more things we thought we understood. Ahh, science!

Consider the source (0)

oldhack (1037484) | about 4 months ago | (#47310047)

It's a Medium piece. Rest assured it's a bullshit click bait.

Basic premise verification (1)

ipsender (727730) | about 4 months ago | (#47310055)

What is the evidence that the process which produces the neutrino flux is contemporaneous with the process which produces the light burst in a collapsing star?

Re:Basic premise verification (0)

Anonymous Coward | about 4 months ago | (#47310143)

And how do we even know they came from the same source? All these assumptions! /s

More or Less Exactly (0)

Anonymous Coward | about 4 months ago | (#47310059)

More or less exactly....

I loled

What the hell... (5, Insightful)

Chocolate Teapot (639869) | about 4 months ago | (#47310079)

...is "more or less exactly" ?

Re:What the hell... (1)

The Grim Reefer (1162755) | about 4 months ago | (#47310193)

It's difficult to explain as it's a fuzzy thin line. ;-)

Re:What the hell... (4, Funny)

new death barbie (240326) | about 4 months ago | (#47310377)

"more or less exactly" == "approximately", more or less exactly.

Re:What the hell... (0)

Anonymous Coward | about 4 months ago | (#47310477)

"more or less exactly" == "approximately", more or less exactly.

I see. Clear as mud now, but perhaps you could crystallize that viewpoint by overlaying this on the Western Scale of Best Guesstimates.

It seems to hold slightly better accuracy than the previous standard scale of SWAG or the CloseEnoughE-Meter.

Re:What the hell... (1)

excelsior_gr (969383) | about 4 months ago | (#47310485)

It is almost precisely what you make it to be.

Re:What the hell... (1)

geekoid (135745) | about 4 months ago | (#47310947)

It means their are error bars due to the limitation of the equipment and new equipment might change the answer at some decimal point down the line.

Example:

On my birthday I will be more or less 50. So if its before 4AM, in general parlance, people would say I"m 50 and they would more or less be exact. But if you accurately look at it I would actually be 50 until 4AM

What gets corrected? (2)

Russ1642 (1087959) | about 4 months ago | (#47310081)

Presumably this happens all the time for light so what we've measured as the speed of light is correct, it's just that the true universal speed limit is higher and only neutrinos travel that fast. So we should find out that speed and use the speed of neutrinos when doing relativistic corrections.

Re:What gets corrected? (1)

Charliemopps (1157495) | about 4 months ago | (#47310303)

Presumably this happens all the time for light so what we've measured as the speed of light is correct, it's just that the true universal speed limit is higher and only neutrinos travel that fast. So we should find out that speed and use the speed of neutrinos when doing relativistic corrections.

But we are pretty sure neutrinos have mass now... so nope.

Re:What gets corrected? (0)

Anonymous Coward | about 4 months ago | (#47310305)

It's more complicated than that:

Neutrinos are suspected as having rest mass (albeit very, very small) so they can't quite hit "the speed of light in a vacuum", c, (or more properly c0, where just plain c is the speed of light in a medium). So, we can't use the speed of neutrinos as the absolute speed limit.

Now, what is being said here, is that, over vast distances, the combined effects of gravitation fields and the probabalistic generation and recombination of virtual particles create an observed "speed of light in a medium" effect upon the observed photons, which is itself lower than the almost-c0 of the neutrinos that were produced at the same event as the original photons. The absolute speedlimit over "short" distances is unaffected.

Re:What gets corrected? (0)

Anonymous Coward | about 4 months ago | (#47310357)

That's not what this is. The article is misleading. What's happening is that a photon is splitting into a virtual particle pair, which is not light anymore, and is not traveling at C. When the pair recombines into a photon, we have C again. This 'correction' is to correct the average velocity of light over great distances. Neutrinos are constantly moving at C, since they aren't interactive in the same way that photons are.

Re:What gets corrected? (0)

Anonymous Coward | about 4 months ago | (#47310373)

Our local measurements of the speed of light are not affected by this, because the pair formation is not frequent enough to affect experimental measurement. A few photons in the pack emitted in an experiment might undergo it, but the majority won't and we end up measuring the speed correctly. But over 168,000 light years, all of the photons undergo it sufficiently to delay the entire aggregate to the tune of 1.7 hours. What needs to be corrected is to take account of this phenomenon when calculating actual distance light will travel in astronomical scales. But not the value of c.

Re:What gets corrected? (1)

muridae (966931) | about 4 months ago | (#47311045)

c doesn't get corrected. Our measurement of the path that the light took gets corrected, as the virtual particle pairs interact with all the forces that photons are less affected by because of speed.

Finite chance? (1)

wisnoskij (1206448) | about 4 months ago | (#47310093)

What is a finite chance?
For that matter, what is an infinite chance?

Re:Finite chance? (2)

Russ1642 (1087959) | about 4 months ago | (#47310119)

Wait until you see these guys split up a bill for lunch.

Re:Finite chance? (1)

Overzeetop (214511) | about 4 months ago | (#47310129)

I'm not sure, but it may or may not involve monkeys, typewriters, and the works of Shakespeare.

Re:Finite chance? (1)

geekoid (135745) | about 4 months ago | (#47310917)

Given a specific period of time it WILL happen.

Given all time and space it might happen. Also: given a sub set of infinity it MAY happen within that subset but WILL happen in a larger subset of infinity.

Now we know everything? (1)

NMBob (772954) | about 4 months ago | (#47310165)

So I guess there's no question that we know every detail of what happens as a star is collapsing and that the photons didn't just take longer than we think they should to make their way out? And, also, wasn't this optical photons they were looking for? What if there was a brightening, but below the threshold of the detectors? If it's radio/X-rays/etc. then see the first sentence.

Cannot read article (-1)

Anonymous Coward | about 4 months ago | (#47310215)

Crappy medium.com presentation is crappy. No, I don't have a tablet, making their website unusable to me. Bit of the wrong way around, no?

Re:Cannot read article (1)

Goaway (82658) | about 4 months ago | (#47310285)

What part of the site needs a tablet?

Is it possible? (1)

TsuruchiBrian (2731979) | about 4 months ago | (#47310251)

Is it possible that they just misjudged the distance between the earth and the supernova by 4.7 lighthours?

Re:Is it possible? (0)

Anonymous Coward | about 4 months ago | (#47310519)

That would be irrelevant. The particles under consideration all traveled the sameish distance, so the travel delay for both groups would be the same.

Re:Is it possible? (0)

Anonymous Coward | about 4 months ago | (#47310531)

No no no.

The point is that the neutrinos and the photons should be traveling at the same speed through space, regardless of the distance from earth. The neutrino just got a 3 hour head start.

The 3 hours is the calculated number for photons to diffuse from the beginning of the supernova event through all the material.
Once a photon gets out into empty space, it should be traveling at the speed of light in a vacuum, lock-step with the neutrino, never gaining or losing distance.

What is being posed is that even in the vacuum of space, a photon particle travels straight-line slower than a neutrino because of influence of gravity, and it matters over galactic distances.

What makes it confusing is the terminology. A photon itself doesn't travel at less than the speed of itself... but given a galactic-scale distance to travel, a photon sometimes briefly morphs into something else, then goes back to being a photon. While it's morphed (something made it do that), it travels slower than the speed-of-light constant.

Is there a 'less nerdy version'? (2)

Voyager529 (1363959) | about 4 months ago | (#47310261)

Genuine question - this seems like an interesting thing, but as someone whose expertise in physics is incredibly limited, is there anyone who would be willing to provide an "explain it like I'm five" version for an individual like myself who is interested in understanding the speed differences observed in the particles?

Thanks, internet!

Re:Is there a 'less nerdy version'? (4, Informative)

suutar (1860506) | about 4 months ago | (#47310401)

photons and neutrinos both travel at approximately the same speed in vacuum - "the speed of light"
However, when it comes to going through a non-vacuum, like a star, neutrinos have a straight shot because they don't interact with anything and the photons have to run through a pinball game (or a pachinko game, if you've seen those) until they actually get out. Best estimates of the time difference to date are about 3 hours.
Because of that, they would expect to see the light about 3 hours after seeing the neutrino burst, but in this case it looks like it was 7+ hours instead.
This guy (if I'm understanding it right) is saying that even "in a vacuum" light does enough zig-zagging to add a few hours to the transit time of a 163000 lightyear trip.

Re:Is there a 'less nerdy version'? (1)

jasax (1728312) | about 4 months ago | (#47310959)

Unless between us and the supernova is some "dark matter" :-) (or something alike) that caused the photons to have the extra delay :-)

Indeed nobody has examined yet, IMHO, the path between us and the SN1987a supernova. Or even its "surroundings" when it was forming: did space time deformation or any other mysterious event occurred?

And if in general science often new knowledge erases old "facts", in Astronomy and Astrophysics that happens almost every day. So we have to take all this novelty with a grain of salt... (remember the recent flop of the particles travelling between CERN-Geneva and Grand Sasso...)

'less nerdy version' for five-year-olds. (1)

new death barbie (240326) | about 4 months ago | (#47310407)

Photons travel slower than neutrinos because they dawdle.

Re:Is there a 'less nerdy version'? (0)

Anonymous Coward | about 4 months ago | (#47310467)

Sure. Reddit will explain things like you're five. They have a whole subforum dedicated precisely to that. This is Slashdot. This is news for nerds - not for you. Don't let the door hit you in the ass on the way out.

Re:Is there a 'less nerdy version'? (1)

Theaetetus (590071) | about 4 months ago | (#47310579)

Genuine question - this seems like an interesting thing, but as someone whose expertise in physics is incredibly limited, is there anyone who would be willing to provide an "explain it like I'm five" version for an individual like myself who is interested in understanding the speed differences observed in the particles?

Thanks, internet!

Neutrinos go straight from start to destination, while photons have to take breaks every few minutes to pee, get a snack, fill up the tank, check out that yard sale, etc. They're like the cousin with ADD.

CAR ANALOGY, SUCKAS! (2)

gman003 (1693318) | about 4 months ago | (#47310765)

Okay, let's say you have two cars, a Porsche and an NSX (representing a photon and a neutrino, respectively). Both are limited by the same speed limit, which they always travel at (the speed of light).

Well, due to some weird quantum mechanics, every so often that Porsche splits into a pair of motorcycles, because apparently they got bought by Wayne Enterprises or something (in actuality, they split into an electron and anti-electron). They almost immediately join back together (forming a photon again), but while they're motorcycles, they are affected by wind (gravity). They still can't break the speed limit, but sometimes it slows them down just a bit.

When you're traveling almost literally between galaxies, that little bit of slowdown for tiny snippets of time can really make a difference. In this case, the NSX made it here a few hours earlier.

Re:Is there a 'less nerdy version'? (1)

geekoid (135745) | about 4 months ago | (#47310899)

"explain it like I'm five"

Because I said so.

Done.

haha, no I've never said that to my kids. I always followed the why question as far as I could. And when I didn't know, the internet did.

I AM SO SMART. S M R T... (0)

Anonymous Coward | about 4 months ago | (#47310281)

I only understood this because it was explained on Cosmos.

subject (1)

Charliemopps (1157495) | about 4 months ago | (#47310349)

Based on the last 100 crackpots that said the speed of light was wrong... or that it was variable...
and that I've never heard of this guy, and no other physicists are talking about this that I can tell...
I'm calling bullshit.

Maybe I'll feel dumb tomorrow, but I'm pretty sure physics blogs would be exploring right now if this were even remotely true.

also, this is just a blog post...

Re:subject (1)

doctor_subtilis (1266720) | about 4 months ago | (#47310617)

Read it again because they are not saying speed of light is wrong. Even the headline isn't saying that but the headline is sensationalism anyways. As a previous commenter stated (and the OP), since the light as it travels periodically (potentially/probably might be better word choices here) changes into an electron-positron pair, those brief times as massed particles are affected by gravity (naturally) and it adds up to quite an impact at large distances.

Re:subject (1)

EvilSS (557649) | about 4 months ago | (#47310643)

Maybe I'll feel dumb tomorrow, but I'm pretty sure physics blogs would be exploring right now if this were even remotely true.

also, this is just a blog post...

You've underestimated the speed of news on SlashDOT. It's much slower than the rest of the universe. Those events you mention should have already happened and you should feel stupid yesterday!

Light odyssey (0)

Anonymous Coward | about 4 months ago | (#47310369)

The article reveals: Light is just like all those other particles, including those "higher beings" like humans.
Odysseus whored his way through Aegaeis (only say kirke), being incredibly slow at returning home, his original destination. What do we learn today?

As a photon travels through space, there is a finite chance that it will form an electron-positron pair. [...] The new idea is that the gravitational potential of the Milky Way must influence the electron-positron pair because they have mass. [...] light will travel more slowly than [Neutrinos] through a gravitational potential.

You should only send neutrinos onto a voyage this long, seems you cannot trust light. It randomly does funny stuff and gets distracted by huge party clubs like our milky way.

This leads us to only one conclusion: Light is made by the devil to lead us into temptation. Think of Ilias!

Neutrinos, on the other side, are made by god.

That's not what I took away from this... (5, Interesting)

SXO148 (3712553) | about 4 months ago | (#47310473)

From what I gathered, the basis of Franson's hypothesis is the idea that a photon can spontaneously split into a matter-antimatter pair (this is also the idea behind Hawking radiation). Unless something crazy happens (again, see: Hawking radiation), that pair will almost instantly recombine, creating a photon with the same size and energy as the original photon.

Franson's idea, as I understand it, is that during the small window between creation and annihilation, the massive particles are under the influence of gravity, which bleeds off energy. When the pair recombines, it results in a reduced velocity of the photon.

Now, as I understand it, reducing the energy of a photon would merely reduce its frequency (red-shifting), not affect its actual velocity.

However, over long distances, the total time required for a photon to travel distance X would thus be slightly more than X/c, based on the proportion of time spent as a pair of massive particles, rather than as a massless photon. From a statistical perspective, this yields an average velocity of slightly less than /c/ (the speed of light in a vaccuum).

This seems reasonable to me, at least at first.

mrsquid0 raises an issue, though: Photons in the visible light range are not sufficiently energetic to create an electron-positron pair. I do not know if the photons in question were in the visible light range or not.

NoNonAlphaCharsHere also raises an important point: the electron-positron pair *cannot* travel at the speed of light. In fact, he/she raises an even better idea than Franson; my reading of Franson's explanation is that gravity is slowing down the particles (gravity field behind the photon), but there's just as much opportunity for gravity to *speed up* the particles (gravity field in front of the photon).

Now, I don't feel like doing all the math for this one little message, so here are the things I would consider before taking this article (and the original paper) at face value:

  • This is predicated upon the idea that gravitational fields affect neutrinos less than they do photons and ordinary matter. Do we know this to be true?
  • For the slowing down of the e-p pairs bit, there are two opposing forces:
    • I expect that higher-energy (higher-frequency) photons are more likely to generate an e-p pair than lower-energy photons. This means they are more likely to be slowed down
    • When a photon of energy /E/ forms an e-p pair with combined mass /m/, there is E - m*c*c energy unaccounted for. I expect that that energy ends up as kinetic energy, resulting in a velocity v = sqrt(2 (E - m*c*c) / m). Therefore, higher energy photons will have more energy left over and the e-p pair will thus being going faster.
  • According to the Wikipedia article on Pair production, the spontaneous formation of a matter-antimatter pair can only occur inside a nucleus (or momentum could not be conserved). However, this necessarily involves the photon traveling through a non-vacuum, which will necessarily slow it down.

This seems a little 'cranky' (0)

Anonymous Coward | about 4 months ago | (#47310505)

Note that this paper has been around for 3 years (which the linked article acknowledges). But it started out as a paper about the superluminal OPERA neutrinos -- which turned out to be wrong (a loose cable). The fact it's been on hep-ph (the high-energy physics preprint server) for 2.5 years in various forms without being published should raise alarms. Not conclusively... but at first sniff this smells very much like semi-crank science by press release. Nothing about the listing suggests it's even submitted anywhere.

Re:This seems a little 'cranky' (0)

Anonymous Coward | about 4 months ago | (#47310525)

Sorry, correction: it's been published, and in a refereed open-access journal. Still...

Einstein? (0)

Anonymous Coward | about 4 months ago | (#47310581)

The source posits that one scientist claims the speed of light must be slower than Einstein predicted.
The scientist is an idiot. Einstein never predicted the speed of light, nor made any contribution to the measurement of the speed of light. He used c, long established, as a constant in his relativity thought experiments.

"more or less exactly" (1)

glwtta (532858) | about 4 months ago | (#47310755)

That is the stupidest thing I've read today.

The headlines seems needlessly sensationalist (I know, shocking!) since apparently we're saying that photons don't always travel at the speed of light, not that the speed of light needs to be "corrected".

wonder if this could relate to observed red shift (1)

Sergey Kurdakov (3652003) | about 4 months ago | (#47310773)

While it is quite speculative, but what if this effect makes father light sources to be more redshifted? Then observed accelerated expansion of the Universe might be explained by just interaction of photons with some matter while light travels, the more it travels, the more the shift and not because of relative speed of galactics

How can neutrinos move at the speed of light? (0)

Anonymous Coward | about 4 months ago | (#47310903)

If they have a nonzero rest mass, they can't. And they do have a nonzero rest mass.

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