Basic Information
Some black holes rotate. These black holes were probably caused by the collapse of spinning stars and dust clouds or collections of stars that were orbiting each other.
Such a black hole can rotate at extremely high speeds - there's binary system in the Milky Way called GRS 1915+105 that is believed to include one that rotates over a thousand times per second and propels matter away at speeds that seem to be Faster-Than-Light. While we cannot see the black hole directly, we can see it's effect as it slingshots matter out of the system.
Kerr Black Hole, and entering the Mirror Universe
A normal black hole has compressed down to a point known as a singularity. A rotating black hole, on the other hand, would slowly flatten out, and its angular momentum would transform it into a ring shape instead of a sphere or point. A ring-shaped rotating black hole with no electric charge is known as a Kerr Black Hole.
According to Einsteinian equations of Spacetime, every black hole contains a wormhole to a mirror universe. In a normal (non-rotating) black hole, you'd never survive a trip into such a black hole because you'd be trapped within the event horizon and destroyed by infinite gravity. However, in a rotating black hole that follows a Kerr Metric, it may be possible to survive the trip. You'd need a very sturdy spacecraft, and you'd have to approach from the top or bottom, perpendicular to the ring. If you approached from the side, you'd still encounter the infinite gravity and destructive forces associated with a normal black hole. However, if you came from the top or bottom of the Kerr black hole and traveled along the axis of its rotation, you could travel across the Einstein-Rosen Bridge to a parallel universe.
Also, a ship traveling through a rotating black hole might be able to violate causality / engage in Time Travel.
Kerr-Newman Black Hole
A rotating black hole with a strong electric charge is known as a Kerr-Newman Black Hole. It's a valid solution for space-time equations, but is considered very hypothetical, as there do not appear to be large celestial bodies in our galaxy with strong electric charges.
It has been suggested that Hadrons (a type of Subatomic Particle, see also Large Hadron Collider) have much in common with Kerr-Newman Black Holes, but on a subatomic scale. [4]
Sources
Game and Story Use
- I wonder if the Hadron-Blackhole connection may be related to the concerns some scientists have raised about the dangers of the LHC generating micro-blackholes? I don't understand the science enough to really know, but it might be useful Jargon in a game, and you could probably get away with some sort of awesome The End Of The World As We Know It scenario where the LHC creates a chain reaction that destroys a band of the earth, and sucks the rest into wormhole.
- If Kerr-Newman Black Holes exist, they're just a fun twist to put on the "standard" black hole depiction, since (I believe) it'd be crackling with incredible electromagnetic energy. Seriously, an odd-shaped black hole that spouts lightning? How cool is that?
- Depending on how strong the charge is, it might become a naked singularity that risks destroying the universe. Whatever led to a black hole becoming charged must be stopped at once!
- If you really trust your GM, it could be fun to play the crew (and inventor) of the first manned expedition into a Kerr (or Kerr-Newman) Black Hole. Not knowing how much damage the extreme gravity will do, whether you'll be able to escape the event horizon on the other side, whether or not return is possible, what you'll find on the other side, etc.
- Huge armored spaceships that emerge from black hole rings to raid the cosmos seems very fitting for a Space Opera campaign.