DawgTalkers.net Forums DawgTalk Everything Else... CERN claims faster-than-light particle measured

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neutrinos — one of the strangest well-known particles in physics — were observed smashing past the cosmic speed barrier of 186,282 miles per second (299,792 kilometers per second).

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how do you even calibrate this measurement?

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the first comparison I had was imagine how any major "concrete" laws that we had in past have been refuted and then how the new schools of thought completely changed the way we lived. The earth is flat / geocentric theory / man can't fly / man can't go into space ...

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Eh, not quite. It would be the same thing that happened when Einstein posited general and special relativity. Newtonian physics still apply to a special set of rules and applications. It's perfect for small experiments, like what you can do in your backyard. However, once you start getting to hundreds of miles in distance, newtonian physics no longer cuts it and relativity must be invoked. We could be seeing something similar here. If it holds up it doesn't invalidate relativity or newtonian physics, it just surpasses them in it's specificity. And honestly, Einstein knew this theory was incomplete, and others have proven it since. We just haven't known in what areas it is incomplete. Maybe that's what we're seeing now.

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I should say that if I were a betting man I would be putting the house on an experimental error being discovered in the future.

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I think that's what most people are thinking. Although probably hoping it's not true

I wasn't trying to decrease the importance of the finding, I think it would be huge if this gets vetted. I just don't necessarily think it's "earth revolves around the sun" earth-shattering. Maybe it's because I can't appreciate what this fully means for the field.

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how do you even calibrate this measurement?

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Physics books would be burned if this were true

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I know a pastor here in Florida that has experience and can help with that. And he's moving his church to the area I live.

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As I understand it, Einsteins theory breaks down in the sub atomic world of Quantum Mechanics. Someone here smarter than me can verify that or not. Maybe this experiment can be a small step towards a unified theory of everything. Isn't that the Holy Grail of Physics?

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No, this is the holy Grail of Physics.

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holy Grail of Physics.

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Just like scientists of the day had to "rethink" if the world was really flat or the sun revolved around the earth or if global warming is man made.

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As I understand it, Einsteins theory breaks down in the sub atomic world of Quantum Mechanics. Someone here smarter than me can verify that or not. Maybe this experiment can be a small step towards a unified theory of everything. Isn't that the Holy Grail of Physics?

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how do you even calibrate this measurement?

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how do you even calibrate this measurement?

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Onstar.

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Gotta love how we can interconnect threads on this forum.

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how do you even calibrate this measurement?

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See Lyoukdea's post above. Here's the wiki for quantum field theory. It talks a bit about relativity in quantum mechanics.

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Faster-than-light travel discovered? Slow down, folks

So the web is buzzing right now over news that scientists have detected some subatomic particles moving faster than the speed of light.

Yeah, well, not so fast. Let’s think about this for a sec.

First, what happened is that they create these particles, called neutrinos, at CERN in Geneva. Neutrinos don’t interact with normal matter well, so they can pass right through the Earth as if it isn’t there. In a fraction of a second, some of them enter a detector called OPERA in Italy where they are recorded (pictured here). If you divide the distance between those two points by the time it takes for the neutrinos to travel, you get their speed.

And when the scientists did that, they find the neutrinos get to Italy about 60 nanoseconds faster than a photon would.

Photons travel at the speed of light — they are light! — so this means the neutrinos, if this is all true, traveled faster than light speed. Holy Kessel Run!

But is it true?

Now first off, if it were this would overturn so much physics that they may as well have discovered that gravity pushes, not pulls. So right away we need to treat this claim with lots and lots of skepticism. I’ll note these are actual particle physicists making this claim, and not some crackpots who will shake their fists at the sky and say how Galileo was laughed at too.

The thing to do is to look at where this claim might have gone awry. First, the timing is interesting. They claim a measuring accuracy of 10 nanoseconds, so 60 ns would be pretty significant. However, my first thought is that light travels about 30 centimeters in 1 ns, so they need to know the distance between the source and the detector to an accuracy of 3 meters. If they are off by 20 meters, then we’re done; that would explain the difference entirely. I suppose this depends on how they measured the distance and the speed of the particles, too. However, they haven’t published a paper on this just yet, so that’ll have to wait.

[UPDATE: The paper is now up on the arxiv preprint server. I took a look, and must say at first glance their reasoning looks solid. They appear to have the baseline distance nailed and the timing as well. However, the devil's in the details, and this isn't my field, so I'll be very curious to see how the pros in this discipline react to the paper.]

Also, as pointed out in a Science Magazine article, knowing the exact moment the neutrinos are created isn’t easy either. Mind you, 60 nanoseconds is 0.00000006 seconds, so they need a pretty good clock here. That page also says they used GPS to determine the distance, which could be off a bit.

There’s another point that actually is quite important here. If neutrinos travel faster than light, then we should’ve detected the neutrinos from Supernova 1987A before we saw the explosion itself. That exploding star was formed when the core of a massive star collapsed, detonating the outer layers. The collapsing core blasted out a furious wave of neutrinos strong enough to be seen here on Earth, over 160,000 light years away.

The distance from the detector in Italy to the source in Geneva is about 730 km. The travel time at the speed of light is about 2.43 milliseconds, and the neutrinos appear to have outraced that speed by 60 nanoseconds. If true, that means they were traveling just a scosh faster than light, by about 1 part in 40,000. The neutrinos from SN1987A traveled so far that had they been moving that much faster than light, they would’ve arrived here almost four years before the light did. However, we saw the light from the supernova at roughly the same time as the neutrinos (actually the light did get here later, but it takes a little while for the explosion to eat its way out of the star’s core to its surface, and that delay completely accounts for the lag seen).

But I wouldn’t use that argument too strongly; perhaps this experiment creates neutrinos in a different way, or the neutrinos from this new experiment have different energies than ones created in the cores of supernovae (a good bet). Still, it’s enough to make me even more skeptical of this FTL claim.

I’ll note that the scientists will be presenting these results tomorrow at a conference at CERN. We’ll learn more then. It’s not clear to me if these results are being published, or have been peer-reviewed, or what. As usual, we’ll need to have other scientists either confirm this result using other equipment, or show where things went wrong. That’s how science works. And the scientists involved are asking for criticism here! That’s just so; incredible results need to be tested incredibly well.

So don’t let your imagination run away with this just yet. This result will, in my opinion, probably turn out to be incorrect for some reasons dealing with measurement. Faster than light travel is still a dream, even though I wouldn’t say it’s impossible… just very, very, very, very unlikely.

Maybe someday we’ll boldly go. But for now, I’m not betting my dilithium on it.

Image credit: OPERA; NASA/ESA/Hubble

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There’s another point that actually is quite important here. If neutrinos travel faster than light, then we should’ve detected the neutrinos from Supernova 1987A before we saw the explosion itself. That exploding star was formed when the core of a massive star collapsed, detonating the outer layers. The collapsing core blasted out a furious wave of neutrinos strong enough to be seen here on Earth, over 160,000 light years away.

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Ok we see a supernova that the light took 160,000 years to get to earth. Correct me if I'm wrong but this means it blew up 160,000 years ago, and we are just now seeing it.

And he claims if these neutrinos travel faster than light then we should have seen them first. but if the neutrinos are faster then over a period of 160,000 years of travel, how far ahead would they have been, and would we have had instruments to measure them then, or even known what they were from since they would arrive before we knew about 1987A.

if you get hit by the bullet before you hear the gunshot, do you know what hit you?

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The neutrinos from SN1987A traveled so far that had they been moving that much faster than light, they would’ve arrived here almost four years before the light did. However, we saw the light from the supernova at roughly the same time as the neutrinos (actually the light did get here later, but it takes a little while for the explosion to eat its way out of the star’s core to its surface, and that delay completely accounts for the lag seen).

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