The discussion revolves around the behavior of a rope being laid into a black hole at a velocity of 0.99c. Participants explore the implications of this scenario on the rope's tension, slackness, and the perception of the event horizon from different frames of reference, touching on concepts of relativity and tidal effects.
Participants express multiple competing views regarding the behavior of the rope, particularly concerning the concepts of slackness and tension as it approaches the event horizon. The discussion remains unresolved with no consensus reached.
Limitations include the dependence on specific frames of reference and the complexities of relativistic effects on the rope's behavior, which may not be fully resolved in the discussion.
Obviously, at the moment the tail end of the rope leaves the reel, it will be slack and observable. Tidal effects would tend to cause the center of the rope to be taut, but the observed "scrunching up" of the rope as you observe it approach the event horizon would not be the result of slackness.jartsa said:So, I lay a rope into a black hole, rope leaves the reel at velocity 0.99 c.
When I observe the lower end of the rope, I never see it reaching the event horizon.
Can I see some slack rope somewhere sometime?
DaleSpam said:See the section entitled "String Unreeled at a Constant Rate"
http://gregegan.customer.netspace.net.au/SCIENCE/Rindler/RindlerHorizon.html
.Scott said:Obviously, at the moment the tail end of the rope leaves the reel, it will be slack and observable. Tidal effects would tend to cause the center of the rope to be taut, but the observed "scrunching up" of the rope as you observe it approach the event horizon would not be the result of slackness.
##.99 \, c \, \tau##pervect said:It might be useful to consider what an observer colocated with you at t=0 and moving with the rope would see.
Said observer would fall into the black hole at some finite proper time ##\tau## on his wristwatch. He'd see the event horizion as a lightlike surface approaching him at "c". Assuming a large black hole and ignoring tidal effects, the distance to the event horizion from the ropes frame of referece would be ##c \, \tau##.
Meanwhile the ship would be flying away from the black hole and accelerating, laying out more rope. When the front of the rope reaches the event horizon, the ship would have p.ayed out approximately ##.99 \, c \, \tau## meters of rope ignoring the acceleration of the ship. Taking into account the acceleration of the ship the rope must stretch, as Egan has indicated.
Trying to consider things in the Schwarzschild frame isn't going to really work well, as our intuition of what a rope "should do" works best in a frame that's co-moving with the rope.
jartsa said:How can rope be scrunched up but not slack??
Yes, it must break.jartsa said:The rope has to break, if the unreeling rate is constant.
In the same way that a rope traveling at near the speed of light will appear flattened, even if remains taut.jartsa said:How can rope be scrunched up but not slack??