faster than light?

Most likely: what went wrong was some subtle systematic measurement error.
Less likely: what went wrong was some interesting new physics.
Not at all likely: neutrinos move faster than c.

 

Photons have no rest mass. You can think of them as having mass when moving, but it's a bit bizarre. Since photons move at the speed of light, time has stopped for them. Because of this, all photos have a zero life span (from their perspective): they are created and destroyed simultaneously. This makes the idea of mass a bit wonky.

Because of contraction, photons also move zero distance between creation and destruction. When you see a photon from a distant star, that photon was just created, traveled no distance, and was then destroyed - from the reference point of the photon. Since the photon travels at the speed of light, space contracts to nothing.

Tom

 

As usual, the Bad Astronomer, Phil Plait, has some thoughts on this announcement. The devil's in the details.

 

Re: Speed of Light Broken

Neither of these articles are evidence that the actual scientist involved in the experiment or paper were skeptical of their results. Thanks for looking however.

 

Wikipedia has a very worthwhile point. The supernova 1987A had neutrinos detected at the same time as the light after light years of travel. So this provides a good constraint on the difference between supernova generated neutrinos and photon speed. It also speaks to the integrity of the reporting of the CERN results that no claim of proof or attempted expanation is given. The vetted results and the request for any and all outside examination is what is provided.

 

Re: Speed of Light Broken

I have seen no indication that they believe they have caused a major scientific theory to bite the dust. That belief seems to have been inserted by others in the reporting chain.

 

As always, the news media takes a single scientific paper, distorts what the paper actually says, and then draws conclusions which are at best unjustified by the paper, or at worst are actually contrary to what the paper says, thus further miseducating a public which is already ignorant of how science works and what science has demonstrated.

This is a common misconception. Not everything is relative. Certain observations are relative to the observer's frame of reference. But only certain observations, and these are highly constrained by specific and precise relations.

 

It comes from the principle of relativity, which states that equations describing the laws of physics have the same form in all admissible frames of reference.

Special Relativity deals with inertial frames of reference. General Relativity deals with arbitrary frames of reference. Special Relativity is special case of General Relativity.

Tom

 

Re: Speed of Light Broken

Perhaps, but the Huff post still stands alone in it's claim that the test scientist at CERN were skeptical of their own results. After all some reports I've read state they ran the test's up to 16,000 times. You'd think after that many times they'd be convinced of what the test's were telling them and release the results, Oh, never mind they did release the results for peer review. Now let's sit back and perchance dream about the possibilities.

 

Re: Speed of Light Broken

They can run the same test a million times and come up with the same results. What is at stake is huge. Huge enough for the scientific community to be plenty skeptical. And huge enough for another group to attempt a repeat, which is how these findings eventually become relevant, if found repeatable. But here's what I don't get... they determined the distance between the two sites by means of GPS measurements. GPS is +- 15 meters. The results wouldn't be significant until the distance was measured to within one meter, and then repeated. More than 1.5 meters error and then, as Phil Plait says "we're done."

I call shenanigans.

 

Re: Speed of Light Broken

According to what I read, the uncertainty in distance is +/- 0.20 meters, so it is already under 1 meter.

 

Certain measurements are relative, depending on the observer's frame of reference. Just not "everything."

 

Re: Speed of Light Broken

Only in real time standalone mode with a C/A code receiver. Phase locked, Dual Frequency Carrier Tracking, off-line, double differencing surveying use of GPS data gives relative position accuracies of a centimeter or less. This is how GPS is used to measure mm shifts in the earths crust. Bottom line is the postion seperation of the two locations was determined with the most accurate means available.

 

My son works for a company that does survey work for natural gas and
coal mining companies looking to extract those resources from gov't
lands in VA, KY, TN, and WV. About a year ago we were chatting and the
matter of accuracy of their work came up.

He said that no matter what the typical GPS manufacturer/seller says,
off the shelf units are accurate to only +/- 15 yds.

IIRC, he said that with differential GPS across 50 miles, if you put a
pencil eraser over their surveyed mark, there is a 99.99% certainty
that the desired location is under the eraser...
"Gun totin' good ol' boys, bears, rattle snakes, and mosquitoes
be damned."

"Cool," says I. "How much does that GPS receiver cost?"

Him, "Well it takes 3 or 4 units, and they go for $10K and up for each."

Me, "And up! I guess that I can live with +/- 15 yards then."

I'm sure CERN has that kind of money to spend on the equipment , or a
world class survey company to contract. I believe that the distance
measured via GPS could have the same or greater degree of accuracy.

 

The published paper is free

[1109.4897] Measurement of the neutrino velocity with the OPERA detector in the CNGS beam

but most of the physics is beyond my reach. They claim position accuracy of 2 cm. They also need very accurate timings at the starting gate and the finish line, and use both GPS and Cesium clocks for that.

Trouble is (and I am limited by physics knowledge here) that I would have thought both GPS and Cesium clocks rely on "c" being what it is. If it isn't , then I feel unsure how to interpret the current result.

But, as suggested earlier in this thread, that supernova light & neutrino arrival time result cast some confidence on "c" being reliable. I'm sticking with that for now.

 

Recall that for this experiment the distance is through the Earth, so the GPS positions were measured in three dimensions. GPS measurements in the Z axis are inherently less accurate because the Earth blocks many of the available satellites in that direction. Still, modern survey type GPS units can easily provide the necessary accuracy.

Off the shelf differential navigation GPS will provide eight foot accuracy under ideal conditions. That is an eight foot radius, or a 16 foot circle. We get this with some regularity with our marine chart plotter. Of course when you really need it the satellites are invariably in bad locations or weather screws up the signal. I've watched our position jump back and forth over a quarter mile in when this happens.

Tom

 

Wow! A lot of hate directed at science and scientist going on here. I guess change is hard for those that cling.