- #1
kamenjar
- 101
- 0
How can a black hole evaporate "instantly" if speed of gravity is c?
Hi all,
This question has been baffling me for quite some time...
Let's say that a tiny black hole is already formed and an observer at some short/safe distance away from it is observing it. The observer sees a flashlight near the event horizon that is 10 billion light years away when measured by the observer due to bending of spacetime.
Now the black hole does evaporate very fast form its own frame of reference, but it should take very long time for that change to be observed (felt) in the reference frame of the observer, right? Gravity waves propagate at speed of light, so at that far displacement it would take more than 10 billion years for the observer to see the black hole evaporate.
Is there something wrong with this logic? I read stories about creating experimental mini black holes on Earth that will evaporate etc, and it doesn't make sense to me.
By the way, I am just a SW Engineer that understands some GR principles, so formulas would be an overkill :)
Hi all,
This question has been baffling me for quite some time...
Let's say that a tiny black hole is already formed and an observer at some short/safe distance away from it is observing it. The observer sees a flashlight near the event horizon that is 10 billion light years away when measured by the observer due to bending of spacetime.
Now the black hole does evaporate very fast form its own frame of reference, but it should take very long time for that change to be observed (felt) in the reference frame of the observer, right? Gravity waves propagate at speed of light, so at that far displacement it would take more than 10 billion years for the observer to see the black hole evaporate.
Is there something wrong with this logic? I read stories about creating experimental mini black holes on Earth that will evaporate etc, and it doesn't make sense to me.
By the way, I am just a SW Engineer that understands some GR principles, so formulas would be an overkill :)