Could you pull someone out of a black hole?

  • Context: Graduate 
  • Thread starter Thread starter LowlyEngineer
  • Start date Start date
  • Tags Tags
    Black hole Hole Pull
Click For Summary
SUMMARY

The discussion centers on the theoretical scenario of rescuing an individual from a black hole using an indestructible cable. It concludes that due to the principles of relativity, particularly the infinite force required to maintain a constant distance from the event horizon, it is impossible to pull someone back out once they have crossed this boundary. The concept of an indestructible cable is fundamentally incompatible with relativity, as it implies a perfectly rigid structure that cannot exist in the context of spacetime distortion near a black hole.

PREREQUISITES
  • Understanding of general relativity principles
  • Knowledge of black hole physics and event horizons
  • Familiarity with the concept of tidal forces
  • Basic grasp of the implications of infinite forces in physics
NEXT STEPS
  • Research the effects of general relativity on objects near black holes
  • Study the concept of event horizons and their implications in astrophysics
  • Explore the nature of tidal forces and their impact on objects in strong gravitational fields
  • Investigate the limitations of rigid structures in relativistic physics
USEFUL FOR

Astronomers, physicists, science fiction writers, and anyone interested in the complexities of black hole mechanics and the implications of general relativity.

LowlyEngineer
Messages
1
Reaction score
0
Suppose you had a very, very large black hole, so large that the tidal forces at or near the event horizon were not fatal. If you lowered someone down via a very long indestructible cable past the event horizon, and you held your spaceship sufficiently far away from the black hole to ignore its gravity, would it be possible to pull the person back out? When you account for the effects of relativity, would the force required to do so be infinite?
 
Physics news on Phys.org
LowlyEngineer said:
a very long indestructible cable
An indestructible cable is no more compatible with relativity than a perfectly rigid rod.
 
The thrust that the rocket's engines must produce to keep this person at a constant distance from the event horizon goes to infinity as the distance goes to zero. So it isn't even possible to lower someone down slowly.
 

Similar threads

  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 40 ·
2
Replies
40
Views
4K
  • · Replies 51 ·
2
Replies
51
Views
6K
  • · Replies 46 ·
2
Replies
46
Views
9K
  • · Replies 62 ·
3
Replies
62
Views
9K
  • · Replies 51 ·
2
Replies
51
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 23 ·
Replies
23
Views
4K
  • · Replies 12 ·
Replies
12
Views
5K