According to QM, does time stop at the event horizon of a BH? TIA, AG
According to QM, does time stop at the event horizon of a BH? TIA, AG
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
>if you fall on an inertial frame inwards there is nothing unusual at the horizon [of a Black Hole]
I say "theoretically" since the clock below the EH cannot be seen from above the EH. AG
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Black Holes: Complementarity or Firewalls?
They say a inertial observer would encounter a firewall and burn up as soon as he passed the Event Horizon, do you disagree?
>I disagree.
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 say "theoretically" since the clock below the EH cannot be seen from above the EH. AG
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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
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
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.
BrentIf 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
Look at Greg Egan's page on this: https://www.gregegan.net/SCIENCE/FiniteFall/FiniteFall.html#HOR
Brent
SF writer Greg Egan |
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