Colliding bubble worlds

We consider a cosmological model in which our Universe is a spherically sym metric bubble wall in 5-dimensional anti-de Sitter-time. We argue that the bubble on which we live will undergo collisions with other similar bubbles and estimate the spectrum of such collisions. The collision rate is found t o be independent of the age of our Universe. Collisions with small bubbles provide an experimental signature of this scenario, while collisions with l arger bubbles would be catastrophic. (C) 2001 Published by Elsevier Science B.V.