: : : : :Suppose I choose a large black hole. One large enough so that my space ship won't be torn apart by the gravitational gradient. : : : : :Suppose my spaceship has an engine powerfull enough to provide some velocity away from the object in the centre of the black hole. Not very difficult, as long as the black hole is a big one. : : : : :Then as long as my engine is stocked with fuel, I can escape the black hole. Can't I. : : : : :My question is, using a fusion engine, whats the smallest black hole I could cross the event horizon and survive to tell the tale??

: : : No, you would not be able to escape the : : : singularity once you cross the event horizon. : : : Inside the event horizon, light rays are curved : : : inward towards the singularity. No matter how : : : powerful your rockets are, you must end up spiraling : : : into the singularity. All matter within the : : : event horizon must follow a path that leads to the : : : singularity. : : :Not true. You are talking about particles that can not generate thrust and acceleration. My spaceship can.

: Or to put it another way, as long as I can counteract the effect of gravity and maintain a forward velocity, no matter how small, I can eventually escape. I do not need to attain escape velocity if I have an engine that will keep burning long enough.

No, inside the event horizon all light rays curve into the singularity. That is part of the proof that there must be a singularity inside. It may be a long, gentle curve, but eventually it must lead into the singularity. For a truly gigantic black hole where the gravity at the event horizon is at or about 1g, your spaceship can cross the event horizon without noticing anything unusual. But once inside the event horizon, you must follow the path that light rays take, and that will lead your ship into the singularity. And as you approach the singularity, tidal forces will become a problem before actually reaching it.

• Re: black holes and spaceships - fred - January 29, 1998 - 18:44 UTC
  • Re: black holes and spaceships - Chris/">Chris - January 30, 1998 - 12:04 UTC
    • Re: black holes and spaceships - David_Tate/">David Tate - January 31, 1998 - 03:11 UTC
      • escaping a black hole - Nathan/">Nathan - October 11, 1999 - 23:40 UTC