1) Remember retarded light falling into a black hole is blue shifted for static LNIFs just outside the horizon. The infinite redshift is for retarded light leaving a static LNIF emitter just outside the event horizon. It is not clear if light emitted by a geodesic LIF emitter falling through the horizon will be similarly redshifted because the LIF metric is approximately Minkowski not g00 = 1 - rs/r. That is, the LIF signal should be same as the static LNIF at r ---> infinity. It is not correct to use the g00 = 1 - rs/r metric representation for any devices that are not static hovering. The Pound-Rebka experiment for example is done with static LNIF detectors clamped to the Harvard Tower. On the other hand we have the GPS satellites which in free orbit should correspond to r --> infinity. Therefore, the question is whether the accuracy and precision of the GPS redshift corrections can detect the difference between r = position of satellite and "infinity"?

Suppose the satellite is twice the distance from the center of Earth to the Earth's surface where the approximately static LNIF ground detector is.

1/f(r)(1 - rs/r)^1/2 = 1/f(2r)(1 - rs/2r)^1/2 f(2r)/f(r) = (1 - rs/r)^1/2/(1 - rs/2r)^1/2

rs/r << 1

f(2r)/f(r) ~ (1 - rs/2r)/(1 - rs/4r) ~ (1 - rs/2r)(1 + rs/4r) ~ 1 - rs/2r + rs/4r ~ 1 - rs/4r

vs 1 - rs/2r if we use r --> infinity for the satellite

note that rs ~ .4cm

& r ~ 6x 10^8 cm

rs/r ~ (2/3)10^-9

for a visible light signal the gravity redshift is of order 10^-9 10^15 Hz ~ megaHz

so the issue is can these fractions be unambiguously detected? It would seem so.

Again the problem is, does the free-float GPS detector see the static LNIF metric or the LIF metric? The equivalence principle says the latter. What is seen depends on a transaction between both the sender and receiver detectors.

2) We can never see retarded light from our future horizon - unlike the black hole situation. Is the dark energy advanced Unruh radiation from our future horizon at temperature T ~ c^2/^1/2?

Following Lenny Susskind - each BIT on the horizon is nonlocally smeared over the entire horizon from our POV. The Stephan-Boltzmann law gives Poynting flux ~ T^4 ~ Lambda^2 per BIT, but the number of BITS is N ~ 1/Lp^2Lambdawhich gives the observed

dark energy density ~ NLambda^2 ~ hcLambda/Lp^2

3) The apparent conflict between the local gauge principle and the Wheeler-Feynman light cone limited advanced-retarded idea needs clarification I agree. I mean the issue of dynamically independent vector fields to mediate forces between spinor fields.

4) The conformal singularity is an artifact of a solution of Guv + /guv = 0. Therefore it cannot be fundamental to the problem of deriving that law of nature.

5) Hoyle and Narlikar do assert that in the de Sitter / > 0 solution that the total absorber condition is obeyed so we need to see if their argument is correct.

6) I am hopeful about my real electron-positron plasma idea from the blue-shift Unruh effect high temperature at our observer-dependent future event horizon.

On Sat, Jan 22, 2011 at 10:50 PM, JACK SARFATTI wrote:

I don't quite understand your verbal argument below on first reading, but my question is, what does it mean that gravity is fundamentally electromagnetic?

How do you get Einstein's field equations

Guv + kTuv = 0

from

Maxwell's EM field equations?

dF = 0

d*F = *J

How do you get a metric field guv from them in Minkowski spacetime?

Or do you mean something else?

EM is the local gauge field of an internal compact U1 group that is not universal for uncharged fields.

Gravity is the local gauge field of an external non-compact universal group, e.g. T4 for a start.

*At first I mean only that EM radiation is a change in the state of the gravitational background. That conclusion seems forced after considering the effect of the future conformal singularity AND the observed fact of retarded radiation. These two are compatible only if the radiation can be re-interpreted a reduction in a negative energy field. The only candidate is gravitation. What does this mean for the relationship between the two? I guess you could take the view that gravity is more fundamental than EM if you wish, so my statement about which is more the fundamental is premature.*

*Regarding the invariances of EM and GR, I would point out that an EM theory that fits the above description, i.e. with a compliant conformal singularity acting as an effective mirror, plus the re-interpretation of radiation I suggested, means that it is possible to construct a direct action version of EM i.e. with no genuine field degrees of freedom consistent with the observation of radiation - just as Wheeler and Feynman had hoped. The direct action version is not mandated by this reasoning, but it would surely be favored over field theory by William of Ockham.*

With no fields, the U1 gauge invariance loses its meaning. Starting from direct action, one is free to manufacture fields to carry the forces in order to facilitate the mathematics, provided of course one does not accidentally introduce additional degrees of freedom (associated with vacuum solutions). If one does so, then those fields must respect U1 invariance.

Perhaps if direct action EM were somehow to underpin gravity, then the resulting theory would likewise be direct action, along the lines of Regge Calculus perhaps. If so, if the tetrad could in principle be eliminated from the theory, then, just as for U1 in EM the associated invarainces would loose their meaning.

This is not to imply the above moves us any closer to identifying the conjectured relationship between EM and GR. All it means is that I would not start by trying to construct a theory exhibiting diffeomorphism covariance.

- Michael

With no fields, the U1 gauge invariance loses its meaning. Starting from direct action, one is free to manufacture fields to carry the forces in order to facilitate the mathematics, provided of course one does not accidentally introduce additional degrees of freedom (associated with vacuum solutions). If one does so, then those fields must respect U1 invariance.

Perhaps if direct action EM were somehow to underpin gravity, then the resulting theory would likewise be direct action, along the lines of Regge Calculus perhaps. If so, if the tetrad could in principle be eliminated from the theory, then, just as for U1 in EM the associated invarainces would loose their meaning.

This is not to imply the above moves us any closer to identifying the conjectured relationship between EM and GR. All it means is that I would not start by trying to construct a theory exhibiting diffeomorphism covariance.

- Michael

On Jan 22, 2011, at 8:29 PM, michael ibison wrote:

On Sat, Jan 22, 2011 at 5:39 PM, JACK SARFATTI wrote:

OK thanks

On Jan 22, 2011, at 12:35 PM, michael ibison wrote:

Jack:

A few notes of clarification in response to your recent exchanges.

*The calculation I did was not purely classical.*

I looked at the evolution of the Dirac wavefunction as it crossed the conformal singularity.

True, I did treat the EM fields classically, but the outcome for the EM fields would have been the same if they had been quantized.

In a sense the fields do continue across the singularity 'forever'. But the constraint that the Friedmann equation is obeyed means that the post singularity evolution must mirror the pre-singularity evolution up to a certain set of discrete symmetries. This turns out to be enough to make the singularity look like a time-like magnetic mirror in the coordinate system I analyzed. In other coordinate representations of the de Sitter asymptotic future, the singularity has a different structure and the set of discrete symmetries are correspondingly different with corresponding consequences for the property of the mirror.

An outcome of this - if correct - is that discrete local symmetries (C P T Mass) are related to the global topology as implied by the particular choice of coordinate system to represent the singularity.

I looked at the evolution of the Dirac wavefunction as it crossed the conformal singularity.

True, I did treat the EM fields classically, but the outcome for the EM fields would have been the same if they had been quantized.

In a sense the fields do continue across the singularity 'forever'. But the constraint that the Friedmann equation is obeyed means that the post singularity evolution must mirror the pre-singularity evolution up to a certain set of discrete symmetries. This turns out to be enough to make the singularity look like a time-like magnetic mirror in the coordinate system I analyzed. In other coordinate representations of the de Sitter asymptotic future, the singularity has a different structure and the set of discrete symmetries are correspondingly different with corresponding consequences for the property of the mirror.

An outcome of this - if correct - is that discrete local symmetries (C P T Mass) are related to the global topology as implied by the particular choice of coordinate system to represent the singularity.

Fine, but does that tell us anything about total absorber condition?

*If you believe the reasoning that leads to the boundary condition at the singularity (frankly I can so no other option) then Cosmology provides a mirror - not an absorber - at the future conformal singularity.*

As I point out in the paper, this has observable consequences unrelated to direct action versus field theory debate. Roughly, the effect of the mirror is to invert the W/F argument and leads to the conclusion that the natural Green's function is advanced, not retarded. By natural I mean automatically consistent with the mirror condition, requiring no additional complimentary-function terms.

As I point out in the paper, this has observable consequences unrelated to direct action versus field theory debate. Roughly, the effect of the mirror is to invert the W/F argument and leads to the conclusion that the natural Green's function is advanced, not retarded. By natural I mean automatically consistent with the mirror condition, requiring no additional complimentary-function terms.

*Though this would seem to be in direct conflict with the observation of (predominantly) retarded radiation there is a way to achieve agreement as follows:*

1. Presume that matter is electromagnetically bound, i.e. inter-particle interaction energies are generally negative.

and then

2. Re-interpret the increase of field energy diverging on the future oriented cone (normally associated with radiation) as a reduction in the negative binding energy of the matter.

Retarded EM radiation from a source is therefore re-intepreted as annihilation of negative energy on the advanced cone of that source.

I argue on the paper that the only way to allow for pair annihilation (the maximum radiation possible from a source) is to identify the negative background energy with (Cosmological) gravitation. And so I see no way to reconcile theory with observation unless gravity is fundamentally electromagnetic.

1. Presume that matter is electromagnetically bound, i.e. inter-particle interaction energies are generally negative.

and then

2. Re-interpret the increase of field energy diverging on the future oriented cone (normally associated with radiation) as a reduction in the negative binding energy of the matter.

Retarded EM radiation from a source is therefore re-intepreted as annihilation of negative energy on the advanced cone of that source.

I argue on the paper that the only way to allow for pair annihilation (the maximum radiation possible from a source) is to identify the negative background energy with (Cosmological) gravitation. And so I see no way to reconcile theory with observation unless gravity is fundamentally electromagnetic.

*Subject: Re: why doesn't light just go on forever?In the retro-causal hologram idea, / is fundamental./^-1 is the entropy of our observable universe.
I mean in the Wheeler-Feynman sense - the area at the intersection of our future light cone with our 2D future event horizon with N(t) BITS.All material objects at our here-now are 3D hologram images of the N(t) BITS.This is really crazy and I don't really believe it, but it is the logical conclusion of what 't Hooft and Susskind started. ;-)On Jan 24, 2011, at 11:10 PM, JACK SARFATTI wrote:On Jan 24, 2011, at 9:07 PM, michael ibison wrote:On Sun, Jan 23, 2011 at 2:09 PM, JACK SARFATTI <*