Unreasonable aim of the Creator?

[moving finger]

I have recently read Penrose's books, including his latest "Road to Reality", in which he describes his bafflement that the universe must have started out in some extraordinarily low entropy and therefore highly "unlikely" initital state. From this he concludes that the "aim of the Creator" (to choose this state from the enormous configuration space of other possible states) must have been unreasonably precise.

What he is trying to get at (I believe) is that there must be an explanation for the stupendously low initial entropy of the universe, but we do not know what the explanation is.

Does anyone have any thoughts (apart from invoking a Creator!) on this issue?

 

[Chronos]

You have a couple of options. One is the multiverse, where every conceivable initial condition eventually occurs. The other option is a mechanism that naturally forces emergent properties to seek the observed values. We may never know the true answer, just further narrow the list of prospects. I think you eventually reach the point where certain properties simply are what they are.

 

[Garth]

One problem with the multiverse explanation, apart from actually being able to observe another universe of course, is that if our universe is in some sense a recycled former universe, either via the Oscillating Universe or the Cosmic Natural Selection process, then I believe it is difficult to stop the entropy increasing through each 'bounce'.

Garth

 

[Phobos]

universe must have started out in some extraordinarily low entropy and therefore highly "unlikely" initital state.

Low compared to what? If the Big Bang was the beginning of everything, then why couldn't entropy start at the lowest state (singularity). If this is an oscillating universe, then would the entropy of the new 'bounce' simply be a reset baseline by which we now make relative comparisons (even if the new entropy is slightly higher than the previous)? If this universe is an inflated speck of a larger meta-universe, then could not our low entropy state have been at the expense of increased entropy in the metauniverse? (or perhaps entropy does not even apply to the metauniverse)

 

[marcus]

... the Cosmic Natural Selection process, then I believe it is difficult to stop the entropy increasing through each 'bounce'.

I wonder if it is significant that, in LQG, the bounce is orientation reversing:

the volume element is everted, negative volume becomes positive and viceversa.

Bojowald has several times remarked on this "turning inside out" of spatial volume that occurs in LQC when passing through the Big Bang former-singularity.

Anyway, this is an interesting problems you mention Garth!

I have no answers I can only tell you what kind of ideas it stimulates. I think that the very definition of entropy involves an orientable surface dividing the inside from the outside. One has to be able to enclose something in a bag, then one can talk about the entropy inside the bag.

So entropy is an essentially geometrical idea. It is no accident that in QG one should find that the black hole entropy (from outside looking inwards) is given by the area of a certain surface.

I am recalling the basic black hole fact that the time arrow is from outside inwards towards the bounce. for a black hole in our universe the bounce and everything that comes after it, is in our universe's future

a black hole creates a new timelike direction (inwards) and therefore a new future. By means of the bounce (nothing can travel back) this future continues out the other side.

I wonder how we shall calculate the entropy per volume of space from the standpoint of someone in that future (in the expansion beyond the bounce and the turning-inside-out eversion).

 

[Chronos]

Phobos made an excellent point. What if the total entropy of the universe is unbounded? Would not any initial state appear to have low entropy? A paper to consider:

Spontaneous Inflation and the Origin of the Arrow of Time
http://arxiv.org/abs/hep-th/0410270

This made my 'must read' list for 2004. It also suggests a possible connection between theoretical values for the maximum possible entropy and vacuum energy density of the universe.