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In post #55 of the A&C reference sticky
there's a link to the February WS-2004 symposium on
Quantum Gravity Phenomenology
http://ws2004.ift.uni.wroc.pl/html.html [Broken]
this is about the predictions coming out of Quantum Gravity and
ongoing or planned opportunities to test.
what I have to say here is "edgy", sorry about that
a lot of cosmology these days is consensus or concordance
but this is not, it is risk-taking on Smolin's part
(and other people: Jerzy KG, Etera L, Girelli and so on)
It's looking like it could be very natural for QG to have a longdistance invariant scale L
which is on the order of 9.5 billion LY.
People who like to think in terms of "IR cutoff" and "UV cutoff" from field theory could regard this (by a stretch of analogy) as our universe's
InfraRed cutoff, just like the short length, Planck length (which is also emerging as an invariant in some QG) is our universe's UV cutoff.
I'm not suggesting we get philosophical about L = 9.5 billion LY, I only want to mention some of the coincidental information that Smolin gave in his third talk at the Winterschool symposium.
1/L2 is Lambda the cosmological constant as currently determined by the supernova data---by definition of L
c2/L is an interesting acceleration. It (or more precisely
aL=c2/6L) comes up in galaxy rotation curves. I am referring to Mondybusiness.
Mondybusiness only affects accelerations which are less than aL
so everything is Newtonian until you get way way out and the
Newtonian acceleration aN has dropped off to below aL
and after that, the observed centripetal acceleration
is the geometric mean of what you Newtonianly expect namely
aN , and the Mondy acceleration aL.
[tex]a_{real}=\sqrt{a_L a_N}[/tex]
In other words the real observed acceleration is MORE than you Newtonianly expect once it gets down very low. It is brought up slightly by geometric-mean-type averaging with what may be a constant of nature namely this aL = c2/6L
now this clearly appears to be the work of the devil and one immediately wants to drive a stake of mistletoe thru its heart, but the damnable thing is what Smolin shows in his third paper which is a lot of snug fits with individual real galaxies' rotation curves.
and then there is the Pioneer anomaly which one hopes was just a mistake (Mother Nature has a "senior moment"?)
But it also happens when the probe has gotten far enough from the sun
so that the Newtonian sunward acceleration gets down to below aL = c2/6L
and then the real sunward acceleration is MORE than you Newtonianly expect. It is a similar sort of thing to the galaxyrotationcurves except on a much smaller scale---but the low low threshold acceleration is comparable.
I notice a lot of people were talking about this on sci.physics.research in May, in the wake of John Baez TWF #206.
https://www.physicsforums.com/showthread.php?t=25124
but as an inveterate shunner of the edge I kept my head safely in the sand at that time. Now I am waking up to the possibility that there may be something to this conjectured longdistance scale.
some recent papers have shown how to arrange for it to look the same to different observers (thats the triply special relativity stuff that there'v been some papers about lately)
there's a link to the February WS-2004 symposium on
Quantum Gravity Phenomenology
http://ws2004.ift.uni.wroc.pl/html.html [Broken]
this is about the predictions coming out of Quantum Gravity and
ongoing or planned opportunities to test.
what I have to say here is "edgy", sorry about that
a lot of cosmology these days is consensus or concordance
but this is not, it is risk-taking on Smolin's part
(and other people: Jerzy KG, Etera L, Girelli and so on)
It's looking like it could be very natural for QG to have a longdistance invariant scale L
which is on the order of 9.5 billion LY.
People who like to think in terms of "IR cutoff" and "UV cutoff" from field theory could regard this (by a stretch of analogy) as our universe's
InfraRed cutoff, just like the short length, Planck length (which is also emerging as an invariant in some QG) is our universe's UV cutoff.
I'm not suggesting we get philosophical about L = 9.5 billion LY, I only want to mention some of the coincidental information that Smolin gave in his third talk at the Winterschool symposium.
1/L2 is Lambda the cosmological constant as currently determined by the supernova data---by definition of L
c2/L is an interesting acceleration. It (or more precisely
aL=c2/6L) comes up in galaxy rotation curves. I am referring to Mondybusiness.
Mondybusiness only affects accelerations which are less than aL
so everything is Newtonian until you get way way out and the
Newtonian acceleration aN has dropped off to below aL
and after that, the observed centripetal acceleration
is the geometric mean of what you Newtonianly expect namely
aN , and the Mondy acceleration aL.
[tex]a_{real}=\sqrt{a_L a_N}[/tex]
In other words the real observed acceleration is MORE than you Newtonianly expect once it gets down very low. It is brought up slightly by geometric-mean-type averaging with what may be a constant of nature namely this aL = c2/6L
now this clearly appears to be the work of the devil and one immediately wants to drive a stake of mistletoe thru its heart, but the damnable thing is what Smolin shows in his third paper which is a lot of snug fits with individual real galaxies' rotation curves.
and then there is the Pioneer anomaly which one hopes was just a mistake (Mother Nature has a "senior moment"?)
But it also happens when the probe has gotten far enough from the sun
so that the Newtonian sunward acceleration gets down to below aL = c2/6L
and then the real sunward acceleration is MORE than you Newtonianly expect. It is a similar sort of thing to the galaxyrotationcurves except on a much smaller scale---but the low low threshold acceleration is comparable.
I notice a lot of people were talking about this on sci.physics.research in May, in the wake of John Baez TWF #206.
https://www.physicsforums.com/showthread.php?t=25124
but as an inveterate shunner of the edge I kept my head safely in the sand at that time. Now I am waking up to the possibility that there may be something to this conjectured longdistance scale.
some recent papers have shown how to arrange for it to look the same to different observers (thats the triply special relativity stuff that there'v been some papers about lately)
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