I meant to write The cosmological constant is Λ ~ 10^{-52}m^{-2}.
LC
On Friday, December 29, 2017 at 7:59:22 AM UTC-6, Lawrence Crowell wrote:
>
> The cosmological constant is Λ ~ 10^{-52}cm^{-2} and the scale factor
> evolves as
>
> a(t) = a_0 exp(t sqrt{Λc^2/3}).
>
> The factor sqrt{Λc^2/3} ~ 10^{-18}sec^{-1}. For a billion years this is t
> ~ 3x10^{16} sec and so sqrt{Λc^2/3}t ~ .03 and the scale factor increases
> by 1.03. The CMB microwave background will be expanded by a small change.
> In 10 billion years this is t ~ 3x10^{17}sec and so sqrt{Λc^2/3}t ~ .3 and
> the scale factor expands by 1.4. At 100 billion and a trillion the scale
> factor expands by 20 and in a trillion years by 10^{13}. This means the CMB
> peak wavelength will be about 10^{10}m. That is not quite the length of the
> cosmos, but in 10 trillion years the expansion factor is close to ~
> 10^{800} which means the wavelength at this point is larger than the
> cosmological horizon scale. At that point the CMB will be removed from the
> view of any observer. The time where wavelength becomes longer than the
> cosmological horizon occurs in about 2 trillion years.
>
> LC
>
> On Thursday, December 28, 2017 at 10:38:29 PM UTC-6, John Clark wrote:
>>
>>
>>
>> On Wed, Dec 27, 2017 at 3:17 PM, <[email protected]> wrote:
>>
>> >
>>> Since galaxies were formed after the CMB came into existence about
>>> 380,000 years after the BB, and those far away will wink out as they cross
>>> the cosmic horizon, why doesn't the CMB also wink out?
>>>
>>
>>
>> The CMB will wink out, its only a matter of time. The CMB came from when
>> the universe was at a temperature of about 4000K and glowing
>>
>> by black body radiation mostly in visible red light, but because of the
>> huge Doppler shift we see it as microwaves
>>
>> and it appears to us as if its only at 2.8K. In a few billion years we
>> won't be able to see that part of the universe anymore
>> ,
>> we'll see a cooler part and it will no longer be microwaves it will be in
>> longer
>>
>> and
>>
>> weaker radio waves. A few trillion years after that the wavelength of
>> light from the BIG Bang will become shifted so much it will be larger than
>> the observable universe and
>>
>> thus
>>
>> it will become impossible even in theory to detect; if there are any
>> astronomers around in that era they will
>>
>> know nothing about the CMB and
>>
>> have no evidence the Big Bang ever happened and no evidence the universe
>> is accelerating or even expanding, for them the entire universe will
>> consist of the Milky Way and the
>>
>> Andromeda
>>
>> Galaxy
>>
>> and thats it.
>>
>> We're lucky to be living when we are, we have access to information the
>>
>> far
>>
>> future will not have.
>>
>> John K Clark
>>
>>
>>
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