## Bremen-Cardiff Physics Seminar

### The History and Interpretation of Penrose's Singularity Theorem

**Speaker: Prof Dr Dennis Lehmkuhl (University of Bonn)**

**Date: Thursday 3 June 2021**

**Time: 15:00 in UK**

**Venue: Zoom**

The Nobel Prize of 2020 was awarded to Roger Penrose for his singularity theorem of 1965, which the Nobel foundation interpreted as 'the discovery that black hole formation is a robust prediction of the general theory of relativity.' However, the 1965 paper does not mention the term 'black hole' but speaks of gravitational collapse and spacetime singularities, starting with remarks on Schwarzschild's 1916 solution to the Einstein field equations. In this talk, I will put Penrose's singularity theorem in its historical context, starting with Einstein's and Schwarzschild's interpretation of the Schwarzschild metric in the late 1910s and 1920s, and discuss how the metric was linked to the question of gravitational collapse by Oppenheimer and Snyder in the late 1930s, and reconsidered by Wheeler and others in the 1950s and 1960s and how Penrose drew on all these developments. I will describe which conceptual and technical advances Penrose had to invent and combine in order to come up with his singularity theorem to go beyond considerations of specific spacetimes like that of Schwarzschild, and show why the theorem was such a game-changer. Finally, I will discuss different possible interpretations of the theorem.