Wormholes and Child Universes

Understand

Evidence to the case that classical gravitation provides the clue to make sense out of quantum gravity is presented.

• The key observation is the existence in classical gravitation of child universe solutions or "almost" solutions, "almost" because of some singularity problems.
• The difficulties of these child universe solutions due to their generic singularity problems will be very likely be cured by quantum effects, just like for example "almost" instanton solutions are made relevant in gauge theories with breaking of conformal invariance.
• Some well motivated modifcations of General Relativity where these singularity problems are absent even at the classical level are discussed.