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Meet Dr. Bechard Nor, pioneer transplant surgeon and one of the many achievers helping to unlock human potential at Cutter Foundation.
Steve: Hi, Steve Mirsky here with a short episode of Science Talk. As you may know, PBS has been running a four-part nova series with physicist, Brian Greene, called "The Fabric of the Cosmos." The last of the four parts is airing tonight, November 23rd. After part one debuted, Greene hosted a live Q&A here in New York City. The first question dealt with something that's been a big story in science news of late, the question of the alleged faster-than-light neutrinos. As you listen, there's a bonus a couple of backstage people who apparently didn't know that their electronic communication was bleeding into the microphone feed. Enjoy!
Questioner: And here is one from Twitter. You spoke about the speed of light in the program, but what about neutrinos going faster than the speed of light?
Greene: Well, that happened after the program was made. No, it's a great question because some of you may have heard there's this interesting recent result, where neutrinos were sent from Geneva through the Earth's crust to Gran Sasso in Italy, a 450 mile, race track, if you will; and the thing is the measurement seemed to show that the neutrinos are reaching their destination 60 nanoseconds before they should, namely they're getting there 60 nanoseconds even before a beam of light would be able to travel that distance. The neutrinos seemed to be going faster than the speed of light. This would be a remarkable discovery, but this is a very difficult experiment. There are many, many uncertainties. Even the researchers who put forward this result know that there are uncertainties. You have to measure that distance precisely, you have to know exactly the length of time for that journey, the moon pulls on the Earth's crust and that can slightly change distances, there are all sorts of complications. These are very smart people, so maybe all of these uncertainties have been taken into account, but I would bet everything I hold dear—well, almost everything I hold dear—that the result won't hold up to scrutiny. And I do say almost everything, because there's a small chance that my two little kids may be watching online right now. So, Alec and Sevilla, Daddy learned his lesson last time! (laughter) I will not bet on you this time around, so you don't need to worry about that. But I should say that if the result turns to be correct, it would be thrilling. I hope it's correct. This is what we live for, this kind of a revolution. I don't think this is one of those moments, but it could be. Okay, questions here—anybody? I'm looking around for somebody who has a mike, anybody have a mike? Right there.
Questioner: [If neutrinos did go faster than light, could you explain] what that means in case if that is confirmed?
Greene: What could it mean if neutrinos did go faster than the speed of light, if special relativity, this idea that Einstein gave us is wrong? Well first, it's useful to know why is that we think that neutrinos wouldn't go faster than the speed of light. Well, Einstein's theory shows that as an object is moving, the faster it goes, the more mass the more energy it has, the more mass means that it's harder to push it, even further. So, if a neutrino is approaching the speed of light, it gets heavier and heavier, needs an ever stronger push; and his math seems to show that if the neutrino went right to the speed of light, you need an infinite push to make it go faster still, and an infinite push isn't something that can happen. And that's why we don't think this is a correct result. If it is, well we'd have to rethink a lot of our basic understanding of relativity. The most naïve interpretation of the result would suggest that you might be able to send a signal to the past. So if something can go faster than the speed of light, if I have a neutrino gun and I fire it at you, the neutrino, in some way of thinking about it, would hit you before I pull the trigger. And that is so weird, that's so bizarre, that we really would need independent confirmation of those results to believe them. And people are undertaking experiments in the next few months, so we'll see whether independent experiments do confirm this result. I don't think they will, but I hope that I'm wrong.
Steve: If you missed "The Fabric of the Cosmos" when it aired, don't fret, the episodes stream in their entirety at the PBS Web site, http://www.pbs.org. And if you want to watch them on your bigger TV screen, check your listings for what will surely be numerous repeats. For Scientific American's Science Talk, I'm Steve Mirsky. Thanks for clicking on us.
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22 Comments
Add CommentBrian Greene's sanguine comments regarding the OPERA experiments were quite appropriate, and much more straightforward than the mostly illusionary portrayals of physics in the NOVA program series.
Reply | Report Abuse | Link to thisIn the most recent OPERA experiment, the ostensibly measured propagation time of neutrinos produced by the decay of protons accelerated to nearly the speed of light between two points was compared to the calculated speed of light in a vacuum over the ~730 km distance estimated using GPS and standard geodesy routines.
The measured time for neutrinos was determined to be 60 ns faster than the calculated time for photons.
If the geodesy routines did not adequately consider all applicable relativistic effects imparted to the neutrino's propagation, including any relativistic boost or Lorentz Boost imparted by the decay of the protons accelerated by CERN, and any non-Euclidean geometric effects imparted the internal spacetime traversed within the Earth, it might be possible that the neutrinos physically traversed a distance somewhat shorter than the estimated ~730 km distance (calculated for photons) to reach their destination.
If this were the case, reproduction of the experiment at physically separate, independent laboratories should produce a slightly different propagation time discrepancy that is not consistent with the OPERA results.
OPERATIC CONCERN
Reply | Report Abuse | Link to this-- James Ph. Kotsybar
Oh, little neutral one of tiny mass,
who flies anomolously from the sun,
you zip through matter photons cannot pass:
Could this explain the races you have won?
From Einstein, few believe that it could be
that any mass can go as fast as light --
it’s deemed complete impossibility,
assuming Relativity is right.
If proved, the implications terrible,
will give complacent physicists a scare.
In terms that twist the ancient parable
it’s you that’s tortoise; the photon’s the hare.
It seems, though steady, light can’t keep up pace.
You oscillate, and yet you win the race.
Agreed.
Reply | Report Abuse | Link to thisI'd just comment that in essence the notion that this result can stand is effectively nil. It would be equivalent to someone in 1700 encountering an unknown land bridge between Africa and South America. Explorers couldn't at that point say a lot about what the interior of Africa looked like, but they were QUITE clear about where its coastlines lay. In effect the situation is analogous here. Were there ANY loophole in GR of the type required to allow this result then causality doesn't exist, conservation of angular momentum doesn't exist, and basically pretty much all of modern Astronomy is a gargantuan mutual delusion.
The "speed of light" is really a misnomer. It isn't some kind of 'speed limit'. The very CONCEPT of 'superluminal velocity' isn't just forbidden by some rule. It is in fact logically inconsistent in exactly the same way that a 'square circle' is logically inconsistent.
OTOH I can just about barely imagine there might be some consistent way to fudge our way around a .000001% 'fuzziness' of some sort. It would still imply some serious implications for causality on a small scale, but its possible the scale could be small enough to live within that shadowy region imagined to be spacetime at the smallest scales. It will be interesting to see.
So far the only races run have been between the fraction of detected muon neutrinos following a course of their own choosing and simulated photons on a track presumed to be of identical distance. These simulated photons may simply be running a longer distance race.
Reply | Report Abuse | Link to thisAs I understand, the restriction to less than the speed of light for particles of positive rest mass is enforced by the process that increases their effective mass when accelerating energy is applied. Eventually an infinite force is necessary to achieve any additional acceleration...
Reply | Report Abuse | Link to thisThe detected oscillation of neutrino flavors is taken as evidence that neutrinos have (tiny) positive rest mass. As I understand, particles with zero rest mass propagate at the speed of light, and only particles with imaginary rest mass could achieve FTL velocities...
Einstein did not think from scratch and only based his stuff on Michelson's experiment and even the increase of speeding mass was already determined, so lets stop the deifying. Suppose Michelson was performing in a closed system? Suppose the ether was not a static entity? The forthcoming "Dynamic Ether" explores a different reality with some surprising results. Too many current theories rely on mathematical tricks, even though we have yet to see the minus apples of the early sums, or clocks going backwards. Science started with philosophical conjectures, so why not try a new philosophical approach? The "Dynamic Ether" philosophy precedes the Big Bang, uses entropy to end things and casts a new light on black holes, dark matter and energy, and even gravity itself. Admittedly it has many hurdles to cross, but nothing like the insurmountable hurdles that new science has brought us to.
Reply | Report Abuse | Link to thisThat's one way of looking at it, yes. Going back to the simpler non-gravitational reference frames of SR shows us that the fundamental underlying reason is that consistent histories only exist for arbitrary reference frames when none of them can ever observe superluminal motion (or vice versa really). You can look at this as 'infinite mass' or the point at which in its own inertial frame of reference an observer would reach infinite velocity (its clock skew becomes infinite WRT another frame of reference). Since infinite velocity would require infinite energy and 'beyond infinite' velocity is a non-sensical concept it is really more meaningful to simply say that 'faster than the speed of light' is a concept that has no logical representation. You can of course mathematically construct FTL situations as you observe, but you run into backwards time, negative energy, etc, all of which appear to have no correlation to anything in observable reality. The more subtle issue though is that at that point the ordinary laws of physics simply don't exist. Different observers not only see different world histories, but it is guaranteed that at least some of them cannot be consistently explained by the same laws of physics (regardless of what those laws are). So either we accept the existence of non-physical realities and discard ANY POSSIBLE formulation of the laws of physics, or we accept that there simply is no such thing as 'faster than light' in the same way there is no 'square circle'.
Reply | Report Abuse | Link to thisThe critical issue in this experiment is that the measured propagation time for neutrinos was determined to be 60 ns faster than the calculated time for simulated photons to traverse an approximately equivalent distance in a vacuum.
Reply | Report Abuse | Link to thisSince the path and distance actually traversed by neutrinos is not precisely determinable, this result is inconclusive.
As I reluctantly calculate, at 300,000 km/sec., the reported 60 ns discrepancy could be completely accounted for if the neutrino propagation distance was actually 18 m less than the ~730 km estimated distance traversed.
Reply | Report Abuse | Link to thisDoes this mean that the neutrinos arrived in Italy before they began their journey from Switzerland?
Reply | Report Abuse | Link to thisAgain OPERA recorded speed of Neutrino which is more than light. Before 23 years, I had proved mathematically that relative velocity may be more than light velocity. CERN proved experimentally that velocity of Neutrinos may be more than light, if this news will be confirmed then that will be new beginning of physics. So, it is necessary to think different than old concept of science.
Reply | Report Abuse | Link to thisPlease read paper "What is matter & dark matter is made up of?" on my web site www.maheshkhati.com. This paper may help to find solution to this problem & other problems like what is dark matter? & about true relativity.I strongly oppose special theory of relativity
Again OPERA recorded speed of Neutrino which is more than light. Before 23 years, I had proved mathematically that relative velocity may be more than light velocity. CERN proved experimentally that velocity of Neutrinos may be more than light, if this news will be confirmed then that will be new beginning of physics. So, it is necessary to think different than old concept of science.
Reply | Report Abuse | Link to thisPlease read paper "What is matter & dark matter is made up of?" on my web site www.maheshkhati.com. This paper may help to find solution to this problem & other problems like what is dark matter? & about true relativity.I strongly oppose special theory of relativity
To be perfectly clear: if, for any reason, the estimated distance traversed by neutrinos of approximately 730 km, or 730,000 meters, was overestimated by at least 18 meters then the detected neutrinos DID NOT exceed the speed of light.
Reply | Report Abuse | Link to this- Whatever the precise distance estimate used in calculating the comparative time of flight at the speed of light, the 60 ns discrepancy is offset by a distance of about 18 meters.
- The actual neutrino propagation path cannot be definitively determined. The neutrino propagation distance cannot be precisely determined.
- The approximate 730 km estimated traversal distance is dependent on a very complex method using coordinated GPS locations and standard geodesy routines. The propagation path length of neutrinos is not necessarily the linear distance between the emission and detection locations, since the gravitational spacetime within the Earth's interior being relativistically traversed must be described using distorted, non-Euclidean geometry. If any relativistic or gravitational effect applying to neutrinos produced from the decay of protons that had been initially been accelerated to relativistic velocities was not adequately represented the resulting location separation distance estimate is not be a valid representation of neutrino propagation distance. I cannot identify or assess all of the many potential sources of distance estimation error, but considering that the actual distance that neutrinos traversed cannot be precisely determined, the distance estimate cannot be confirmed.
I'm sort of curious and the lenght contraction of these neutrinos L=L0*sqrt(1-v^2/c^2) sort of implies the back end of the netrino is observed reaching its destination before the front end since it has a negitive (imaginary)lenght
Reply | Report Abuse | Link to thisMy boyfriend says I can talk faster than light.
Reply | Report Abuse | Link to thisblablablablablqablablaalbalblbaaabblabla
There! See?!
In case you idiots haven't noticed ...
Reply | Report Abuse | Link to thisThis is NOT a frikin BLOG! DUH.
Go find a BLOG. Comments are not a
CONVERSATION ... I am reporting you as
abusers...
Actually instead of negitive time it'd be moving in imaginary (b*sqrt(-1)) time
Reply | Report Abuse | Link to thisI guess Brian Greene is using the decrepit concept of "relativistic mass" because he is talking down to us common Americans who are not physicists. The biggest problem with this usage is that it must be defined as a 4-vector, not a scalar, to be consistent with relativity. This is why "invariant mass," which is a scalar independent of velocity, is generally used by real physicists. (See http://www.weburbia.com/physics/mass.html, for example.) It is the magnitude of momentum (only in the direction of the velocity) that becomes infinite as an object's velocity approaches c.
Reply | Report Abuse | Link to thisTotal energy also becomes infinite:
E = (m2c4+p2c2)^1/2
In this equation, m is just a number and does NOT change with velocity.
I guess Brian Greene is using the decrepit concept of "relativistic mass" because he is talking down to us common Americans who are not physicists. The biggest problem with this usage is that it must be defined as a 4-vector, not a scalar, to be consistent with relativity. This is why "invariant mass," which is a scalar independent of velocity, is generally used by real physicists. (See http://www.weburbia.com/physics/mass.html, for example.) It is the magnitude of momentum (only in the direction of the velocity) that becomes infinite as an object's velocity approaches c.
Reply | Report Abuse | Link to thisTotal energy also becomes infinite:
E = (m2c4+p2c2)^1/2
In this equation, m is just a number and does NOT change with velocity.
I wouldn't put faith in an asymptotically bound function such as that given for special relativity. The world of mathematics is asymptotic with infinite ratios and uncountably many numbers between any two reals, but the real world clearly isn't like this. The real world is discrete--space is descrete, and that unit is the planck length. Planck areas mapped over the surface area of an event horizon are related to it's entropy, requiring black holes' horizons to grow as they consume mass. If the Universe and everything in it were continuous, then this wouldn't be necessary. The surface area could simply be sliced up into small areas and remain the same in size There is a smallest unit on the surface of a black hole, and that smallest unit area is a planck area.
Reply | Report Abuse | Link to thisIt may well be that things appear to be asymptotically bound, and it may look as though the energy requirement for pushing something with rest mass toward c goes up accordingly (toward infinte), but the idea that the requirement is truly infinite doesn't make sense. It is just very very large. Thus, things with rest mass can break the light limit, and they still won't go back in time. That's what they'll find out over time, I think. The light limit is just a guide like Newton's original gravity relation.
And in fact, neutrinos are sufficiently small in mass such that they can be pushed slightly beyond this limit. If there were truly a mathematical continous function requiring infinite energy to push unbounded increasing mass beyond the light limit, that would look like a top-down designed Universe, and that's not the case. The Universe is natural, undedesigned, and there are no such rules, it seems to me.
I haven't seen a diagram of the experiment, so I might be making some wrong assumtions. Also I'm not a scientist and have not gone beyond second year physics, so here are my thoughts and questions.
Reply | Report Abuse | Link to thisThe measurement of the neutrinos between Switzerland and Italy gave a result faster than a photon could have traveled the same distance in a vacuum. The difference I see in the measurement of the neutrinos and that of photons -ignoring the fact that neutrinos don't quite reach the speed of light - is that they were measured traveling through the solid crust of the Earth. The neutrinos of course are so small and fast that they pass right through the "empty" regions of the atoms that make up the crust. Because the atoms in the solid crust are packed together tightly, it seems to me that the speed of the neutrinos is being measured mostly through the void or "vacuum" within the atoms. My question is: could the "quality" of the "vacuum" within the atoms somehow be different than the "vacuum" outside? Could the speed of light be different within the void of the atom?
This is also not a place to tell boyfriends "jokes" or opinions that make light of the subject matter presented by Dr. Greene, so I reported that comment as abuse. I left your other comment alone since it was a reply.
Reply | Report Abuse | Link to thisThis IS NOT a blog (it's a podcast), most certainly, although many articles in Sci. Am. online ARE blogs. However, small conversations often arise here when knowledgeable or curious members wish to debate, ask questions about or expand on others' comments. Although I thought a couple comments here could've been shorter, they're definitely NOT worthy of being reported as abuse.
I know that jtdwyer is a regular contributor to these Scientific American online articles and has a lot of good ideas or questions. I find most of his comments very interesting, although I don't always agree with him 100%. He frequently adds more than one comment to articles in which he is interested, some of them based on other comments, so I believe the guy and MOST others to whom he replies should be cut some slack!