3 ms·

> Complete ignorant question: there is always the discussion of "falling" in to a black hole, but could it be possible to "hang" something from outside the even

> Complete ignorant question: there is always the discussion of "falling" in to a black hole, but could it be possible to "hang" something from outside the event horizont?(given an infinitely strong and quite long wire). It's a good question, because it exposes some subtle assumptions being made. The string breaks, because you cannot have an infinitely strong wire in a universe that allows black holes. If we could have such a wire, black holes would not be formed, since the wire's material would be able to resist being crushed into a black hole. Therefore collapsing stars would compress into this material rather than into black holes, and there would be no black holes. Once inside the event horizon, every path leads to the singularity. You cannot get further away from it, and you cannot orbit it (or otherwise keep distance constant).

astrodust 14y ago
All that the math suggests is that the escape velocity from inside the event horizon is beyond the speed of light, so it's physically impossible. It doesn't seem impractical to be able to establish an orbit inside that radius, though, even a highly elliptical one, provided this orbit never slings you back out. It just seems if your orbit decays even slightly, you'll never be able to recover, leading to the inevitable conclusion of being pulled directly into the singularity.
- yaks_hairbrush 14y ago
  Inside an event horizon, orbiting implies traveling faster than c from your reference frame. No can do. (Note: this applies to an electrically neutral non-rotating black hole.)
  - astrodust 14y ago
    Since the event horizon itself is supposed to be a fairly non-event to cross, why can't you just fly in a lazy circle around a large black-hole at a relatively "safe" distance and maintain an orbit that's decaying only very slowly?
geoffschmidt 14y ago
Why is it necessarily the case that "stars would compress into this material rather than into black holes"? For example, why can't it be the case that there are two kinds of matter, one that can be used to build infinitely strong wire, and one that can't, with stars being made of the latter? Or why can't it be the case that the crushing process doesn't take matter through the infinitely strong configuration on the way to black hole configuration?
- yaks_hairbrush 14y ago
  > Why is it necessarily the case that "stars would compress into this material rather than into black holes"? There's a good argument to be made that this isn't necessarily the case. I was thinking that all particles are interchangeable at sufficiently high temperatures (i.e. they can switch from one particle to another so long as energy is conserved). I overlooked the fact that stars don't get hot enough. > Or why can't it be the case that the crushing process doesn't take matter through the infinitely strong configuration on the way to black hole configuration? If the "infinitely strong" configuration got crushed into a black hole, it wasn't infinitely strong. > For example, why can't it be the case that there are two kinds of matter, one that can be used to build infinitely strong wire, and one that can't, with stars being made of the latter? How would the infinitely strong wire be held together? Electromagnetic force? Strong force? Weak force? Those forces (which are the only ones we know about apart from gravity) travel at c. If part of the wire is in, while part is out, we will necessarily break the bonds holding the material together if we attempt to pull the wire clear. If nothing else, this breaking will occur because those bonds rely on force carriers traveling at c, and so somewhere along the wire those force carriers will not see the items they are supposed to bind together. Let us say we hold the wire so that a portion of it is past the event horizon. The bit of the wire at the event horizon, if held stationary, is traveling at c because light is also stationary there. Whatever bond existed at that point is no more; the force carriers can't make it to the particles they're supposed to bind together.

astrodust 14y ago

All that the math suggests is that the escape velocity from inside the event horizon is beyond the speed of light, so it's physically impossible. It doesn't seem impractical to be able to establish an orbit inside that radius, though, even a highly elliptical one, provided this orbit never slings you back out. It just seems if your orbit decays even slightly, you'll never be able to recover, leading to the inevitable conclusion of being pulled directly into the singularity.

yaks_hairbrush 14y ago
Inside an event horizon, orbiting implies traveling faster than c from your reference frame. No can do. (Note: this applies to an electrically neutral non-rotating black hole.)
- astrodust 14y ago
  Since the event horizon itself is supposed to be a fairly non-event to cross, why can't you just fly in a lazy circle around a large black-hole at a relatively "safe" distance and maintain an orbit that's decaying only very slowly?

geoffschmidt 14y ago

Why is it necessarily the case that "stars would compress into this material rather than into black holes"? For example, why can't it be the case that there are two kinds of matter, one that can be used to build infinitely strong wire, and one that can't, with stars being made of the latter? Or why can't it be the case that the crushing process doesn't take matter through the infinitely strong configuration on the way to black hole configuration?

yaks_hairbrush 14y ago
> Why is it necessarily the case that "stars would compress into this material rather than into black holes"? There's a good argument to be made that this isn't necessarily the case. I was thinking that all particles are interchangeable at sufficiently high temperatures (i.e. they can switch from one particle to another so long as energy is conserved). I overlooked the fact that stars don't get hot enough. > Or why can't it be the case that the crushing process doesn't take matter through the infinitely strong configuration on the way to black hole configuration? If the "infinitely strong" configuration got crushed into a black hole, it wasn't infinitely strong. > For example, why can't it be the case that there are two kinds of matter, one that can be used to build infinitely strong wire, and one that can't, with stars being made of the latter? How would the infinitely strong wire be held together? Electromagnetic force? Strong force? Weak force? Those forces (which are the only ones we know about apart from gravity) travel at c. If part of the wire is in, while part is out, we will necessarily break the bonds holding the material together if we attempt to pull the wire clear. If nothing else, this breaking will occur because those bonds rely on force carriers traveling at c, and so somewhere along the wire those force carriers will not see the items they are supposed to bind together. Let us say we hold the wire so that a portion of it is past the event horizon. The bit of the wire at the event horizon, if held stationary, is traveling at c because light is also stationary there. Whatever bond existed at that point is no more; the force carriers can't make it to the particles they're supposed to bind together.