Spheres are man made. There is no such thing as a sphere in the natural universe. So why should the universe be a sphere? The only reason that I can think why people would visualize the universe as a sphere is that they can't accept the fact that the universe responds to chaotic interaction of matter and energies. When reality and theory collide, I bet on reality.
It is known that space is warped by its mass/energy. If the mass/energy is sufficiently dense space will curve back on itself. If the mass/energy is sufficiently smooth it will curve back on itself evenly. In the model generally under discussion it is assumed â€” assumed in the model; not in the Universe â€” that the density and smoothness are sufficient. A closed, smooth, even 3-D curve is called the surface of a hyper sphere.
By way of analogy I used a closed, smooth, even 2-D curve called the surface of a sphere because it is easier to grasp. As has been mentioned, the parts of a model that are not being explained need not be incorporated into the analogy.
The fluffy, little cloud out side my office window is made of trillions of teeny-tiny, nearly perfect spheres. Thanks to you I now know itâ€™s man made. Must be nice men who made that nice cloud.
The flatness problem. The horizon problem. The monopole problem.
CAMBRIDGE COSMOLOGY lists the following. http://www.damtp.cam.ac.uk/user/gr/public/bb_problems.html
The flatness problem Why is the matter density of the universe so close to the unstable critical value between perpetual expansion and recollapse into a Big Crunch?
The horizon problem Why does the universe look the same in all directions when it arises out of causally disconnected regions? This problem is most acute for the very smooth cosmic microwave background radiation.
The density fluctuation problem The perturbations which gravitationally collapsed to form galaxies must have been primordial in origin; from whence did they arise?
The thermal state problem Why should the universe begin in thermal equilibrium when there is no mechanism by which it can be maintained at very high temperatures.
The cosmological constant problem Why is the cosmological constant 120 orders of magnitude smaller than naively expected from quantum gravity?
The singularity problem The cosmological singularity at t=0 is an infinite energy density state, so general relativity predicts its own breakdown.
The timescale problem Are independent measurements of the age of the Universe consistent using Hubble's constant and stellar lifetimes?
In AN INTRODUCTION TO COSMOLOGICAL INFLATION ANDREW R. LIDDLE put forth:
3. Problems with the Big Bang 3.1. The flatness problem 3.2. The horizon problem 3.3. The monopole problem (and other relics)
4. 4.1 Inflation solves the flatness problem more or less by definition. 4.2 The rapid expansion of the inflationary stage rapidly dilutes the unwanted relic particles, 4.3 The inflationary expansion also solves the horizon problem.
In summary Liddle said:
At present, inflation is the most promising candidate theory for the origin of perturbations in the Universe. Different inflation models lead to discernibly different predictions for these perturbations, and hence high-accuracy measurements are able to distinguish between models, excluding either all or the vast majority of them. Since its inception, the inflationary cosmology has been a gallery of different models, and the gallery has continually needed extension after extension to house new acquisitions. In all the time up to the present, very few models have been discarded.
Guth's first evidence for inflation is that there is so much mass in the universe. 1090 particles in the visible region. The only way to get that is if the mass doubles a few hundred times.
Guth's second evidence is expansion itself.
Guth's third evidence for inflation is that it is the only theory known that can explain the homogeneity and isotropy of the universe.
In the standard big bang theory there is no explanation whatever for this uniformity. In fact, one can even show that within the context of the standard big bang theory, no explanation for this uniformity is possible.
Guth's fourth evidence is the flatness problem. Critical density.
Guth's fifth evidence becomes a reason for believing. So now he has FIVE REASONS FOR BELIEVING IN THE INFLATION THEORY.
The fifth reason for believing the inflationary description is the absence of magnetic monopoles.
This is the 2001 version not the original.
For the explicit constructions of eternally inflating models, the answer is clear. Such models start with a state in which there are no pocket universes at all, just pure repulsivegravity material filling space. So there is definitely a beginning to the models that we know how to construct.
I like this one he starts out with space filled with repulsivegravity material. I wonder where all that space and material came from.
According to Cambridge Cosmology there are many problems with the standard BBT.
According to Liddel there are several problems with the standard BBT.
According to Guth there are several problems with the standard BBT.
According to Liddel and Guth Inflation solves all the problems.
Now if there was just some way to get evidence that inflation happened.
But then you would need evidence of where the space came from.
Then you would need evidence of where the repulsivegravity matter that was in the space came from.
Then you would need evidence for where the positive matter that reacted with the repulsive matter came from.
There are many hypothesis of inflation but none have reached the point of theory even though they are called a theory.
Now if you have information that refutes what these gentlemen say I would be interested in reading it.
I am still not sure why you think any of this is a hige problem for BB theory?
Guth, Liddel and Cambridge Cosmology think there is a problem. They are much more qualified than I am to determine if there is a problem or not.
Or do you fear that if you read a convincing book on the subject you might be tempted over to the dark side........? ;)
Why would I want to read one persons opinion. I would much rather read what Stephen Hawking, Alan Guth , Andrew R. Liddle ,Robert H. Brandenberger, Sean M. Carroll, Arthur Kosowsky among many others have to say.
COBE, WMAP etc. have since largely verified inflatiionary theory and it is now part of the established BB model.
Not that I don't trust you but I need a little more than an assertion that the inflationary theory is largly verified.
I found the statement below and can not find one that says it is verified.
Michael S. Turner (U. Chicago and Fermilab) made this comment in his paper The New Cosmology Mid-Term Report Card for Inflation. http://arxiv.org/abs/astro-ph/0212281
While inflation has by no means been verified, its successes have raised the bar for competitor theories:
"John 5:39 (KJS) Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me."