All-Sky Stunner from Planck

wjwbudro, You need a bit of electronics to catch a CMB photon.

As for visualizing the CMB boundary, it is important to bear in mind this an observation of the past. So you are not just observing far out in space, but backwards in time as well. The CMB we observe is about 54 billion light years out — further out than the age of the observable universe in light year units. That sounds odd, and I will give an explanation of that below. The material at that distance away, as we observe now, is in a state similar to what we have locally — galaxies, stars, planets, and so forth. An observer 54 billion light years away on the simultaneous Hubble frame would see our region in the universe in the past as the CMB.

Is quantum gravity an axiomatization of physics? I think that would certainly be premature. For various reasons I think any theory of quantum gravity and cosmology can only at best be an effective theory. One reason for this is that what I am working on with the Jordan matrix algebra and the Mathieu quantum coding algebra is an automorphism over a much larger system. This is pure mathematics at this point, but this much larger system is the monster group, and it is truly enormous in size. This system I am working on is a sort of extension of string theory, where the logico-algebraic system preserves quantum information. It is the minimal system that can do this which will embed string theory. The relationship between this system and the monster group is such that it strongly suggests this monster is what underlies quantum gravity far more fundamentally. Curiously there is nothing found beneath that, which means we in effect run out of mathematics. If there is some structure beneath this it involves a completely new type of mathematics.

More immediately second quantization is not a route to quantum gravity. That has been pretty firmly established. The problem is that general relativity and quantum physics have two concepts of time. The invariant time of general relativity is the proper time, or the distance in the Lorentzian metric. Coordinate time in general relativity is a sort of book keeping device, or something imposed by the analyst. Quantum mechanics on the other hand, and in particular quantum field theory, involves dynamical wave-field equations that use the coordinate time. One then must define a spatial surface where the “arrow of time” at every point is known, the field amplitude specified as data at every point and this is then run in the field equation. This view runs into a bit of trouble with curved spacetime. The existence of event horizons results in a thermalization of quantum field into black body radiation. Yet there is no fine grainded underlying interpretation, which lead to the idea that quantum information is destroyed. Yet, this is a disaster.

There were some schools of thought on axiomatic quantum field theory, mostly in France though it has been taken up some in S. America. The enterprise has failed to produce much, and I suspect it will not for a long time.

LC

That works, but you need a filter to remove the shot noise internal to the electronics. Once you do that you do get a residue of snow that are CMB photons. In a way this is how Penzias and Wilson detected them in the first place.

LC

Sorry, I said I would give a brief explanation of that. The distance to the CMB is larger than 13.7 billion light years because the space is being dynamically stretched out. On any local region the motion of particles is slower than light, but globally that rule does not apply because the space is over a large enough a distance is dynamically expanding, or a scale factor for lengths is increasing. As a result particles are being frame dragged apart and in ways which appear to violate relativity.

It is similar to the reason that a particle falling into a black hole reaches and surpasses the speed of light upon crossing the event horizon. Of course an external observer never sees the particle cross the horizon, but only approach very slowly in a time dilated motion. However, for an observer falling into the black hole this horizon is quickly crossed. That observer looking outwards would see things redshifted in a ways which corresponds to a v > c. In effect the space around the black hole is flowing into the black hole (dynamically stretching in a way) which frame drag particles into the BH faster than light upon crossing the event horizon.

LC

The metric appears to be expanding outwards from every point. The only caveat on that is the observable universe may be a pocket universe, where there are inhomogeneous boundaries. Byeond that boundary the vacuum assumes inflationary values. This boundary defines a bubble with a radius of about 10^8 billion light years.

LC

The pocket universe is the first level of the multiverse. Each pocket exists in a single spacetime cosmology. Thnk of each pocket as a ball containing a regions with near zero vacuum energy. These balls are contained in a huge vacuum density and are flying apart at inflationary accelerations. The type II multiverse involves other spacetimes, each with their pockets and so forth. These are due to brane- stacks or quantum tunneling of vacuum energy from one spacetime cosmology into the the M-string bulk. These first two types are what I hope we manage to get some tangential evidence for. The structure of quantum fluctuations of spacetime, which may be imprinted on the CMB, may bear signatures of this sort of physics.

The third type involves the quantum many worlds eigen-branching of elementary quantum events. I will resist going into this, for this really is based on an interpretation of quantum mechanics that is not an effective theory. Then there is Tegmark’s fourth type which is an infinite number of alternate realities with entirely different mathematical structures. This is also highly speculative and I suspect beyond any observational prospect.

LC

The thing which has to be done is to filter out the cloudy stuff due our local galaxy. That effort is not something I understand entirely well. In fact with the WMPA data I often wondered whether data on the equator and particularly where the galactic center (around Taurus) is could be taken as that reliable.

LC