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Thread: Was Einstein wrong about the equivalence principle? |
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Thread Status: Active Total posts in this thread: 20
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges: 
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http://physicsworld.com/cws/article/news/2014...ain-sn1987-neutrino-burst
----------------------------------------Briefly, since light can transform back and forth between photons and particle-antiparticle pairs, light should be affected by gravity more than neutrinos and that might explain why in 1987, the light from a supernova arrived at Earth several hours after the neutrinos did. Here is the intro to the article: The effect of gravity on virtual electron–positron pairs as they propagate through space could lead to a violation of Einstein's equivalence principle, according to calculations by James Franson at the University of Maryland, Baltimore County. While the effect would be too tiny to be measured directly using current experimental techniques, it could explain a puzzling anomaly observed during the famous SN1987 supernova of 1987. In modern theoretical physics, three of the four fundamental forces – electromagnetism, the weak nuclear force and the strong nuclear force – are described by quantum mechanics. The fourth force, gravity, does not currently have a quantum formulation and is best described by Einstein's general theory of relativity. Reconciling relativity with quantum mechanics is therefore an important and active area of physics. An open question for theoretical physicists is how gravity acts on a quantum object such as a photon. Astronomical observations have shown repeatedly that light is attracted by a gravitational field. Traditionally, this is described using general relativity: the gravitational field bends space–time, and the light is slowed down (and slightly deflected) as it passes through the curved region. In quantum electrodynamics, a photon propagating through space can occasionally annihilate with itself, creating a virtual electron–positron pair. Soon after, the electron and positron recombine to recreate the photon. If they are in a gravitational potential then, for the short time they exist as massive particles, they feel the effect of gravity. When they recombine, they will create a photon with an energy that is shifted slightly and that travels slightly slower than if there was no gravitational potential. And the closing paragraph: Raymond Chiao of the University of California, Merced, agrees with Franson that, observationally and experimentally, "there are a lot of caveats that need to be clarified," most notably, that if Franson's hypothetical interpretation of SN1987a is correct, there are two clear neutrino pulses separated by five hours, but little evidence of two corresponding pulses of light. Nevertheless, he says "There is a deep seated conceptual tension between general relativity and quantum mechanics...If, in fact, Franson is right, that is a huge, huge step in my opinion: it's the tip of the iceberg element that quantum mechanics is correct and that general relativity must be wrong."   [Edit 1 times, last edit by twilyth at Aug 25, 2014 11:27:56 PM] |
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
Probably not. Neutrinos aren't slowed down getting out of the core of a star, even an exploding one. Light takes some time because it is getting scattered. I read of a calculation of our sun that claimed light produced in the core could take 50,000 years to reach the surface due to all the scattering. In a supernova the outer layers are being blown away and fused, etc. This still takes up to several hours.
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KWSN - A Shrubbery
Master Cruncher Joined: Jan 8, 2006 Post Count: 1585 Status: Offline |
Geophychic is right. The neutrinos escape an exploding star much faster than the photons do.
----------------------------------------Any time I see one of these (and they are amazingly frequent) Einstein was wrong about [insert theory], it's more for sensationalism than anything else. So far his theories have been subject to refinement. No major theory has gone down in flames... yet.  Distributed computing volunteer since September 27, 2000 |
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges:
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I think they would have taken something like that into consideration. That would be a pretty obvious flaw in the theory. And this was being reported in Physics Today not USA Today so I think we need to give them a little bit of credit.
----------------------------------------edit: I'd also point out that historically, general relativity has been impossible to reconcile with quantum mechanics. That's been highlighted recently by the whole black hole firewall issue . So it's starting to look more and more likely that there are serious issues either with relativity or the standard model. [Edit 1 times, last edit by twilyth at Aug 26, 2014 4:14:18 AM] |
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KLiK
Master Cruncher Croatia Joined: Nov 13, 2006 Post Count: 3108 Status: Offline Project Badges: 
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As the neutrinos do travel only in one vector, not being influenced by gravity. It would be easy to say that neutrinos travel the speed of light!
----------------------------------------Light, made of photons, which bends in influence of the gravity. And therefore is influenced by space-time continuum, changes to mass electron-positron phase. In that phase the the particle looses speed, bends in their vector of traveling & then resumes again as photon as the gravity diminishes. As I do keep a lot of close look to the Stars, something like that is familiar to me. Seems a logical thing and can be proofed! Problems: 1. if photon is "swirling" on their way to Earth, then it must "travel a longer distance" than the one way vector of neutrinos...those swirling aren't much, but they do calculate up to 7,7 or 3h on the scale of 168k ly...imagine a neutrino going on a fine straight stick & a photon going like a snake "swirling" influenced by gravity. 2. thermodynamics 2.law? yes, all is well. if photon gets energy from gravity, then it dissolves into electron-positron, gets mass in this higher state, slows don't and swirls (light bends) in the direction of the gravity...and as gravity diminishes, electron-positron combines again, releasing energy and speeds up the speed (almost) as light. 3. almost speed of light? even though it is proposed that photons do travel with the speed of light, but I do not think so. as we know today, we have a total of observable Universe today is 47G ly...and what we see is the 42G ly of Universe seen today in Universes 13,8G y of existence (Universe didn't expand linear, we know that). So if photons do diminish from distance of 47G ly, that means that they are influenced by gravity and slowed down. Even though they could travel the speed of light complete vacuum, the Space isn't the 100% vacuum. So the light slows down on every interaction with "significant gravity force" that has enough energy to gets photons to higher state of electron-positron and swirls them a little. 4. two sets of neutrinos, can be explained: a) by the radio signals from the SN1987a, that another spectrum in supernova type 2a has been emitted b) we haven't observed enough of supernovas type 2a to be sure about the second part of neutrinos emission c) we haven't got enough information about the SN1987a, so we don't know that else could have blown there in supernova...and got that neutrino emissions so these are my thoughts about the subject...feel free to add in!  |
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges:
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I'm not sure where you're getting the idea that photons don't travel in a straight line but as far as neutrinos not being affected by gravity, that's simply wrong.
----------------------------------------Photons wouldn't be affected by gravity - at least not directly. According to general relativity they are affected by the warping of space-time which happens in the presence of massive objects. But neutrinos do have mass. Photons don't. Their mass is incredibly tiny but since they oscillate between flavors we know for a fact that they have at least some amount of mass. [Edit 1 times, last edit by twilyth at Aug 26, 2014 10:00:47 AM] |
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Sgt.Joe
Ace Cruncher USA Joined: Jul 4, 2006 Post Count: 7686 Status: Offline Project Badges:
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Most of this discussion is way over my understanding of both classical physics and quantum mechanics. If you go to the original article, read the comments also, they are interesting. Even though General Relativity and Quantum Theory have not yet been reconciled, both have experiments which have greatly validated them in their own realms. Obviously there is still much work, both theoretical and experimental, which needs to be done for understanding how our universe works from the very tiny to the cosmological. Unifying gravity with other forces, detecting gravity waves and/or gravitons, understanding black holes and the nature of dark matter and dark energy are some of the big unanswered questions of physics. Here are a couple of links which I found useful.
----------------------------------------http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html http://en.wikipedia.org/wiki/Photon Cheers
Sgt. Joe
*Minnesota Crunchers* |
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges:
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It's not just that no one has been able to reconcile quantum mechanics and relativity but that on a fundamental level, the two seem to be at odds with one another. I can't remember the details but one example is that relativity requires space-time to be smooth and seamless on very small scales - the realm of quantum mechanics. However in quantum mechanics, the zero point field is lumpy with virtual particles popping in and out of existence all of the time. So at a very basic level, the two theories seem to oppose one another.
----------------------------------------Also, it's worth noting that one doesn't need the fiction of space-time for general relativity to work as has been shown by Julian Barbour. He showed that you can use a "Machian dynamic" scale instead of one based on space-time and get the same results. I might be wrong about this but I think a lot of the issues between QM and GR arise from this fiction. But it's definitely true that both theories have a great deal of experimental evidence behind them. However I get the feeling that people are coming around to the idea that one or the other will need some significant tweaking if they are ever to be reconciled. |
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Sgt.Joe
Ace Cruncher USA Joined: Jul 4, 2006 Post Count: 7686 Status: Offline Project Badges:
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But it's definitely true that both theories have a great deal of experimental evidence behind them. However I get the feeling that people are coming around to the idea that one or the other will need some significant tweaking if they are ever to be reconciled. That is an understatement. Cheers
Sgt. Joe
*Minnesota Crunchers* |
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twilyth
Master Cruncher US Joined: Mar 30, 2007 Post Count: 2130 Status: Offline Project Badges:
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I have no idea how this is supposed to work but I ran across this again today and if it pans out, it could be one way to resolve the conflict between QM and GR - the holographic principle. From what I can gather, the idea is that our 3D universe is actually encoded in 2D fashion. But how that works and why it would resolve the conflict, I have absolutely no idea.
----------------------------------------Anyway, a new experiment just started gathering data at Fermilab that will try to determine if there is any merit to this idea. It's called a holometer. Here are a couple of articles on it and the the holographic principle. http://www.symmetrymagazine.org/article/augus...nt-begins?email_issue=562 http://gizmodo.com/physicists-want-to-know-if...ally-living-in-1627042162 |
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