On Thursday, January 30, 2020 at 11:33:44 AM UTC-7, Alan Grayson wrote:
>
>
>
> On Thursday, January 30, 2020 at 10:40:26 AM UTC-7, Lawrence Crowell wrote:
>>
>> On Thursday, January 30, 2020 at 11:21:25 AM UTC-6, Alan Grayson wrote:
>>>
>>>
>>>
>>> On Thursday, January 30, 2020 at 10:16:48 AM UTC-7, Lawrence Crowell
>>> wrote:
>>>>
>>>> On Wednesday, January 29, 2020 at 2:57:25 AM UTC-6, Alan Grayson wrote:
>>>>>
>>>>> Considering the distant galaxies, they're receding at near light
>>>>> speed. So according to SR, their clocks should be ticking at a much
>>>>> slower
>>>>> rates than, say, a local clock in our galaxy. OTOH, there's a physical
>>>>> clock for the entire universe; namely, the temperature of the CMBR. If we
>>>>> tell time by this clock, all clock readings of all galaxies are
>>>>> identical.
>>>>> So which is it? Are clocks in distant galaxies running slower than a
>>>>> local
>>>>> clock in our galaxy, or are both clocks running at the same rate? TIA, AG
>>>>>
>>>>
>>>> The physics with distant galaxies is general relativistic, not special
>>>> relativity.
>>>>
>>>
>>> *I know. Now, if you can, please answer my question. AG*
>>>
>>
>> I did below
>>
>> LC
>>
>>
>>>
>>>
>>>> The redshift factor v = Hd, in the near linear form, has the redshift
>>>> factor v/c = z = Hd/c. In the FLRW metric this is a bit more general with
>>>> z
>>>> = e^{Ht} - 1, where for small HT << 1 then t = d/c and z =~ Ht. The
>>>> reshift
>>>> factor for the CMB is z = 1100, which means that anIR photon with
>>>> wavelength 1000nm is expanded to 1100 microns, or a millimeter. The peak
>>>> of
>>>> the CMB blackbody radiation is 160 GHz and this was produced by radiation
>>>> peaked at 17.6x10^{4}GHz. This is in the IR region with a wavelength of
>>>> 5,87x10^{-5}cm, in the IR, The z multiplicative factor is the same as a
>>>> time dilation, where we can think of these red shifted photons are
>>>> representing the slowdown of clocks (clocks being the quantum oscillations
>>>> of atoms etc) in this surface of last opaque scatter.
>>>>
>>>> LC
>>>>
>>>
> Maybe I was making the wrong assumption; namely, that the CMBR "clock"
> reads the same "time" for the far galaxy as compared to its reading in our
> galaxy. But this is probably wrong since CMBR as viewed from the far galaxy
> is from a much earlier epoch, so the reading cannot be identical. Do you
> agree? AG
>
That's not it. I think the two observers, one in a galaxy far removed and
one here, would read the same CMBR "time", regardless of the distant
galaxy's speed of recession. But relativity says otherwise. This is what
puzzles me. AG
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