Little fixes to SR and QFT can’t account for gravity either. If (big if) neutrinos can travel FTL, then they probably weren’t boosted there by EM force alone.
When we integrate Friedmann’s equation with cold dark matter and dark energy, using the standard LCDM model, we get a space with a radius...
All velocity measurements are ultimately coordinate system dependent, and that includes those of light. Nevertheless, we aren't talking here about the velocity of light per se; we are talking about the velocities of neutrinos, electrons, and positrons. Specifically, we are talking about the...
The Cohen-Glashow paper predicts that electron-positron pairs will be produced if and when a neutrino exceeds the maximum attainable velocity of the electrons and/or positrons. Their analysis does not depend on the interaction of neutrinos with a medium, or on the speed of light in the medium...
The Cohen-Glashow paper, in view of the ICARUS results, implies that, should the FTL neutrino results be confirmed, then electrons and/or positrons would have to be capable of FTL travel as well.
The CMB frame is an interesting landmark, but the CMB photons are not randomly distributed photons. They represent the temperature of a surface that is visible from every direction; a spherical surface (of last scattering). Every enclosed room has a similar field of photons that can be measured...
If you were at rest in the center of any black spherical shell of reasonably uniform temperature, you could measure a spectrum for the blackbody radiation that would be originating from any point on the inside surface of the shell and there would be no Doppler anisotropy regardless of what...
stglyde,
You can't properly apply LET to the CMB any more than someone else could properly apply the standard formulation of SR to a simple problem involving gravity here on earth.
GR is the proper tool for dealing with gravity and the CMB, and GR let's you choose any coordinate system...
LET is exactly the same physical theory as is the standard formulation of SR, but it uses a different coordinate system. Both LET and SR are similarly limited to application within small space-time regions.
If the OP really does, as you say, "believes in a single 'absolute' LET rest...
The comoving frame in which all observers see a homogeneous and isotropic universe could also be considered as such a universal landmark frame. So, which one is "the aether" frame? Neither one really, but in the transition to GR some of the sterile concepts of SR get relaxed.
LETists don't have any better telescopes than do the SRists. Both would have to look into a GRists telescope if they wanted to understand things like the CMB for example.
You need to use GR if you want to understand the CMB. The CMB is not "the aether". The CMB is a field of photons that were...
Some details about how the OPERA team synchronized their clocks is given on the first half of page 9 of the paper. I am not otherwise familiar with this particuar method that they used to synchronize their clocks.
Einstein's clock synchronization procedure involves an exchange of signals at...
Although it would be nice to be able to send a laser beam along the neutrino path between CERN and Gran Sasso, this is not necessary. By accurately measuring the distance between the two points, and by synchronizing the clocks properly, then the speed of light in vacuum between the two points...
No.
It right, then it would be something new, but nobody knows for sure whether the result is right or wrong. It will have to stand up to the test of time before anyone can know that.
They don't. That is why the constancy of c is a postulate within the standard formulation of Special Relativity.
That helps to prevent the people at OPERA from biasing their analysis (blind/double-blind study).
Time and money only helps when it is applied intelligently.
We define the one-way speed of light in vacuum to be c as a step along the way in constructing inertial frames, but that is an entirely untestable hypothesis within the framework of Special Relativity. That is why the constancy of c has to be a postulate within the standard formulation of...
Each relevant event is time-stamped using a clock that is located nearby, and the travel time for each neutrino depends on how the clocks at each end of the experiment are synchronized.
Yes, but they don't need to know this right away.
In fact, the time-stamps from CERN are not immediately made...
It is not possible to actually measure the one-way speed of light in any way that is consistent with Special Relativity. Neither is it possible to "calculate what it should be". What actually happens is that the one-way speed of light is assumed to be c, and a coordinate system (an inertial...
The idea is that if neutrinos can move faster than the maximum attainable velocity of electrons (and positrons), then neutrinos should rapidly decay into electron-positron pairs when they exceed the ultimate speed limit for electrons and/or positrons.
For example: if neutrinos can move...
These twenty neutrinos that were individually detected showed a fairly wide variation over their various measured times-of-flight. It would be interesting to see these individual time-of-flight measurements plotted against each respective particle's energy since the potential for an...
I don't think so, but I haven't looked at the thread "Neutrino Oscillations for Dummies" (yet). The energy spectrum that you posted is what seems (to me) to imply, in view of Cohen & Glashow's paper, that the maximum attainable velocity of electrons must be close to that of the muon neutrinos...
The common view GPS method of clock synchronization isn't the same thing as slow clock transport, but we know that slow clock transport is fully equivalent to Einstein clock syncrhonization using two-way light pulses. So, when you can't send two-way light pulses directly between two points, such...
According to http://news.sciencemag.org/scienceinsider/2011/10/faster-than-light-result-to-be.html?ref=hp" [Broken] article, new experiments will be conducted soon with a proton pulse width of 1 to 2ns, and an interval between pulses of 500ns. That will allow for about 2million pulses per...
http://physicsforme.wordpress.com/2011/10/19/neutrino-watch-speed-claim-baffles-cern-theoryfest/" [Broken] article seems to confirm what I said before about the Cohen-Glashow/ICARUS hypothesis: "...neutrinos can’t travel faster than light unless electrons do too...".
But, why must super-luminal...
This device, for example, is a http://nanoengineer-1.com/content/index.php?option=com_content&task=view&id=45&Itemid=55" [Broken] which can be reversed to operate as a compressed neon-powered motor...
In GR, physics is modeled with tensor equations. We don't need a different "GLET" because the tensor equations of LET are known to be valid (e.g., they are the same as those given by the standard formulation of SR in at least one inertial frame).
I don't know what thread you are referring to...
LET and the standard formulation of SR are not different physical theories. They are the SAME physical theory cast in different coordinate systems. LET does not have any physically "weird and inconsistent properties" that are not also shared by the standard formulation of SR. LET is just as...
Yes, except that when we generate an expansion history it is well defined almost all the way down to t=0 (the SLS is at around t=370,000 years).
Yes, but how we parameterize the Friedmann equations in order to generate an expansion history that is consistent with visual appearances today, an SLS...
We can only see out to our own particle horizon which currently has a radius of about \eta_0 \cdot c = 46 Glyr. It is the difference between this distance and about t_0 \cdot c = 13.7 Glyr which is accounted for in the computation of expansion histories by means of inserting dark energy and dark...
No, I am specifically referring to FLRW space at any given time.
I do not mean to imply that there is spatial curvature necessarily. I am only trying to show an alternative to standard FLRW space at any given time.
I mean that a hypersphere of homogeneity is spherically symmetric.
To actually project the CMBR anisotropies back onto a SLS, you need to model the expansion history of the universe. The SLS is just one point on that timeline. Dark matter and dark energy are required to generate an expansion...
For example, what if we wanted to simply get rid of "dark energy" and/or "dark matter" by modifying the FLRW metric to re-define its standard simultaneity in such a way that the CMBR projects onto a simultaneous big bang at t=0, but not onto a spatially homogeneous universe at t=370,000 years...
Do you want to consider the SLS as being outside of the context of GR? How would you know that there was an SLS without GR?
The definition of simultaneity in the FLRW metric, which comes from assuming that the universe is spatially homogeneous, is the only justification that I know of for taking...
The SLS is calculated using GR (FLRW metric + GR --> Friedmann equations, Friedmann equations + CMBR --> SLS). How would you know that there was an SLS without GR?
Don't go there Idjot. Scientists are not fanatics.
SLS is "surface of last scattering" and that's what most of the photons of the CMBR last reflected off of, a few hundred thousand years after the big bang, so that's what we are actually looking at when we look at the CMBR. When you see...
I don't intend to label the FLRW coordinates in a non-standard way, and have already withdrawn the term "absolute" in favor of "definition" with respect to the standard simultaneity of FLRW coordinates. I am now only using the term "absolute" in reference to the simultaneity convention of the...
I am referring to the FLRW metric that I linked to in post #18 above which gives one definition of simultaneity (the hypersurface of homogeneity).
Okay, I didn't claim that this definition was unique, only that it was "one GR coordinate system that is convenient to use in cosmology".
We can...
There is one notion of simultaneity in the FLRW metric, and if we zoom in on smaller and smaller regions of curved spacetime in GR until finally we make a transition to using SR spacetime (with or without inertial frames) then we are moving from one GR coordinate system that is convenient to use...
I clearly said that I was talking about the "absolute simultaneity of coordinate systems that are convenient for use in cosmology".
Why don't you go back to the other thread where you were claiming that the isotropy of space has been firmly established on the basis of conservation of momentum...
There are perfectly valid coordinate systems in GR (and in SR) within which absolute simultaneity holds (conventionally).
I have not claimed that there is more "physical signifiance" for one valid coordinate system over another.
I know.
Okay.
As we zoom in on smaller and smaller regions of curved spacetime in GR, at what point exactly does the absolute simultaneity of coordinate systems that are convenient for use in cosmology become equivalent to the relative simultaneity of inertial frames? At the point where one stops using...
In cosmology, using General Relativity, there are concepts of universal time which are prettly close to what you seem to be interested in here. If you look here (http://en.wikipedia.org/wiki/FLRW_metric) under the heading of "General Metric", you can see that two symbols are used there for time...
Rotational invariance implies conservation of angular momentum only if one first assumes that linear momentum is conserved. For example: if angular momentum is mvXr, and rotational invariance implies that r is isotropic, then (assuming constant m) the conservation of angular momentum is...
Okay.
I was thinking only of linear momentum when I made that statement above, so I will restrict my claim to linear momentum for now. Can you cite an experiment where the conservation of angular momentum has been used to probe the isotropy of space?
Inertial frames are defined in part by an...
I read that chapter, and he seems to be saying (he doesn't show any math in this chapter) that on a ten-dimensional manifold the Planck length can be made to be invariant under all coordinate transformations (like the line interval ds). He doesn't say whether or not this becomes true for all...
What do you mean by "it's angular momentum"? That angular momentum is conserved, but linear momentum is not?
I mean that inertial frames are constructed, by definition, so that linear momentum is conserved, but other equally valid coordinate systems can be constructed where linear momentum is...
You said:
However, Planck length was already a constant within all inertial frames in the same way as the speed of light in Einstein's formulation. There must be something more, maybe subtle, to what they were saying about this. Please quote the relevant passage directly.