|Subject: Swift MIDEX and quantum gravity?
Date: Mon, 26 Sep 2005 17:14:07 +0300
From: Dimi Chakalov <email@example.com>
To: Julian Osborne <firstname.lastname@example.org>
CC: George Fraser <email@example.com>,
Alan Wells <firstname.lastname@example.org>,
Nial Tanvir <email@example.com>,
Richard Lieu <firstname.lastname@example.org>,
Lloyd Hillman <email@example.com>,
Daniel Reichart <firstname.lastname@example.org>
Dear Professor Osborne,
Sorry for my bulk email. May I ask you and your colleagues
I wonder if Swift can provide evidence of the continual
Secondly, I wonder if GRBs could be related to the so-called
I will keep your feedback strictly private.
[Ref. 1] Does sharp image of distant
galaxy shred the fabric of space and time? UHA Selected News, February
"This limitation opens the possibility of Planck-scale fluctuations in the speed of light, said Lieu. Because these fluctuations would be extremely small, however, they would only be evident in light that travels a great distance. The extended travel gives the slightest variations in speed an opportunity to spread out and become noticeable.
"(The same principle applies to racing events. A sprinter, for instance, one percent faster than his opponents might win a 100-meter race in a photo finish, while a marathon runner one percent faster than the field would finish a race hundreds of meters ahead.)
"After billions of years, the faster components of a light
wave would be far enough ahead and the slower components far enough behind
that the light's wave front would be sufficiently distorted (or blurred)
to be seen and measured by a telescope."
[Ref. 2] Most distant cosmic blast sighted,
BBC News, 12 September 2005,
[Ref. 3] Swift ready for Universe's worst,
BBC News, 5 April 2005,
Subject: Business as usual at Planck
Dear Professor Lieu,
Please accept my congratulations to you and Prof. Hillman for your outstanding research article, entitled: "The Phase Coherence of Light from Extragalactic Sources: Direct Evidence against First-Order Planck-Scale Fluctuations in Time and Space" [Ref. 1]. It was announced on February 6th at the web site of the University of Alabama in Huntsville [Ref. 2], and two days later it reached the readers of Times [Ref. 3].
You wrote: "If time moves along like business as usual even at Planck scales, however, you have to reconcile the Big Bang model with an event that isn't just off the scale, it's infinite!" [Ref. 2]
Well, I think it depends on how you model the idea of continuum,
Perhaps it is possible to suggest a new kind of quantization of spacetime, in which we can 'have our cake and eat it': a *perfect* (not FAPP) continuum in the local mode of time, and a discrete lattice in the global mode of time. The latter corresponds to the "thickness" of 3-D space -- please see the balloon metaphor at
Hence in the local mode of time the "thickness" of 3-D space is zero. Zilch. Non-existent. We have a perfect 3-D continuum, while the "discrete" or global mode of time is hidden by the so-called speed of light. Well, then comes the question of how is this 3-D space created as a continuum, which is certainly a difficult task. I hope to learn more from some leading theoretical physicists,
Again, what I suggest is not some extra-dimension which is "curled up", as in brane worlds hypotheses or other "multidimensional superstitious",
It's a whole new ball game, since the hypothesis suggested at my web site (soon on CD ROM) may be needed to explain the human brain and to reconcile Einstein's GR with Quantum Theory. More at
Thank you, once more, for setting the standard requirements for a complete theory of quantum gravity from just 4 per cent of the physical stuff of the universe,
You can read this email also at
With best regards,
[Ref. 1] Richard Lieu and Lloyd W. Hillman.
The Phase Coherence of Light from Extragalactic Sources:
Direct Evidence against First-Order Planck-Scale Fluctuations
in Time and Space, Astrophysical Journal Letters,
585, L77-L80 (10 March 2003).
[Ref. 2] Does sharp image of distant galaxy
shred the fabric of space and time?
HUNTSVILLE, Ala. (Feb. 6, 2003) - The sharp image of a galaxy halfway across the universe might shred modern theories about the structures of time and space, and change the way astrophysicists view the "Big Bang," according to two scientists at The University of Alabama in Huntsville (UAH).
Their findings might also provide important clues to (and cause significant upheaval among) researchers trying to merge two of the most significant scientific theories of the last century: Einstein's theory of general relativity and Planck's theory of the quantum.
Using Hubble Space Telescope images of galaxies at least four billion light years from Earth, UAH's Dr. Richard Lieu and Dr. Lloyd Hillman tested a popular theory of modern quantum physics: That time flows in incredibly small but finite and measurable quantum bits.
Their research findings are scheduled to be published in the March 10 edition of "Astrophysical Journal Letters," and have been released in the journal's website.
Lieu and Hillman used images gathered by the Hubble Space Telescope to look for patterns that shouldn't be present if prevailing notions of time quantum were correct.
"I fully anticipated that the pattern wouldn't show," said Lieu, an associate physics professor at UAH.
Instead, when they looked at Hubble images of galaxies at least four billion light years from Earth, each image unexpectedly showed a sharp interferometric pattern - a ring around the galaxy.
Using that data, the UAH team was able to determine that the speed of that light didn't fluctuate by more than a few parts in 10^-32 as it traveled across the cosmos. That measurement is significantly more accurate than should be possible if quantum theories of time and space are correct.
Their findings will create problems for astrophysicists and cosmologists who agree with Albert Einstein's theory that time, gravity and the fabric of space are different manifestations of the same phenomenon, sort of like thunder and light are different signatures of lightning. More recently, when scientists theorized that gravity is composed of quantum energy "packets" called gravitons, it made sense that time and space would also be composed of related quantum bits.
Which brings us to Planck time and Planck length, thought
to be the shortest possible measurements of time and distance. Both are
based on calculations of the most energetic radiation theoretically possible.
There are twenty million trillion, trillion, trillion Planck time intervals
(5 x 10^-44) in one second. Planck length is the distance a beam of light
would travel in that time - about
Tying together the theory of gravitons with the shortest possible measurements of time, quantum theory says time would move in miniscule, Planck time-sized bits - like grains of sand passing chaotically through an hourglass, or a sequence of jittery freeze frames that on average last one Planck time rather than a continuous, seamless flow.
Scientists say time and distances smaller than Planck scales are "fuzzy," since they can't be measured. If there is a finite limit to the smallest units of time and distance, however, that means there are limits on how accurately scientists can measure things like the speed of light.
This limitation opens the possibility of Planck-scale fluctuations in the speed of light, said Lieu. Because these fluctuations would be extremely small, however, they would only be evident in light that travels a great distance. The extended travel gives the slightest variations in speed an opportunity to spread out and become noticeable.
(The same principle applies to racing events. A sprinter, for instance, one percent faster than his opponents might win a 100-meter race in a photo finish, while a marathon runner one percent faster than the field would finish a race hundreds of meters ahead.)
After billions of years, the faster components of a light wave would be far enough ahead and the slower components far enough behind that the light's wave front would be sufficiently distorted (or blurred) to be seen and measured by a telescope.
It was that distortion that Lieu and Hillman expected to find in the Hubble images. Not finding that distortion means time isn't a quantum function, says Lieu, and that time might flow fluidly and precisely at intervals infinitely smaller than Planck time.
"If time doesn't become 'fuzzy' beneath a Planck interval, this discovery will present problems to several astrophysical and cosmological models, including the Big Bang model of the universe," said Lieu. "The Big Bang theory supposes that at the instant of creation, the quantum singularity that became the universe would need to have infinite density and temperature. To avoid that sticky problem, theorists invoked the Planck time. They said if the instant of creation was also a quantum event, when space and time were both blurry, then you don't need infinite density and temperature at the start of the Big Bang.
Subject: Re: Business as usual at Planck scales
I believe Lieu and Hillman can say quite a lot regarding Eq. 8 in your recent astro-ph/0302372.
You wrote: "To the best of our knowledge, the Planck time is here to stay."
Since we're talking science, can you formulate the condition(s) under which you will accept the conclusions of Lieu and Hillman,
As to the phase changes of light waves due to the spacetime foam (if any), may I ask you to clarify your standpoint on the following issue. I will quote from Chris Isham's "Canonical Quantum Gravity and the Problem of Time", gr-qc/9210011:
"For example, whether or not a hypersurface is spacelike depends on the spacetime metric g . But in any quantum theory of gravity there will presumably be some sense in which g is subject to quantum fluctuations. Thus causal relationships, and in particular the notion of 'spacelike', appear to depend on the quantum state."
Do you believe that the *phase* of light waves can somehow bypass this total mess?
Subject: Re: Business as usual at Planck
Dear Dr. Camacho,
In your recent gr-qc/0302096, you stated that "the emergence of GUPs is a dynamical phenomenon, namely, it is related to the existence of fluctuations of the background metric" and "presence of a GUP may be understood as an additional force in the dynamics of our particle".
Regarding the forthcoming article by Lieu and Hillman,
may I ask for your opinion on the possibility for altering the *phase* of light waves by fluctuations of the background metric. Please see the reference to C. Isham's gr-qc/9210011 at
It seems to me that the puzzling result reported by Lieu and Hillman, and the whole bundle of issues involved in the generalized uncertainty principle (GUP), require the solution to the problem identified by D. Ahluwalia in gr-qc/9711075, "that the collapse of a wave function is associated with the collapse of the energy-momentum tensor",
We don't suffer from such catastrophes, do we? Please see
Finally, let me quote from D. Ahluwalia's gr-qc/0205121:
"We began, with the question: Can general-relativistic description of physical reality be considered complete? The answer which seems to emerge is: No, but precise nature of this "no" is yet to be settled. It is there in those arguments, in those ponderings, that the IGQR and QPG offer some of the greatest fun.
"May the phases be with you!"