List of Figures

• Converging light ray in optics
• Representation of the neighborhood of the boundary in one of the asymptotically flat regions. the rest of the spacetime is not represented here.
• Penrose diagram of a spacetime which illustrate the topological censorship. note that the singular region is not fully represent.
• Representation of the inner and outer directed null geodesics which do not go to the same asymptotically flat region.
• Penrose diagram of de Sitter spacetime
• Representation of the compact set S around the trapped surface
• Upper limit on the fraction of the universe that form primordial black hole of that mass from different kind of measurement. M is normalized to gramme
• Penrose diagram of Minkowski spacetime