Cosmology question: binary black holes

[Koyaanisqatsi]

I have a question coming out of a tortured metaphor somebody used the other day that I'm hoping the resident physicists can help with: If you have a stable binary system of (let's say stellar) black holes, would there be strange effects at the midpoint between them or would the two opposing forces just cancel out (other than rotation issues)? I'm guessing it largely depends on the distance between them, but if they were close enough to get into the "strange effects" territory would it necessarily mean that they were close enough that one would destroy/consume the other in relatively short order?

Just curious...

[Lorizael]

As I understand it (which is not very well), if the system were stable, then nothing strange would happen. If the system weren't stable, then one black hole would eventually eat the other. Or they would each other. Or something like that. I have no idea. So yes.

[KrazyHorse]

I have a question coming out of a tortured metaphor somebody used the other day that I'm hoping the resident physicists can help with: If you have a stable binary system of (let's say stellar) black holes, would there be strange effects at the midpoint between them or would the two opposing forces just cancel out (other than rotation issues)? I'm guessing it largely depends on the distance between them, but if they were close enough to get into the "strange effects" territory would it necessarily mean that they were close enough that one would destroy/consume the other in relatively short order?

Just curious...

1) This has nothing to do with cosmology. This is a pure general relativity question
2) There will be something weird going on due to frame dragging. Also, the central point (with two equal masses, say) will be a saddle point of potential....not intuitively sure how this works out, actually, and I am not willing to attempt to actually set up and solve einstein's equation for a relatively complex geometry like this. This is not a trivial problem, and may not have an analytic solution (there are IIRC only 17 known geometries which have such solutions)
3) Such a rotating system will be a significant source of gravitational waves (like a spinning electric dipole). These will suck energy out of the system and eventually lead to a collapse of the two singularities into one. Note that this is an accelerating process (the closer they are the more energy gets pumped out per unit time).

[Tupac Shakur]

If I were to set a science fiction novel on a planet positioned at the central point between these two black holes, what kind of "strange effects" could I get away with writing? For example, could I collapse two genders into one, creating a race of dickgirls?

[KrazyHorse]

speaking as a physicist, it would be inevitable

[Tupac Shakur]

Don't be surprised if I ask you for permission to use that as a back cover blurb.

[Lorizael]

speaking as a physicist, it would be inevitable

Pfft. You're just a quant.

[KrazyHorse]

speaking as a physicist/whore, it would be inevitable

Fixed.

[Tupac Shakur]

The word of a physicist/whore will probably be even more convincing to the intended demographic for my dickgirl space opera.

[Lorizael]