On Thursday, November 7, 2019 at 10:54:33 PM UTC-7, Brent wrote:
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>
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> On 11/7/2019 8:43 PM, Alan Grayson wrote:
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>
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> On Thursday, November 7, 2019 at 5:20:13 PM UTC-7, Brent wrote:
>>
>>
>>
>> On 11/7/2019 4:06 PM, Alan Grayson wrote:
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>>
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>> On Thursday, November 7, 2019 at 11:41:11 AM UTC-7, Brent wrote:
>>>
>>>
>>> On 11/6/2019 10:31 PM, Alan Grayson wrote:
>>>
>>> On Wednesday, November 6, 2019 at 11:20:23 PM UTC-7, Brent wrote:
>>>>
>>>>
>>>> On 11/6/2019 9:00 PM, Alan Grayson wrote:
>>>>
>>>>
>>>> On Wednesday, November 6, 2019 at 7:17:21 PM UTC-7, Brent wrote:
>>>>>
>>>>>
>>>>>
>>>>> On 11/6/2019 4:44 PM, Alan Grayson wrote:
>>>>>
>>>>>
>>>>>
>>>>> On Wednesday, November 6, 2019 at 3:46:54 PM UTC-7, Brent wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 11/6/2019 12:05 AM, Alan Grayson wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Tuesday, November 5, 2019 at 10:23:58 PM UTC-7, Brent wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On 11/5/2019 9:09 PM, Alan Grayson wrote:
>>>>>>>
>>>>>>> Crossing the horizon is a nonevent for the most part. If you try to
>>>>>>>> accelerate so you hover just above it the time dilation and that you
>>>>>>>> are in
>>>>>>>> an extreme Rindler wedge will mean you are subjected to a torrent of
>>>>>>>> radiation. In principle a probe could accelerate to 10^{53}m/s^2 and
>>>>>>>> hover
>>>>>>>> a Planck unit distance above the horizon. You would be at the
>>>>>>>> stretched
>>>>>>>> horizon. This would be almost a sort of singular event. On the other
>>>>>>>> hand
>>>>>>>> if you fall on an inertial frame inwards there is nothing unusual at
>>>>>>>> the
>>>>>>>> horizon.
>>>>>>>>
>>>>>>>> LC
>>>>>>>>
>>>>>>>
>>>>>>> Do you mean that clock rates continue to slow as an observer
>>>>>>> approaches the event horizon; then the clock stops when crossing, or on
>>>>>>> the
>>>>>>> event horizon; and after crossing the clock resumes its forward rate?
>>>>>>> AG
>>>>>>>
>>>>>>>
>>>>>>> He means the infalling clock doesn't slow down at all. Whenever
>>>>>>> you see the word "clock" in a discussion of relativity it refers to an
>>>>>>> *ideal
>>>>>>> clock*. It runs perfectly and never speeds up or slows down. It's
>>>>>>> called *relativity* theory because observers *moving relative* to
>>>>>>> the clock *measure it* to run slower or faster than their (ideal)
>>>>>>> clock.
>>>>>>>
>>>>>>> Brent
>>>>>>>
>>>>>>
>>>>>> I see. So if for the infalling observer, his clock seems to be
>>>>>> running "normally", but for some stationary observer, say above the
>>>>>> event
>>>>>> horizon, the infalling clock appears to running progressively slower as
>>>>>> it
>>>>>> falls below the EH, even if it can't be observed or measured. According
>>>>>> to
>>>>>> GR, is there any depth below the event horizon where the infalling clock
>>>>>> theoretically stops?
>>>>>>
>>>>>>
>>>>>> I just explained that *clocks never slow* in relativity examples.
>>>>>> So now you ask if there's a place they stop??
>>>>>>
>>>>>> Brent
>>>>>>
>>>>>
>>>>> I know, but that's not what I asked. Again, the infalling clock is
>>>>> measured as running slower than a stationary clock above the EH. As the
>>>>> infalling clock goes deeper into the BH, won't its theoretical rate
>>>>> continue to decrease as compared to the reference clock above the EH? How
>>>>> slow can it get? AG
>>>>>
>>>>>
>>>>> It *appears* (if the observer at infinity could see the extreme red
>>>>> shift) to *asymptotically approach stopped *as it approaches the
>>>>> event horizon. This is because the photons take longer and longer to
>>>>> climb
>>>>> out because they have to traverse more and more spacetime.
>>>>>
>>>>> Brent
>>>>>
>>>>
>>>> I'm referring to two clocks; one at finite distance above the EH, and
>>>> other infalling. Doesn't the infalling clock seem to run progressively
>>>> slower from the POV of the other clock, as it falls lower and lower? AG
>>>>
>>>> I appears to run slower as seen by the distant observer.
>>>>
>>>> Brent
>>>>
>>>
>>> As it goes deeper and deeper into the BH, does the clock ever appear to
>>> STOP? AG
>>>
>>>
>>> It doesn't appear at all when it passes the event horizon. It appears
>>> to stop as it approaches the event horizon.
>>>
>>> Brent
>>>
>>
>> I know it can't be observed as it falls through the EH. That's why I
>> referred to clock "readings" after falling through as "theoretical".
>>
>>
>> Well it doesn't make much sense to call observations theoretical when
>> it's the theory that says they can't be observed.
>>
>> On the other hand, LC says falling through the EH is a non-event, as if
>> the infalling clock behaves as we expect based on a clock entering a region
>> of strong gravitational field. But let's say the clock appears to stop as
>> it approaches the EH, which is what I thought. How do you reconcile this
>> prediction, which is certainly weird? AG
>>
>>
>> Reconcile it with what? It's a consequence of the metric which is
>> derived from Einstein's equations. It's not as if it's some unexplained
>> observation. It's not an observation at all. It's a theoretical
>> prediction.
>>
>> Brent
>>
>
> You don't see a problem with a theory that predicts a clock which stops as
> seen by an outside observer, when the observer using the clock, which
> measures proper time, must see it moving forward? AG
>
>
> No. Why should it be a problem? You're watching the clock approach the
> event horizon and the photons from it come further and further apart until
> you have to wait seconds between photons, and then hours, and then days,
> and years...why because they have to travel thru more spacetime. If it's a
> rotating black hole, as most of them will be, each photon will have to
> orbit many times on it's way out.
>
> Brent
>
If clock which is fixed some distance from the EH, and the BH isn't
rotating, why must the photons traveling to the fixed observer have to
travel progressively longer times? AG
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