Einstein-Rosen Bridge is a technical term for the wormhole at the center of a black hole. This wormhole connects our universe to a mirror universe. This mirror universe, and the bridge to it, is a mathematical necessity that can be inferred from the field equations of spacetime, but it was of little concern to Albert Einstein or Nathan Rosen, because you could never see or interact with the other universe. To see it, you'd have to enter the Event Horizon of a black hole, dooming yourself to the inescapable crushing horror of infinite gravity.
However, since Einstein's day, solutions have been found for two types of Rotating Black Hole that would have only finite (not infinite) gravity if approached from the correct angles, but would still have an Einstein-Rosen Bridge. It's possible that an extremely sturdy spacecraft might cross the E-R bridge of a rotating black hole and survive.
Game and Story Use
- As shown on the TV show Sliders, the Einstein-Rosen bridge (on Sliders it was called the Einstein-Rosen-Podolski bridge, suggesting they'd conflated it with the EPR Paradox) could be created and manipulated without a black hole, to open doors to a parallel universe or another dimension. This would of course be superscience possibly even shading into mad science given the great energies needed and the fact that we don't know what we'll find on the other side.
- If you really trust your GM, it could be fun to play the crew (and inventor) of the first manned expedition into a rotating 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 holes to raid the cosmos seems very fitting for a Space Opera campaign.