Re: The speed of light : Mon Nov 21, 2011 6:24 pm  

People once thought the world was flat, they were wrong. People once thought E=mc2, they were wrong too.

Re: The speed of light : Mon Nov 21, 2011 7:31 pm  

Ajw71 wrote:

People once thought the world was flat, they were wrong. People once thought E=mc2, they were wrong too.

Two wrongs don't make a right.
Sorry I couldn't resist.......

[Kosh]

Re: The speed of light : Tue Nov 22, 2011 8:42 am  

My money is still on experimental error TBH. Right up until the point that another team manages to duplicate their results.

Re: The speed of light : Tue Nov 22, 2011 10:32 am  

Kosh wrote:

My money is still on experimental error TBH. Right up until the point that another team manages to duplicate their results.

I hope they've stripped whatever down and put it back together. My money is on an 18m coax cable with a kink in it that that should be 1m long and marked "break this and I break you".

Re: The speed of light : Tue Nov 22, 2011 12:58 pm  

vbfg wrote:

But isn't it that that's in doubt here? If greater than c is possible then upper limits on speed, at least according to current understanding, become irrelevant, and would tend towards instantaneous at the kind of distances me or Dally can keep a steady aim at.

I'm sure there's some notion of instantaneous over great distances in quantum theory too. But I don't get any of that. At all.

The Forever War? Ages since I've read it so not sure myself, but wars across interstellar distances and time dilation are the main plot elements. Excellent book, with sequels that aren't sequels which I haven't read yet.

I liked the way The Forever War dealt with fighting battles in space at near to light speed and over great distances. The ships computers tried to predict the likely course of other ships and their munitions rather than flooding areas of space with ordnance. That scenario seems more reminiscent of Peter F Hamilton.

Forever Peace is a not a sequel but similar in style in that it is told in the first person and central character is a soldier in the future. Like The Forever War, it won a stack of awards.

Forever Free is a sequel to The Forever War and tells the story of William Mandela and other veterans disenchantment with life on the Planet of Middle Finger where they settled at the end of the war.

Re: The speed of light : Tue Nov 22, 2011 1:06 pm  

I think just duplicating the results would be hard for another team.
I'm thinking not just another team using the same gear, but another team with different gear preferably elsewhere. Because they couldn't trust the current set-up.
That would probably be hellishly expensive and for what?
They could rejig the current set-up I suppose.

They would have to come to the same percentage difference, or thereabouts,for there to be a match. Otherwise even if they may have indicated that the neutrinos were faster, it would look like an instrument characteristic problem that was playing a part in it.
And it's difficult to see how two or more different sets of gear would agree perfectly anyway.

I'm glad it's not my problem, still we can carry on with laws that seem to have worked so far and spend the money on famine relief ... naah! we can't do that, man is just too damn curious.

Re: The speed of light : Tue Nov 22, 2011 1:20 pm  

vbfg wrote:

I don't think that survives Occam either tbh. AFAIK the root of what he says is that they didn't account for all the frame of reference errors from the relative motion of the satellites and the earth. But GPS itself does that. ...

It does indeed, but the (alleged) error seems to be in the fatal assumption that their timing clocks were stationary. It is easy to think your clocks at each end of the experiment are staironary, but in fact they are not; the readout appears on the clocks, but the measurements rely on a moving satellite. The clocks' synchronizing reference point is located not where the clocks are, but in orbit.

van Elburg wrote:

because the satellites are moving, from their point of view, the positions of the neutrinos and the detector are changing. The neutrinos are moving toward the detector, and the detector appears to be moving toward the neutrino source. So the distance between the origin and destination appears to be shorter than it would if it were being observed on the ground.

“Consequently, in this reference frame the distance traveled by the [particles] is shorter than the distance separating the source and detector. This phenomenon is overlooked because the OPERA team thinks of the clocks as on the ground — which they are, physically — and not in orbit, which is where their synchronizing reference point is located.

Using the altitude, orbital period, inclination to the equator and other metrics, van Elburg calculates the error rate:

“The observed time-of-flight should be about 32 ns shorter than the time-of-flight using a baseline bound clock,” he writes. This is done at both clock locations, so double that, and you get an early-arrival time of 64 nanoseconds. "

He hasn't published this formally as yet, and of course it will then go to peer review. But I like it.

Re: The speed of light : Tue Nov 22, 2011 2:18 pm  

Stand-Offish wrote:

I'm glad it's not my problem, still we can carry on with laws that seem to have worked so far and spend the money on famine relief ... naah! we can't do that, man is just too damn curious.

It's a good job we are, or we'd be stuck in the dark ages. Cutting edge physics research is one of the very last areas that should be facing a funding cut.

Re: The speed of light : Tue Nov 22, 2011 5:34 pm  

Ferocious Aardvark wrote:

It does indeed, but the (alleged) error seems to be in the fatal assumption that their timing clocks were stationary. It is easy to think your clocks at each end of the experiment are staironary, but in fact they are not; the readout appears on the clocks, but the measurements rely on a moving satellite. The clocks' synchronizing reference point is located not where the clocks are, but in orbit.

Using the altitude, orbital period, inclination to the equator and other metrics, van Elburg calculates the error rate:
He hasn't published this formally as yet, and of course it will then go to peer review. But I like it.
“The observed time-of-flight should be about 32 ns shorter than the time-of-flight using a baseline bound clock,” he writes. This is done at both clock locations, so double that, and you get an early-arrival time of 64 nanoseconds. "

Very interesting and I hope correct.
Relativity fights back, how poetic that would be.

They (the OPERA scientists) can't have overlooked this possibility can they?

OPERA ... it ain't over until the fat lady sings.

Re: The speed of light : Tue Nov 22, 2011 6:02 pm  

Stand-Offish wrote:

Very interesting and I hope correct.

They'll be close enough to Dignitas to do the decent thing if it is correct.