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DiracPool
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1. Inflation--I've been doing a little study into cosmic inflation, and a question that many people (including myself) seem to have a hard time wrapping their head around is why was there a need for inflation rather than just assuming that the universe just started off flat, homogeneous, and even "temperatured." I can imagine a tiny sphere right around the time of the big bang whose geometry is (almost) perfectly flat and whose temperature is (almost) perfectly the same everywhere. I can then imagine this sphere (the universe) expanding at a steady rate to the point where at the size it is today it would have remained almost perfectly flat with an even temperature across the sky. However, when you present this scenario to a cosmologist they always seem to say "oh no, that could never happen." But then when they go into explaining why, I don't get the explanation.
The explanation always seems to go along the lines that 1) light wouldn't have time to communicate among the varied regions in order to keep the temperature even, and 2) that the inflation was needed to "flatten out" all the bumpiness in the pre-inflation situation. But my quandary is that, didn't we already take care of this in the description in the first paragraph? Is this just some kind of anomaly that just falls out of the mathematics that can't really be communicated visually? Or is it something like the size of the quantum fluctuations pre-inflation created a bumpiness in the primordial sphere I alluded to above such that it couldn't have started off that uniform, and that's the problem and that's why need the inflation concept? Or is it something else? I'm hoping someone can explain this fairly simply so that it makes sense, or can direct me to some literature/videos that do so.
2. Magnetic monopoles--Susskind has said that another problem inflation seems to solve is the monopole problem, saying that inflation diluted these monopoles to a concentration that may not be detectable (if my memory serves correct), and that is why no one has detected them. However, he also says that there was pretty much nothing pre the reheating epoch that existing other than the inflaton field. But now we also seem to have these monopoles existing before the reheating epoch as well as some "bumpiness" in the early inflaton field that needed smoothing or flatting out by the inflation process itself.
So my question is what, if anything, did the inflaton field consist of other than "inflaton potential energy" pre the inflationary phase and during the inflationary phase before reheating?
The explanation always seems to go along the lines that 1) light wouldn't have time to communicate among the varied regions in order to keep the temperature even, and 2) that the inflation was needed to "flatten out" all the bumpiness in the pre-inflation situation. But my quandary is that, didn't we already take care of this in the description in the first paragraph? Is this just some kind of anomaly that just falls out of the mathematics that can't really be communicated visually? Or is it something like the size of the quantum fluctuations pre-inflation created a bumpiness in the primordial sphere I alluded to above such that it couldn't have started off that uniform, and that's the problem and that's why need the inflation concept? Or is it something else? I'm hoping someone can explain this fairly simply so that it makes sense, or can direct me to some literature/videos that do so.
2. Magnetic monopoles--Susskind has said that another problem inflation seems to solve is the monopole problem, saying that inflation diluted these monopoles to a concentration that may not be detectable (if my memory serves correct), and that is why no one has detected them. However, he also says that there was pretty much nothing pre the reheating epoch that existing other than the inflaton field. But now we also seem to have these monopoles existing before the reheating epoch as well as some "bumpiness" in the early inflaton field that needed smoothing or flatting out by the inflation process itself.
So my question is what, if anything, did the inflaton field consist of other than "inflaton potential energy" pre the inflationary phase and during the inflationary phase before reheating?