Sorry typo that should be GRB not BRB!

On 11 January 2014 12:36, LizR <> wrote:

> On 11 January 2014 11:20, Stephen Paul King <>wrote:
>> Dear LizR,
>>   I am trying to get a somewhat complicate question out and understood.
>> Let me state it crudely: Given the infinite number of possible 1p content
>> that the UD can "run", how do we obtain from the UDA or UD or UD* the
>> situation that we believe to be true: that there exists a space-time that
>> *contains* some huge number of observer -each with its own 1p- *and* the
>> appearance of interactions among them *and* a set of physical laws, GR and
>> QM that have a mathematical structure that prohibits the assumption of an
>> absolute 1p that "could see everything all at once"?
>> BTW, there are empirical reasons to strongly doubt that space-time has
>> some form of granularity, as such would violate SR by making signal
>> propagation velocities dependent on the energy of the photons. Ultra high
>> energy and medium energy gamma rays have been observed to arrive
>> simultaneously (modulo small error bars) from sources that are millions of
>> light-years away. This makes the notion of "quantized" space-time dubious.
>> Apparently the jury is still out on this - see the 4/1/14 edition of New
> Scientist with the (typically non-sensationalist :) headline "BREAKING
> RELATIVITY - The celestial signals that defy Einstein", which claims the
> opposite - that BRB130427A (from a distance of some billions of light
> years, redshift 0.34) had a delay of 100s of second between low and high
> energy gamma rays. This is the most energetic event observed to date (on
> 27/4/13). Also, on 30/6/05, the MAGIC telescope in the Canary Islands
> detected a gamma ray burst from half a billion light years away with a 4
> minute delay between the low and high energy radiation. There is also some
> data from the Ice Cube neutrino observatory that indicates hints of an
> energy dependent time lag in neutrino bursts...
> But there are other observations that don't show these features, plus
> there are some assumptions involved that may change how we interpret them,
> and so on. What is needed of course is "more light!" - as observations
> continue it should become clearer whether there is some dispersion (maybe
> only at gamma ray energies that even GRBs struggle to reach very often,
> which would indicate that the granularity of space-time is quite small) -
> or not, in which case any granularity that exists would have to be very
> small, even compared to the Planck length,

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