On Thursday, October 3, 2019 at 3:45:41 AM UTC-6, Lawrence Crowell wrote:
>
> On Wednesday, October 2, 2019 at 7:31:56 PM UTC-5, Bruce wrote:
>>
>> On Thu, Oct 3, 2019 at 10:14 AM Lawrence Crowell <
>> goldenfield...@gmail.com> wrote:
>>
>>> On Wednesday, October 2, 2019 at 6:41:32 PM UTC-5, Bruce wrote:
>>>>
>>>> On Thu, Oct 3, 2019 at 9:21 AM Lawrence Crowell <
>>>> goldenfield...@gmail.com> wrote:
>>>>
>>>>> On Wednesday, October 2, 2019 at 5:46:50 PM UTC-5, Bruce wrote:
>>>>>>
>>>>>> On Thu, Oct 3, 2019 at 3:03 AM Alan Grayson <agrays...@gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>>
>>>>>>> In this case I was just responding to Bruce's certainty that
>>>>>>> inflation is mostly a red herring. I highly respect his opinions, but
>>>>>>> in
>>>>>>> this case, based on my study of this particular issue, I disagree. I am
>>>>>>> open to being proved wrong, but insults don't cut it. At least you
>>>>>>> agree
>>>>>>> that inflation does explain homogeneity. Aren't you curious about
>>>>>>> Bruce's
>>>>>>> take on this particular issue? AG
>>>>>>>
>>>>>>
>>>>>> Inflation can result in an increase in flatness and homogeneity. But
>>>>>> that is relevant only if flatness and homogeneity were problems in need
>>>>>> of
>>>>>> explanation.
>>>>>>
>>>>>> Bruce
>>>>>>
>>>>>
>>>>> The real problem is how did disparate regions of the universe become
>>>>> uniform when there would have been no causal connection between them. In
>>>>> particular with homogeneity inflation provides a mechanism whereby
>>>>> deviations from homogeneity and isotropy are uniform.
>>>>>
>>>>
>>>> Fine. Provided they were not uniform at the start. It is all a matter
>>>> of distributions and in initial conditions. And you know nothing about
>>>> either, so why solve a problem before you know it exists? Besides, can you
>>>> achieve thermal equilibrium in a non-equilibrium state in 10^{-35} sec?
>>>>
>>>> Bruce
>>>>
>>>
>>> Inflation started on a fiducial at 10^{-36}sec and lasted until 10^{-32}
>>> sec. Since the particle fields were near the Planck scale in energy this
>>> inflationary cycle lasted some 10^{10} times the periodicities of fields.
>>> That is enough to approximately have thermal equilibrium.
>>>
>>
>> The problem is not the periodicity of the fields. The problem is the
>> uniformity of the initial conditions. As Sabine points out, inflation just
>> replaces one set of unknown initial conditions with another.
>>
>> I would also take issue with her suggestion that inflation solves some
>> problems with the origin of the fluctuations seen in the CMB. Inflation
>> might provide a framework, but it does not provide an explanation for these
>> fluctuations. The fluctuations are built in by hand, and the gaussian
>> nature of the fluctuations is also built in by hand. So these features of
>> the CMB are not "explained" by inflation in any sense at all. There
>> gaussian nature, and the relative magnitude of 10^{-5} are both free
>> parameters that are set by hand.
>>
>>
> The initial conditions, what ever they were, were flattened out though by
> inflation. The anisotropy in the CMB is due to details in the field
> configuration of the scalar field. The theory just provides the action S =
> ∫d^4x√g(φR + L(φ)), but not the explicit initial conditions or the
> configuration of the field at reheating. The point though is these details
> were exponentially attenuated by inflation so their magnitude is small.
> Estimates of this works out pretty well.
>
> LC
>
I have a different model. Inflation didn't attentuate the initial
condition. Rather it *preserved* an initial condition of virtually perfect
uniformity, which was about the one part in 100,000 observed in the CMBR.
Before inflation began, the universe was tiny, say much less than the
diameter of a proton. It was so small in comparison to the SoL, that it was
in thermo equilbrium *before* inflation began. The sudden huge expansion
preserved the already existing thermo equilibrium. If inflation didn't
happen, the time of recombination would have occurred much later than
380,000 years after the BB, and by that time the original very tiny
fluctuations would have increased, resulting in relatively large variations
in the CMBR, much more than one part in 100,000. What I haven't calculated
-- because I don't know how -- is whether the time duration before
inflation was long enough, despite the large SoL, for the universe to reach
an approximate thermo equilbrium of one part in 100,000. AG
>
>
>>
>> Winding the timeline of the universe back in time based on no inflation
>>> results in a problem because of high z physics, in particular the CMB.
>>> Without this high vacuum energy and extreme acceleration there is no way to
>>> get everything in the same region so they causally evolved according to the
>>> same set of initial conditions. In fact before inflation this was a problem
>>> that buggered cosmologies back in the 1960s and 70s.
>>>
>>
>> Perhaps it took a while to realise the importance of initial
>> conditions......
>>
>> Bruce
>>
>>
>
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